ASH8

Well if you are rebuilding a rotary and the stationary gear bearings are worn down to the copper and beyond, would you put them back in if they were even "withing tolerances", I am trying to recall if "Mazda" even has a tolerance range for these standard size bearings, in most cases (all I have seen) if there is ANY wear they are renewed.

I have seen many Old engines in the old days done as many or more miles than most RX-8's and their bearings are like NEW...not a single mark or scratch....EXACT SAME BEARINGS USED TODAY in Renny.

Ask Mr. E at Mazmart or Paul...Don't like what they say...??

I would put Mr. E's views and recommendations over anyones here (including my own) because he does them, he sees them, he re-builds them more times than anyone else here.

IMO the Bearing Wear is either 3 issues, OIL, Oil Pressure and OIL.

That is owners not renewing oil often enough, particularly when the RENESIS holds back more stale old oil than any other rotary EVER before.

OIL Viscosity....if you believe or want to believe that it has no BEARING (sorry no pun) on the matter...then fine...

However, like RG originally stated (this is his line of employment) that these bearings look like they are starved of oil, so if all the indications are what they are, it appears there is not enough oil pressure (Volume) in the e-shaft, in other words the Rear by pass valve is by passing oil 30-50 PSI too early or lower than it otherwise should be....

This is what I am leaning to.

ASH8

Sorry about that.......your son etc...

Yes and Mazmart say something different again about OIL, and they build engines too.

Frankly, I really don't give a toss what OIL you put in as long as you RENEW it Regularly...

kennyfrc1

iTrader: (6)

I change mine every 1500 miles.............

olddragger

iTrader: (3)

and does oil analysis about as frequently!! You go dude!

The bearing wear i have seen is not all over the bearing, its not uniform---it is one area of the bearing--Paul describes it as being in the power pulse point of the engine. Now if the clearances of the bearing is not uniform then that is an automatic replacement in my book.
Running a bearing like that will cause an out of balance condition--you wont be able to feel it, but in time you are going to have probs.
Besides I cant imagine cracking an engine and NOT replacing the bearings during a good rebuild.
I am with Ash on this.
OD

Flashwing

If the rear bypass valve is opening too soon then do you think that increasing the viscosity (and thereby increasing pressure sooner) is the solution? You'd want as much flow as possible to limit the amount of oil that is being sent through the bypass.

Nowhere in my post did I say that viscosity has no importance on lubrication. What I did say was the following:

That's the whole basis for this thread correct? The fact that a UK motor was using 5w-30 and there were signs of serious wear...case closed.

However, what questions have we asked regarding the motor in question that cannot be answered?

How long did the owner go between oil changes?

What kind of brand/type of oil was used?

I would suggest talking to Mazdamaniac and asking him about his power outputs and overall impressions of his "junk yard" motor that Charles Hill put together for him. Ray measured every inch of that motor and the stuff that was within tolerance was slapped back together. We used mismatched side seals, used apex seals and the like. The only new part of that motor is the oring kit.

The whole drum beat of my argument is for the lonest time (myself included) the people of RX8club chanted that Mazda was totally off base with their oil suggestions. While I don't think that 5w-20 is the answer, I don't think using the thickest stuff is the answer either. I think using something in the middle (depending on how you use the car) and proper testing will give you the best results.

I put my money where my mouth is. I'm running 0w-20 in my own car. If anyone on here think viscosity is the only thing that matters, and you believe that startup wear doesn't happen then go buy straight 50 weight oil and run that in your motor. I doubt a single one of you will do that.

olddragger

iTrader: (3)

i do think that too many people use viscosity and film strengh as being the same.
It is a rough coorelaton (spelling) but not exact. However roughly speaking you will get a better film strengh from a heavier viscosity oil. And as I have always believed "dont fix it if it is not broke" the heavier vis oils have been proven through the years by a number of pros that have no direct gain from sharing that info. nuff said.
If a lighter oil will work then it will take time for those people (including me) people to believe it. Maybe its possible-- i dont really know but I am sceptical?
What some of us think , including me, is that you need more oil flow with a better film strengh oil. (higher vis).
OD

ASH8

Flash, read it again...
Fruchs 5W30, and the owner said he regularly Serviced his car..

Every Re-man engine going through MNAO plant is having Brand New Bearings fitted because they are OK....and they re-use the Rotor Housings and Replace the Rotors!!???,
Too bloody lazy to clean them, if unmarked rotors are Reusable??

Your bearing comeback...'''" as a precaution""...

ASH8

Agree,

Flash... at the start of this (My) thread, I had not investigated the parts Mazda are using in the REAR Sump By Pass Valve or FRONT Oil Pump Control Valve, everyone (many) here who have Oil Pressure Guages have been saying'.. "I get really low OP numbers..blah..blah" yes they are reading it after the oil is by passed as it goes into the oil filter.

