5W30 Oil Don't Cut it, Engine Bearing Pics 58K S1 RX-8 from England.
11-09-2009, 04:45 PM
#576
George what I meant was this type of engine problem should have never exisited and therefore we shouldnt have had to talk about it. I agree this conversation is good--learn a lot.
The other countries result may be due that the U.S. is the only country that 5w/20 was mandated. I believe other countries had the usual temp/oil wgt charts?
Ash is right on this--i really believe it. I believe it because of the following objective info:
1--internal engine specs unchanged---and in the past a heavier wgt oil was used and no bearing wear occured like this.
2- many many examples of the same bearing wear exist
3- reasons that ash says on the reman motors. Low compression engines used to be able at times to reuse bearings.
4- mazda radically changed the lubrication system ----why? Because its better thats why.
5- the most reputable rotary engine builders that we know recommend at least a 40wgt oil if you do any spirited driving and live in non EXTREME temps.
6- a 30 wgt oil (most of them by far) will sear to a 20wgt oil in less than 2K miles--used oil analysis has shown this time after time.
Then the logic of it all--
Like Ash said---increased output, increased rpms, no change in engine tolerances and very small changes in components weight, and they LOWER the recommended viscosity in America only? Come on dude ---even a Caveman can tell somethings up with this?
There are more problem areas in this engine--side seals, omp, heat issues etc and they all can contribute to engine failure, by themselves or in combination. So engine failure and bearing wear are related but different at the same time.
OD
The other countries result may be due that the U.S. is the only country that 5w/20 was mandated. I believe other countries had the usual temp/oil wgt charts?
Ash is right on this--i really believe it. I believe it because of the following objective info:
1--internal engine specs unchanged---and in the past a heavier wgt oil was used and no bearing wear occured like this.
2- many many examples of the same bearing wear exist
3- reasons that ash says on the reman motors. Low compression engines used to be able at times to reuse bearings.
4- mazda radically changed the lubrication system ----why? Because its better thats why.
5- the most reputable rotary engine builders that we know recommend at least a 40wgt oil if you do any spirited driving and live in non EXTREME temps.
6- a 30 wgt oil (most of them by far) will sear to a 20wgt oil in less than 2K miles--used oil analysis has shown this time after time.
Then the logic of it all--
Like Ash said---increased output, increased rpms, no change in engine tolerances and very small changes in components weight, and they LOWER the recommended viscosity in America only? Come on dude ---even a Caveman can tell somethings up with this?
There are more problem areas in this engine--side seals, omp, heat issues etc and they all can contribute to engine failure, by themselves or in combination. So engine failure and bearing wear are related but different at the same time.
OD
11-09-2009, 04:55 PM
#577
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Meh, I ran Castrol 10W-30 with 3,000 mile OIC and the second engine only lasted 73,000. I never did a UOA but I'm not sure just running a 40 or 50 would have made it last longer. Personally I think Premixing and the SOHN adapter is the best bet when combined with a good oil. But without pulling any of my motors apart it is pure speculation.
Last edited by 9krpmrx8; 11-09-2009 at 05:01 PM.
11-09-2009, 05:00 PM
#578
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11-09-2009, 08:40 PM
#580
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I seriously doubt Retail re-builders would replace Rotors at nearly $1800.00 for two, and the two S Bearing Assemblies $370.00 retail, when in many cases they just wire buff and clean up the rotors and press in bearing Tubes if needed, otherwise one would imagine an extra $2000 for a retail rebuild.
As for MNAO re-man Plant, Mazda Japan would be rebating MNAO under their warranty arrangement and as we know it is obvious they needed a 'Quality' re-man plant purely because of the number of RX-8's sold there, roughly half of all made.
I somehow doubt Mazda would want to pay and extra $3 to 400.00 for rotor and gear sets if they did not have to.
Yes, it is a cost analysis, and Mazda must be saving a little on doing the re-mans Stateside, rather than sending brand new units, because in the end we are probably talking about 35,000 engines out of the 60,000 plus new S1 Rx-8's sold.??
Sending you a PM Flash (soon) for some Advice...thanks..
