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Old 09-06-2005, 01:36 AM
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Originally Posted by Racer X-8
And they listened to him and took his advice. :p Oooh, now that's bad.

Was he an expert in the field of suicide bombers? Croud control? Darn...

But anyway, good thread, good info, and RG, your experience in the use of synthetic motor oils in rotaries and the experience that you found elsewhere and shared with us is very encouraging and I commend and thank you for that!!! It's just that the way ASH8's gracious contribution to this was treated, that he's an old-timer, set in his ways, that when it comes to the new technology, he don't know **** from shinola, made this thread a hard read.

I will unfortunately have to agree with your stance on Mazda's position. The corporate world which includes and controls their engineering almost always mantains many old-time stances on things of this type. Sure, Mazda has a zillion engineers and many of them surely do know more than all of us here combined on this very topic. It takes a long time for those in control to be convinced about these kinds of things though, and until they are convinced enough to do a corporate change, the change is not. That can take years after the people who know know, even after those who need to know in order to make the corporate change know. It's funny like that.

I wish I had a dollar for every time I was confronted with "Oh, that. We've tried that already, years ago, and it doesn't work, trust me." Yeah, well, how long ago was that? When you tried it, did you try it correctly? Lemme just try... "NO, I told you we tried it and it doesn't WORK!" Blah blah blah. Now, that is information you should NOT take freely, but there it is. It happens all the time.

I didn't sense that kind of mentality coming from ASH8. That's what has me going off like this. He was holding on to some old beliefs alrighty, but that's good. Get the old standards and show that they no longer apply. ASH8 should not have been compelled to feel ashamed to have put those old standards on the table here though. He didn't to me come off as closed-minded about it all.
Thankz
As I said before, I am not against Synthetic oils in "Normal" combustion (piston) engines at all.

I am still though against their use in Rotary Engine which use and burn oil for apex and side seal lubrication.

Until the factory (MMC Japan) agrees with the use of fully synthetic oils in their rotaries including the RENISIS, I will not use them.

BTW. Since 1978 the oil control "o" rings is the same material compound in ALL rotaries including the 8, and old replacement parts superceed to the new type when installed as a complete set with of course the oil control rings, therefore the warnings from the Factory (MMC JAPAN) about the possibility of long term damage to the 'O' rings when fully synthetics are used still apply and advice has yet to be updated by Japan.
Old 09-06-2005, 02:44 AM
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Originally Posted by ASH8
Until the factory (MMC Japan) agrees with the use of fully synthetic oils in their rotaries including the RENISIS, I will not use them.
They do. Go look at all of their race cars. Same seals.
Old 09-06-2005, 10:31 AM
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Originally Posted by nycgps
...After reading all these posts. I think I might switch over to Royal Purple. (where to buy it by the way, I live in New York, any online sites recommend?)...
Racing Beat http://www.racingbeat.com

I don't think you'll find better pricing for Royal Purple anywhere else. I tried myself a little while back anyway.

Get yourself some Max Gear Lube (75W90) for your tranny & rear differential while you're at it.

I don't see 5W20 for the engine there. Waddup wit dat?

BTW, for some reason, you won't find any listed for the RX-8. Click on the double-rotor image "Rotary Performance", then, click on one of the three licence plate images for RX-7's, NOT the RX-8. Then select "Oil System" from the pull-down menu.

Last edited by Racer X-8; 09-06-2005 at 10:39 AM.
Old 09-06-2005, 11:37 AM
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I'll post the engine viscosity links again...though everyone seems to blantantly ignore the links, and continue arguing without absorbing the information.

Quick summary...
1) Viscsotiy is not a measure of protection.
2) People yelled and complained that 30 wt oils weren't thick enough to protect when they first hit the market...now those same people complain that 20 wt oils aren't thick enough....
3) Most 30 wt oils on the market are 20 wt oils within 1000 miles of service. (They sheer down).
4) Some 20 wt oils on the market have higher HTHS numbers then 40 wt oils. (look up HTHS)
5) Thicker viscosity oils have higher oil temps then thinner oils.
6) Some vehicles specing heavier weight oils have shown drops in wear metals in UOA's when switching to lower weight viscosities.

