Official S65 Bearing Specification/Clearance Wiki

[swamp2]

All right, this should be simpler... Ugh.

Originally Posted by regular guy

SFP is incorrectly lumping together failures that I never included in this discussion and should not be part of this discussion.
...

You are saying that this summary:

Originally Posted by SenorFunkyPants

Had another look at the S65 bearing failure registry.
19 links on page 1.

1 failure due oil pump
1 rod snapped.
1 Cylinder/piston damage.
2 crankshaft failures
2 No failure.
2 Valve failures
3 failures of Supercharged engines
7 almost certain rod bearing failure

contains some, all or none of the engines that fit your narrowly and properly selected criteria of no mods, no signs of trouble and direct knowledge/photographic evidence of bearings?

Your post #2 contains multiple supercharged and modded engines. There are 5 engines there, all numbered, #1-#5, 3 were SC, one unknown and one bone stock.

The rest of the thread adds additional engines/cases starting in your post #8 but does not continue to number or ID them in any way.

How many total cases fit the no mods (or no SC, no major nor no internal mods), no signs of trouble and then your direct knowledge or sufficient documentation and photographic evidence, along with the observation of significant bearing wear?

Certainly if I've not precisely stated what criteria clearly puts an engine into your "bearing clearance issue" category please refine my rough understanding of that.

[SenorFunkyPants]

Originally Posted by aussiem3

I would like to hear from Mike Benvo of BPM Sport as to what his thoughts are on this bearing issue especially with ECU modification. His tunes are very conservative compared to others. His input here will be invaluable.

Definitely...I like reading Mike's posts, they are always super informative.
I came across several yesterday while I was looking for info on engine tunes. I especially like that he doesn't try to make himself look smarter by putting down less informed posters.

[SenorFunkyPants]

Originally Posted by regular guy

Would you be kind enough to tell us the MINIMUM AKI octane required to run a 12.0:1 compression ratio engine without a knock sensor, and without an advanced ECU spark management system? Once you find the answer, then could you please explain how any high compression engine can do it even with a knock sensor and advanced ECU spark management system? Then please explain why your theory doesn't hold up for other similarly high compression engines running on the same pump gas?

Either you know the answer already, in which case make your point and if it puts holes in my theory then fair enough....or you don't know the answer, well then you need to do your own research. In either case if what I write can't stand up to peer review then it needs changing or abandoning.

Look I know I'm not the smartest person here or the one with the most understanding of how engines work...and I am sort of making this up as I go along. Sometimes you have an idea and you don't know if it will stand up to scrutiny so you put it out there and see how it goes. If its bollocks then that is fine, I'll quietly drop it and pretend I never said it! But the difference between us is that I want to know if there is a design issue or if some/most/all of this can be accounted for by usage. You on the other hand just seem to want to be right.

[aussiem3]

Originally Posted by SenorFunkyPants

Definitely...I like reading Mike's posts, they are always super informative.
I came across several yesterday while I was looking for info on engine tunes. I especially like that he doesn't try to make himself look smarter by putting down less informed posters.

Couldn't agree more. I wish we had him around on this subject.

[rev9k]

Originally Posted by SenorFunkyPants

Definitely...I like reading Mike's posts, they are always super informative.
I came across several yesterday while I was looking for info on engine tunes. I especially like that he doesn't try to make himself look smarter by putting down less informed posters.

U must be kidding

[rev9k]

Originally Posted by aussiem3

Couldn't agree more. I wish we had him around on this subject.

He's an IT guy first and foremost. There's plenty of knowledgable people in this forum.


I'll ask again, how many more cars have blown up since this thread. People worry too much about cars that run fine. People should worry about their health as much as their cars

[kawasaki00]

Originally Posted by hughs65e90

U must be kidding

If the tuners want to comment on tunes and timing i am good with that but not singling Mike out but tuners dont know about bearing issues or what they are looking at unless they are engine builders themself. A couple are, but I know for a fact a few that have no clue what they are looking at.

[Harpua]

Thanks to all the contributors on the thread for an excellent discussion on a topic (rod bearings) that is of concern to many M3 owners

I barely know sh!t from shinola when it comes to engines, but I will make one comment on some of the disagreements -- A move should be made away from sliding towards demanding/requesting "proof of a negative".
Anyone with a modicum of education will know that this is a fruitless endeavour and will inevitably cause deterioration of the discussion into personal attacks and ego-riddled "the best defence is a strong offence" replies.

