Official S65 Bearing Specification/Clearance Wiki

[Yellow Snow]

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.

The funny thing about that post is that it's posted by Regular Guy in his former guise.

Originally Posted by regular guy

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.

Can you imagine the horror if anyone else suggested getting 'A friend who used to work for BMW' or a 'Clevite senior rep' without a name? A one sided argument doesn't add up to a proper debate.

Originally Posted by DLSJ5

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?

That was my original thought but I'm still not convinced there is anything at all to worry about when running on 98 Ron and careful cold running.

[8k3]

Wait wasn't pencilgeek the guy with the S85 who changed his bearings?

[DLSJ5]

Originally Posted by Yellow Snow

That was my original thought but I'm still not convinced there is anything at all to worry about.

Fair enough.

[Cool Steel]

Seems like everyday I ask myself why did I pay so much for this POS engine?

http://www.m3post.com/forums/showthread.php?t=916539

[Cool Steel]

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...

Too late my friend, half this discussion is ego vs ego.

Bottom line: This engine is not what we expected. Is it a POS? No, relative to other engines probably normal. Hell, all performance engines have problems.
However, for the price we paid for these cars, we got a normal engine for a premium price.

I have a friend that works in Suzuki in Switzerland, in supply, and has many friends with BMW. He told me straight up, that he was told that the S65 has problems. However, due to the advertising budget that BMW has in the media, it is all being hushed up. He is the industry, with connections in all European auto companies and bike companies.....he has no reason to lie. However, I hope his information is tainted in some way......I hope.

[DLSJ5]

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.

That was more than a few years ago! I was skeptical back then too, didn't think there was an issue with the rod bearings, at least not on the level of the S54, but after seeing all the pictures, threads, and now the clearance info, I think there's a potential issue here, and it's okay to change your mind, especially if the evidence is pointing in that direction.

FTR on my motor, I don't know exactly what specific part failed, the piston, the rod or the bearings, but I'm confident of why something eventually gave way, and it's not related to this issue IMHO. The car at the time was running 9psi on 91/0ctane meth, the meth failed because an aluminum tank was used, I had no idea the meth had failed, one morning while doing some spirited 60-130 runs, the engine shut down, and something was not right, after that it developed a slight ticking noise. I was told by two BMW techs that it's normal engine sound, not long after that the motor blew, through a rod. The Meth failure caused something to weaken then eventually give out, but I don't think it's related to this thread, as we have a good idea as to why the car blew up and most engines in this specific case with the Meth issue, running 91 octane, 9psi on a 12:1 motor, probably would have failed as well, while I understand why it was brought up, I don't think it's relevant or related specifically to rod bearing clearances.

[SenorFunkyPants]

Originally Posted by Yellow Snow

The funny thing about that post is that it's posted by Regular Guy in his former guise.

So Regular Guy is Pencilgeek....probably explains why when I looked at the photos in that thread on m3forum some of them looked familiar....they are on page 1 here on M3post as well.

[thekurgan]

Originally Posted by Cool Steel

Too late my friend, half this discussion is ego vs ego.

Bottom line: This engine is not what we expected. Is it a POS? No, relative to other engines probably normal. Hell, all performance engines have problems.
However, for the price we paid for these cars, we got a normal engine for a premium price.

I have a friend that works in Suzuki in Switzerland, in supply, and has many friends with BMW. He told me straight up, that he was told that the S65 has problems. However, due to the advertising budget that BMW has in the media, it is all being hushed up. He is the industry, with connections in all European auto companies and bike companies.....he has no reason to lie. However, I hope his information is tainted in some way......I hope.

Hearsay based upon hearsay ... "problems" = too vague but I hope you're right about the tainting.

[swartzentruber]

Originally Posted by gatorfast

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.

I'll provide my position. What regular_guy and his contributors have done is to measure what is relatively straightforward to measure. I'm not trying to minimize the effort involved, but all that measuring clearances, taking photos, etc. gets you is somewhat there in terms of proving a case for correlation -- low clearance and worn bearings correlates to blown engine. That portion of the "case" is pretty clear. Beyond that, it gets a little murky. Through all that, though, all you end up with is a very strong argument of correlation, and as anyone that knows even a little about statistics knows, correlation <> causation. The sciences are littered with cases of correlation being mistaken for causation, with much money spent and nothing to show. Thus, despite whatever regular_guy or kawasaki post over the next few days, I can't see this moving beyond a strong correlation case for me.

The only things that can likely move this from a correlation case to a causation case are one of two things. Either experimentation, which swamp has called for, but is probably unrealistic given our collective resources, as well as the amount of time required for the the experiment to run its course (though I'd be happy if people want to pony up). The other way is some form of regression analysis, where you can at least try to determine which variables -- miles, tolerance stackup (i.e. luck), octane, tune, # of cold starts -- have the strongest relationship with the undesired outcome of engine failure.

Unfortunately, given the low number of failures, and even lower number of untainted failures, there is absolutely no way we could find any strong relationships, even if we did have access to the detailed data for all those data points for the existing failures, which we do not. Ironically, the best thing that could happen to help this type of analysis is if we suddenly had a rash of engine failures, though I'm sure none of the skeptics want that. Given the amount of failures that have occurred thus far, this "issue" doesn't seem to rise much above the level of noise. Maybe it will at some point, but not so far.