Technology advances. You either adapt and absorb the new information, or sit back in the rocking chair..

I'll post the links again...maybe someday somebody will click on them.

http://theoildrop.server101.com/cgi/...=001235#000000
http://theoildrop.server101.com/cgi/...=001235#000000
http://theoildrop.server101.com/cgi/...=001235#000000
http://theoildrop.server101.com/cgi/...=001235#000000
http://theoildrop.server101.com/cgi/...=001235#000000
http://theoildrop.server101.com/cgi/...=001246#000000
http://theoildrop.server101.com/cgi/...=001251#000000
http://theoildrop.server101.com/cgi/...=001257#000000
http://theoildrop.server101.com/cgi/...=001266#000000
http://theoildrop.server101.com/cgi/...=001271#000000
http://theoildrop.server101.com/cgi/...=001279#000000
http://theoildrop.server101.com/cgi/...1;t=006127;p=1

Last edited by crossbow; 09-06-2005 at 11:42 AM.
Old 09-06-2005, 12:59 PM
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Ummm, the first link doesn't work (missing the . in the ultimateebb.cgi) and the next 4 all go to "motor oil 101" and the sixth goes to "motor oil 105.1"

I'm guessing the first 5 are each to take us to chapters 1-5? The rest of 'em work...

motor oil 101 = http://theoildrop.server101.com/cgi/...=001235#000000
motor oil 102 = http://theoildrop.server101.com/cgi/...;f=42;t=001234
motor oil 103 = http://theoildrop.server101.com/cgi/...;f=42;t=001233
motor oil 104 = http://theoildrop.server101.com/cgi/...;f=42;t=001232
motor oil 105 = http://theoildrop.server101.com/cgi/...;f=42;t=001236
motor oil 105.1 = http://theoildrop.server101.com/cgi/...=001246#000000
motor oil 106 = http://theoildrop.server101.com/ubb/...=001251#000000
motor oil 107 = http://theoildrop.server101.com/ubb/...=001257#000000
motor oil 108 = http://theoildrop.server101.com/cgi/...=001266#000000
motor oil 109 = http://theoildrop.server101.com/cgi/...=001271#000000
motor oil 201 = http://theoildrop.server101.com/cgi/...=001279#000000

and, not forgeting that last one, "Engine oil viscosity has VIRTUALLY NO EFFECT ON WEAR." = http://theoildrop.server101.com/cgi/...1;t=006127;p=1

Bob's search engine works great

Last edited by Racer X-8; 09-06-2005 at 01:43 PM.
Old 09-06-2005, 02:01 PM
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Ah thanks for correcting the links. I tried to cut and paste them from the previous two posts, but it seems the rx8 club forum code is just simplying the code...which is going to the wrong links. Thanks for fixing them!

Btw the guy writing the articles runs 0w-20 mobil1 in his ferrar 575M which calls for 15w40 I believe, and is getting better wear, mileage, and power, then other owners running the heavier weight oil.
Old 09-06-2005, 04:30 PM
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This whole debate, on both the oil weight and composition, is getting less important with every generation of the standards.

To meet the current (SM) standards, the oil has some base components that are severly hydrocracked, or synthetic. The FM components are mostly synthetic. The add pack is laced with moly, boron, or other components. These oils, even the -20 weights, will stand up to severe usage. The -20 weights may have started out to be a gas saving solution, but now are blessed with the most research and development, including synthetic, or near synthetic components.

Finding any type of mostly group 1 oil at the 5w-20 weight, and at even the previous SL standard, will be difficult.
Old 09-06-2005, 08:15 PM
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[QUOTE=crossbow]I'll post the engine viscosity links again...though everyone seems to blantantly ignore the links, and continue arguing without absorbing the information.
Quick summary...
1) Viscsotiy is not a measure of protection.

Nobody says it is. But you need a certain minimum viscosity (at the particular operating temperature, that depends on outside temp, radiators, engine type and RPM) throughout the life of the oil to prevent metal parts contacting each other. If they do, the engine freezes and dies - no need for UOA.