As you were...

[regular guy]

Originally Posted by Harpua

Thanks to all the contributors on the thread for an excellent discussion on a topic (rod bearings) that is of concern to many M3 owners

I barely know sh!t from shinola when it comes to engines, but I will make one comment on some of the disagreements -- A move should be made away from sliding towards demanding/requesting "proof of a negative".
Anyone with a modicum of education will know that this is a fruitless endeavour and will inevitably cause deterioration of the discussion into personal attacks and ego-riddled "the best defence is a strong offence" replies.

As you were...

Agreed. Too many people are now invested in finding missing "i-dot's" and "t-crosses" and are now looking for the flaw in the ink of the "i-dot" as well instead of trying investigate and find useful information.

To that end, I think we've made some progress in the last week. Kawasaki has a complete set of pistons, rods, and partial set of old bearings, and full set of new bearings. Based on a preliminary email, I think he will report some very interesting things.

I haven't been idle either. Over the past week, I've had about 16 emails with two Clevite senior reps about this issue. A few of the emails are very detailed and contain multi-page responses. Many challenge questions have been asked. I learned a lot from the conversation. As Kawasaki previously mentioned, Clevite senior rep's don't want to go on record because BMW is a major client. Clevite has requested I send as many sets of bearings as possible. Over the next week or two, I will collect as many sets as I can, and send to Clevite for analysis. Anybody with old bearing sets who want Clevite to analyze them, please PM me for details.

Clevite also restated their offer to make a custom bearing run with increased oil clearance. They have requested I provide a blueprint. To provide the blueprint, I contacted my former colleague and former BMW ///M engine designer friend. He was involved in the original S14 engine design, and the BMW M10 (Formula-One) race engine projects. He's also very familiar with the S65 engine and has consulted BMW on racing versions of the S65. He also designed the aftermarket S65/S85 valve springs used by Dinan on all their stroker motors. I have now contacted him to request a bearing blueprint. At the same time, I asked his opinion of the factory oil clearances in the S65.

More information coming when it becomes available.

[rantarM3]

Originally Posted by regular guy

Clevite also restated their offer to make a custom bearing run with increased oil clearance. They have requested I provide a blueprint. To provide the blueprint, I contacted my former colleague and former BMW ///M engine designer friend. He was involved in the original S14 engine design, and the BMW M10 (Formula-One) race engine projects. He's also very familiar with the S65 engine and has consulted BMW on racing versions of the S65. He also designed the aftermarket S65/S85 valve springs used by Dinan on all their stroker motors. I have now contacted him to request a bearing blueprint. At the same time, I asked his opinion of the factory oil clearances in the S65.

If there is a problem I think that's the only reasonable alternative - to have custom bearings made.

Would your M engine designer friend know if they increased clearances on the racing S65 engines? That would be interesting to know even though it's for a race application.

[regular guy]

Originally Posted by rantarM3

If there is a problem I think that's the only reasonable alternative - to have custom bearings made.

Would your M engine designer friend know if they increased clearances on the racing S65 engines? That would be interesting to know even though it's for a race application.

He might know. I didn't think to ask in my initial email. That would be a good follow up question once he shows interest in designing the bearing for us. Sometimes I don't hear answers for weeks. Hopefully the offer of $$$ for a bearing design will get a faster response.

[swamp2]

regular_guy (and others):

Here we go again. The issue "is solved" yet we have no idea on many critical questions and we still have a hypothesis not even close to a theory. We "need" to move ahead and design a custom bearing for a "problem" we have yet to completely isolate from clearly confounding effects (no reply to my post just above about your post #2 opening this issue and thread with 3 supercharged engines?). Furthermore the size of this problem seems to have a reasonably estimated upper limit of 0.5% occurrence, other estimates have been as low as 0.02%.

How many bloody engines have exhibited significant bearing wear and did not have significant internal nor power increasing mods?

And now folks are jumping on the bandwagon and are just positive that we "need" a custom bearing. I guess we should do both mains and con rods as well? Although I certainly won't question Clevite's technical competency they clearly have a financial gain at stake in this issue.

[klammer]

This is great! Love to watch the scientific/engineering method taking place in real time! The naysayers, the defenders, the believers, the skeptics, the curious, all essential to a legitimate scientific discussion and hopefully resolution. Keep it up everyone

[kawasaki00]

I will elaborate more later but from the set I just looked at that had terrible looking bearings we can take the detonation theory and chuck it out the window.
You guys can believe what you want to believe but after 5 different opinions from guys that have been doing this for a long time and from others in the industry and looking at things under a scope the consensus is just plain there is not enough clearance with the 10-60.
It is still a internal combustion engine and sometimes no amount of engineering or though can change the fact that you have to have sufficient clearance to get the oil in and out.

