Just got back from a face to face talk with my Mazda Dealers Service Head Tech, I sent him the pics of the Internal UK RENESIS Engine Damage/Wear for comment yesterday.

**********

Simply put there are two reasons why the back bearing is wearing the way it is and that is "Oil Pressure" and to a lesser extent oil viscosity.

The RENESIS 1 has the same Oil Pressure... Oil Pump Rotors, Oil By Pass Valve and Eccentric Bearings as Mazda's last NA Rotary, the 13B FC RX-7.

Back when this model was around the recommendation for engine oil was 15W40 (here).
Because of this higher Viscosity Oil, Oil Pressure and Bearing Wear was not an issue like we see at the moment in some S1 RX-8's.

When the RENESIS RX-8 came out the recommendation (because of Fuel MPG and Emission targets) was a 5W20 or 30.
While there is nothing wrong with these oils, what was occurring over oil use/age was a lower engine oil pressure value
therefore not enough oil getting to the Rear Stationary Gear Bearing for lubrication....particularly at start ups.

**********

In the Series II (09~) Oil Pressure was almost doubled, but the same oil grade recommended??

I asked why the large increase in Oil Pressure Values.
60% is there to supply the two new EMOP's Lubrication System for the Apex Seals, with the other 40% for engine oil supply,
particularly all the Rotor and Stationary Gear Bearings and improved oil flow through oil coolers.

He believes the 5W20-30 weight oils for the S2's are fine because of the engines higher oil pressure.

***********

So, my next question was what can RENNY 1 owners do about the oil pressure, (unofficially official)

.....to use a higher viscosity grade of engine oil which will help increase the engines oil pressure at the "critical" locations.

In other words a higher oil viscosity will equate to Oil Pressure values like the NA 13B RX-7 which has the same oil pump and related parts and values as the S1 RX-8.

**********

I also asked him about the use of Magnets on Oil filers and or sump drain plugs...his word was DO IT....it is all good.

Then what to do about middle Apex Seal wear, and we know the "unofficial" answer to that one, and it goes in your gas tank...

**********


So, there you have it, I know it is not all Groundbreaking or Revolutionary news, I thought it deserved it's own thread.

What was interesting to hear is the lower oil pressure because of the lighter (thinner) weight oils, which is what some members discussed.

RG also mentioned the Bearing Wear was due to a lack of engine oil getting there.

PLEASE No Cussin....

:werd:

I use RP 0w40 and Idemitsu premix. I should be ok with that I think.

So........Viscosity huh.

Yep, I am not that keen on 0W oils but RP is a good product, so is Idemitsu...u are fine.

I forgot to add the issues can also be a too long a period in engine oil changes, low level of engine oil and no baffles in the sump pan, which are being installed on the re-man engines in the US.

So........Viscosity huh.

I know it can be boring, but I was really interested to hear what he had to say.
And a lot of it makes sense, Mazda really stuffed up on two things..

Oil Pressure and Oil Metering.

Oil pressure actually goes up as viscosity goes up. Greater pressure could come from a different pressure regulator. Of course this only regulates max pressure which is really only at higher rpms. What are the oil pressure values for each engine at 3000 rpm? That should show if there is a difference in pump or if it is merely a regulator change.

If the RX-8 uses the same oil pump as the last n/a RX-7, then the TII oil pump should be a direct swap. I know it fits as I've bolted one to the Renesis test housing that I have.

I know it can be boring, but I was really interested to hear what he had to say.
And a lot of it makes sense, Mazda really stuffed up on two things..

Oil Pressure and Oil Metering.

Hey man its not boring at all. I wish Mazda would have told us all this instead of keeping us in the blind. I read a lot and did my own freezer test and I just could'nt see using a heavier weight oil.


I only wish I had a chance to take apart my engines to inspect the damage myself.

Oil pressure actually goes up as viscosity goes up.

If the RX-8 uses the same oil pump as the last n/a RX-7, then the TII oil pump should be a direct swap. I know it fits as I've bolted one to the Renesis test housing that I have.


Sorry for my rotary ignorance but can I ask what you are getting at RG?

Yep that is what he said and have said....RG

I actually edited my response twice while you guys were responding.

I see that. Thanks.

ASh, do you have oil pressure data at 3,000RPM?

Oil pressure actually goes up as viscosity goes up. Greater pressure could come from a different pressure regulator. Of course this only regulates max pressure which is really only a the highest rpms. What are the oil pressure values for each engine at 3000 rpm? That should show if there is a difference in pump or if it is merely a regulator change.

If the RX-8 uses the same oil pump as the last n/a RX-7, then the TII oil pump should be a direct swap. I know it fits as I've bolted one to the Renesis test housing that I have.

The S1 RX-8 oil pump rotors, shaft and drive chain are the same as an NA FC
Mazda Part number N326-14-140, N326-14-151. there is No IF there RG.;)

The By Pass Regulator Pressure Valve is also the same #3648-14-250 on rear iron housing.

This 3648 regulator is not on the Series II's, that has been taken over by the New Oil Pump, in other words the Oil Pump has the by pass valve built in.

Series II RX-8 uses the same Oil Pump chain but there are no serviceable parts available for pump itself , only as an assembly N3R1-14-100A.

So what would the TII pump get us series 1 guys?

I see that. Thanks.

ASh, do you have oil pressure data at 3,000RPM?

Reference value PSI....50.8 @3000 RPM Series 1 RX-8, 72.5 @ 3000 RPM Series II RX-8..at 100c

If the NA RX-7 has the same Oil Pump, chain, rotors and Oil Pressure By Pass Valve then the values have to be the same, give or take a few PSI....

The RX-8's Opening Pressure regulator for the Oil Pumps..

S1..64-71 PSI
S2..156.6 PSI

RX-8's Oil Filter By Pass Open..

S1..11.4-17.1 PSI
S2..20.3-26.1 PSI

I'll try to quickly explain the pressure vs viscosity relationship. I work in design and engineering large mud pumps (up to 2200HP) for oil drilling. Our pumps are piston style good up to 7500 psi but we can do plunger style to 15000 psi if necessary. Our pumps are positive displacement style as opposed to a centrifugal style which just can't build the needed pressure. The oil pumps on our rotary engines are positive displacement using what are basically rotors such as a roots blower. Nothing more complex that than. However they don't compress. They just move. That's why they are displacement pumps. They displace. In order to compress, you have to choke off the outlet.

This raises the pressure. However it doesn't do it for free. In order to increase the pressure, we need to decrease the total flow. For a simple example, go play with your garden hose. Take the nozzle off and you have lots of flow but little pressure. It doesn't spray very far. There is no restriction. Now install a nozzle. It is always a restriction. When you open the nozzle all the way, it sprays far. It is a restriction over no nozzle which raises the pressure and causes the water to spray farther. Take 2 empty buckets. Fill one completely with the hose on full but without the nozzle. Time it to see how long it takes. Now fill the other one with the nozzle on and open all the way when it sprays hardest. How long does it take? If they fill at the same rate, there was enough power available in the form of water pressure to maintain flow at the nozzle pressure. Max flow will actually be without the nozzle but this is the least pressure.

On our pumps at work, we can change the piston and liner size. As built the pistons are 6" diameter. We can go down to a 4" on the small size or a 8" on the large size. If we want to run higher pressures, we use smaller pistons and liners. Stroke stays the same. You can probably tell that flow will decrease with smaller pistons as it's the same as reducing the displacement. However if we maintain the same amount of horsepower into the pump, we increase our leverage on our working fluid and we can compress it more.

Here's another test to demonstrate how this works. Let's use Coke cans. We need 2 of them, empty. Put 2 of them on the ground side by side. You can see that you have the top area of 2 cans. Now see if you can stand on them. If you are careful, you can unless you are really heavy! Your weight and the pull of gravity represent a force that is being applied to it. Obviously if you jump on it you can crush them but this is just an example. The area of both of those cans represents a larger piston as we can just pretend it is 1 object. Now lets take those 2 cans and stack one on top of the other. Now assuming you can stand on them without falling off and breaking a leg, you'll notice really quickly that they crush. They same total area was there and the input force was no different. However we increased our leverage and from a can standpoint there was twice the pressure being exerted on them.

Now this assumes we have the same input horsepower. However the chain driven oil pumps on the cars have practically an endless amount of power. If the pump speed is not changed, but the viscosity of the oil is changed, that means the amount of power to move it must also have changed. If we use a thicker oil, the pump having it's speed maintained must have more power being put into it in order to move this oil. That means more power robbed from the engine which is why oil weight is a modern issue.

Now lets take this one step farther. Let's go back to our hose. We know how far water can spray with the nozzle at full blast. How far do you think maple syrup would spray if the pressure were the same? Of course it wouldn't go as far. It would have more pressure but less flow. In order to match the flow level, we'd have to raise the pressure. The only way to do that is to increase the input horsepower. Remember how we just said the pump uses engine power? An interesting side effect of using a thicker oil is that no more of it gets to any parts of the engine and perhaps less of it does. If you aren't completely confused by now then consider yourself lucky. There's actually much more to it but I'll spare you any more for now.

Just as an fyi and I'm sure this will add to the oil debate, in my 1990 n/a RX-7, I run 5W20 synthetic oil.

Reference value PSI....50.8 @3000 RPM Series 1 RX-8, 72.5 @ 3000 RPM Series II RX-8..at 100c

If the NA RX-7 has the same Oil Pump, chain, rotors and Oil Pressure By Pass Valve then the values have to be the same, give or take a few PSI....

The RX-8's Opening Pressure regulator for the Oil Pumps..

S1..64-71 PSI
S2..156.6 PSI

RX-8's Oil Filter By Pass Open..

S1..11.4-17.1 PSI
S2..20.3-26.1 PSI

156.6 psi. Holy freaking crap batman!!!! Wow!

Judging by the info, it's probably safe to say that the S2 uses a larger oil pump which means more pump displacement per what may as well be the same amount of oil passages. That means more pressure.

Wow, great info as usual RG. So if in my S1 I'm getting around 65-70psi at 3,000RPMS its due to the 0W-30 I'm using?

I will double check my PSI at 3,000RPMS first thing tomorrow to be sure.

1080 Kpa (S2) to 441-490 Kpa (S1)

What do you think would have to be done to put the Later oil pump on a RENNY 1, apart from the obvious, and could it be done.

Wow, great info as usual RG. So if in my S1 I'm getting around 65-70psi at 3,000RPMS its due to the 0W-30 I'm using?

I will double check my PSI at 3,000RPMS first thing tomorrow to be sure.

Don't forget at 100C or a HOT Engine.., for what it is worth your figures ^^ 65-70 psi are what the factory says it should be, but is it enough PSI??

Yes definitely on a hot engine. Oh okay so what does the reference value of 50.8 PSI@3000RPM mean? Sorry for the confusion.


Edit: Woot! 4,000 posts.

If the front housings aren't different then I'm sure the changes would just be the obvious ones such as front housing, pump, etc.

Incidentally we'll probably never see the oil system go completely electric due to the variance in viscosities among oils. The omp in reality flows so little that it's not much of an issue. If we ran an electric oil pump, the electric motor would only have so much power. Unlike the chain driven, we don't have all the power of the engine available to do the work. If we had a full electric oil pump, then as oil pressure went up, flow would definitely go down. As it stands with the current mechanical pumps it doesn't. Pressure just goes up but so does parasitic loss on the engine.

While we think in terms of numbers, and even looking in viscosity in cSt may look daunting between oils, the reality is that a 5W20 and a 20W50 aren't very different in warm temperatures. When the engine is fully warmed up and the oil is hot, the difference in viscosity between a 5W20 and a 20W50 is only about 8-10 cSt (centistokes). That same 5W20 oil at even 100*F will be several TIMES thicker in terms of cSt number. What I'm getting at is that the difference is so small when warm that I doubt you'll see anything different on a gauge when the engine is fully warmed up.

True. But what is your opinion on cold starts (let's talk Texas temps)? How much damage do you think is being done there? Some say very little but in reality I haven't found any real data (if there is a way to determine this).

I got Ash's opening post, and got confused by RG's explanation, but I think what you are saying RG, is that we could increase the pressure by using a thicker oil, but that doesn't mean that the increased pressure will actually be effective, and that it is better to increase pressure mechanically with a thinner oil than to use a thicker to increase pressure through fluid dynamics?

:uhh:

Sorry, trying to understand the points :)

OK, let's say you increase the viscosity of the oil you are using. The pressure goes up, but you decrease the flow. Hopefully, the only thing the oil has to carry away is heat. Doesn't the increase in viscosity allow you to run higher oil temps?

Bearings don't need oil pressure to be lubricated. They merely need oil flow to them. They need oil film strength to survive and it is falsely believed by many to be based purely on oil weight. It is really a formulation issue. Weight is a part of it though.

When we increase oil pressure in our engines, the goal is to get more flow. We can't get more flow without using more horsepower unless we use a thinner oil. Keep in mind what is technically true on paper doesn't mean that in the real world it's enough to matter. We want high oil flow only because we are trying to cool our rotors. Only the oil does that and the faster we can get oil in and our of the hollow rotors, the faster we can get heat out. The better we can control rotor temperatures, the better we can control emissions and power since reduced hot spots on the rotor faces means less liklihood for preignition or detonation. There is more to the oil system change than just the apex seals although that is definitely a big part of it.

OK, let's say you increase the viscosity of the oil you are using. The pressure goes up, but you decrease the flow. Hopefully, the only thing the oil has to carry away is heat. Doesn't the increase in viscosity allow you to run higher oil temps?
I wouldn't say it allows you to but rather causes you to and this is only true if that oil takes longer to heat up and hence cool down once heat soaked.

Midnight here. Heading to bed now.

I guess the point I was trying to make was that because you are using a heaver weight oil, the oil is not prone to breakdown and can handle the higher temps.

I'll try to quickly explain the pressure vs viscosity relationship. I work in design and engineering large mud pumps (up to 2200HP) for oil drilling. Our pumps are piston style good up to 7500 psi but we can do plunger style to 15000 psi if necessary. Our pumps are positive displacement style as opposed to a centrifugal style which just can't build the needed pressure. The oil pumps on our rotary engines are positive displacement using what are basically rotors such as a roots blower. Nothing more complex that than. However they don't compress. They just move. That's why they are displacement pumps. They displace. In order to compress, you have to choke off the outlet.

This raises the pressure. However it doesn't do it for free. In order to increase the pressure, we need to decrease the total flow. For a simple example, go play with your garden hose. Take the nozzle off and you have lots of flow but little pressure. It doesn't spray very far. There is no restriction. Now install a nozzle. It is always a restriction. When you open the nozzle all the way, it sprays far. It is a restriction over no nozzle which raises the pressure and causes the water to spray farther. Take 2 empty buckets. Fill one completely with the hose on full but without the nozzle. Time it to see how long it takes. Now fill the other one with the nozzle on and open all the way when it sprays hardest. How long does it take? If they fill at the same rate, there was enough power available in the form of water pressure to maintain flow at the nozzle pressure. Max flow will actually be without the nozzle but this is the least pressure.

On our pumps at work, we can change the piston and liner size. As built the pistons are 6" diameter. We can go down to a 4" on the small size or a 8" on the large size. If we want to run higher pressures, we use smaller pistons and liners. Stroke stays the same. You can probably tell that flow will decrease with smaller pistons as it's the same as reducing the displacement. However if we maintain the same amount of horsepower into the pump, we increase our leverage on our working fluid and we can compress it more.