2) People yelled and complained that 30 wt oils weren't thick enough to protect when they first hit the market...now those same people complain that 20 wt oils aren't thick enough....

So the need for a viscosity modifier in any oil is a general scam?!? As well as OEMs recommending different grades for different driving conditions - something even Mazda does for Australia?

3) Most 30 wt oils on the market are 20 wt oils within 1000 miles of service. (They sheer down).

It is accepted in the test that a W30 oil becomes a W20 after few thousand miles. New oils do not drop from W20 to W10 though, so hold much better. But how do you know what you get at the dealer? Might be a good oil, or a cheap one (for them, you pay the same anyway).

4) Some 20 wt oils on the market have higher HTHS numbers then 40 wt oils. (look up HTHS)

If the W40 oil is really crappy, it could happen. But find an example when both weights come from the same brand and you see the reversed viscosities!

5) Thicker viscosity oils have higher oil temps then thinner oils.

True, if the cooling capacity is not enough or the oil pump is weak (or too far from the oil sump). But the questions is, at those temperatures, which one has higher viscosity?

6) Some vehicles specing heavier weight oils have shown drops in wear metals in UOA's when switching to lower weight viscosities.

Did they ever switched back to higher viscosity and seen again high metals? Were the two weights from the same company? As point 1 states, viscosity alone is not a measure of protection. Friction modifiers and moly take care of wear, in general.

And a point you did not address at all: if viscosity does not usually kills an engine, but deposits do, how does UOA looks at that? What if the great oil by UOA leaves lots of deposits behind? Unless you rebuild the engine and actually analyze the stuck parts, you'll not even know. The way to get it right: watch the particular oil brand for passing the Chrysler tests. Those are on top of API and ILSAC tests.
Old 09-06-2005, 08:43 PM
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See, now, that's why I just use what Mazda says to use. Wake me up when y'all come to a general consensus. As for me, I'm still trying to figure out why in general, if automotive internal combustion engines absolutely require an oil lubrication system (we all agree on that, right?), why, when, who figured out that they also need water as a coolant? Anybody ever try filling the coolant system with two gallons of oil? :o

Last edited by Racer X-8; 09-06-2005 at 09:08 PM.
Old 09-06-2005, 09:52 PM
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I have reached a consensus long ago. Royal Purple synthetic is what I like. There are zero issues with it whatsoever. None. Zip. Ziltch. Nada. Not even a hint of one. I also run 5W20. Remember I have RX-7's which typically run 20W50. No problems and I abuse the hell out of my engines. Theory and what is written on paper can't undo real world results.
Old 09-06-2005, 10:02 PM
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Originally Posted by rotarygod
They do. Go look at all of their race cars. Same seals.

Racing rotary engines are replaced after every race or every other race.
Even if the engine is rebuilt, oil control rings,o rings and springs are always renewed, even if they have had low Ks or use.

As I have said before its the long term use of synthetics is the concern for everyday owners....not race cars and teams, there are also many racers who will only use mineral 20w50 oils., even in Rx-8 racing.
Old 09-06-2005, 11:44 PM
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That's the most predictable and worst excuse I've ever heard. It's also untrue. Many of their race engines go entire seasons and sometimes multiple seasons without a rebuild. Why? Because they don't need it!

I've been using synthetics for about 7 years now in my rotaries. I didn't just change to it last month and start to praise it. Racing Beat and many others have been using them for far longer than I have with absolutely wonderful results. No issues. How long do we have to use them before they become "long term"? Is that not long term to you? I put over 100K miles on my old 2nd gen RX-7 engine after switching to synthetics. I even use 5W20 and not 20W50!
Old 09-07-2005, 07:44 AM
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As well as OEMs recommending different grades for different driving conditions - something even Mazda does for Australia?
This has as much to do with general supply as it does with environmental conditions. In certain countries there is a drastically larger amount of specific oil weights then other types. For example its nigh impossible to find a 20 wt oil in south america, it has to be imported...conversely, its quite easy to find a 20 wt oil in northern canada.