[swamp2]

Originally Posted by klammer

This is great! Love to watch the scientific/engineering method taking place in real time! The naysayers, the defenders, the believers, the skeptics, the curious, all essential to a legitimate scientific discussion and hopefully resolution. Keep it up everyone

I basically agree, however, one absolutely must not forget the foundational pillar of the scientific method - EXPERIMENTATION. It is missing here, 100%, period, no ifs ands or buts.

[swamp2]

Originally Posted by kawasaki00

You guys can believe what you want to believe but after 5 different opinions from guys that have been doing this for a long time and from others in the industry and looking at things under a scope the consensus is just plain there is not enough clearance with the 10-60.
It is still a internal combustion engine and sometimes no amount of engineering or though can change the fact that you have to have sufficient clearance to get the oil in and out.

And...

1. BMW M screwed this up big time, not just a little bit. It is a gross engineering error.
2. The problem will manifest itself on a large percentage of S65 engines.
3. BMW had no particular benefits or key design goals from this specification.
4. Their very tight clearances require much tighter tolerances and this was very inexpensive overall for them to achieve. The did this arbitrarily or for fun because achieving low single digit micron tolerances is "neat manufacturing".
5. BMW haven't been running clearance ratios in violation of the Clevite rules of thumb for 20 years.
6. We have 5 experts here on bearings and they have shared their qualifications with us.

The answers to all of these are pretty clearly "no".

Look I still agree with the very plausible nature of the bold part above. But without better addressing the above point healthy skepticism is entirely justified here. The justification will even be seen as retroactively justified in from a "historical" perspective even if your hypothesis graduates to a theory and is completely validated.

Again

[kawasaki00]

Originally Posted by swamp2

And...

1. BMW M screwed this up big time, not just a little bit. It is a gross engineering error.
2. The problem will manifest itself on a large percentage of S65 engines.
3. BMW had no particular benefits or key design goals from this specification.
4. Their very tight clearances require much tighter tolerances and this was very inexpensive overall for them to achieve.
5. BMW haven't been running clearance ratios in violation of the Clevite rules of thumb for 20 years.
6. We have 5 experts here on bearings and they have shared their qualifications with us.

The answers to all of these are pretty clearly "no".

Again

Wait for my full write up and you can eat your crow

[swamp2]

Originally Posted by kawasaki00

Wait for my full write up and you can eat your crow

I'm so completely fine being wrong (as opposed to many here). But as of now this list all being answered "no" is not wrong. Again, my skepticism is without reproach. This is more about science as a process than who is right. I'll be perfectly happy to pay for this wonderful new custom bearing and have it installed and reap its benefits should it be a justified change.

[SenorFunkyPants]

Perhaps we can get this guy in - he seems to have some experience in the matter:

http://www.m3forum.net/m3forum/showthread.php?t=361456

"Does the S65 motor have rod bearing issues? The simple answer is an unequivocal NO.


After the failure of DLSJ5's supercharged S65 motor, stories immediately began to appear explaining this particular motor failure as a "known BMW rod bearing failure." This is the evidence that was provided in those discussions:
BMW changed the part number of the rod bearings -- therefore, a rod bearing failure exists.
"Many people" on the car forums have reported rod bearing failure and warranty motor replacement.
Auto Talent recently disassembled three S65 motors (to be built as RD Sport stroker motors) and discovered that all three of them had excessive rod bearing wear on the verge of rod bearing failure.

It could be a simple misunderstanding, but none of those stories were accurate, nor could be proven true. For example:
In fact, BMW has NOT changed the rod bearing part numbers of the S65 motor since it began production.
No examples were cited of forum members with rod bearing failure on this motor to back up this claim.
Auto Talent did not find ANY rod bearing failure on ANY S65 motors they have disassembled
It's this latter claim (Auto Talent discovers rod bearing failure) that I'd like to focus on for the remainder of this article.

When I heard that Auto Talent was cited as the source for three motors with rod bearing failure, I knew the story wasn't true. I had been to Auto Talent a few weeks earlier and saw these three crankshafts from recent stroker motor builds. The shop mechanic called me aside and pulled up one crankshaft and showed me a main bearing journal that was pretty badly damaged. Unfortunately I didn't snap any pictures at that time.