Here's another test to demonstrate how this works. Let's use Coke cans. We need 2 of them, empty. Put 2 of them on the ground side by side. You can see that you have the top area of 2 cans. Now see if you can stand on them. If you are careful, you can unless you are really heavy! Your weight and the pull of gravity represent a force that is being applied to it. Obviously if you jump on it you can crush them but this is just an example. The area of both of those cans represents a larger piston as we can just pretend it is 1 object. Now lets take those 2 cans and stack one on top of the other. Now assuming you can stand on them without falling off and breaking a leg, you'll notice really quickly that they crush. They same total area was there and the input force was no different. However we increased our leverage and from a can standpoint there was twice the pressure being exerted on them.

Now this assumes we have the same input horsepower. However the chain driven oil pumps on the cars have practically an endless amount of power. If the pump speed is not changed, but the viscosity of the oil is changed, that means the amount of power to move it must also have changed. If we use a thicker oil, the pump having it's speed maintained must have more power being put into it in order to move this oil. That means more power robbed from the engine which is why oil weight is a modern issue.

Now lets take this one step farther. Let's go back to our hose. We know how far water can spray with the nozzle at full blast. How far do you think maple syrup would spray if the pressure were the same? Of course it wouldn't go as far. It would have more pressure but less flow. In order to match the flow level, we'd have to raise the pressure. The only way to do that is to increase the input horsepower. Remember how we just said the pump uses engine power? An interesting side effect of using a thicker oil is that no more of it gets to any parts of the engine and perhaps less of it does. If you aren't completely confused by now then consider yourself lucky. There's actually much more to it but I'll spare you any more for now.

Just as an fyi and I'm sure this will add to the oil debate, in my 1990 n/a RX-7, I run 5W20 synthetic oil.

Good information - it's been a bit since I last read the article in this link but your explanation is spot on (according to the article).

http://ferrarichat.com/forum/showthread.php?t=136052

Found the RX8 Club link:
http://www.rx8club.com/showthread.php?t=178739&highlight=ferrari+chat

Oh I really like that article but It been discussed to death (by me :lol:) in the other thread. Good read though, learned a lot.

I am curious what we can find out about the TII pump.

Many guys here have posted that when they increase their oil viscosity they see a Higher Oil Pressure reading, but I also agree with RG and the fact that there really is little difference between all the oils.

The reference I made previously when talking to the Mazda Dealer Tech was all things being equal between S1 RX-8 and the last NA Rotary Mazda made the FC RX-7, is they "coincidently" have the same Oil Pump, and same By Pass Regulator, same Rotor Bearings but as others here who have done many 13B rebuilds have not seen the bearing failures like they have in RENESIS 1, almost every pic I have seen here and in other Forums show the same wear....So Why..

Is it Oil Pressure...same as an NA FC RX-7..
Is it Oil Type or Viscosity, not the same as FC RX-7 (15w40 was the recommended then).

I thought this bearing failure was mainly in the US 5W20, but as seen it appears in the UK also, 5W30. Australia also uses 5W30 but, I have yet to see one apart.

Then you have to look at all the mods done to the RENESIS II, main ones are MOP's which we know, the only other mod is Oil Pressure, with the same 5W20-30 oil recommendation.

There are far greater minds than mine here but, to me the many answers are obvious...I think.

RG, the front Iron housing by Part Number is different in Renny 2, as is the front alloy timing cover surrounding/over the oil pump, the S2 also has the Oil Filter located on the Front Alloy Timing Cover.

Yes definitely on a hot engine. Oh okay so what does the reference value of 50.8 PSI@3000RPM mean? Sorry for the confusion.

I am not exactly sure of where they 'reference' this value from, I am going by what the Factory Services Highlights say..

IMO...I think it is an area or location that a reference pressure is read, but, where do they read it?, at the bearings , half way down the eccentric shaft, if any of this is possible, or is it an AVERAGE of a few areas?

So in the case of your S1 Renny...you have..

OP Reference Value @3000 RPM 100c of 50.8 PSI
OP at Oil PUMP Relief Valve Opening Pressure 64-71 PSI
OP at Oil Filter By Pass 11.4 - 17.1 PSI

Sorry, no more info there.

By the way does anyone know, what viscosity has the Dexelia oil?
Viscosity 40 °C, mm²/s - ?
Viscosity 100 °C, mm²/s - ?
Viscosity Index - ?
Flash Point COC, °C - ?

I can't nowhere to find it!

Here are 3 pics of the S1 and S2 Oil Pumps and where they go.
First two are from EPC Parts, last is of S2 oil pump in pieces.

Both of these mount in the same 'way', but the housing they bolt onto are different part numbers, unsure of the exact "design" changes though.

Will an S2 pump fit on an S1, possibly, but as the output pressure of this pump has more than doubled I would have concern about other areas.

Like what do you do with the existing separate By Pass Regulator in rear iron housing?, do you remove it as it would be continually by passing oil, do you blank it off?, you would also have to change Oil Filters, the oil pick up in sump is different..there are a number of issues..

The GREEN Circle shows the 3648-14-250 Oil Pressure By Pass Valve which goes on the Rear Iron Housing in S1 RX-8 (FC RX-7) sump, this type of Pressure Valve is incorporated in the S2 Oil Pump Assembly and Not in the rear iron like S1.

Anyway I hope this shows you the difference in oil pumps.

http://www.rx8club.com/attachment.php?attachmentid=146136&stc=1&d=1254295526

http://www.rx8club.com/attachment.php?attachmentid=146134&stc=1&d=1254294977

http://www.rx8club.com/attachment.php?attachmentid=146135&stc=1&d=1254294977

Is it Oil Pressure...same as an NA FC RX-7..
Is it Oil Type or Viscosity, not the same as FC RX-7 (15w40 was the recommended then).

c)Neither of the above and caused by people taking the cars to 9krpm redline before the oil is warm.....

:)

Yeah I think maybe us Renny owners need to be super diligent and do the following things listed below religiously. I just don't think the Series 1 Renny has the margin for error/laziness that most engines have. But even if I get a Series II I will still do a lot of the same. I am thinking my second engine only lasted so much longer than my first because in part because of the OMP update and I was so crazy about oil changes and maintaining it. Had I premixed and ran the GC 0W-30 I am running now, it would probably still be running today. Now if/when my third engine fails prematurely we will tear it apart and really see if we have figured anything out because this engine will have had all of the following done its entire life.

We have to be serious about:

1. Selecting a great synthetic oil.
2. Warm up our cars fully every time before we go anywhere.
3. Change our oil often based on climate/environment.
4. Premix with SOHN Adapter.
5. Do whatever mods lower oil temp (ASH's mod and maybe additional oil coolers).
6. Drive it like it was meant to be driven.

Thank you Ash :)

*NYCGPS ran to the basement to give the RP 20w50 bottle a big hug*

I guess the point I was trying to make was that because you are using a heaver weight oil, the oil is not prone to breakdown and can handle the higher temps.

Not exactly, it's vicosity remains higher at those high temperatures, but it'll still breakdown rapidly once the average oil temp starts to rise above ~115*c

If you want to avoid that, you need to be using a full ester synthetic + premix...

Dry sump FTW

As any fyi, the oil pressure in my 90 RX-7 at 3K rpm is somewhere over 60 psi. The gauge resolution falls off quickly after that point. My best guess would be 65-70 psi.

Dry sump FTW


Can this be done reliably on the street? For this we need an accumulator and a second pump right?


Also, I would like to see the viscosity numbers of a 20W-50 vs say a GC0W-30 or Mobil 1 0W-40.

Mazmart sells a modified regulator that raises the oil pressure in the system by about 12-13 psi, as I recall. It sells for about $30, and is easy to install. Talk to the guys there and they'll tell you raising the pressure is the only way to go for RX-8s that see track time or are FI.

Huh? Can this be done without major hassle? Paging Mazmart for more info.

Huh? Can this be done without major hassle? Paging Mazmart for more info.

1. Drain oil
2. Drop pan
3. Unscrew factory regulator, insert new regulator
4. Re-install pan
5. Add oil
6. Enjoy higher oil pressure

That's pretty much it in a nutshell.

Sweet.

Remember your large deep well socket.

Sweet.

The Regulator Red Devil is talking about is located on the Rear Iron Housing,
the original is the 3648-14-250 see Green Circle above in pic.

The modification is to put a slightly stronger spring behind the 0221-14-115 Plunger (Piston) so your oil won't by pass as early it will hold back oil increasing OP.

To remove unit as R Devil says you have to drop your sump pan and use a shifter, the regulator body is about 20 mm bolt head for memory.

BTW...Trivia. This 0221 Parts Model code is a part from the 1966 Mazda 800 4 cyl.
This By Pass Plunger and Spring is the exact same one used in dozens of Mazda cars from Rotary and Piston...Like Mazda 1500, Capella, RX-2,3,4,5,7,8.
Mazda 626,929,MX-5,6.

http://www.rx8club.com/attachment.php?attachmentid=146153&stc=1&d=1254331587

I keep coming back to the same basic thought based on Mazda Spare Parts facts, that is the parts that are original by Mazda Part Numbers.

ALL By Pass Plunger/Piston and Springs are the same for ALL NA Rotaries, from 1969 R100 to 2008 RX-8 S1. #0221-14-115 and 0221-14-116., so therefore the BY Pass Pressures are ALL the same...Right.

The variations in the OIL Pumps themselves are so small they are so close to being all the same...Right.

There is the Eccentric Shaft By Pass Valve (really a Pellet) is there to warm up engine oil faster...you can leave this one out.

And then the Oil Filter By Pass, all Rotary oil filters are the same for NA's including RX-8 S1...Right.

The ONLY variable that could change Oil Pressure between rotary models are the Location or Position or Distance of the Oil Cooler (s) and Lines/Hoses.

So, the very last Difference which can have an effect on Oil Pressure is the ENGINE OIL.

In other words the ONLY thing that has changed in NA rotaries over the past 38 years is the Engine OIL...Not the Oil Pressure (Leaving out S2 RX-8), not the Oil Filter Valves, not the By Pass Valves.

Good info.

To remove unit as R Devil says you have to drop your sump pan and use a shifter

What do you mean by shifter?

Good info.

What do you mean by shifter?

Adjustable Open Ended Spanner...

Adjustable Open Ended Spanner...


Your gonna kill me but what is this ^ :lol:

Didn't we already go through a lot of this in the last extensive oil thread with the article? Higher pressure when measuring through the gauges is not necessarily better or means that you get more lubrication. Higher pressure will also result from using thicker oil and that is not necessarily good. We've been through this, the only pressure I see relevant to assisting the car is:

- keeping it close to the specs
- making sure it's not 5w-20 fail sauce
- monitoring it and comparing pressure overtime at the same RPM using the same and perhaps different oils
- Using the AP to bump the OMP pressure up (which is the real significant pressure issue IMO) to feed the seals more oil contrast to stock

Keep in mind this reply is mainly for the cloud surrounding the oil related to pressure comments again, not the pressure boost in the Gen 2 motors.

Higher pressure will also result from using thicker oil and that is not necessarily good.

Yes but generally thicker oil does not get where it's supposed too fast enough or efficient enough.

This is why I would like to see specific oil data instead of looking at bottle numbers.

http://www.rx8club.com/attachment.php?attachmentid=146157&stc=1&d=1254336142

:cussing:

AHHHHHHHHHAAAAAAAAA, a Crescent Wrench, :lol:

The purpose of this thread is to talk about Why we are seeing so many Bearing failures when it is virtually non existent in earlier rotaries with similar miles, the only thing that has changes are engine oils in the past 40 years....and higher RPM.

Come to your own conclusions....MOP has nothing to do with OP.

LOL!!! I was thinking a spanner was something that spanned the distance between 2 objects! Silly Australians!

u all nubs.

Spanner = Crescent Wrench.

Is it bcuz I used to study "British" English so I know ? ...

:fingersx:

good info. subscribed...

Here is another one for you Silly Americans!...

What do you think is the percentage of Engine Oil Left behind when you do a normal drain?

I will be back with the Answer after this COMMERCIAL BREAK!

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:thumbtwiddle:

here is another one for you silly americans!...

What do you think is the percentage of engine oil left behind when you do a normal drain?

i will be back with the answer after this commercial break!

40-50%

In Litres because that is what WE Silly Australian's use not the OLD antiquated Weights and Measures..

Series I RENESIS 6 port.
Bone Dry Engine.....6.4 litres Engine Oil to fill.
Normal Drain...........3.3 Litres, 3.5 with Oil Filter

SO You are leaving almost 50% of old dirty oil in your engine...

Series II RENESIS 6 Port.
Bone Dry Engine.......7.0 Litres Engine oil to fill.
Normal Drain..............4.2 Litres, 4.4 with Oil Filter

Slightly better ratio, but not great...

This is why I do a Double Change....Drain, Fill with New oil, run engine till Hot, Drain and Re-Fill...I use a good quality Mineral, so my cost is about the same as if I used Synthetic Oil. :)

Great Commercial Break!.....;)

In Litres because that is what WE Silly Australian's use not the OLD antiquated Weights and Measures..

Series I RENESIS 6 port.
Bone Dry Engine.....6.4 litres Engine Oil to fill.
Normal Drain...........3.3 Litres, 3.5 with Oil Filter

SO You are leaving almost 50% of old dirty oil in your engine...

Series II RENESIS 6 Port.
Bone Dry Engine.......7.0 Litres Engine oil to fill.
Normal Drain..............4.2 Litres, 4.4 with Oil Filter

Slightly better ratio, but not great...

This is why I do a Double Change....Drain, Fill with New oil, run engine till Hot, Drain and Re-Fill...I use a good quality Mineral, so my cost is about the same as if I used Synthetic Oil. :)

A double change is great if you feel that your oil is extremely dirty. However, if the oil doesn't look like crap, and you do your oil changes on a 3k schedule, a complete flush isn't really necessary.

I wouldn't mind doing a complete flush every 9-15k miles or so, but I just recently did my first oil change (@2900 miles). I may change my opinion on the flush depending on my next oil change (@~6000 miles).

What commercial break? u mean this ?

http://www.youtube.com/watch?v=Yu_moia-oVI

With 1L being 1.05Q, we can assume they are basically the same for now. Where all is the oil hung up in the engine? I get ~4.2q(L) out every change, and being ~half a quart low on the dipstick, but then I jack up each side for the oil coolers. So if I topped off before draining, I would be draining almost 5Q(L)....where is the rest?


^noone clicks links any more. Gotta be more stealthy than that :)

What commercial break? u mean this ?

http://www.youtube.com/watch?v=Yu_moia-oVI

AHHH, the gay 80's...:rollingla:rollingla:rollingla:rollingla

AHHH, the gay 80's...:rollingla:rollingla:rollingla:rollingla

HEY ! HAVE A LITTLE RESPECT THERE ALRIGHT ! :rollingla:rollingla:rollingla

Rick'roll' FTMFW LOL !

With 1L being 1.05Q, we can assume they are basically the same for now. Where all is the oil hung up in the engine? I get ~4.2q(L) out every change, and being ~half a quart low on the dipstick, but then I jack up each side for the oil coolers. So if I topped off before draining, I would be draining almost 5Q(L)....where is the rest?


^noone clicks links any more. Gotta be more stealthy than that :)

Figures are from the factory...Mazda..

Where is the oil??, is lying in the eccentric shaft (not much), in the oil pump, not much, in the Oil Coolers (2) and lines...MUCH.

HEY ! HAVE A LITTLE RESPECT THERE ALRIGHT ! :rollingla:rollingla:rollingla

Rick'roll' FTMFW LOL !

I bet you have that YT Link "bookmarked'????:yelrotflm:yelrotflm

Yep, I am not that keen on 0W oils but RP is a good product, so is Idemitsu...u are fine.

I forgot to add the issues can also be a too long a period in engine oil changes, low level of engine oil and no baffles in the sump pan, which are being installed on the re-man engines in the US.

no baffles in US reman engines????????