The southern countries have not had sufficent time to adapt to the relatively new technologies in the current generation of 20 wt oils, and thus the specifications reflect the mass supply of the oil in those countries (based on previous specifications). If south america required a 20 wt oil in the rotary, where would you get it? You'd most likely have to hit up a speciality shop, or import the oil...a manufacturer can't expect the population to do that in a consumer level car. (non exotic)

This of course is changing, which is reflected in the 06 manuals. In the mazda 6 one at least (05), countries outside the US are now spec'ing 5w-20.

But how do you know what you get at the dealer? Might be a good oil, or a cheap one (for them, you pay the same anyway).
I agree with this whole heartedly. You don't know what the dealer is using...or if they even use the oil that you give them. Thus one of the reasons why I will always change my own oil in my own cars. Only way to be sure that everything is to spec and torqued correctly. Plus you can use a futamov valve .

But find an example when both weights come from the same brand and you see the reversed viscosities
Aye, but I'm just pointing out that some 20 wt's have HTHS #'s well beyond previous gen 30 wts. Redline 5w-20 for example, has a higher HTHS (high temp high sheer) # then Mobil1 10w-30. HTHS for those reading in, is the relatively strength of the oil in a HTHS situation like a bearing under WOT conditions. Higher HTHS #'s (up to a point) tend to show less material loss over time then those oils with lower #'s. (But this is changing as well).

But the questions is, at those temperatures, which one has higher viscosity?
Thats what the raging debate is. It seems that dropping down a few grades can drop oil temps as much as 30F in some situations...which actually puts the thinner weight oil at nearly the same equivilant viscosity as the thicker oil. Some of the threads I posted touch upon this.

Did they ever switched back to higher viscosity and seen again high metals? Were the two weights from the same company?
Yes, and yes. Mobil1 0w-20 to mobil1 10w-30 and back to mobil1 0w-20 (back to 10w-30 again for this UOA section). Upper engine wear (valvetrain, cams) was lower with the 20 wt oil, most likely due to the fact the car has relatively short trips. As always driver, environment, and conditions play a big part. The ferrari threads in the bobs links I posted also play with this concept somewhat, as the 575M owner swaps between 0w-20 and 5w-40 and various oil grades, checking temps and watching wear. (Must be nice to be a millionare )

Last edited by crossbow; 09-07-2005 at 07:46 AM.
Old 09-07-2005, 07:57 AM
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This has as much to do with general supply as it does with environmental conditions. In certain countries there is a drastically larger amount of specific oil weights then other types. For example its nigh impossible to find a 20 wt oil in south america, it has to be imported...conversely, its quite easy to find a 20 wt oil in northern canada.

The southern countries have not had sufficent time to adapt to the relatively new technologies in the current generation of 20 wt oils, and thus the specifications reflect the mass supply of the oil in those countries (based on previous specifications). If south america required a 20 wt oil in the rotary, where would you get it? You'd most likely have to hit up a speciality shop, or import the oil...a manufacturer can't expect the population to do that in a consumer level car. (non exotic)

This of course is changing, which is reflected in the 06 manuals. In the mazda 6 one at least (05), countries outside the US are now spec'ing 5w-20.

if i remember correctly, mazda spec'd the 5w20 dino oil for the australian 8, but the owners of the 8 had the hardest time finding 5w20 except in a synthetic for at least the first year that the 8 was available there.
Old 09-07-2005, 04:36 PM
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Originally Posted by rotarygod
That's the most predictable and worst excuse I've ever heard. It's also untrue. Many of their race engines go entire seasons and sometimes multiple seasons without a rebuild. Why? Because they don't need it!

I've been using synthetics for about 7 years now in my rotaries. I didn't just change to it last month and start to praise it. Racing Beat and many others have been using them for far longer than I have with absolutely wonderful results. No issues. How long do we have to use them before they become "long term"? Is that not long term to you? I put over 100K miles on my old 2nd gen RX-7 engine after switching to synthetics. I even use 5W20 and not 20W50!
Multiple Seasons ...without a rebuild??, year after year, what a load of rubbish RG.

RG, on another issue.