This past weekend, I was visiting my friends (and my car) at Auto Talent, and I asked about this crank with main bearing failure. Since I had heard Auto Talent was cited as the source for the rod bearing failure story, I decided to ask the shop mechanic personally how many cranks he had seen with any type of bearing failure. These are his answers.

How many S65 cranks have you seen with any bearing failure? One.
Did any cranks have rod bearing failure? No.

The crank with main bearing failure was still in the shop, so I took pictures. I wanted to post these pictures to clear up the misconception that BMW has a "known problem" with S65 rod bearing failure, and to clarify with Auto Talent how many cranks and what type of bearing failures they have seen on the S65 motor.

Here's the pictures I took."

You have to go to the page to see loads of bearing photos.

[gatorfast]

Interested to see Kawasakis findings.

On another note, it seems like the few who believe there is a clearance issue have gone above and beyond to investigate actual parts are failures, taken measurements, etc, and posted their findings. On the other hand, the few detractors seem to be arguing in theory and have not done any actual hands on research.

[regular guy]

Originally Posted by SenorFunkyPants

Perhaps we can get this guy in - he seems to have some experience in the matter:

http://www.m3forum.net/m3forum/showthread.php?t=361456

"Does the S65 motor have rod bearing issues? The simple answer is an unequivocal NO.


After the failure of DLSJ5's supercharged S65 motor, stories immediately began to appear explaining this particular motor failure as a "known BMW rod bearing failure." This is the evidence that was provided in those discussions:
BMW changed the part number of the rod bearings -- therefore, a rod bearing failure exists.
"Many people" on the car forums have reported rod bearing failure and warranty motor replacement.
Auto Talent recently disassembled three S65 motors (to be built as RD Sport stroker motors) and discovered that all three of them had excessive rod bearing wear on the verge of rod bearing failure.

It could be a simple misunderstanding, but none of those stories were accurate, nor could be proven true. For example:
In fact, BMW has NOT changed the rod bearing part numbers of the S65 motor since it began production.
No examples were cited of forum members with rod bearing failure on this motor to back up this claim.
Auto Talent did not find ANY rod bearing failure on ANY S65 motors they have disassembled
It's this latter claim (Auto Talent discovers rod bearing failure) that I'd like to focus on for the remainder of this article.

When I heard that Auto Talent was cited as the source for three motors with rod bearing failure, I knew the story wasn't true. I had been to Auto Talent a few weeks earlier and saw these three crankshafts from recent stroker motor builds. The shop mechanic called me aside and pulled up one crankshaft and showed me a main bearing journal that was pretty badly damaged. Unfortunately I didn't snap any pictures at that time.

This past weekend, I was visiting my friends (and my car) at Auto Talent, and I asked about this crank with main bearing failure. Since I had heard Auto Talent was cited as the source for the rod bearing failure story, I decided to ask the shop mechanic personally how many cranks he had seen with any type of bearing failure. These are his answers.

How many S65 cranks have you seen with any bearing failure? One.
Did any cranks have rod bearing failure? No.

The crank with main bearing failure was still in the shop, so I took pictures. I wanted to post these pictures to clear up the misconception that BMW has a "known problem" with S65 rod bearing failure, and to clarify with Auto Talent how many cranks and what type of bearing failures they have seen on the S65 motor.

Here's the pictures I took."

You have to go to the page to see loads of bearing photos.

Second time this article was linked. Here's the same response.

There is one thing in that thread is definitely wrong: the rod bearings and part numbers of the rod bearings have definitely changed. I thought we've discussed that before. If you want to get hypertechnical, then the rest of that thread is true: there is a clearance issue, not a bearing issue. I haven't seen any evidence of a bearing design or manufacturing flaw...have you?

[DLSJ5]

Originally Posted by gatorfast

Interested to see Kawasakis findings.

On another note, it seems like the few who believe there is a clearance issue have gone above and beyond to investigate actual parts are failures, taken measurements, etc, and posted their findings. On the other hand, the few detractors seem to be arguing in theory and have not done any actual hands on research.

Totally agree. They haven't yet, two of the biggest detractors, Swamp and Yellow Snow, have both stated that they may switch to 0w40, am I missing something here or doesn't that indicate that both of them feel that there is a potential clearance issue and that the tws is probably too thick for the S65?