11-09-2009, 09:38 PM
#581
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GeorgeH...Paul said that 5w20 is probably not a good idea, which most people will agree with. He also said it was premature to reccomend 50w oil, if I recall correctly.
Here are some very important ones. They show stationary gear bearing damage. The rotor bearings are alright. Better viscosity would have improved these conditions.
Paul.
Paul.
According to Mr Engman: A thicker viscoscity would have provided a greater cushion countering to some extent the mis-alignment that is somewhat natural in engines. The greater cushion allows the fine particles, that are by-products of combstion, to move along without doing as much polishing away at the babbit as occurred in this case. This is his opinion based upon examining bearings for decades.
My own thoughts on the viscoscity issue is this: The requirements for a 5W oil are not present here in the US at any time in the year. The flow rate test for a 10W are conducted at -30C and therefore more than adequate. The 40 weight side that I recommend is important to behavior of the oil when hot (And especially in hot climates). You want to, again, provide that cushion for the shaft. Let's not forget that several other countries have thicker oil recommendations from Mazda for their RX8s. The engines that we build for race teams (Renesis) don't have bearings looking like this because they're running 20W50.
Why are we being told that we should run 5W20? I would think it facilitates a quicker warm up and helps both fuel economy and horse power numbers ever so slightly. I think we have unique emission requirements here that warrant doing every last thing to enhance both the fuel mileage and power numbers.
Paul.
My own thoughts on the viscoscity issue is this: The requirements for a 5W oil are not present here in the US at any time in the year. The flow rate test for a 10W are conducted at -30C and therefore more than adequate. The 40 weight side that I recommend is important to behavior of the oil when hot (And especially in hot climates). You want to, again, provide that cushion for the shaft. Let's not forget that several other countries have thicker oil recommendations from Mazda for their RX8s. The engines that we build for race teams (Renesis) don't have bearings looking like this because they're running 20W50.
Why are we being told that we should run 5W20? I would think it facilitates a quicker warm up and helps both fuel economy and horse power numbers ever so slightly. I think we have unique emission requirements here that warrant doing every last thing to enhance both the fuel mileage and power numbers.
Paul.
Of course rotaries from the past didn't turn 9k routinely as street cars and this motor has seen track time. This one has been taken care of and used 5W20 RP synthetic for 40k miles or so. What we've seen in the others we've built still leads us to recommend 10W40.
11-10-2009, 12:00 AM
#584
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It will be interesting to see what comes of the S2 renesis in due time.. As long as oil capacity is the same between the two series (is it?) and the problem goes away, then we should be able to conclude that flow rate was insufficient in the S1 with lower viscosity oils. If the problem remains, then we might be able to conclude with the evidence of a UOA that it is broken-down oils causing the bearing wear.
Even though this bearing wear is probably not the cause of many renesis deaths, I still don't like the thought of this happening in mine. This is why I appreciate all those that have contributed to this thread. This info is to benefit us all. So, hopefully we can keep that in mind before we get bent out of shape over disagreements.
Even though this bearing wear is probably not the cause of many renesis deaths, I still don't like the thought of this happening in mine. This is why I appreciate all those that have contributed to this thread. This info is to benefit us all. So, hopefully we can keep that in mind before we get bent out of shape over disagreements.
11-10-2009, 12:04 AM
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11-10-2009, 12:29 AM
#587
It will be interesting to see what comes of the S2 renesis in due time.. As long as oil capacity is the same between the two series (is it?) and the problem goes away, then we should be able to conclude that flow rate was insufficient in the S1 with lower viscosity oils. If the problem remains, then we might be able to conclude with the evidence of a UOA that it is broken-down oils causing the bearing wear.
Even though this bearing wear is probably not the cause of many renesis deaths, I still don't like the thought of this happening in mine. This is why I appreciate all those that have contributed to this thread. This info is to benefit us all. So, hopefully we can keep that in mind before we get bent out of shape over disagreements.
Even though this bearing wear is probably not the cause of many renesis deaths, I still don't like the thought of this happening in mine. This is why I appreciate all those that have contributed to this thread. This info is to benefit us all. So, hopefully we can keep that in mind before we get bent out of shape over disagreements.
S2 has "slightly" larger oil capacity.