[swartzentruber]

Originally Posted by DLSJ5

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?

Not really, at least on the clearance "issue". I think it seems to be relatively undisputed on the oil analysis side that if the following are true, TWS 10W-60 is not a great idea:
a) never on the track
b) high % of mileage spent on the cold start cycle (short commutes)
c) colder winters

Those fit me to a T. Additionally with 0W-40, I should get the following benefits:
a) quicker warmup (less time spent <= 3k rpms)
b) lower cost oil changes
c) slightly better mpg (always a good thing)
d) potentially a little quicker revving

Since even BWM has stated that LL-01 oils are acceptable, this option has so much win, it's kind of a no brainer. None of this require conceeding that clearances are too tight, merely that with tight clearances and factors mentioned above, TWS 10W-60 isn't the best choice in all cases, which is a far different conclusion.

[Yellow Snow]

Originally Posted by gatorfast

On the other hand, the few detractors seem to be arguing in theory and have not done any actual hands on research.

I provided accurate measurements of a crank and bearings, but they didn't appear to fit in with what was deemed suitable.

I'm pretty sure that if the measurements confirmed a problem they would have been met with open arms.

[aussiem3]

Originally Posted by gatorfast

It would be interesting to hear some tuners chime in on why their tunes are safe and would not contribute to engine damage.

Originally Posted by catpat8000

There is no such thing as a "safe" tune. Otherwise tuners would offer drivetrain warranties and the OEMs wouldn't disqualify your warranty upon discovering you have one. Can anyone name a single tuner who will stand behind the factory warranty with their tune? If so, that's the only safe tune.

Factory tunes are set to optimize performance and safety over a broad set of parameters and conditions. A lot of analysis goes into setting up the factory parameters. Most tuners almost certainly don't have that level of investment nor do they have to stand behind their work, economically speaking.

Pat

Originally Posted by gatorfast

Im the sure the main tuners on this board would disagree. Hopefully they will chime in.

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. But for some unknown reason he is banned from this forum. Forums are all about knowledge sharing and helping each other out but some one on this forum has an axe to grind against Mike, and keep extending his ban even when he is not posting. Isn't that funny.

Originally Posted by thekurgan

hashtag: political-ban

Originally Posted by FogCityM3

Agreed, would be interesting to hear from the major tuners. I have logged (on rolling road) timing with BPM tune and can attest to the conservative timing numbers ie 32-33 degrees at WOT. Would like to know at what point too much is too much before it gets dangerous for the engine.

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.

Originally Posted by hughs65e90

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

The reason the tuners came up because of the kind of tune each develop. The only reason I mentioned Mike's name was because his ability to impartially reason and state the fact so everyone can understand and absorb. Like SFP pointed out his reasoning are not meant for tech nerds but people like me who have very little technical know how.

What we want to know is how much room is there for them to play with the factory parameters before pushing the limits. We are not asking any tuner to chip in on bearings and their wear.

I think patience is the key to getting some reasonable and good answers. I think people are jumping way too head when they see a post even without understanding what this post is about.

[regular guy]

Originally Posted by swartzentruber

I'll provide my position. What regular_guy and his contributors have done is to measure what is relatively straightforward to measure. I'm not trying to minimize the effort involved, but all that measuring clearances, taking photos, etc. gets you is somewhat there in terms of proving a case for correlation -- low clearance and worn bearings correlates to blown engine. That portion of the "case" is pretty clear. Beyond that, it gets a little murky. Through all that, though, all you end up with is a very strong argument of correlation, and as anyone that knows even a little about statistics knows, correlation <> causation. The sciences are littered with cases of correlation being mistaken for causation, with much money spent and nothing to show. Thus, despite whatever regular_guy or kawasaki post over the next few days, I can't see this moving beyond a strong correlation case for me.

The only things that can likely move this from a correlation case to a causation case are one of two things. Either experimentation, which swamp has called for, but is probably unrealistic given our collective resources, as well as the amount of time required for the the experiment to run its course (though I'd be happy if people want to pony up). The other way is some form of regression analysis, where you can at least try to determine which variables -- miles, tolerance stackup (i.e. luck), octane, tune, # of cold starts -- have the strongest relationship with the undesired outcome of engine failure.

Unfortunately, given the low number of failures, and even lower number of untainted failures, there is absolutely no way we could find any strong relationships, even if we did have access to the detailed data for all those data points for the existing failures, which we do not. Ironically, the best thing that could happen to help this type of analysis is if we suddenly had a rash of engine failures, though I'm sure none of the skeptics want that. Given the amount of failures that have occurred thus far, this "issue" doesn't seem to rise much above the level of noise. Maybe it will at some point, but not so far.

This mirrors many of my thoughts on this subject as well.

Originally Posted by aussiem3

I think patience is the key to getting some reasonable and good answers. I think people are jumping way too head when they see a post even without understanding what this post is about.

So true.