In your opinion what and why do you think there have been so many engine replacements in the 8 in your past US hot summer, particularly Texas and Nevada.
Poor owner oil care, lack of servicing, stuck in traffic gridlock.

Have you heard of any in other countries that sell the RX-8 with the same issue.

As far as I know here in Australia there have been no renewed engines, but, we are about to start our summer and it will probably be a scorcher!, also we sell about 100 new RX-8s per month compared to the USAs 1200!

Have you heard a technical reply/reason from US dealers who returned old engines to NAO then Japan. I know of the R flash response.

Last edited by ASH8; 09-07-2005 at 05:02 PM.
Old 09-07-2005, 07:04 PM
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ASH8: Just to get some tension out of the thread, I don't have any issues with you personally so don't think I hate you for anything. We just happen to disagree on a particular issue. I do have to throw out though that you should take a look at Mazmart's response at the end of this thread.

https://www.rx8club.com/rx-8-racing-25/so-renesis-confirmation-4-rotor-71201/page2/

I think the biggest single issue with the engine failures has been related to consistent oil temperatures being way too high. It isn't a synthetic/conventional related problem as too hot is too hot. I do find it strange that there haven't been any known failures in other countries but as you pointed out your summer is about to start. Keep an eye out for them. Most of our problems happened over the hottest months and in the hottest areas of the country. Another correlation is that most (not all) of the reported failures have been in drier climates. The drier the air, the less moisture in the atmosphere to help dissipate heat. The highest temperatures are going to be seen in slow moving traffic and stop and go city driving. The parts of the country where most of the failures have been reported are also high commuter locations. Many just like to live a long way from their jobs. Most of our failures (but again not all) have been in the single oil cooler automatics. The oils are just coking to death. It would require very abnormally short oil changes to help with the issue. Also the coolers don't have fans to help aid their cooling ability when not moving.

The 3rd gen RX-7's didn't have fans either but they did have a ducting system on the back of the coolers that routed the hot air upwards and out the vents in the front fenders. Although not the best solution when not moving, there were convection currents in the ducting system that always moved heat away from the coolers, even if it was slowly. The RX-8 just has slits in the inner fender covers to help air get out. The slits point downwards too. I feel that better ducting behind the cooles and fans for low speed would solve many of the issues.

None of the technical responses that I have heard of for the failures has made any sense to me. They have acknowledged the fact that it is an oil temperature issue though. Not sure yet what they are doing about it. A good start would be to add the 2nd cooler to the automatics.
Old 09-07-2005, 07:31 PM
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Originally Posted by rotarygod

They have acknowledged the fact that it is an oil temperature issue though.....
They have? There was some talk that the problem may be related to radiator cooling fan issues.....

Can you expand on what you know of Mazda's findings in relation to the engine problems in Vegas?

Cheers,
Gomez.
Old 09-08-2005, 11:09 AM
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Look at it this way...

Your in an AT with one oil cooler. This oil cooler has no active airflow...it relies completely on the fact that the car is moving.

Its 105F outside, and your sitting in traffic. (no airflow). In these ambient temps, the surface of the road can easily be around 160-180F radiating heat upwards. How high is that oil cooler off the ground? Is there any type of reflective shield underneath it to prevent the road heat from transfering upward?

I'm guessing in this situation, in 100F+ ambient, stuck in traffic, with no airflow, single oil cooler, and 180F hot air flying off the surface of the road, that the vehicles are probably seeing 270F+ oil temps. In those temp ranges, pretty much anything other then synthetic is going to break down and get roughly the equivilant lubrication qualities of a glass of water.

IMHO...solution would be moving to synthetic (highly debated so I'll throw that out), adding fan(s) to the oil cooler(s), or adding an additional third cooler which sits in front of the condensor...allowing the radiator fans to cool it actively when the car is stuck in traffic. (These ideas aren't mine, I am just reiterating alot of the discussion from other board members).
Old 09-08-2005, 12:29 PM
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Originally Posted by ASH8
Multiple Seasons ...without a rebuild??, year after year, what a load of rubbish RG.

.