Yes, there are slight OP differences with oil weight and engine temps, however as I have said it is the volume or oil pressure flow IMO is now the issue, or Not enough Oil flowing into the e-shaft to lube Bearings, etc.

As I said in the other thread of mine Mazda are using an RX-4,5,FC 7, Rear By Pass Valve assembly that is 30 years old, at the front an FC Oil Pump (28 yo), with and RX-2 (38 yo) Oil Pressure Control Valve, BUT, with a S1 RX-8 a specific SPRING for Oil Pump Valve, is this spring an upgrade to higher or lower by pass???
Know one really knows, somehow I think Mazda Figures could be in error?.

As the guy from Pineapple said if you change the By Pass Pressure in the rear (Which Mazda have not done) you must upgrade the front Control Valve (which Mazda may have done)....so there is a possible mismatch.

I could also say Mazda are using 30 year old parts that used to run High Viscosity Oils with now todays "New" oils....good recipe???

So, yes now after my investigation I am leaning more to changing the Oil Pressure units at both ends to lift it 20 or 30 PSI....more oil flow to those bearings, Rotors...

You??

madcows

Unfortunately, none of will probably ever have any data regarding whether a lower flow volume of higher viscosity (and ideally, higher film strength) oil would be more beneficial than lower viscosity at a higher flow rate in the renesis and vice versa.

Common sense would suggest that a higher viscosity oil at low rev ranges (and therefore, below the bleed-off pressure of the valves) would provide better protection than a lower viscosity oil. After all, we don't even know at what RPM range the damage is being done! It could very possibly be in the lower band.

-rotarookie

ASH8

I can only go by what Mazda installs in their Rotaries, and as I have said before Part Numbers Never Lie..

When you consider that all the parts that control Oil Pressure or By Pass Pressure(s) or Oil Pump and the Rotor Bearings and Stationary Gear Bearings and Oil Jets for Rotor Lubrication and Oil Filter are between 20 and 35 years old in the RX-8 RENESIS 1, the only thing that has changed are the "recommended" Engine Oils and 1 small Oil Pump Pressure Control Spring.

And that Mazda revised and replaced components that control ALL of the above in the 09 RENESIS 2, one can come to their own conclusion as to Why?

Many of us have a pretty good idea Why.

And there are relatively simple DIY procedures to improve Lubricity if you own a Series 1 RX-8.

olddragger

iTrader: (3)

and actually doing the mods does not hurt anything!
OD

ASH8

Agree again OD!..

In the end I am trying to 'contribute' and help, not criticize ANYONE who has constructive ideas...rather than ignorant swipes..

Why am I bothering...I own an 09.?

What I would like to see is Someone take on board what I have shown (as in the Actual Mazda Parts Used) and test this out... if I had a Series 1 I would not hesitate.

What I can't understand is why MNAO are not doing "Anything" in regard to Oil Pressure in the re-man engines (had this from a former 'active' club member), so why not for the sake of a $5 part?

Mazda changed the Oil Pressure circuit in Renny 2's for a reason.

IMO I think the Stationary Gear Bearing damage is being done at a high RPM.
As you said OD 1000+ RPM's higher than any other production Rotary with the same Oil Pump, Bearings, Oil filter and Pressure/By Pass Valves used over 25 years ago.

Yes, Oil types have moved on, but the Oil Circuit in Renny 1 remained unchanged.

Apart from one little Oil Pump Pressure Control Spring.

Remember at 8-9000 RPM you have the same Oil Pressure into the Eccentric Shaft which an FC RX-7 had 25 years ago, but the RPM limit was 7750-8000 RPM, with 20W50 oils (recommended), not 5W20.

nycgps

iTrader: (1)

sad thing is that people are too ***** about using 20w50, keep throwing that start up lubrication blah, doesnt flow as good blah, higher temp blah. Well, I dont buy that. Cuz my gauge tells me something different.

yeah Im on my 2nd engine, so? Mazda messed the ECU up, my engine got toast. Its not oil's fault. Now I expect my engine to last at least 3 times the life of my original one (150K) with 20w50. hmm its 40-50 degrees today, but a good Synthetic would be ok even at 20-30f. so yep Im sticking with RP/RL's 20w50, and M1 15w50 all year long

slidey

The mileage works out roughly 11500mls a year, on the Uk mazda service plan the car should be serviced every year or 12500mls, so it's had approx 5 oil changes if the car has been serviced by mazda, also in the uk the first oil change and first service is 12500mls, so no oil change after being run in. I think the oil is fine it's the service life that's to long.

dave

Flashwing

This is why I'm curious as to what the owner defines as "regular service" on their RX8.

ken-x8

What is it about startup lubrication that's blah? That's where a large part of engine wear occurs.