I am not exactly sure of where they 'reference' this value from, I am going by what the Factory Services Highlights say..

IMO...I think it is an area or location that a reference pressure is read, but, where do they read it?, at the bearings , half way down the eccentric shaft, if any of this is possible, or is it an AVERAGE of a few areas?

So in the case of your S1 Renny...you have..

OP Reference Value @3000 RPM 100c of 50.8 PSI
OP at Oil PUMP Relief Valve Opening Pressure 64-71 PSI
OP at Oil Filter By Pass 11.4 - 17.1 PSI

Sorry, no more info there.

I believe the reference pressure is taken at the location of the oil pressure switch (change it out for a pressure gauge)

Regards.

Cool.

In other words the ONLY thing that has changed in NA rotaries over the past 38 years is the Engine OIL...Not the Oil Pressure (Leaving out S2 RX-8), not the Oil Filter Valves, not the By Pass Valves.


You don't think the oil passages, bearing clearances, etc. haven't changed in 38 years? :rhetoricalquestion:

no baffles in US reman engines????????

Regards.

Sleepezy, the member here who works at the Mazda US reman plant said they are replacing sump pans to the later type with more baffles....his words.;)

You don't think the oil passages, bearing clearances, etc. haven't changed in 38 years? :rhetoricalquestion:

Possibly, I look at the Part Numbers and how the old # supersedes to the new part numbers or later ones used in say the RENESIS.

If the parts supersede forward it always means that they are safe and or compatible without any modifications, but it is extremely rare (almost never) that the old part will fit in the later car, or one uses the old part in the newer model.
It can happen but not "officially".

Many a time I have seen part numbers completely change and are "supposedly NOT Interchangeable", but when you look at them side by side there is No difference at all.?

Like oil pumps and By pass regulators (Piston plunger and spring) are the same part numbers, so the pump is pumping the same pressure, even the oil pump chains are the same from FC and FE (RX-8).

The 3648-14-250 By Pass Regulator used in the FC and FE S1 RX-8, by original parts model code (3648) originates from the 1976 13B RX-4., but the internals of this regulator (the plunger and spring) are originally from the Mazda 800 of the 60's. (0221 parts model code).

Lots of info.

As RG stated in this thread, this kind of bearing can't damage if there are oil in it. It's not really depend on what is the warm side viscosity of the oil, 20-30 or 40.
So what is the situation when the bearing could be dry, without oil flow? At startup, and after starting, for a while, until the pressure does not build up in the eccentric shaft. Maybe in some situation this time is to long.

I have one thought. There is a thermo pellet in the eccentric shaft.

1. When is it opened (until the temp does not reach 60 C), the oil pressure can't build up so quickly inside the e-shaft, so it's is related to the bearings which gets oil from the e-shaft. They don't get enough oil flow.

2. If you stop the warm engine, the pellet will open when the e-shaft will cool down to 60C. When it's happen, the oil maybe will drain out from the e-shaft. So the next startup its time to fill it with oil again, and build up the pressure. And this period is dangerous for the bearings.

I know, this pellet was on the earlier 13B's too, but maybe there are some changes in the oil passages of the Renesis? I don't know.

Interestingly the Eccentric Shaft Pellet and Spring are the same Mazda Part Number for ALL 13B and RENESIS Rotaries from the very first 1985 NA FC RX-7, FD RX-7 REW and RX-8 FE...from 1985-2010

# N326-11-D15 Pellet
# N326-11-D17 Spring

And Opens at 60C..
N326 is the Part Number model code for 1985 NA FC RX-7 parts.

So I guess if the Eccentric Shaft was starving for engine oil until 60C we would have seen the same bearing wear issues in all these 13B's over the past 25 years?

Many re-builders blank Pellet it off. :)

I always modify them, the lack of lubrication is what kills the engines here since many owners only do short trips (10-12mi or so). Lack of oil during the warm up, several short trips and you see the engines failing before 60.000mi.

Yeah, I am not that keen on the idea, rotaries before 1985 never has this E Shaft heat pellet., But there is a reason for them

Same here, i think that a higher viscosity oil will also flow out of the eccentric shaft in a slower way, helping a bit during the next start-up.
It is frustrating to see engines that are in fairly good shape go bad for $10 parts.

This thread of yours actually put together some puzzle pieces i was missing while continuing a study that had as a subject some engine failures here.
I really have to thank you since now my picture is pretty much complete :)

:) and your conclusions...if you have some...;)

The conclusions didn't change much :)
5w30 is not adequate to the task of lubricating the rear, hotter, rotor and the thermal pellet does the rest. Raising the system pressure is fine but i don't know how much it will help once you always have oil flowing there.
All in all your points are a good explanation to why our engines fail with a higher rate than the ones in the u.s. We do short trips and do way more cold start ups as a consequence :)
Any clue on why mazda did use the thermal pellet in such configurations?

The Pellet is actually there to speed up engine temps from cold start up, rather than the full flow of Cold oil, the pellet does not actually stop the oil jets oil flow to the two rotors and their rotor bearings it restricts the flow...as soon as it reaches 60c it's then full flow to the rotors oil jets.

So the rotor bearings still gets engine oil just not as much until temps get to 60c +.

It probably is in all seriousness a good idea provided it does not fail, they are said to last the life of an engine, but if they fail you can have big troubles.
I guess this is why many rebuilders put a sold pellet or washers to stop E Shaft oil bypass...to be safe.

But I like the idea that it make the engine warm up far quicker, hotter rotors are better for emissions, gas burning and helps the prevention of carbon build up on rotors.

When you think of it without the pellet short trip drivers would never see a fully warmed engine or engine oil.

In the end it is probably the best compromise...

I am sorry guys but I still keep coming back to the same finding...Oil Viscosity..., particularly after oil is over a few thousand miles old..

****************************
BTW: Don't forget we have another form of Oil Heating and that is the Oil Cooler pellets or thermostat that opens at 65C.

So at 60c+ you get full flow of engine oil through the actual engine with NO oil cooling by Oil Coolers, then when oil reaches 65C you have complete Full flow from Oil Coolers through to Engine and back.

Then when Coolant Temperature Reaches 82c your Coolant thermostat opens for Full Flow and Engine Cooling. :)

I don't know what to think then, it is a give or take!
Oil flow vs oil temperature... I would pick oil flow since i believe that the problem with short trips is not the engine warm up (stop and go traffic is the law here...) but the lack of massive flow\huge number of start ups mixed with short trips.

As for the pellets lasting an engine's life i don't know, at times they fail :)

Forgot to add, I guess also with the recent increase in Oil Pressure (doubled) on S2 RX-8's (two thirds of which is used for the EMOP set up) the other third for actual engine would also result in engine oil cooling quicker as it is moving faster through the oil network and hopefully removing excess engine heat more efficiently one would think.

*****************************

Frankly I am still jacked off as to why Mazda released the RX-8 in the first place with both Oil and Water cooling inadequacies, and the lubrication of Apex Seal issue....

YET AGAIN Mazda will pay a very expensive price for this engineering failure as there are many RX-8 owners who love the car but hate the engine failures, the Rotary Engines reputation takes yet another dive when it could have been prevented.

I totally blame Ford's ownership and influence at the time, it is obvious the RX-8 did not have enough Hot weather and longevity testing...before final production.

The Pellet is actually there to speed up engine temps from cold start up, rather than the full flow of Cold oil, the pellet does not actually stop the oil jets oil flow to the two rotors and their rotor bearings it restricts the flow...as soon as it reaches 60c it's then full flow to the rotors oil jets.
****************************
BTW: Don't forget we have another form of Oil Heating and that is the Oil Cooler pellets or thermostat that opens at 65C.

So at 60c+ you get full flow of engine oil through the actual engine with NO oil cooling by Oil Coolers, then when oil reaches 65C you have complete Full flow from Oil Coolers through to Engine and back.

Then when Coolant Temperature Reaches 82c your Coolant thermostat opens for Full Flow and Engine Cooling. :)

ASH. our oil coolers thermostat opens at 90C. You know it.

I think the e-shaft pellet is mainly for environmental reasons. It's work only means 1-2 minutes quicker warming.

I don't believe that Mazda doubled (!!!) the oil pressure in the S2 Renesis just for the e-mops. Maybe it was the step to avoid the e-shaft pellet's negativ effects on flow. They can't throw away the pellets, because of the environment factor.

We have to put together the pieces, because I think such a bearing wear is not a viscosity matter. It's a weak oil flow matter. There are not so much difference between a warm xxw-30 and xxw-40 oils, and for example almost every combustion engines working well in all over the world with 40 weight oils.

one day, I will take the stock e-shaft pellet out and swap it with the bypass pellet and to prevent further "possible" failure ... who cares about that extra what 1,2,3, even 5 minutes of extra start up emission :)

one day, I will take the stock e-shaft pellet out and swap it with the bypass pellet and to prevent further "possible" failure ... who cares about that extra what 1,2,3, even 5 minutes of extra start up emission :)

Talking about italian tune-ups, a guy recently swapped one without taking the engine down! He used a 6feet bar to remove it and nearly broke his fender :ylsuper:

Anyway i've been running without airpump as well for a while and recently passed our emission test so...

I would like to know why this issue, per Ash, is more related to oil viscosity than oil flow because i put the second reason first, at least for the engines i have seen :)

Mandated oil viscosity per SAE:

http://www.rx8club.com/attachment.php?attachmentid=129102&stc=1&d=1226414676

20W50 for me

- Have been using 20w50 after the first 400 miles on Reman Engine, will continue to do so

oh, I premix too. since day 1 :)

- Have been using 20w50 after the first 400 miles on Reman Engine, will continue to do so

oh, I premix too. since day 1 :)

having read all the posts in the more than 100 pages of oil discussions on this site ur 20w50 seems to be where im heading.

post #21 said:

When the engine is fully warmed up and the oil is hot, the difference in viscosity between a 5W20 and a 20W50 is only about 8-10 cSt (centistokes).

at 100 C

20 weight: 5.6 mm^2/s or 5,200,000 centistokes
50 weight: 16.3 mm^2/s or 16,300,000 centistokes

a difference of 11,100,000 centistokes . all calculations done here: http://www.cleavebooks.co.uk/scol/ccviskin.htm

the 50 weight has almost 3 times the nominal viscosity of the 20 weight. Now, we can debate how important that is, but the differences in viscosity are significant.

Okay so wouldn't a 0W-50 be ideal for pumpability and protection?

dang good info
i identified that the engine will not even hold factory spec pressure at 3K with a 5/20w oil 2-3 yrs ago.
pressure versus flow versus volumne? Just remember a heavier oil will be pumped with the same volumne of a lighter oil--it just takes more power to do it. Its a mechanical pump so what it takes in--it IS going to get it out!
Flow? not as relavent in the rotary as a recip, but it is still something to consider.
Viscosity?--that is why i use deisel oil--look at the oil analysis reports I have posted. Deisel was the ONLY one to maintain its viscosity after 1K miles. It will NOT harm the engine--Good God.
Dont let the car set and fully warm up, drive it with a very light load.
I actually get more oil out with a vacuum pump than when i use the plug.
I dont use synthetic anymore. To damn expensive for a 3K oil change schecule
Magnets on my filter. The real kind.
My only concern at present is with the bypass.
olddragger

Its a mechanical pump so what it takes in--it IS going to get it out!

That's true. You mean the oil cooler bypass?

yep and that most dont have oil temp gauges.
oh by the way can the pre 09's use the 09 filter?
OD

ASH. our oil coolers thermostat opens at 90C. You know it.

I think the e-shaft pellet is mainly for environmental reasons. It's work only means 1-2 minutes quicker warming.

I don't believe that Mazda doubled (!!!) the oil pressure in the S2 Renesis just for the e-mops. Maybe it was the step to avoid the e-shaft pellet's negativ effects on flow. They can't throw away the pellets, because of the environment factor.

We have to put together the pieces, because I think such a bearing wear is not a viscosity matter. It's a weak oil flow matter. There are not so much difference between a warm xxw-30 and xxw-40 oils, and for example almost every combustion engines working well in all over the world with 40 weight oils.

Well my oil coolers are starting to heat after 60 seconds or so from warm up.
About the same time after the first LED goes off 40C.

Where do you get 90C from?,,, RX-7 are also 65C.

I have had it confirmed from my dealers tech that the new EMOP pumps do not actually PUMP on their own, there are just a "Gate" facilitator.
ie, Solenoid Plunger opens lets oil through Via Engines Oil Pump.

"IF" the EMOP's were a "True Pump" there would not be the need to have a Sensor Switch on EMOP to monitor the entire Engine's Oil Pressure would there?
The Engine Oil pressure Sensor/Switch would still be located under the oil filter neck/area like on Series 1 RX-8's? if the EMOP were an actual pump.
There are No other locations on S2s where Engine Oil Pressure is monitored, except on one EMOP.

If it is an "Oil Flow" issue then how come Mazda have stuck to this same design and parts on NA's since 1985.
Two Stationary gear bearings on a 4 port Renny are close to 40 years old...from the Mazda R100 10A.
http://www.rx8club.com/showpost.php?p=3255864&postcount=120

Frankly, I’m surprised by some of the comments in this thread. Particularly those that state that it’s a pressure problem, not a viscosity problem.

In Shigley and Mitchell’s Mechanical Engineering Design (a reference/bible for Mechanical Engineering) they state that hydrodynamic lubrication does not depend on the lubricant being introduced under pressure, although it is critical that an adequate supply is present.

That is why the oil is pressurized – the pressurization is a by-product of the need to flow oil through the system and remove heat. But wear is prevented by the presence of a film of oil between the journal and the bearing, and the thickness of that film is dependent on viscosity, not pressure. If you are getting metal to metal contact it is because the oil is not presenting a thick enough film, which means a thicker oil is called for.

Of course, if there is a cold-start issue where for some reason the bearing is nearly dry for longer than a moment or two, then that is a different problem. But I am reluctant to believe that is true.

Yes, this is armchair engineering, and I’d be happy if an experienced lubrication engineer chimed in and explained why basic hydrodynamic theory doesn’t apply to the bearing wear problem on the RX-8. But until that happens, I’m inclined to believe that the bearing wear problem is a viscosity problem. Of all the various theories & solutions I’ve seen posted here relative to engine wear issues, this is the only one that seems like a slam-dunk to me.

Now, what effect the higher viscosity would have on the seal wear is another question.

Good input GeorgeH.

Here you go...this is the Stationary Gear part number from a 1973 Mazda RX-3 Parts book....

0820-10-502B (2) same ones used in a 4 port RENNY...

http://www.rx8club.com/attachment.php?attachmentid=146213&stc=1&d=1254456635

AND THE SAME BEARINGS SHOWN IN A SERIES 1 RX-8 Parts File...

http://www.rx8club.com/attachment.php?attachmentid=146215&stc=1&d=1254457492

post #21 said:



at 100 C

20 weight: 5.6 mm^2/s or 5,200,000 centistokes
50 weight: 16.3 mm^2/s or 16,300,000 centistokes

a difference of 11,100,000 centistokes . all calculations done here: http://www.cleavebooks.co.uk/scol/ccviskin.htm

the 50 weight has almost 3 times the nominal viscosity of the 20 weight. Now, we can debate how important that is, but the differences in viscosity are significant.

These are the minimal value. But a 20 weight could be 9,3 at 100C, and a 50w could be 16,3 at 100C. What do you call a big difference? At 40C the 20w-50 is 150 cst, and a 5w-20 is about 50 cst. So 7cst or 100 cst is a big difference?

Well my oil coolers are starting to heat after 60 seconds or so from warm up.
About the same time after the first LED goes off 40C.