This is not an opinion, its fact. You can call the Mazdaspeed/Speedsource/Star Mazda/B-K Motorsports folks and check if you want, but they don't tear them down after every race.

This thread/blog is getting silly at this point. If you don't want to use synthetics fine, don't. But there is no tangible proof that it hurts our engines.

Mercedes has the same policy in reverse, they require mobil 1. Why? becuase they know it works and don't want to spend the money to test all there cars on another oil.

Mazda doesn't recommend synthetics IN ANY CAR they make, not just the rotary ones. You can find that on mazdausa.com. Why, again, they don't want to go to the trouble and effort to test all there cars on different oils.

Getting off this synthetic/non B.S., I can say that my use of Royal Purple 5W-20 and tranny fluid is certainly helping with my gas mileage. Between the RP and my intake I can actually get 18mpg all city in the dead of summer with my A/C turned on. I bet my 25-27mpg on the highway is a result of this as well.

So on top of better protection, fewer oil changes, and ultimately lower costs, gas mileage is a plus.
Old 09-08-2005, 08:57 PM
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Originally Posted by rotarygod
ASH8: Just to get some tension out of the thread, I don't have any issues with you personally so don't think I hate you for anything. We just happen to disagree on a particular issue. I do have to throw out though that you should take a look at Mazmart's response at the end of this thread.

https://www.rx8club.com/showthread.php?t=71201&page=2

I think the biggest single issue with the engine failures has been related to consistent oil temperatures being way too high. It isn't a synthetic/conventional related problem as too hot is too hot. I do find it strange that there haven't been any known failures in other countries but as you pointed out your summer is about to start. Keep an eye out for them. Most of our problems happened over the hottest months and in the hottest areas of the country. Another correlation is that most (not all) of the reported failures have been in drier climates. The drier the air, the less moisture in the atmosphere to help dissipate heat. The highest temperatures are going to be seen in slow moving traffic and stop and go city driving. The parts of the country where most of the failures have been reported are also high commuter locations. Many just like to live a long way from their jobs. Most of our failures (but again not all) have been in the single oil cooler automatics. The oils are just coking to death. It would require very abnormally short oil changes to help with the issue. Also the coolers don't have fans to help aid their cooling ability when not moving.

The 3rd gen RX-7's didn't have fans either but they did have a ducting system on the back of the coolers that routed the hot air upwards and out the vents in the front fenders. Although not the best solution when not moving, there were convection currents in the ducting system that always moved heat away from the coolers, even if it was slowly. The RX-8 just has slits in the inner fender covers to help air get out. The slits point downwards too. I feel that better ducting behind the cooles and fans for low speed would solve many of the issues.

None of the technical responses that I have heard of for the failures has made any sense to me. They have acknowledged the fact that it is an oil temperature issue though. Not sure yet what they are doing about it. A good start would be to add the 2nd cooler to the automatics.
Wooo hold on RG!
I cant understand where you may see that there is tension or hate?, there is debate, I certainly do not hate anyone here, to an ozzy that is a strong word to use, and if ANYONE here has assumed that my speak (words) has created hate...I am sorry. I have respect for your thoughts RG, there are some though who are very young ...like we all are at some point, experience and knowledge comes with age and hands on work.... not everything that is published on the web is "fact".
Many "researchers" can show data that is not complete and even untrue.

RG, here in Australia all our 8s have only ONE oil cooler.. I have emailed MA about my concerns. I cant understand Mazda Japan not installing a second cooler on the Autos in the US as the Auto trans fluid is cooled by the radiator which adds more "heat" into the "system"...
OK, a manual will rev higher, but the Auto Trans has cooling requirements.
If Mazda is trying to save a dollar...it is costing a lot more in Warranty, engines, and the most expensive of all....public opinion/advertising.
I think you will find the next RX-8 upgrade will have 2 oil coolers on all models.
Cheers
Old 09-08-2005, 09:59 PM
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Im not sure but I dont think they will tear down the engines after each race.

I will say that, theres no absolute prove that Synthenic hurt our engines.