S2 has "better" oil pan to prevent certain g-force issue (but newer S1/Reman engines from Mazda has this mod also)
S2 has "improved" water pump design (PLASTIC?????WTF!?)
S2 has "about" double oil pressure than S1
S2 has "updated" Coolant Radiator
S2 has "improved" oil cooler duct for "better" cooling
S2 has "better" underbody tray/cover for better aero dynamics(get the heat away)
11-10-2009, 05:10 AM
#588
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Which still all point (along with the oil test results) to at least part of the wear being caused by the oil breaking down due to heat, (partly due to the installation looking at some of the parts on that list) which is why I believe you are getting away with heavier weight oils - even though they are still breaking down, they're only dropping to 30-40w, it's not a full solution though, as I pointed out earlier, if the oil is shearing then the additive packages will start dropping out of suspension - it also accounts for why I'm not seeing any of that wear even running the lighter weight oils, I've got much, much more airflow around my engine, as well as larger radiators, fans and oil coolers.
Last edited by PhillipM; 11-10-2009 at 05:13 AM.
11-10-2009, 09:12 AM
#589
No sarcasm. He's wearing me down.
For the sake of completness, I'd still like to know of the Renesis e-shaft bearing diameter got a little larger than the older cars. That would indicate a tighter oil clearance, and reinforce the need for lower viscosity than has been used historically.
Not trying to be a PITA, but that would help complete the picture.
11-10-2009, 10:36 AM
#590
No sarcasm. He's wearing me down.
For the sake of completness, I'd still like to know of the Renesis e-shaft bearing diameter got a little larger than the older cars. That would indicate a tighter oil clearance, and reinforce the need for lower viscosity than has been used historically.
Not trying to be a PITA, but that would help complete the picture.
For the sake of completness, I'd still like to know of the Renesis e-shaft bearing diameter got a little larger than the older cars. That would indicate a tighter oil clearance, and reinforce the need for lower viscosity than has been used historically.
Not trying to be a PITA, but that would help complete the picture.
)The clearances are the same. We checked a long time ago.
Paul.
11-10-2009, 10:45 AM
#592
As a side note, and I hope Ash doesn't mind a bit of drift, anybody have thoughts on 10w40 vs. 0w40? This would probabaly be RP.
I'm thinking 0w40 would be better for me, since, when autocrossing, you can pretty much assume the first run is on oil that's not fully up to temp. I will be dual-driving, however, which means most runs will be hot. It's just that first run I worry about.
I'm thinking 0w40 would be better for me, since, when autocrossing, you can pretty much assume the first run is on oil that's not fully up to temp. I will be dual-driving, however, which means most runs will be hot. It's just that first run I worry about.
11-10-2009, 10:54 AM
#593
As a side note, and I hope Ash doesn't mind a bit of drift, anybody have thoughts on 10w40 vs. 0w40? This would probabaly be RP.
I'm thinking 0w40 would be better for me, since, when autocrossing, you can pretty much assume the first run is on oil that's not fully up to temp. I will be dual-driving, however, which means most runs will be hot. It's just that first run I worry about.
I'm thinking 0w40 would be better for me, since, when autocrossing, you can pretty much assume the first run is on oil that's not fully up to temp. I will be dual-driving, however, which means most runs will be hot. It's just that first run I worry about.
Paul.
11-10-2009, 11:07 AM
#594
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Unless my UOA on my GC 0W-30 has greatly improved this time, I will switch to Mobil1 0W-40 this next oil change. The 0W's break down quicker but offer better cold start protection (albeit probably not huge diff between 0W and 10W). And I don't have to worry about how Mobil 1 burns because I am running a SOHN adapter.
11-10-2009, 02:43 PM
#595
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What a bunch of FLIP FLOPPER'S!!!
11-10-2009, 03:14 PM
#597
11-10-2009, 03:56 PM
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11-10-2009, 04:27 PM
#600
got my 1st oil analysis kit in the mail yesterday for my present engine. running diesel 15w/40. I need another 1K on this oil before I send it in. Diesel has shown before to hold its viscosity.
One thing about the 09's---- they cannot run a sohn adapter.
OD
One thing about the 09's---- they cannot run a sohn adapter.
OD