Where do you get 90C from?,,, RX-7 are also 65C.



http://www.rx8club.com/showthread.php?t=167731&highlight=oil+cooler+thermostat

I would like to stand at the oil flow, and maybe the e-shaft pellet. I have oil temp and oil pressure gauge for four weeks, and yesterday I made a test.

Before the results of my test here are some sentences for repetition:

If you warm up an oil from a lower temp to a higher temp, the thickness of the oil is decreasing continuously. If you do it in an engine at a fixed rpm, the oil pressure has to decrease also continuously, as the temperature of the oil is raising.

So my results in the S1 Renesis:

I use Mobil1 0w-30, the outside temperature was 71 F.
I started the cold engine. The oil pressure went up with the very cold and thick oil to 60 PSI, immediately after startup.
After 2-3 minutes on idle, the oil temp still did not reach the 122F. At this point I started with the car, and FIXED THE RPM AT 2000 in fourth gear (no really matter which gear), and looked at the gauges what will happen as the oil is warming.

After some minutes when the oil temperature was closing to the 122F mark, the oil pressure went down to 31,9 PSI (!!!) with the very, very thick cold oil.
It is more strange if you see, what happenned when the oil temp was closing to 140 F. The pressure was continuously raising to the max 58 PSI at 140F.
All this happened on a fixed 2000 rpm. Remember, that in normal case the pressure is decreasing with warming.

After that, there did not happened any more strange thing, the pressure went down as the oil temp raised. But you have to know that even at 160-165F is still 44 PSI pressure (2000 rpm), with the 30 weight oil.

So I have to say, there is something in the Renesis, which decrease (very much)the oil flow under 60C. Is it a dangerous pressure level? Maybe, if you see how thick is the oil in that low temp. This pressure control part has to be the e-shaft pellet. (I don't have any other idea.)

Of course, there is a little chance, that my oil pressure gauge sensor is faulty, so maybe we need more datas from others, before conclusions.

http://www.rx8club.com/showthread.php?t=167731&highlight=oil+cooler+thermostat

Got it, It is more than likely the Oil Cooler Thermostat works in the same way as the Eccentric Shaft Pellet, as in it restricts the flow rather that a complete on/off situation.

Otherwise my oil coolers would never get warm at 40C (Coolant temp) like they do now, there has to be oil flowing through the cooler otherwise there would be no heat felt.

I guess they work almost parallel with the coolant thermostat which has an opening temperature between 80-84 C and fully open at 95 C.

So I have to say, there is something in the Renesis, which decrease (very much)the oil flow under 60C. Is it a dangerous pressure level?
I see no reason to believe that 32 psi is a dangerously low pressure. As I stated earlier, it's the viscosity of the oil that determines how well the bearings are protected, not the pressure, as long as a continuos supply of oil is present at the bearing, and 32 psi should be plenty to ensure that.

I do agree the dip is somewhat curious, however. But my Miata (the old ones that came with functioning pressure gauges from the factory) would always idle in the 30 psi range (or lower) when hot. Yes, it's a different motor design, but it does illustrate that 30 psi is reasonable to keep the bearings well supplied with oil.

I see no reason to believe that 32 psi is a dangerously low pressure. As I stated earlier, it's the viscosity of the oil that determines how well the bearings are protected, not the pressure, as long as a continuos supply of oil is present at the bearing, and 32 psi should be plenty to ensure that.

I do agree the dip is somewhat curious, however. But my Miata (the old ones that came with functioning pressure gauges from the factory) would always idle in the 30 psi range (or lower) when hot. Yes, it's a different motor design, but it does illustrate that 30 psi is reasonable to keep the bearings well supplied with oil.

OK when your engine is hot.

But the danger is that this (RX-8) pressure was measured at very low temps, when the oils are very thick. The rpm was higher than idle (2000). And this means very slow flow, after startup under 140F. Lubrication is the flow, the pressure does not mean it in itself.

..and the oil pressure changing between 104F and 140 F is more than interesting. What is the explanation? Only the e-shaft pellet? If the oil cooler's thermostats would play at such a low temps, there would not be higher pressure at 140F then at 122F, and later (above 140F) would not be continuous the pressure decreasing as the temp is raising.

Weird, my oil pressures are way off from yours. Immediately when I start my car cold my pressures are at 30-40PSI at 1500RPM idle. Once things warm up fully at idle my pressures are essentially the same. and from 3,000RPM all the way to red line my pressures stay between 75-85PSI.

Okay here is some data I forgot I posted elsewhere.
http://c3.ac-images.myspacecdn.com/images02/61/l_4472942dc1f94f56b6559d62d0bba2a2.jpg

Also, I did a max run up to red line and I got these numbers which are pretty in line with what I recorded before.

RPM: 8335
Water Temp: 195 degrees F
Intake Temp: 104 degrees F
Oil pressure: 83PSI

But the danger is that this (RX-8) pressure was measured at very low temps, when the oils are very thick. The rpm was higher than idle (2000). And this means very slow flow, after startup under 140F. Lubrication is the flow, the pressure does not mean it in itself.

Not quite correct. Flow does not equate to lubrication. All that is important to ensure lubrication is an adequate quantity of oil in the journal, which is pretty much assured at 32 psi. Flow rate does equate to heat transfer, which is unimportant when the engine is warming up. Or rather, it is important, and you want to reduce heat transfer to warm the engine faster.

I still don't see a problem with that pressure under those conditions. At least, without additional hard data and/or knowledge, I don't see a reason for alarm.

I do agree the dip is somewhat curious, however. But my Miata (the old ones that came with functioning pressure gauges from the factory) would always idle in the 30 psi range (or lower) when hot. Yes, it's a different motor design, but it does illustrate that 30 psi is reasonable to keep the bearings well supplied with oil.

That's because the Miata uses the same By Pass Regulator Piston and Spring as a S1 RX-8, 0221-14-115 and 0221-14-116, used in about 70% of all Mazda made including rotaries, and or basically their banger engines above 1500cc...below this the only change was the spring 0324-14-116B same piston/plunger though.

Not quite correct. Flow does not equate to lubrication. All that is important to ensure lubrication is an adequate quantity of oil in the journal, which is pretty much assured at 32 psi.

This is completely wrong.

If pressure was what lubricated and not flow we would all be running around with 80 weight oil in our cars.

Bearings stay separated from other metal parts because of flow.

This is completely wrong.

If pressure was what lubricated and not flow we would all be running around with 80 weight oil in our cars.

Bearings stay separated from other metal parts because of flow.


Can you provide a reference for this? Everything I have read has indicates that the volumetric flow rate isn't particularly important, at least in terms of establishing a proper film thickness.

Yes, flow rate plays into other concerns, like heat transfer, as well as keeping the oli cool enough that it doesn't degrade, and therefore is crucial in the overall longevity of the engine, but the statement that cold oil at 32 psi is dangerously low because the resultant flow rate won't provide adequate lubrication is, as far as I can tell, false. Do you agree with me on that or not?

[edit] and, I'm not saying it is pressure that provides lubrication - it's clearly not. It is the presence of the oil that provides lubrication - flow just ensures that a fresh supply is always present.

Interesting. Love this forum.

Actually, I think Flashwing and I are stating the same thing, but I’m just splitting a hair to make a point.

Comparing flow rate to pressure, flow rate is what is truly important, since it determines how much heat the oil will pull out of the engine, and how much heat the oil coolers pull out of the oil. Mess up the flow rate and you have a system that either runs too hot or too cold.

Pressure is a by-product of flow rate, viscosity, the physical size of the oil passages, and of course the details of the oil pump. The reason we watch oil pressure as opposed to flow is that pressure is easier to monitor. And, as we all know, if you are at the track and the car is fully up to temp, and the pressure drops suddenly, you have a problem. Maybe something broke, maybe you have a leak, or maybe the oil overheated. Whatever, the drop in pressure means the oil flow or viscosity has decreased from the norm, and you better stop the car and figure out what is wrong before something really bad happens.

But, the hair I’m splitting is that it is oil viscosity (and condition) that ultimately (or at least primarily) determines how well the bearings are protected. Assuming there is enough flow to keep the oil within a proper temperature range, it’s the oil that matters. And, when the engine is cold, a low flow rate isn’t going to cause a problem, in fact it may be beneficial as it will get the oil up to temp faster. Just as long as the flow increases when the engine is up to temp there shouldn’t be a problem.

isnt that what the op noticed? it wasnt that number itself, it was the fact that the pressure (number) changed in a spot where it was not anticipated?
remember the volumne of the oil being pumped in our engines is a fixed amount --irreguardless of the viscosity of the oil in the pan. Now the free flow of the oil can be different.

What we should really be discussing is the film strengh and particle suspension properties?
But like what was said --it is easier to monitor the pressure--so it is easier to talk about it also?
OD

Man, OD, we are in too many threads. We should all find a spot to discuss everything revolving around lubrication in the Renesis.

you know I just relaized that myself Lol!!
OD

isnt that what the op noticed? it wasnt that number itself, it was the fact that the pressure (number) changed in a spot where it was not anticipated?
remember the volumne of the oil being pumped in our engines is a fixed amount --irreguardless of the viscosity of the oil in the pan. Now the free flow of the oil can be different.

True. But the pellet is doing something to drop pressure, as I understand it. Perhaps part of the flow is being redirected? Or else, the pressure is being dropped due to flow resistance but the net flow to the bearing is unchanged. Either way, it doesn't seem to me a cause for alarm (yet).


What we should really be discussing is the film strengh and particle suspension properties?
But like what was said --it is easier to monitor the pressure--so it is easier to talk about it also?
OD

Agreed about the film strength comment. That is my point all along. As long as oil is being delivered to the bearing - even at a reduced pressure - during warm up, it seems to me there will be sufficient film strength.

Okay here is some data I forgot I posted elsewhere.
http://c3.ac-images.myspacecdn.com/images02/61/l_4472942dc1f94f56b6559d62d0bba2a2.jpg

Also, I did a max run up to red line and I got these numbers which are pretty in line with what I recorded before.

RPM: 8335
Water Temp: 195 degrees F
Intake Temp: 104 degrees F
Oil pressure: 83PSI

Your datas don't tell too much without oil temps.

Otherwise not the actual pressure is the question. The question is that why there is a big pressure drop, and after that a big pressure increase at a fixed rpm (between 104-140 F), while the oil is warming continuously?

True. But the pellet is doing something to drop pressure, as I understand it. Perhaps part of the flow is being redirected? Or else, the pressure is being dropped due to flow resistance but the net flow to the bearing is unchanged. Either way, it doesn't seem to me a cause for alarm (yet).



Agreed about the film strength comment. That is my point all along. As long as oil is being delivered to the bearing - even at a reduced pressure - during warm up, it seems to me there will be sufficient film strength.

OK, let us see. I stop the warm engine. It (the e-shaft) cools down to below 140F, so the pellet opens the bypass passages of the e-shaft, so the oil drains out from the e-shaft. Is it true until this point?

I start the engine at this point. The pressure has to build up inside the e-shaft, and inside the bearings. But it needs more time as usually, because the bypass passages are opened, and these are bigger diameter channels, than the intake hole of the bearings.

A double change is great if you feel that your oil is extremely dirty. However, if the oil doesn't look like crap, and you do your oil changes on a 3k schedule, a complete flush isn't really necessary.

I wouldn't mind doing a complete flush every 9-15k miles or so, but I just recently did my first oil change (@2900 miles). I may change my opinion on the flush depending on my next oil change (@~6000 miles).
I dont go as far as ASH does but I do flush good. I dont see why not. After time and as stated in this thread oil will not hold its temp.

True. But the pellet is doing something to drop pressure, as I understand it. Perhaps part of the flow is being redirected? Or else, the pressure is being dropped due to flow resistance but the net flow to the bearing is unchanged.

Yes, as far as I am aware on a cold engine the Pellet restricts the oil flow through the eccentric shaft, the pellet allows enough oil to lubricate front and rear stationary gear bearings and the two rotor bearings/journals, but the pressure is not great enough for the two E-Shaft Jets to actually squirt oil over the inside of the rotors, this as we know assists in a faster engine warm up time frame, the oil not sprayed inside rotors is by passed.

I think, when we are seeking the causing factor of the Renesis bearing wear, we have to seek what is the difference between the oil system of a piston engine's crankshaft, and the e-shaft of the Renesis. The pellet is a difference.

Why there aren't bearing wear in the conventional engines using any viscosity oil? As I know there are bigger forces on the bearings.

Since Ash has been so kind to let me post some pictures here about the pellet etc here they are, for reference. I hope this helps making the subject clearer for the less experienced and who never saw an engine open :)
146320

146321

146322

Please forgive my horrible working area but that's the only table i can dirty and soil while disassembling engines :) Then off to the working table :smoker:

GOOD pics G ;)

I see that nice NA RX-7 oil pump there too, the E shaft looks like it has Rust on it??? NAAAAaa must be dirt?

What is the mileage of the engine...."G"

I think, when we are seeking the causing factor of the Renesis bearing wear, we have to seek what is the difference between the oil system of a piston engine's crankshaft, and the e-shaft of the Renesis. The pellet is a difference.

Why there aren't bearing wear in the conventional engines using any viscosity oil? As I know there are bigger forces on the bearings.

But, the same Pellets, Springs, Bearings have been used in ALL RX-7's since the FC and RX-8.
The S1 RX-8 shares the same Oil Pump and Bypass Valves as a 1986 NA FC RX-7...

GOOD pics G ;)

I see that nice NA RX-7 oil pump there too, the E shaft looks like it has Rust on it??? NAAAAaa must be dirt?

What is the mileage of the engine...."G"

G! First Charles, then the whole BHR crew and now you :) I like it :aroused:
Anyway that engine had a broken side seal spring on the rear rotor, and a stuck corner seal on the same side. Barely 1000miles per the owner. Surely less than 10.000 even if the rotor is not so clean, considering bearing wear etc.

The eccentric shaft has got some light rust that can be cleaned by hand, long story why it is rusting... i took everything inside my box for storage this summer but i forgot the shaft in the balcony. Dunno if it is reusable, guess i'll try to clean it and see how deep the rust is. What do you suggest that i do? Trash it? :)

G! First Charles, then the whole BHR crew and now you :) I like it :aroused:
Anyway that engine had a broken side seal spring on the rear rotor, and a stuck corner seal on the same side. Barely 1000miles per the owner. Surely less than 10.000 even if the rotor is not so clean, considering bearing wear etc.

The eccentric shaft has got some light rust that can be cleaned by hand, long story why it is rusting... i took everything inside my box for storage this summer but i forgot the shaft in the balcony. Dunno if it is reusable, guess i'll try to clean it and see how deep the rust is. What do you suggest that i do? Trash it? :)

I remember the engine now..G
Its a 4 port job..
If the E shaft has no damage on it from the bearings then I would try the following, Rub clean engine oil all over the shaft and leave it sit there for a few weeks and then wipe it off, rust may just come off clean, though hard to tell from pic you don't really want any pit marks on the journals, I would see how it cleans up.

The engine in my case is a 6 port but that really doesn't matter imho.
No rust signs after the shaft is cleaned by the way, i think i will just oil it with gun oil to preserve it and see what the next guy that'll need engine needs :)

shaft
You said shaft :cwm27:

The engine in my case is a 6 port but that really doesn't matter imho.
No rust signs after the shaft is cleaned by the way, i think i will just oil it with gun oil to preserve it and see what the next guy that'll need engine needs :)

Well there you go....(Rust)
Yep, how silly of me I was looking at the end plate...derrr..
But, I remember you talking about the broken side seal spring ages ago..

Good on your G

Unfortunately i'm lacking the time to finish this particular engine :)
Anyway i would be curious to see what would happen with a differently rated pellet spring!