If what RG said is true, he's been using Synth Oil for the past 7 years. Maybe hes just lucky.

but so many companies, including Mazdaspeed team themself use the very same Synth Oil, there shouldnt be a problem.

Not only Australia, I think the RX-8 in japan also has only 1 oil cooler (except for Mazdaspeed version) The reason? I dont know. but I think theres a reason that they do that other than cost.

New York was pretty hot this past summer too, lots of times the temp just went over 100F, and I drive every day. One thing I notice is that, my Fan spin "less" as soon as I changed my oil to Quaker State Advance Q, which is a 5w-20 Full Synth Oil.

So I dunno, I might be killing my engine now, but I think only time will tell.
Old 09-08-2005, 10:29 PM
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Synthetic is good, synthetic is beautiful. Use it without fear! EVERY top rotary shop does.
Old 09-08-2005, 10:36 PM
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Got this from Royal Purple's site. Yeah You might think its all marketing full of crap. but Read it anyway (in case you havent do so)

Rotary Engines

Can Royal Purple Motor Oil be used in a rotary engine?


Yes. A rotary engine is a modified four cycle engine that recommends the use of an API licensed motor oil for street applications.

More information and FAQs on lubrication of Rotary Engines:

In a rotary engine, the oil lubricates the eccentric shaft bearings, thrust needle bearings and rotor bearings similar to a crank and rod bearing of a piston engine as well as being injected into the combustion chambers to lubricate the apex seals, corner seals, and side seals helping to create the sealing mechanism doing the equivalent job of the piston rings.

Royal Purple provides outstanding protection for the e-shaft, rotor bearings, thrust bearings and is suitable for the oil injection system as it has proven to run cleaner than other oils and is an excellent choice for rotary apex seals, corner seals, and side seals.

Mazda makes a statement in the Owner’s Manual not to use synthetic oils in a rotary engine, why do you say that it is OK?

Royal Purple has performed seal compatibility testing on the components used in a rotary with excellent results, including older rotary engine seals dating back to the Cosmo. Royal Purple’s Technical Services Manager David Canitz has been an owner and racer of rotary engine cars and has used synthetic motor oils in rotaries since 1985 with excellent results. He has been trying to find an answer to this Mazda statement for the last 18 years.

In the early development of synthetic oils decades ago, there were purportedly some seal compatibility issues. Today’s synthetic oils do not have the compatibility issues of the old oils. There is no substantiated evidence of seal compatibility issues with Royal Purple.

Here are some facts:


The Mazda Factory racing departments recommend and use ‘synthetic’ oils including the winning 1991 Leman’s 20-G 4 rotor Mazda 787B.


MazdaComp USA printed manual (now Mazdaspeed) recommends the use of synthetic oils for racing conditions.


Royal Purple Motor Oils have been used in rotary engines (both race and street) for ten plus years with excellent results.


Royal Purple Motor Oil is compatible with the bearing material, sealing elastomers, and combustion seals used in a rotary engine.

I heard that synthetic oil doesn't burn like mineral based oils and will coat the inside of the engine with deposits.

If this was a problem with synthetic motor oils in general, then all internal combustion engines using a ‘synthetic’ would experience increased deposits on internal surfaces. The opposite is actually the norm.

Conventional four cycle motor oils will typically leave deposits of carbon and ash when injected into the rotary apex seal, corner seal, and side seal areas. Royal Purple’s motor oil actually burns cleaner due to the synthetic base stock being free of contamination and many of the additives being ‘ashless’. This may not be true for all synthetics but Royal Purple has been proven to work extremely well in rotary engines.

Royal Purple’s formulation of synthetic hydrocarbon motor oil does burn at the nominal combustion temperatures experienced in both street and racing applications, whether normally aspirated, turbocharged, or supercharged. (500 – 1700° F idle to race rpms typical combustion temps)

Will the synthetic oil effect the oil seals?

No. Royal Purple’s Motor Oil is fully compatible with the elastomers found in rotary engines as well as more conventional piston engines. The oil seals, housing seals and other elastomers used in rotary engines typically consist of Buna N, Nitriles, Neoprene, or Viton materials which are also commonly found in piston engine cars.