What does the gauge tell you about startup lubrication? When I've had cars with a real oil pressure gauge, the gauge told me two things:

1. Whether the oil was warm, by the pressure at idle being low

2. Whether the engine had blown, or was really low on oil

I had the interesting experience of replacing a stock oil pump pressure relief spring with a stiffer one. To my surprise, it did not affect hot oil pressure. It did affect cold pressure, but once the engine warmed up the pressure was apparently controlled by bearing clearances.

Ken

olddragger

iTrader: (3)

did you modify both regulator? Or only one? If you do just the front one it will not affect oil pressure readings taken at the oil filter. if you did both or just the rear then that means the pump is at capacity and we are sol.
OD

nycgps

iTrader: (1)

All I know right now is that, people getting screwed by 5w20 and even 5w30. It could be the pressure being too low for the Renesis. But lets not forget most people probably never even rev their engine high but still got that bearing wear. so, what does that mean?? "recommended" oil weight is not good for this engine.

So far no one use 20w50 all the way. I dont mind to be a lab rat. I know how oil works. Your engine still "feel fine" and "Start" does NOT mean that your engine never had any pre-mature wear.

Plus In my opinion, the start-up wear is greatly exaggerated. each to their own?

Im a maintenance freak (I guess ppl most ppl should know) and my original engine still got pwned. It could be a bad build from factory, it could be just bad luck that some parts inside decided it should go heaven faster than it should, who knows? All I know is I keep oil change every 1.5-2.5 K, my engine has no carbon (decarb couple times, even tried ATF), Coolant change as much as 3 times this year(trying out coolant brands), Last year twice(right after and before the next winter), still died.

So how many people out there are driving a dying engine around right now? There is almost no way to tell if your engine is "dying/slowing down" from butt dyno.

Since I got a reman engine, I have no idea what part is new and whats re-use. but I will still open the engine up after 50 K miles (3 years of time) and check the internals. then we'll see what happens.

madcows

+1

Another question is have you used various oil viscountcies before and after? For instance 5w-30 before and after the mod, but also something like a 15w-40 before and after as well?

ASH8

?, Ken, If you only changed the OIL Pump Pressure Reg (Front) and not the Rear Valve, then it would make little to no difference as you have to modify the rear valve also.

Without the rear one altered the "higher" oil pressure is just by-passing before it goes through oil filter and e-shaft.

Direction of Oil Flow goes from front Oil Pump- Pressure Valve, then Oil Coolers, then Rear Valve, Oil Filter, lastly Eccentric Shaft from Rear to Front and then out of shaft (At Front Heat Pellet) back into Sump Pan.

Where are you taking Oil Pressure Readings from?

ASH8

Yeah, I get you mate, even if many don't....

After comparing almost every single part in all rotaries made in the past 40 Years with the RENESIS I am certain theses wear issues are...

1. Oil Pressure Related (and Higher RPM). (Hence Series II Upgrades)
2. Engine Oil and frequency of Oil Changes (remember for most owners nearly Half of the old stale Oil is reused!, because of extra and larger Oil Coolers and Longer/Extra Oil Lines (piping) holding back more stale oil than ever before.

IMO, MNAO should be upgrading the Oil Pressure "system" to at least FD specks in their re-man RENESIS 1's (110 PSI rear By Pass, not the pissy 60-70 PSI).

Because this wear issue will only appear again.

ASH8

Yes Dave, I agree, the UK service intervals are WAY too far apart, 20,000 KMS is ridiculous, I understand Mazda and others have aligned themselves with brands like Renault, Peugeot, Citroen who have this longer service interval.

Imagine the "quality" of the engine oil after 20K, particularly the short distances you Englishmen travels when compared to the US and Australia or South Africa.

I would suspect many RX-8 owners would hardly get their engines up to Full operating temperature.

Please, I am not saying all you guys drive short distances but the size of the UK does not compare.

AS we know short distance driving is BAD for any rotary.

Having said that doesn't Mazda UK (Europe) recommend you change your oil every SIX Months?...irregardless of distance traveled?

bse50

1 year, irregardless of traveled distance in europe, dunno if it is the same in the uk but should be!

Ash, after 13 pages isn't about time to write some conclusions on what may be useful to mod and what not? I think that this is a very important discussion so having a good, incisive, post may help!

G

nycgps

iTrader: (1)

I wonder how Renault, Peugeot, Citroen, etc cars survive these oil change intervals. sure a "good" Synthetic should be able to last 20 KM. but .... argh. EU loves it I guess ?

slidey

Ash, at the back of the service book it tells the uk owners to change the oil every 12500mls or yearly, except if you do alot of town work or short journeys then change the oil every 6000mls. I would say most change the oil at 12500mls, not many people work on their own cars here in the uk, so it's down to the dealer yearly


dave