Unfortunately i'm lacking the time to finish this particular engine :)
Anyway i would be curious to see what would happen with a differently rated pellet spring!

MMmm, trouble is G, there is only one type of Pellet Spring used by Mazda for all rotaries made from the FC RX-7 onwards...

So any experimentation with the springs size (thickness or length) could be hit or miss, and then I would have to ask what are you trying to achieve, you really don't want to up it's heat range from 65C, only lower it, and if that is the case you might as well put a sold pellet in to stop any oil flow restriction.

MMmm, trouble is G, there is only one type of Pellet Spring used by Mazda for all rotaries made from the FC RX-7 onwards...

So any experimentation with the springs size (thickness or length) could be hit or miss, and then I would have to ask what are you trying to achieve, you really don't want to up it's heat range from 65C, only lower it, and if that is the case you might as well put a sold pellet in to stop any oil flow restriction.

I would like to try a weaker spring to lower its opening temperature. Since sourcing it is uncomfortable i will go with usual and proven route :)

But, the same Pellets, Springs, Bearings have been used in ALL RX-7's since the FC and RX-8.
The S1 RX-8 shares the same Oil Pump and Bypass Valves as a 1986 NA FC RX-7...

If you write it 1000 times again, it won't help to find the answer.

Are the e-shafts the same, and mainly the oil passages of it? There are xxw-20, xxw-30 oil users in earlier 13B-s. Have they got bearing wear problem?

What are the differentces between a crankhaft's and an e-shaft's oiling system? One is for sure, the pellet, but what are the others? The higher temp?

As I wrote earlier, the pellet cause pressure fluctuation while the oil is warming from cold start up, and because of the pellet, the oil can drain out from the e-shaft as it cools under 140F, which is a matter at the next start up.

We need the experts of this forum.

If you write it 1000 times again, it won't help to find the answer.

Are the e-shafts the same, and mainly the oil passages of it? There are xxw-20, xxw-30 oil users in earlier 13B-s. Have they got bearing wear problem?

What are the differentces between a crankhaft's and an e-shaft's oiling system? One is for sure, the pellet, but what are the others? The higher temp?

As I wrote earlier, the pellet cause pressure fluctuation while the oil is warming from cold start up, and because of the pellet, the oil can drain out from the e-shaft as it cools under 140F, which is a matter at the next start up.

We need the experts of this forum.

Back in 1986, there were no xxw-20 oil.

There were xxw-30. But most owners were smart enough to use something better than that.

As for e-shaft, size is the same, you can use a MSP e-shaft into a EGI, no problem. Material about the same, its about 0.6 lbs lighter than the old one. a bit more balanced. Thats all I can think of right now.

We need the experts of this forum.

When it come to Mazda Parts...I think I should know what I am talking about, It has been half my life..if it is the SAME it is the SAME it is the SAME..

Sure when it come to a Mechanic or Tech at a Dealer replacing said parts most know how to Remove and Replace.....and that is about ALL..

When it comes to the actual Parts, I will back ANY long Term Mazda Parts guy Any-day, because Techs know JACK SHIT... most of them are are Lawn Mower mechanics that happen to be a grease monkey's too at the same time...and that is most of them.

My sincere apologies to all the great Mazda Techs who actually work on the Product and Know what they are about and take an interest...and that includes many on this and other forums.

In my time so many of the Mazda service staff could not give a dam about the Customer or the Service...they just want a pay check.

As for "Experts" what is it you are actually after?..What do you 'want' to hear?

As you well know the "Internet" like the "Telephone" can't always Diagnose an issue you may have with your (a) car...it needs to be Physically Presented.

Well lets see...
1. The E shaft Jets are the same as a 1986 FC RX-7 the Springs from a 1971 RX-2, one would think all being equal (including Pellet) that the oil passages in the e-shaft are the same...Wouldn't You?.
2. Have the 13B E-Shaft SG Bearings got wearing problems, not according to guys here who assemble naked 13B's, nothing I can see on RX-7 Forums...Have you looked?
3. Who Bloody Cares about CRANKSHAFT Bearing Wear with the same oil, we are talking Rotary, go and chase all the other 287 car forums that have Banger Engines and use the same oil, I can see some of it's relevance, but they ain't a rotary are they?
4. As for "alleged" Oil Pressure Fluctuations when engine oil is warming, it has been said before and on the RX-7 Forum that the Bearings are NOT Starved of OIL, if they were do you think Mazda would have stayed with the SAME set up for the past 23 Years? So what, the oil can drain out of e-shaft when turned OFF under 65C until next start up.. what do you think happens on a Banger engine with Overhead Camshafts???, Piston Pins??? at Start Up.

You are the one who keeps asking oil pressure questions and don't like the answer(s)...try somewhere else then..

NO we Don't need Experts on this Forum we need some Comprehension.

Forgot to add..it is not relevant to Oil Pressure, but the Needle Bearing and Oil Seal at the Gearbox end inside the Eccentric Shaft is also the SAME as a ALL Rotaries over the past 35 years so I guess the hole it fits into is also the same.

2. Have the 13B E-Shaft SG Bearings got wearing problems, not according to guys here who assemble naked 13B's, nothing I can see on RX-7 Forums...Have you looked?

That's what I'm talking about. Why they don't have this problems? Easier to say, it's only viscosity, but this kind of wear is rather caused by no oil, than thin oil.

3. Who Bloody Cares about CRANKSHAFT Bearing Wear with the same oil, we are talking Rotary, go and chase all the other 287 car forums that have Banger Engines and use the same oil, I can see some of it's relevance, but they ain't a rotary are they?

This kind of approaching won't answer the question. Did you answer the question, that are there bigger loads on a crankshaft bearings? Am I missed it? They use the same oil pressure (average), and thin oils. ..and they don't have this kind of problem. So is the problem that the e-shaft is working hotter, and the oil is thinning too much?

You are the one who keeps asking oil pressure questions and don't like the answer(s)...try somewhere else then..

I like the answers, if I find one that is comprehensive. But If we always stuck at "every parts is the same", it is not that.

Forgot to add..it is not relevant to Oil Pressure, but the Needle Bearing and Oil Seal at the Gearbox end inside the Eccentric Shaft is also the SAME as a ALL Rotaries over the past 35 years so I guess the hole it fits into is also the same.

But relevant, if the Renesis e-shaft temperature can be higher, than the e-haft's temperature of the earlier (non modified) rotaries.

But I haven't got e-shaft's temperature datas.

Frankly, I’m surprised by some of the comments in this thread. Particularly those that state that it’s a pressure problem, not a viscosity problem.

In Shigley and Mitchell’s Mechanical Engineering Design (a reference/bible for Mechanical Engineering) they state that hydrodynamic lubrication does not depend on the lubricant being introduced under pressure, although it is critical that an adequate supply is present.

That is why the oil is pressurized – the pressurization is a by-product of the need to flow oil through the system and remove heat. But wear is prevented by the presence of a film of oil between the journal and the bearing, and the thickness of that film is dependent on viscosity, not pressure. If you are getting metal to metal contact it is because the oil is not presenting a thick enough film, which means a thicker oil is called for.

Of course, if there is a cold-start issue where for some reason the bearing is nearly dry for longer than a moment or two, then that is a different problem. But I am reluctant to believe that is true.

Yes, this is armchair engineering, and I’d be happy if an experienced lubrication engineer chimed in and explained why basic hydrodynamic theory doesn’t apply to the bearing wear problem on the RX-8. But until that happens, I’m inclined to believe that the bearing wear problem is a viscosity problem. Of all the various theories & solutions I’ve seen posted here relative to engine wear issues, this is the only one that seems like a slam-dunk to me.

Now, what effect the higher viscosity would have on the seal wear is another question.

Very well said. I consulted the man who I have learnt most of my rotary knowledge from and his statement was almost identical: Getting the oil there is really the purpose of pressure. He said something about hydrosatic something or the other (Above my head). The layman's version would be: Once you get that proper film of oil where you need it (And can maintain it) you're in fine shape. From the close to 1000 rotaries that Rick has taken apart we have concluded that the bearing issue is viscosity related as well. BTW, Rick worked at Lockeed doing hydraulics back in the 60s prior to his Mazda involvement.

Paul.

From the close to 1000 rotaries that Rick has taken apart we have concluded that the bearing issue is viscosity related as well...

Paul.

So was the bearing wear is an issue on the earlier 13B's?

thats good enough for me!
Paul/Ash probably a stupid question but why is the bearing wear on just one side/one spot or are yall seeing the bearing wear in different areas?
Reminds me of some recips with the belts too tight:)
OD

So was the bearing wear is an issue on the earlier 13B's?

Nope. Maybe in an engine with close to 200k miles. All the engines that ran 20W50 back in the day never showed this bearing wear so we should be able to say rotaries aren't all that prone to cold start lubrication issues (Is that due to slow shaft speed? :dunno:).

Paul.

So was the bearing wear is an issue on the earlier 13B's?

To be honest, one day the bearing wear will reach copper.

its just that in the older days most owners (smart ones that is) would not even touch anything lower than 10w40. most run 20w50 and they all got good results.

Thats why whenever I see those "omfg u need 5w most wear happens at start up blah blah blah." makes me sick. cuz seriously, I seen more dead engines these days than older times. and the engine these days supposed to be "better and and last longer" correct? no ?

Search, learn, Happy. Not on this forum of course, go other 7 forum. Oh yes Im a 7 guy too :)

thats good enough for me!
Paul/Ash probably a stupid question but why is the bearing wear on just one side/one spot or are yall seeing the bearing wear in different areas?
Reminds me of some recips with the belts too tight:)
OD

That's the area of greatest load or represents where the power pulse occurs (10 o'clock). This can be further affected by overly tight belts which will shift the pattern a little, often closer to 12 o'clock.

Paul.

To be honest, one day the bearing wear will reach copper.

its just that in the older days most owners (smart ones that is) would not even touch anything lower than 10w40. most run 20w50 and they all got good results.

Thats why whenever I see those "omfg u need 5w most wear happens at start up blah blah blah." makes me sick. cuz seriously, I seen more dead engines these days than older times. and the engine these days supposed to be "better and and last longer" correct? no ?

Search, learn, Happy. Not on this forum of course, go other 7 forum. Oh yes Im a 7 guy too :)

spoke to a 3rd gen rx7 owner this weekend he was running 20-50 and has had no troubles other than the coolant issues those cars have. bought some 20-50 and switched it on sunday..

Nope. Maybe in an engine with close to 200k miles. All the engines that ran 20W50 back in the day never showed this bearing wear so we should be able to say rotaries aren't all that prone to cold start lubrication issues (Is that due to slow shaft speed? :dunno:).

Paul.

Thanks.

More thoughts

1.If the issue comes from cold start, would not it be better to increase the speed of the cold oil flow, to decrease the time to get the bearing? A cold 0w is much thicker, than a warm xxw-50.

2. Is the rotaries e-shaft hotter than a crankshaft? I think yes, but what about you? Maybe the wear comes from too thin hot oil.

If the 1. and 2. points are true, than we need 0w-40, 0w-50.

Is it true?

spoke to a 3rd gen rx7 owner this weekend he was running 20-50 and has had no troubles other than the coolant issues those cars have. bought some 20-50 and switched it on sunday..

Why run 20W-50 when you can run 0W-50. I know your in Miami so cold is not much of a concern but I grew up in FL and it does occasionally get cold. I would not want that cold 20W in my car when its 30 degrees out.

Thanks.

More thoughts

1.If the issue comes from cold start, would not it be better to increase the speed of the cold oil flow, to decrease the time to get the bearing? A cold 0w is much thicker, than a warm xxw-50.

2. Is the rotaries e-shaft hotter than a crankshaft? I think yes, but what about you? Maybe the wear comes from too thin hot oil.

If the 1. and 2. points are true, than we need 0w-40, 0w-50.

Is it true?

That's just it; the problem is not from cold start. A XW-30 or 40 would both be better for a rotary than 5W-20.

Paul.

Why run 20W-50 when you can run 0W-50. I know your in Miami so cold is not much of a concern but I grew up in FL and it does occasionally get cold. I would not want that cold 20W in my car when its 30 degrees out.

ambient temp with humidity is anywhere from 90f- 96 here, so my oil is warm from sitting in the sun all day the temp wont drop for another month and a half when my next oil change comes around. i try and change it before 2k miles (about 2 months). at that time i'll run something a little thinner dont think i'll be doing a 0w tho.

Why run 20W-50 when you can run 0W-50. I know your in Miami so cold is not much of a concern but I grew up in FL and it does occasionally get cold. I would not want that cold 20W in my car when its 30 degrees out.

a "true/good" Synthetic based oil would flow just fine as cold as 10f degrees.

So 30 degrees is not really "that" cold :)

Even Dino based 20wXX would flow just fine at around 25f (its gonna get pretty thick, but manageable.)

20w50 oil cost about the same as the 0w50, so ... lemme finish 10 qts of my 15w50 mobil1 and 5 qts RP 20w50 first ... :)

Yeah I just don't see the point when they cost the same.

Yeah I just don't see the point when they cost the same.

people afraid of wide range oil bcuz of the additives package. they have to add tons of them to get such "wide range" viscosity.

Im ok with it tho. Like I said I will try some when Im done with my 15/20w50 stock :)

a "true/good" Synthetic based oil would flow just fine as cold as 10f degrees.

So 30 degrees is not really "that" cold :)

Even Dino based 20wXX would flow just fine at around 25f (its gonna get pretty thick, but manageable.)

20w50 oil cost about the same as the 0w50, so ... lemme finish 10 qts of my 15w50 mobil1 and 5 qts RP 20w50 first ... :)

Really, you guys are lucky, here a 20W50 is dirt cheap ($22), a 0W50 is about $60 and only Synthetic of corse.....

Really, you guys are lucky, here a 20W50 is dirt cheap ($22), a 0W50 is about $60 and only Synthetic of corse.....

...

yeah Dino 20w50 is dirt cheap here. I can get 5 qts with filter for 17.99 :)

But Synthetic ... well. its not that much. I got Mobil1 5 qts + Mobil1 filter @ autozone couple days ago for 29.99 + tax.

More exotic brands like Redline/Eneos/Royal purple will cost about twice as that without filter.

ambient temp with humidity is anywhere from 90f- 96 here, so my oil is warm from sitting in the sun all day the temp wont drop for another month and a half when my next oil change comes around. i try and change it before 2k miles (about 2 months). at that time i'll run something a little thinner dont think i'll be doing a 0w tho.

A 0w has the same operational temperature viscosity as a 5w or 10w oil does. The only difference is when the oil is cold. A 0w-50 will technically have a lower cold viscosity than a 20w-50 will. This ensures you have the best protection when starting your vehicle. 0w oils are also true synthetics.

To respond to the Eccentric Shaft 'Heat' thought....as we know FD RX-7's were a massive Heat Machine with twin Turbo a 15W40 was the oil recommended (here).

One would "think" the e-shaft on a RENESIS would get no hotter, so was SG bearing wear an issue with FDs...have not heard/seen., but the Oil Pump is different by part number for the Turbo...like the oil pump is different in the FE S2.

As for weights, we should be looking beyond the numbers on the bottle, no?

For example, looking at Royal Purple's data, at 40c, 0w40 is heavier that 5w20 and 5w30, but is lighter than 5w40.

At 100c, 0w40 is heavier than both 5w20 & 5w30 (of course), but only slightly thinner than 5w40, which is very thick at 40c.

So, I can see why 0w40 is popular. But, you have to look at more than just the label on the bottle.

[edit] I see other responses above on this - I started this response 20 minutes ago. Sorry for the duplication.