I hear that synthetic is ‘thinner or lighter’ oil, is there a greater possibility that the oil will leak between the seals?

No. If an engine’s sealing surfaces are in good condition, synthetic oil should not cause any leakage. However, if an engine has marginal seals, there is a 50/50 chance the seals will leak less or more. A synthetic motor oil is going to have similar viscosity to that of a conventional motor oil – except at extreme temperatures. Due to a flatter viscosity curve, at low temperatures it will not thicken as much (easier winter cranking) and it does not thin out as quickly at higher operating temperatures (better oil film at higher rpm).

Should I go longer or shorter between oil changes?

Royal Purple recommends that the maximum oil drain / filter change interval listed in the Owner’s Manual be followed while under warranty (new RX8). For FA, FB, FC, FC Turbos, and FD rotaries, extending drain intervals from two to five fold is possible if desired. Since the rotary engine injects oil through the use of a metered oil pump, either adding oil into the carb base plate air / fuel mixture or directly injecting oil into the rotor housing, rotary engines will consume oil of one quart per 1000 – 3000 miles. It is important to maintain the proper crankcase oil level in your rotary engine if you decide to extend oil drain intervals.

If I pre-mix my fuel for the rotary engine, do I use the same ratio as with mineral based oils? Does it burn at the same rate?

In an ideal world, the rotary engine metered oil pump should inject an ashless oil designed to burn in the combustion chamber and use a four cycle oil in the crankcase for the eccentric shaft, rotor bearings, and thrust bearings. For the street, Mazda simplified the OE system to use just one oil, that being a typical four cycle oil for both the e-shaft as well as the combustion chamber. Royal Purple recommends using our standard TCW III 2 Cycle Oil if the metered oil pump is still enabled. The two cycle oil being added to the fuel tank is in addition to what Mazda designed to inject and acts as a supplement or insurance. Depending on which engine, the level of modifications (street port, Bridgeport, peripheral port, nitrous, turbocharged) and application, the typical mix ratio could vary from 200:1 to 800:1.

For a pure racing application where the metered oil pump has been disabled or removed, again based on the actual engine and modification level, the ratio could vary from 150:1 to 600:1. For this application, we recommend our Racing 2 Cycle TCW III product or the standard 2 Cycle TCW III can also be used.

A stock FD twin turbo 13B with the MOP oil injection system can typically use about one quart per 1500 miles under hard street driving. If this vehicle is getting 15 mpg, the gasoline to oil ratio is 400:1. If the oil consumption on this vehicle reduces to 1 quart per 2500 miles and fuel efficiency increases to 20 mpg, the gasoline to oil ratio increases to 600:1. The stock metering oil pump is a great system as it varies with throttle position (load on the engine). Pre-mixing has to be calculated for the ‘worst case’ that will be seen by the engine for that fuel load. Under racing conditions, that’s wide open throttle at racing rpms. This means that at idle, the ratio may be slightly fat (rich).


ONe thing tho, Our (at least mine) RX-8's Manual did not say jack about "Synth Oil no good" kind of thing. So I will use it. Simple as that.

Oh even they do, I dont think I will listen, as what I can see , I think I said it before in another post, is that the quality of Synth oil improves EVERYDAY. Mazda never "recommened" us to Race our Engine, but hey, lets be honest here, Im sure to say 99.999997% of the Rx-8 Owners race their engine at LEAST ONCE.

I will say, believe what you want to believe, but please ASH8 dont try to convince someone to trust you unless you have some "prove"

Last edited by nycgps; 09-08-2005 at 10:46 PM.
Old 09-08-2005, 11:30 PM
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i recently had a conversation with david canitz over at royal purple, where he is the tech services manager, and he has 3 rotary's that he uses royal purple on, a 94 fd street car, and a rx-3 and rx-7 tube framed race cars.
Old 09-10-2005, 06:42 AM
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RG...going back to your inherent message...when I first took my MM Singapore purchased 8 in for servicing (under warranty), I was asked if I wanted synthetic or mineral for the oil change. This surprised me a bit....so I asked which they recommended...either, was the answer, it's basically up to me


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