I pulled the 5W20 out of my RX-7 and filled with 5W30. It feels the same. Then again it felt the same with 10W30 and 10W40 too.

I pulled the 5W20 out of my RX-7 and filled with 5W30. It feels the same. Then again it felt the same with 10W30 and 10W40 too.

Butt Dyno is not that Accurate. you should know better ;)

A 0w has the same operational temperature viscosity as a 5w or 10w oil does. The only difference is when the oil is cold. A 0w-50 will technically have a lower cold viscosity than a 20w-50 will. This ensures you have the best protection when starting your vehicle. 0w oils are also true synthetics.

i understand that point but if its hot all day in the 90's (f) do i really need to go 0w? during the summer it never drops below 85f (at night!) so im under the impression that my oil is always gonna be warm(?) i may be wrong so plz feel free to correct. in about 2 months when it actually is cold ill switch it up but for the rest of the season i think 20-50 is the way to go.

.:)

To respond to the Eccentric Shaft 'Heat' thought....as we know FD RX-7's were a massive Heat Machine with twin Turbo a 15W40 was the oil recommended (here).

One would "think" the e-shaft on a RENESIS would get no hotter, so was SG bearing wear an issue with FDs...have not heard/seen., but the Oil Pump is different by part number for the Turbo...like the oil pump is different in the FE S2.

As I said in the other thread, bearing heat generation and wear is related to the square of the surface speed differential across them, so the jump from 7krpm to 9krpm is quite a step in terms of heat/friction in the bearing, that's 65% more heat and wear right there.

As I said in the other thread, bearing heat generation and wear is related to the square of the surface speed differential across them, so the jump from 7krpm to 9krpm is quite a step in terms of heat/friction in the bearing, that's 65% more heat and wear right there.

Yes Phillip, the Higher RPM of the RENESIS has always been in my mind as a possibly issue, because most (all) things being equal, Oil Grade recommendations and Higher RPM's are new...when compared to the RX-7.

Perhaps part of the reason Mazda increased Oil Pressure & By Pass Pressure in Series II RX-8's, oil flowing/circulating faster through Engine and Oil Coolers 'should' remove heat more efficiently.

Series I RX-8's for Australia only had One Oil Cooler, Manual and Auto!..
But, now Series II's here in Manual have two, but Auto's still only have one, they now have the higher power 6 port engine auto????

One would think Australia has a Hotter climate than the UK?
But the UK models always had the 2 Oil Coolers???...

Go Figure??

^ Leads one to believe that the folks over at mazda have their thumbs up their as*es..

remember all what Paul said---"THIS IS NOT A START/WARM UP PROBLEM"
(sorry for the capitals), so its not about the weight of the oil when it is cold.
Actually in a way it is not about the weight when the oil is hot either---its about film strengh . But, it is a whole lot easier to talk about viscosity than film strengh and they are fairly closely related unless you want to get exotic.

You dont have to worry about the oils temps so much. Just get your coolant temps where you want them and the oil temps will follow.

Paul/?Ash yall rock dudes!
OD

Perhaps part of the reason Mazda increased Oil Pressure & By Pass Pressure in Series II RX-8's, oil flowing/circulating faster through Engine and Oil Coolers 'should' remove heat more efficiently.


yes, it should do, it'll also stop the oil breaking down as fast which some people are experiencing (i.e. 30w oils becoming 20w after 3k miles) - that's normally caused by excessive heat and load shearing the oil molecules.

IMO that's why people are leaning toward thicker oils - when they do break down they're at the right viscosity, but the problem with that is when they've broken down most of the additive packages have been used up - leading to carbon buildup, crankcase sludge and a lesser ability to suspended foreign particles - which also ties in with the scuffing seen on some of the stationary gearsets - those particles are settling and damaging the gearset instead of being help in suspension, and because the MoS2 and other dry lubricants are falling out of suspension too, their film thickness drops as they aren't being replenished - so they can't help either.
It'd also lead to a bit more scuffing wear on startup.

Now, I know our engine is different as it's not for road use, but the way I see it, everything is basically the same, going by the 'thicker oil is needed' theory, we should be destroying engines every ten minutes.

We're constantly above 6krpm, regularly at the limiter, always under heavy loads, and we generate enough heat that we've melted the electronics off the side of the alternator...
And yet, we're getting away with 5w-30 with no trouble, no scuffing and the bearings were good enough to again after a checkover.

So what's different?
Well:

a)Good quality fully synthetic oil - I know it's another debate in itself, but the stability of a good synthetic and resistance to shear is a step above most semi-synth or dino oils.

b)Absolutely massive oil cooler - the oil going into our engine is going in at ~35*c, yet it's still coming out at ~130*c on the sensor in the oil cooler inlet - now, given most dino oil starts to break down rapidly above 120*c, you can see why I suspect the high oil temperatures are part of the problem - imagine what temperatures you're oils are getting to given your coolers have perhaps half the area of ours....


What you've mentioned Ash, with the higher pressure for the new models, just reinforces that to me - seem like they're trying to get the oil in and out of the engine faster to lower the peak temperatures the oil is experiencing.
Incidentally, that extra flow will also boost the loads the bearings can cope with massively

What you've mentioned Ash, with the higher pressure for the new models, just reinforces that to me - seem like they're trying to get the oil in and out of the engine faster to lower the peak temperatures the oil is experiencing.
Incidentally, that extra flow will also boost the loads the bearings can cope with massively

Just hope the Rear Main Oil Seal Holds up with the increased pressure, same seal as ALL FD and ALL FE's.
Front Timing Cover Seals is also the same for both series RX-8's.:)

Incidentally, that extra flow will also boost the loads the bearings can cope with massively

And, just to be clear, you state this because the higher flow rate will remove the heat generated by the bearings (which as you have stated is higher than past rotaries due to the Renesis' higher redline) more quickly, correct?

Butt Dyno is not that Accurate. you should know better ;)

Gas mileage hasn't changed either. That would be indicitive of an efficiency difference in the oil. I ported my throttlebody and got a mpg gain. Oil isn't doing anything.

Actually in a way it is not about the weight when the oil is hot either---its about film strength.

Bingo!

I realize that this thread is about bearings, but how important is film strength for the apex seals? Seems like that is more related to additives & oil condition. Am I right?

Good topic for another thread.

And, just to be clear, you state this because the higher flow rate will remove the heat generated by the bearings (which as you have stated is higher than past rotaries due to the Renesis' higher redline) more quickly, correct?

Yes, it will, it actually generates more engine heat (more oil flow in a bearing = more heat generated), but the extra flow carries that heat away faster.

I realize that this thread is about bearings, but how important is film strength for the apex seals? Seems like that is more related to additives & oil condition. Am I right?

Good topic for another thread.


I'd imagine the dry lubricants contained within the additives are doing the lions share of lubrication on the apex seals.

The relationship between pressure, available flow from the pump, and bearing speed is an interesting one. CFD anyone?

Especially when you figure in cavitation + foaming too...

listen to all of this--and wonder why i like diesel oil. Superior base stock--better film strength, increased additives and far superior particle suspension ability.
Fits the bill dudes--listen to us old men.
Once again get your coolant under control and your oil temps will follow. Stay away from 8K-9K range--that 1K of rpm puts more strain on multiple things that most realize.
Getting off topic here--sorry
OD

curious, you use diesel oil? what weight?

listen to all of this--and wonder why i like diesel oil. Superior base stock--better film strength, increased additives and far superior particle suspension ability.

So with all those great qualities why isn't diesel oil used in gasoline engines?

As I said in the other thread, bearing heat generation and wear is related to the square of the surface speed differential across them, so the jump from 7krpm to 9krpm is quite a step in terms of heat/friction in the bearing, that's 65% more heat and wear right there.

One more very important info.

- So same oil pressure, and same oil bypass valve's opening press., but way more heat, than earlier rotaries. (and same e-shaft pellet)
They raised the rpm, but you can't raise the pressure (flow) at the higher rpms, because of the by-pass valve's low pressure opening (too early in the rpm range).

Answer:
In the S2 Renesis Mazda raised the bypass valve's opening press (and new pump), which means higher flow.

- Otherwise I think the other problem is that the pellet is causing getting the oil later to the bearings after start under 140F e-shaft's temp. Maybe it is a long time effect, but it is there.

I think I will kill my e-shaft pellet. What material (metal) is used to fill the hollow of the pellet?

-I remain at 0w, which increase the speed of the oil at cold start, but maybe I will change from 0w-30 to 0w-40 for the hot side.

deisel oil IS used in gasoline engines. On most deisel oil cannisters there is even a message saying "OK to use in gasoline engines"
I use Valvoline Blue 15/40W Deisel oil. Easily available at autopart stores.
Search oil sample analysis for some I have posted in other threads.
Mr Rick E and Paul also give it their "OK"

One more very important info.

- So same oil pressure, and same oil bypass valve's opening press., but way more heat, than earlier rotaries. (and same e-shaft pellet)
They raised the rpm, but you can't raise the pressure (flow) at the higher rpms, because of the by-pass valve's low pressure opening (too early in the rpm range).

Answer:
In the S2 Renesis Mazda raised the bypass valve's opening press (and new pump), which means higher flow.

- Otherwise I think the other problem is that the pellet is causing getting the oil later to the bearings after start under 140F e-shaft's temp. Maybe it is a long time effect, but it is there.

I think I will kill my e-shaft pellet. What material (metal) is used to fill the hollow of the pellet?

-I remain at 0w, which increase the speed of the oil at cold start, but maybe I will change from 0w-30 to 0w-40 for the hot side.

My 13B-EGI has a redline of 8K. is not that far off from 9K, not to mention, How many "street" user Rev the shit outa their car and keep it there for Hours like in a race does ? and what do we get? crappy wear.

Also lets not forget, 13B-EGI has technology thats 20 years older than what we have now(Even the very same part has received material update/process update)

my conclusion is, even w30 is not enough. and forget about w20 oil.

deisel oil IS used in gasoline engines. On most deisel oil cannisters there is even a message saying "OK to use in gasoline engines"
I use Valvoline Blue 15/40W Deisel oil. Easily available at autopart stores.
Search oil sample analysis for some I have posted in other threads.
Mr Rick E and Paul also give it their "OK"


As olddragger says, diesel oil is fine to use, over here our petrol and diesel oils are pretty much the same thing bar the benefit of slightly more detergents in the diesel specific stuff, as most of our oils are multiuse, so it's not so much of a concern for UK/EU users though.

you know what is going to be interesting? Since the series 2 engine is running so much more pressure with a 5/20W oil, what is going to happen if they show up with this type of bearing wear and a higher viscosity of oil is needed? Will the seals etc hold?
This is worth watching for?
OD

you know what is going to be interesting? Since the series 2 engine is running so much more pressure with a 5/20W oil, what is going to happen if they show up with this type of bearing wear and a higher viscosity of oil is needed? Will the seals etc hold?
This is worth watching for?
OD

Its worth it. Mazda might release the next Rotary in 2012 or 2013 so we still have about 3 yrs of time to watch.

deisel oil IS used in gasoline engines. On most deisel oil cannisters there is even a message saying "OK to use in gasoline engines"
I use Valvoline Blue 15/40W Deisel oil. Easily available at autopart stores.
Search oil sample analysis for some I have posted in other threads.
Mr Rick E and Paul also give it their "OK"

OD, this makes sense looking at Valvoline Premium Blue info. The only negative could find why not to use diesel oil in a gas engine was do to it having more detergents and may clean so well that could cause loss of compression. Just can't figure out how something could clean so well that it would cause loss of compression? (but than again what the hell do I know?)

you know what is going to be interesting? Since the series 2 engine is running so much more pressure with a 5/20W oil, what is going to happen if they show up with this type of bearing wear and a higher viscosity of oil is needed? Will the seals etc hold?
This is worth watching for?
OD

:fingersx:

My 13B-EGI has a redline of 8K. is not that far off from 9K, not to mention, How many "street" user Rev the shit outa their car and keep it there for Hours like in a race does ? and what do we get? crappy wear.

Also lets not forget, 13B-EGI has technology thats 20 years older than what we have now(Even the very same part has received material update/process update)

my conclusion is, even w30 is not enough. and forget about w20 oil.

So, what can we do? If a xxw-50 or xxw-60 is not enough.

Maybe we would have to do what Mazda did on the S2 Renesis. Higher oil pressure.

Is our oil pump capable to make higher pressure at higher rpm's? If yes, we would have to change the bypass valves in the oil line, to higher opening pressure bypass, so we would get higher oil pressure at higher rpms.

There has been a few comments regarding low temps. NYCGPS, you are probably the closest to me in latitude of the people here. Are New England winters too cold for 20w50? Like for December through mid February, I would want to go thinner?


From what I have been following, it seems that the primary complaint against 5w20 isn't initial lubrication, but lack of viscosity, primarily after 1,000+ miles when it starts breaking down due to heat. With very low ambient temps in the winter, does this hold off that breakdown? If 20w50 doesn't move enough in cold startup in the winter, but thinner oils break down too fast from heat, what is a good compromise? Go thin and change it every 1-2k? Go thick and hope it starts moving?

I am on board for outside of winter, but for winter....there are still questions :Wconfused

(I was hoping to have a beater car this winter, but circumstances made that impossible.)

Go 0w-40...

Go 0w-40...

Thanks, though I am not one to just take a comment as short as that as fact. I prefer to know the dynamics and the 'why', to come to the conclusion myself...even if it is the same conclusion in the end. :)

I probably need to get an oil temp gauge to really be sure. Is that one of the ODB2 data streams available?

I do agree that if you live in an area where the winter temps dip to the 40s or below, and you park outside, then it is a good idea to use 5wsomething, or perhaps 0wsomething.

I'm using 5w30 RP now, and this thread has caused me to consider using 0w40 instead. Interestingly enough, RP 5w30 is actually thinner at 40c than RP 0w40.

Given my driving style & trip lengths in the winter, I'm sure it matters, but in the spring I may change over to 0w40.

NYCGPS, you are probably the closest to me in latitude of the people here.

I would not openly admit that :lol:

Just slap some 20W-40 in the freezer along with some 0W-40 and after a few hours pour the into clear containers and you will see the difference. The difference will vary depending on brand, weight etc. but if you want grab some Castrol GTX and compare it against some German Castrol 0W-30.

Anyway read this article. ALL OF IT. Then report back and I will give you more to read.

http://www.ferrarichat.com/forum/faq.php?faq=haas_articles

I would not openly admit that :lol:

Just slap some 20W-40 in the freezer along with some 0W-40 and after a few hours pour the into clear containers and you will see the difference. The difference will vary depending on brand, weight etc. but if you want grab some Castrol GTX and compare it against some German Castrol 0W-30.

Anyway read this article. ALL OF IT. Then report back and I will give you more to read.

http://www.ferrarichat.com/forum/faq.php?faq=haas_articles

Not sure why doing a freezer test myself didn't occur to me :) I'll do that.

I have been faithfully reading the thread, reading new posts each night if I can't get to them during work. Here are the points in the thread that have me on that train of thought, and the questions generated from each, summarized above:


Not exactly, it's vicosity remains higher at those high temperatures, but it'll still breakdown rapidly once the average oil temp starts to rise above ~115*c With temps here going from ~ -20c to ~5c in the winter, I have to believe that my oil coolers are cooling the oil faster than during the summer. Does this actually help the oil avoid the breakdown more? It should right?

But the danger is that this (RX-8) pressure was measured at very low temps, when the oils are very thick. The rpm was higher than idle (2000). And this means very slow flow, after startup under 140F.

1.If the issue comes from cold start, would not it be better to increase the speed of the cold oil flow, to decrease the time to get the bearing? A cold 0w is much thicker, than a warm xxw-50.

I would not want that cold 20W in my car when its 30 degrees out.

a "true/good" Synthetic based oil would flow just fine as cold as 10f degrees.

So 30 degrees is not really "that" cold :)

Even Dino based 20wXX would flow just fine at around 25f (its gonna get pretty thick, but manageable.) Manageable at 25f, which is ~35f degrees higher than the min temp I have to allow for.

yes, it should do, it'll also stop the oil breaking down as fast which some people are experiencing (i.e. 30w oils becoming 20w after 3k miles) - that's normally caused by excessive heat and load shearing the oil molecules.

IMO that's why people are leaning toward thicker oils - when they do break down they're at the right viscosity,

...

b)Absolutely massive oil cooler - the oil going into our engine is going in at ~35*c, yet it's still coming out at ~130*c on the sensor in the oil cooler inlet - now, given most dino oil starts to break down rapidly above 120*c, you can see why I suspect the high oil temperatures are part of the problem - imagine what temperatures you're oils are getting to given your coolers have perhaps half the area of ours....

I recognize the 0w-40 and 0w-50 that people are commenting on, but there are also alot of comments against a lubrication spread that far apart, due to the additives needed to maintain that spread.


I did read the FerrariChat oil post once before, and I read it again. He only talks about really cold temps a few times:
At 32 F the difference between the two is even greater. At 0 F the mineral oil is useless yet the synthetic works fairly well.
A “30” weight oil has a viscosity of 3 at 302 F ( 150 C ) and thickens to 10 at 212 F ( 100 C ). It further thickens to a viscosity of 100 at 104 F ( 40 C ) and is too thick to measure at the freezing point of 32 F ( 0 C ).

30 weight oil:

Temperature ( F )....Thickness

302...........................3
212..........................10
104..........................100
32..........................250 (rough estimate)

So it seems that the answer is a 0w40 or 0w50, full synthetic, for the winter?

Again, just trying to understand. It is floating around just over my head... :)

It's a lot to absorb. There is no one answer and every oil is different. You just have to find a balance that is acceptable to you.

I have no scientific data but in my reading (my own opinion) the hardest things on the engine are:

1. Cold starts(any start where the oil has drained to the pan and has been sitting for hours)
2. Lack of proper OMP (SOHN needed)
3. Improper warm up procedure (personally my car does not move until I get my coolant temp near 150 degrees F)
4. Short trips where the oil does not get to temp fully
5. Poor Maintenance (OIC, quality of oil, etc.)

3. Improper warm up procedure (personally my car does not move until I get my coolant temp near 150 degrees F)

Isn't it generally accepted that this will result in dilution problems?

Sitting idling is not a good way of warming an engine up, there's not enough heat to thin the oil out quick enough, you need a balance - light throttle openings and 2-3krpm until the oil is warmed through.

Interesting thread!

While I'm not an expert, I would like to clarify any confusion regarding how pressure and flow of a fluid is interrelated. So, I went ahead and drew up a crappy image showing a fluid (lets just say oil) pump with a series of 3 different diameter passages. We can pretend that the pump has an infinite source of oil going to it, and the end of passage C lets the oil spill all over the floor.

http://img43.imageshack.us/img43/6818/oilflow.jpg

Lets say that we take two separate measurements of oil flow through passage A; the first one with a working pressure of 50psi, and the other at 100psi. At 100psi, the flow through passage a will be double that of 50psi. I'm sure we all know that already. Ok, now lets take a look at passage B; it's smaller than both passage A and C. What's my point? If we want the oil through passage C to fill it's entire volume while flowing, there will need to be some minimum pressure in passage A to maintain it. Too low a pressure, and only a small stream might be flowing through C (nevermind A and B).

Now lets try to use our imagination a little bit, and try to imagine the image as such:
The oil pump is, well, the engine oil pump
Passage A is an oil passage leading to a bearing journal
Passage B is the bearing journal
Passage C is the space between the bearing and a shaft

With that said, our goal is to ensure that the gap between the bearing and shaft is filled with oil. In order to do that, we need to make sure enough oil flows through the bearing journal. In order to ensure enough flow through the journal, there needs to be enough pressure in the passage way. The amount of pressure necessary to achieve this is dictated by the size of the journal, and the total area between the shaft/bearing that needs to be filled with oil. Also, keep in mind, oil is constantly flowing OUT of the area too, where it finally ends up in the oil pan.

So, when taking a look at the oil between the rotor and e-shaft, we need to make sure enough oil is FLOWING in order to prevent metal to metal contact. But in order to make sure enough oil is FLOWING, the PRESSURE in the oil passages need to be at some minimum pressure. The minimum pressure is different for various engines, and thus, needs to be determined at design time. 30psi could certainly be sufficient, but then again, it might not be - most likely, it's only the mazda engineers that know precisely.

So to say that only pressure, or flow, or oil presence is all that matters is a bit misleading, as they're all interrelated, and you can't have one without the other. Hopefully this makes sense, and is able to help some of you out.

Once we finally get the oil in the bearing, we don't want it to shear. Heavier weight oil usually ensures this. However, there is a point where the oil becomes too thick to adequately flow within the confines of the bearing without requiring too much working pressure/flow (and thus, engine power). Luckily, even very high performance engines don't use more than 60-weight anyways.


It would be nice to see an oil analysis report from a large group of renesis owners with various oil weights as well. I imagine that 5w-20 had to break down to the point where it was basically dirty water. It wouldn't be hard to see why there would be massive bearing failures.

Just read through the first section of the article posted @ http://ferrarichat.com/forum/showthread.php?t=136052 and have found a bit of contradiction.

The writer claims "If your engine is running hot use a thinner oil.", he then says that in hot climates, his ferrari manual recommends 10w-60 in hot climates under racing conditions, and 0w-40 in cooler climates and city driving.

I'm not sure how much more of this guy's crap I'm willing to read.

Oh, and lastly, just another factor for the OP's question of "what has changed" between older rotaries and the renesis. While it appears that there are a lot of the same parts, an obvious difference is power output. Couple higher working pressures during the combustion phase with lower viscosity oils, and you have a potential recipe for disaster that didn't exist in previous N/A rotaries.

ASH, what kind of similarities do we see see between oil system related parts in the 13b-msp and the the 13b-rew?

Just to throw a bit of information out there. Back in the late 60's when the rotary program was pretty young, Mazda immediately started racing the rotary trying to prove it's durablity. In one of the 24 hour races they entered back then, I think it was a Spa Francorchamps from one of those years, their car developed a split in the oil cooler about halfway through the race. The cooler was made of copper and apparently a braze joint had failed. They couldn't get it fixed but they could bypass it completely. They did. They drained the oil and ran the rest of the race on a thicker oil. It worked. Not optimal but it worked.

ASH, what kind of similarities do we see see between oil system related parts in the 13b-msp and the the 13b-rew?

From the Oil Pumping aspect, for all FD RX-7's the oil pump parts were the same.

The only difference to the FE1031 RX-8 (S1) are the OIL Pump 'Rotors' by Part Number, but they use the same oil pump shaft as the RX-8 S1 and FC, same oil pump chain, mounting bolts, etc, so I am pretty sure the FD pump would fit on the S1 RX-8, the actual design of all these components are the same.

I don't have an FD Service manual to check/compare the Oil Pump's PSI pressure.

Even the FD uses the same BY Pass Plunger (0221-14-115) as the RX-8 S1, EPC shows the spring but NO Corresponding Part Number?, I am assuming it is 0221-14-116, but it may not be.

As we know the FC RX-7 which is the originator of N326 model code for Mazda Part Number uses the exact same Oil Pump and Valves in the FE1031 RX-8. The FE1032 RX-8 (S2) has an all new high pressure oil pump, but even the oil pump chain is the same as all rotaries from the FC.

As I have said before even the FD uses the same SG Bearings, Including Rotor Bearings as the RX-8.

From the Oil Pumping aspect, for all FD RX-7's the oil pump parts were the same.

The only difference to the FE1031 RX-8 (S1) are the OIL Pump 'Rotors' by Part Number, but they use the same oil pump shaft as the RX-8 S1 and FC, same oil pump chain, mounting bolts, etc, so I am pretty sure the FD pump would fit on the S1 RX-8, the actual design of all these components are the same.

I don't have an FD Service manual to check/compare the Oil Pump's PSI pressure.

Even the FD uses the same BY Pass Plunger (0221-14-115) as the RX-8 S1, EPC shows the spring but NO Corresponding Part Number?, I am assuming it is 0221-14-116, but it may not be.

As we know the FC RX-7 which is the originator of N326 model code for Mazda Part Number uses the exact same Oil Pump and Valves in the FE1031 RX-8. The FE1032 RX-8 (S2) has an all new high pressure oil pump, but even the oil pump chain is the same as all rotaries from the FC.

As I have said before even the FD uses the same SG Bearings, Including Rotor Bearings as the RX-8.


Good info... What kind of oil are the majority of the FD guys using?

Good info... What kind of oil are the majority of the FD guys using?

On Castrol Australia's website a 15W40 is recommended....not sure what the factory manual says, I think it would be around this mark.

This was the grade we used at our Mazda dealership when the FD was out.

Isn't it generally accepted that this will result in dilution problems?

Sitting idling is not a good way of warming an engine up, there's not enough heat to thin the oil out quick enough, you need a balance - light throttle openings and 2-3krpm until the oil is warmed through.

Really, so I guess I should drive around the block then for that time period? I learn something new everyday. I will research.

Good info... What kind of oil are the majority of the FD guys using?

the question should be --- What kind of oil are the majority of EARLIER rotary guys are using ?

5w20? u gotta be f-ing kidding me.
5w30? maybe if you hate your car.
xxw40? bare requirement.
xxw50 or higher? if you love your rotary.

20w50 here btw :)

xxw50 or higher? if you love your rotary.

20w50 here btw :)

So when are you switching to a straight 50 weight?

after he installs the oil pan heater

So when are you switching to a straight 50 weight?


Maybe whenever all the previous rotary owners have proven it through the test of time.;)

Really, so I guess I should drive around the block then for that time period? I learn something new everyday. I will research.

If you're headed someplace, no need to drive around the block. Just take it easy on the first part of the trip. :)

If you're just moving the car, like pulling it out of the garage to wash it, then you'd be better off driving it around the block rather than letting it idle til warm.

Ken

My 3c worth. After reading thru this entire thread, it's obvious there's a lot of info info here sort of distilled from so many threads before. Still, much here is based on speculation or 'assumptions' about oil and how it works, plus a little bit of comment based on actual experience and tear down. But strangely as far as I saw only a couple people mention (or comment on) the importance of the intrinsic quality of an oil to start off with.

This factor of basic importance is one shrouded in mystery as oil companies seldom offer up their additive formulations. But regarding pressure discussions, engine oil quality has an impact, as viscosity effects pressure. It's not all about synthetic vs dino oil, but it does seem to end up that way. Why?

1. Synthetic oils don't depend on viscosity additives much if any at all. Viscosity stays stable over oil usage lifetime, where dino oils require additives and degrade and loose viscosity flexibility with use as these dissipate. If viscosity matters, synthetics are plainly superior over their useful lifetime.

2. The more additives in an oil, the less oil there is there to lubricate. Multi-V Dino oil depends on large amounts of additives to maintain its very nature. Less % true oil means less lubrication.

3. Superior oil film shear strength is THE defense against engine wear. It's what engine oil does 1st and foremost, followed by heat removal. Yes, pressure moves the oil, flow rate cools the engine, but the oil with the highest film strength keeps metal surfaces apart best, cold or hot, high or low rpm....and wins in fighting engine wear.

5. Accumulating deposits, particles, acids, water, etc. in any oil eventually will degrade oil's ability to do it's work. As it's so difficult to judge this, error on the conservative side of oil change intervals is the smart choice. And do it with an oil that has designed in, not added on, superior and stable properties from start to finish.

Sum it up and the more additives in an oil (typically dino oil), the quicker it looses it advertised properties for wear, viscosity, film strength, etc., due to use. I know only one (maybe two) oils that highlight these factors specific to the needs of a rotary engine, and they're both synthetic. I would offer that we could debate the theory of oil...viscosity, flow, pressure [thread topic], film strength, etc., forever, and perhaps reach conclusions....but all of that it pretty much a theoretical discussion of the dynamic properties of viscous fluids.

It's the quality that counts, start to finish. If the quality of the product flowing though the engine is subpar, or doesn't have originally or is depleted of the correct additives, is dirty with suspended particles and chemical compounds, then all the pressure or flow possible isn't going to stop wear in the engine.

So when are you switching to a straight 50 weight?

If I live in places like Florida or AZ or Hawaii :)

after he installs the oil pan heater

That too :mdrmed:

Maybe whenever all the previous rotary owners have proven it through the test of time.;)

Thats one thing.

but the biggest reason is that I dont have a reading/understanding problem(disability?). unlike some stubborn people in this forum, at least I understand "recommended != required."

and I just love seeing people who cry out loud all the time about "omg Mazda recommend you to use #####,"

but the next minute he/she took his car to the local Auto shop to do whatever it needs to be done.

for some reason he/she can see the part he likes in the manual, but then he/she totally misses out the part that Mazda recommend all work to be perform @ a Mazda dealer.

Funny :)

My 3c worth. After reading thru this entire thread, it's obvious there's a lot of info info here sort of distilled from so many threads before. Still, much here is based on speculation or 'assumptions' about oil and how it works, plus a little bit of comment based on actual experience and tear down. But strangely as far as I saw only a couple people mention (or comment on) the importance of the intrinsic quality of an oil to start off with.

This factor of basic importance is one shrouded in mystery as oil companies seldom offer up their additive formulations. But regarding pressure discussions, engine oil quality has an impact, as viscosity effects pressure. It's not all about synthetic vs dino oil, but it does seem to end up that way. Why?

1. Synthetic oils don't depend on viscosity additives much if any at all. Viscosity stays stable over oil usage lifetime, where dino oils require additives and degrade and loose viscosity flexibility with use as these dissipate. If viscosity matters, synthetics are plainly superior over their useful lifetime.

2. The more additives in an oil, the less oil there is there to lubricate. Multi-V Dino oil depends on large amounts of additives to maintain its very nature. Less % true oil means less lubrication.

3. Superior oil film shear strength is THE defense against engine wear. It's what engine oil does 1st and foremost, followed by heat removal. Yes, pressure moves the oil, flow rate cools the engine, but the oil with the highest film strength keeps metal surfaces apart best, cold or hot, high or low rpm....and wins in fighting engine wear.

5. Accumulating deposits, particles, acids, water, etc. in any oil eventually will degrade oil's ability to do it's work. As it's so difficult to judge this, error on the conservative side of oil change intervals is the smart choice. And do it with an oil that has designed in, not added on, superior and stable properties from start to finish.

Sum it up and the more additives in an oil (typically dino oil), the quicker it looses it advertised properties for wear, viscosity, film strength, etc., due to use. I know only one (maybe two) oils that highlight these factors specific to the needs of a rotary engine, and they're both synthetic. I would offer that we could debate the theory of oil...viscosity, flow, pressure [thread topic], film strength, etc., forever, and perhaps reach conclusions....but all of that it pretty much a theoretical discussion of the dynamic properties of viscous fluids.

It's the quality that counts, start to finish. If the quality of the product flowing though the engine is subpar, or doesn't have originally or is depleted of the correct additives, is dirty with suspended particles and chemical compounds, then all the pressure or flow possible isn't going to stop wear in the engine.

I agree!

..and we have to know that a 5w-30 full syn oil comes from 30w oil, but a 5w-30 dino based oil comes from 5w oil, so if a full syn 5w-30 loses its additives it will stay in the 30w range, but if a 5w-30 dino based loses its additives, it will close to the 5w range, and will be too thin at working temp.

Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.

Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.


I am seriously considering this. Just don't know of I wanna do it on the stock pan or an aftermarket one.

Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.

Wouldn't the more critical place be to read temperature of the oil that's actually going into the motor?

Wouldn't the more critical place be to read temperature of the oil that's actually going into the motor?

Where would that be that we could put a typical oil temp sensor?

Someone needs to install an oil temperature gauge in the oil pan. Temps shouldn't exceed 250*F there which is pretty damned hot. Any reference cSt at 100*C will be even thinner at 250*F. This is actually the most relevant place to monitor as it tells us what the oil is getting up to where it counts.


Doesn't the oil head to the coolers from the oil pan before doing it's lubrication/cooling duties? Or are you suggesting monitoring the highest oil temps to determine if it may be breaking down (does it break down with heat, or only contaminants?)

The highest temps are what is important. The oil can only absorb so much heat going through the engine. If the oil in the pan averaged 250*F but the oil entering the engine averaged 210*F, we can see that the coolers can dissipate 40*F worth of heat. More importantly the highest temps of the oils can tell us how thin our oil is really getting where it counts. It's not hard to see that if we increased our oil cooling ability so that it could enter the engine at 200*F, the temp in the pan should go down a corresponding amount. To me what matters is max oil temps in the engine. What it is going in shouldn't really matter as long as it only gets so hot max. The oil should not be allowed to exceed 250*F max. That's an arbitrary number of course as it can go hotter but understanding that it will also break down faster. That is the number that Mazdacomp recommends as a max as measured in the pan.

So then the pan is where it is hottest the right?

No, the bearings/rotors is where it's hottest, it'll cool down a little when it gets to the pan, but not much.

so then an increased capacity oil pan + water injection onto the oil coolers, + oil pan heater + 50 weight oil + filter magnets + premix = no more problems? Seems to me like these would all help with the problem.

Maybe just a higher displacement oil pump would do?

(edit: BTW, I'm becoming more and more a believer in the filter magnet thing. ordered some and will be popping them on there @ my next oil change (hopefully early next week)

I will have to look for a bung to have welded for the oil temp sending unit.

The highest temps are what is important. The oil can only absorb so much heat going through the engine. If the oil in the pan averaged 250*F but the oil entering the engine averaged 210*F, we can see that the coolers can dissipate 40*F worth of heat. More importantly the highest temps of the oils can tell us how thin our oil is really getting where it counts. It's not hard to see that if we increased our oil cooling ability so that it could enter the engine at 200*F, the temp in the pan should go down a corresponding amount. To me what matters is max oil temps in the engine. What it is going in shouldn't really matter as long as it only gets so hot max. The oil should not be allowed to exceed 250*F max. That's an arbitrary number of course as it can go hotter but understanding that it will also break down faster. That is the number that Mazdacomp recommends as a max as measured in the pan.

The problem is that you're assuming the cooling capability of the oil system remains static through the whole process which we know isn't true. Oil cooler capability is influenced by driving speed so you could easily see 250 degrees in the pan but lose much more heat than that before the oil enters the motor.

You could, in theory, see static temperatures in the pan but have variations as the oil enters the motor. Would you suggest tapping coolant temperatures at the thermostat or inside the radiator?

Arguing about temperature is a dead end. The majority of RX8 owners have no idea what their oil temperatures are. If you want to increase your cooling capacity simply open up the space behind the coolers. I'm missing my passenger side mud guard at the moment and I have problems with oil even getting up to temperature.

so then an increased capacity oil pan...

No no no. Increasing the pan size is not the answer and will only result in you shelling out big bucks for your oil change. Adding 3 or 5 quarts to the oil system will only delay the inevitable. Plus, with more oil in the system it will take a much longer time to cool due to oil not shedding heat as easily as water. That and the fact that it will take a seriously long time for your oil to come up to temperature.

The GReddy oil pan increased your oil capacity because they designed it to work with their turbo system. Since you have now added another oil using device to the mix they balanced out the capacity to compensate.

Aside from the OMP issues, the oil system is perfectly fine. Knowing what your oil temps in the pan are is about as worthless IMO as knowing what your temps are inside the coolers. The only thing that is important is knowing the temperature of the oil going into the motor.

No, the bearings/rotors is where it's hottest, it'll cool down a little when it gets to the pan, but not much.

The oil has got about 8" of free fall within a very hot environment to cool down in. I don't think it's giving up a measurable amount of heat in that time.

The problem is that you're assuming the cooling capability of the oil system remains static through the whole process which we know isn't true. Oil cooler capability is influenced by driving speed so you could easily see 250 degrees in the pan but lose much more heat than that before the oil enters the motor.

I know it changes through the coolers depending on airflow through them. The worst case scenario should be 250*F. It shouldn't be a target to aim for. If we top that at idle but nowhere else, we know that we need to find a way to gain airflow through the coolers at idle. If it's fine at idle but at high speeds and rpms the oil gets too hot, we know we need to beef up the coolers or make efficient ducting to them. The oil isn't going to get too cold. The thermostat will ensure that.

So then the pan is where it is hottest the right?

Not quite but close. It is either hottest in the rotors or the bearings. When the oil leaves these areas, it drains straight down into the pan which is only a distance of a few inches. That's the first location after it gets collected into one area that we can get a temperature reading from and it is as close as we can get to the hottest parts of the engine. It's definitely close enough.

A problem with monitoring temps going into the engine is that we have no way of knowing how hot the hottest parts of the engine are getting to. What if oil entering was at 200*F but oil in the pan was 300*F? This isn't the case but how would anyone know. Average temps will fluctuate anywhere in the engine with changes in cooler efficiency regardless. The only difference with taking a reading from the pan is that we will know the highest temps and that is what matters. We can't determine that anywhere else.

The oil has got about 8" of free fall within a very hot environment to cool down in. I don't think it's giving up a measurable amount of heat in that time.

However it's cooled by the mass of oil it land in in the pan, which is cooled by the engine block + the surface area contact with the pan, like I said, it is slightly cooler than the peak, we've got sensors both before and after the oil cooler, but none in the pan yet, might fit one and see.

If you do, watch what happens when you drive at 4-7krpm, and then what happens when you drive at 6-9krpm, it'll certainly show you how much extra heat is there...

or just control the overall temps and the oil temp will follow? Anyone ever seen a 200F coolant temp and an oil temp of 230-240F? i know on my car it isnt but maybe someone else has this?
OD

I think we can come to the conclusion that everything between Mazda's NA (Naturally Aspirated) Rotary Engines used in the Series 1 RX-8 and the 1985-1989 FC RX-7 are the same, Engine and Rotor Bearings, Oil Pump and oil pressure, Oil Filter and Engine By-Pass Valves plus anything else that distributes or sprays engine oil for Internal Lubrication are the same when engine reaches "normal" operating temperatures..

Therefore there are only 3 other "Design Features" and Parts that are not the same.

1. Oil Recommendations (Viscosity/Temperature Range) listed in Owners manual.
2. Oil Coolers.
3. Length of Oil Cooler Lines.

************************************************** ************

So going into more detail...

1. I will leave this subject matter alone, been done to death.;)

2. The FC RX-7 only has ONE Oil Cooler, and that is a small one in height that is fitted directly under the cars Radiator which matches the same radiator width.
Keep in mind the "Cooling Air Flow" is constant/variable via a Viscous Bladed Cooling Fan running off the engine via a belt.
The RX-8 (in most cases) manuals had two Oil Coolers at the sides and front (under Headlights) with no cooling fan assist.

3. RX-8 has "Longer" Oil lines and twice the number of these longer supply and return Oil Lines, 4 for RX-8 and 2 for FC RX-7.

************************************************** **************

To put it simply, as we know the longer say a "Garden Hose" is in length the less pressure or water volume will move or "recirculate", apply this thought crudely to a cars Oil Pressure and Oil Cooling System.

So, does the RX-8 suffer from not enough oil pressure or flow through the oil coolers because of the Oil Pumps capacity?..I would say... yes.

The Series 1 RX-8 is the first time Mazda had installed 2 Outer and Front mounted Oil Coolers without increasing the Oil Pumps capacity or output or pressure!

The ONLY other export Mazda RX- to have two Oil Coolers in a similar layout and design to the RX-8 was the 1992-2002 FD RX-7, BUT, the FD RX-7 (Turbo) has a Different Oil Pump, and a Different Oil Pressure Regulator Valve Spring.
The FD RX-7 uses the same Oil Pump as the FC Turbo RX-7.

BUT the FC RX-7 Turbo and FC NA keep the same Oil Pressure Regulator (same in the S1 RX-8) and has the same single Oil Cooler under the Radiator, plus the FC RX-7 Turbo has an additional "Electric" Cooling Fan and Motor mounted on the other side of the radiator.

So my conclusion...Mazda really stuffed up in the Series I RX-8.
There is just not enough oil pressure or oil volume circulating through the entire engine/system for oil lubrication and oil cooling.

The solution??, while practicality and cost wise S1 RX-8 owners can not migrate or install the different Series II Oil Pump System, But, you could change the By-Pass Regulator inside the Sump Pan which is located on the rear Iron Housing to the one used on the FD RX-7, and or modify the Regulator spring so it will hold Oil Pressure Longer before the By-Pass Valve Opens..

Please GUYS, I am not trying to put Dirt on your model RX-8...I love them ALL..

But again, I am trying to find a solution that may help improved reliability.

It would be interesting to know if MNAO's re-man plant are changing oil pumps or valves....they should be...at the very least change over to the FD and FC Turbo Oil Pumps.

HMMMM. Anyone have pis of the oil cooler feed and return lines readily available??

HMMMM. Anyone have pis of the oil cooler feed and return lines readily available??

Here you go, this is the best I can do, from parts manual... ( see RED Lines)

One is of FC RX-7, the other FE RX-8 (S1)...:wink2:

http://www.rx8club.com/attachment.php?attachmentid=146934&stc=1&d=1255667125

http://www.rx8club.com/attachment.php?attachmentid=146935&stc=1&d=1255667125

Thanks. So, the feed and the return are on the same side of the block as the spark plugs?

or just control the overall temps and the oil temp will follow? Anyone ever seen a 200F coolant temp and an oil temp of 230-240F? i know on my car it isnt but maybe someone else has this?
OD

I have seen this but it was due to my cooling system working much better than the oil coolers were.

Last time I seriously overheated my oil temperatures (around 240 degrees) it was on one of the canyon runs here in Phoenix. Very tight turns so I spend most of my time in upper 2nd gear and 3rd gear.

I let off seeing 240 degrees and my water temps came down right away. Oil, as usual, was heat soaked.

Thanks. So, the feed and the return are on the same side of the block as the spark plugs?

YES, the OIL feed is via a Banjo fitting line bolted to the left lower side of the front timing Cover..oil is fed by the Oil Pump.

The Return comes back on the same left side of engine and this line/hose connects just under the Oil Filter Body Alloy Neck.

Should I go out and take a pic of my FC's oil cooler lines or something ? :)

So my conclusion...Mazda really stuffed up in the Series I RX-8.
There is just not enough oil pressure or oil volume circulating through the entire engine/system for oil lubrication and oil cooling.

The solution??, while practicality and cost wise S1 RX-8 owners can not migrate or install the different Series II Oil Pump System, But, you could change the By-Pass Regulator inside the Sump Pan which is located on the rear Iron Housing to the one used on the FD RX-7, and or modify the Regulator spring so it will hold Oil Pressure Longer before the By-Pass Valve Opens..

Yes, yes, yes. I think the same for about a month.

We have to increase the MAX oil pressure. Maybe our pump has the higher pressure possibility, so enough to change the bypass valve, valves. It's not enough if we want to force the AVERAGE oil pressure (flow). In this case we have to change the pump itself.

...and we have to plug in the e-shaft's draining holes (at the pellet) , to shorten the time while the oil flow builds up in the bearings, after startup.

or just control the overall temps and the oil temp will follow? Anyone ever seen a 200F coolant temp and an oil temp of 230-240F? i know on my car it isnt but maybe someone else has this?
OD


Yes.

Had coolant at 95*c (~200F) and the oil heading past 120*c (250F) regularly when we were on the same size coolers as a stock car, which is what I was referring to earlier for someone with a temperature gauge to watch what happens if you start driving in the 6-9krpm range instead of the 4-7krpm range.

When we we're just on test and short-shifting at 7krpm, the oil temps would sit in line with the coolant at 200F, even with full throttle, as soon as you start using that last 2krpm, they shoot up faster than an eagle with a Saturn 5 rocket up its arse.

interesting on the coolant/oil temps relationships. Those that have seen this range were all doing the driving that we all like to do:)
I know that the corvettes all see 250F oil temps on the track without any concern--so the oil itself seems to be able to take it ?

Ash--once again you are the man. A real parts man to point all this out and offer possible solutions. For anyone doing a rebuild the 09 oil pump would be a good choice.
So in essence we have figued out why Mazda increased the oil supply/ flow for the 09--.
The clearances are basically the same as earier models? And they recommended 5/20w oil.
Much more distance involved resulting in decreased pressure?
E shaft oil supply could be better?
Who at mazda did this --its just common sense!!
Glad I have a Rick E engine who has done some work on this.
Damn good info.
OD

It's going to be even hotter than that when it's passing through the rotors and bearings though - my sensors are only before + after on the oil cooler.

It really does all point to simply not enough oil flow through the system, if the '09 pump fits, I'd be going with you two and be fitting one on a rebuild for a standard car.

I think we're getting away with it because we're cooling the oil so far before it gets fed into the engine, frequent changes and using decent synthetics. Band aid solution, as it were.

Well... if film strength is what's separating the bearings (it is) and the heat of the engine is going too high and breaking down the oil (which, it also is) then a higher viscosity synthetic + premix + increasing OMP rates (or, using a sohn adapter, ideally) should be sufficient to solve most of the problems. When the oil breaks down, it'll still have better film strength to keep the bearings apart than if we used straight 5w20, and the synthetic won't break down as quickly as the dino oil. The thicker oil will have a tougher time getting past the OMP nozzles, so increasing the OMP rates and using premix would be a must. Ideal fix would be to put a higher displacement pump in, as that would prevent cold start issues too. Too bad we don't really have that option at the moment

The higher viscosity will help, because when it's breaking down it's still going to be somewhere near the viscosity you actually want - but if the breakdown is due to heat, then be aware that many of the additives will be mullered by then anyway, the surfectants especially.
I'd see what sort of temperatures you are getting on the oil entering the engine and see if there's anything you can do there too.

still you need the proper amount of oil to get to the places requiring lubrication and cooling. It cant do its job unless enough of it is there? We need more volume of the proper oil? Right?
The omp is volume driven--viscosity does not affect it.
Premix is a different animal because its deliverly system has to go through smaller filters and the fuel system/engine is sensitive to pressure changes?
Now i am dizzy and have to set down.
OD

Ideally you'd want a pump delivering more oil full stop, yes.

However it's cooled by the mass of oil it land in in the pan, which is cooled by the engine block + the surface area contact with the pan, like I said, it is slightly cooler than the peak, we've got sensors both before and after the oil cooler, but none in the pan yet, might fit one and see.

You are WAY overthinking this. Show me a hotter place to measure the oil at. I'm willing to bet that any heat lost from peak temps to the oil pan are within 5*F. Not enough to matter. The oil pan isn't holding a swimming pool worth of hot oil. It is collecting it so it can recirculate. Yes you lose a little heat there through the pan itself but overall not much. The higher the rpms, the faster the oil gets circulated and the hotter the temps will be. Measuring temps after the oil cooler doesn't seem to make sense. Measuring it at the hottest point possible to get a reading, which is the pan, does.