[DLSJ5]

Originally Posted by swartzentruber

Not really, at least on the clearance "issue". I think it seems to be relatively undisputed on the oil analysis side that if the following are true, TWS 10W-60 is not a great idea:
a) never on the track
b) high % of mileage spent on the cold start cycle (short commutes)
c) colder winters

Those fit me to a T. Additionally with 0W-40, I should get the following benefits:
a) quicker warmup (less time spent <= 3k rpms)
b) lower cost oil changes
c) slightly better mpg (always a good thing)
d) potentially a little quicker revving

Since even BWM has stated that LL-01 oils are acceptable, this option has so much win, it's kind of a no brainer. None of this require conceeding that clearances are too tight, merely that with tight clearances and factors mentioned above, TWS 10W-60 isn't the best choice in all cases, which is a far different conclusion.

Point taken, are you running 0W40?

[klammer]

Originally Posted by DLSJ5

Point taken, are you running 0W40?

Know this wasn't directed at me, but I have almost identical characteristics to whom the question was actually addressed and I have moved to 0w40 over the winter, but will probably switch back to 10w60 for the summer/track season. And agree with everything swartzentruber said, very well stated, the correlation/causation mixup is one of the biggest problems facing science and its entry into more of the culture and everyday life.

[FogCityM3]

So do engine builders have any knowledge about how much timing advance may in fact me too much?

Also, with all due respect to some of the posters above, I'm not sure we'll ever get to a "scientific method" test using deductive reasoning because the sample size is too small (so far) so nothing can really be proven at this juncture. However, there is absolutely nothing wrong with using inductive reasoning, ie generating theories from actual "bottoms-up" observations (which is also used in science). In this vein, I think two really interesting points of using thinner oil and knowing if various tuning strategies are safe are information pieces that are useful to us even though they may not be "proven" causes of a problem--ie, if there is no downside to doing something that could possibly be preventative measure, then why not do it as a precaution? So really appreciate the contents of this thread.

Originally Posted by kawasaki00

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.

[swamp2]

Originally Posted by DLSJ5

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?

The major theme of the vast majority of my commentary here is on healthy skepticsm. Minor participation has involved some basic fact corrections and some questioning of creditials/credibility. I do not think "detractor" is an accurate description.

Originally Posted by swartzentruber

Since even BWM has stated that LL-01 oils are acceptable, this option has so much win, it's kind of a no brainer. None of this require conceeding that clearances are too tight, merely that with tight clearances and factors mentioned above, TWS 10W-60 isn't the best choice in all cases, which is a far different conclusion.

^ = +1

I've never said that there isn't something that makes some fundamental sense with tight clearances + thick oil = potential for problem. Who wouldn't want some conservatism toward a $25k engine replacement if there are no downsides to the switch? I will switch to 0W40 and I will run some oil analysis. I won't disassemble my bottom end on a completely normal engine and put new bearings with identical clearances in.

[swamp2]

Originally Posted by swartzentruber

I'll provide my position. What regular_guy and his contributors have done is to measure what is relatively straightforward to measure. I'm not trying to minimize the effort involved, but all that measuring clearances, taking photos, etc. gets you is somewhat there in terms of proving a case for correlation -- low clearance and worn bearings correlates to blown engine. That portion of the "case" is pretty clear. Beyond that, it gets a little murky. Through all that, though, all you end up with is a very strong argument of correlation, and as anyone that knows even a little about statistics knows, correlation <> causation. The sciences are littered with cases of correlation being mistaken for causation, with much money spent and nothing to show. Thus, despite whatever regular_guy or kawasaki post over the next few days, I can't see this moving beyond a strong correlation case for me.

The only things that can likely move this from a correlation case to a causation case are one of two things. Either experimentation, which swamp has called for, but is probably unrealistic given our collective resources, as well as the amount of time required for the the experiment to run its course (though I'd be happy if people want to pony up). The other way is some form of regression analysis, where you can at least try to determine which variables -- miles, tolerance stackup (i.e. luck), octane, tune, # of cold starts -- have the strongest relationship with the undesired outcome of engine failure.

Unfortunately, given the low number of failures, and even lower number of untainted failures, there is absolutely no way we could find any strong relationships, even if we did have access to the detailed data for all those data points for the existing failures, which we do not. Ironically, the best thing that could happen to help this type of analysis is if we suddenly had a rash of engine failures, though I'm sure none of the skeptics want that. Given the amount of failures that have occurred thus far, this "issue" doesn't seem to rise much above the level of noise. Maybe it will at some point, but not so far.

Excellent post.

However, I'm not ever quite sure we have a case of the first bold statement above. regular_guy keep mentioning a focus on those engines with no outward signs of any problems. Again, why so many of those have had their bottom ends torn down, I can't quite figure out.

Now as to your statement in red, I couldn't agree more. Since there will almost for sure be no actual testing, I don't think there is much that anyone can post that will magically make the requirement testing as a necessary condition for "proof". Of course if a BMW M engineer came along, identified himself and admitted they botched it big time (perhaps with some reasonable explanation how that could actually happen) then we might have something concrete.

Heck we can't even get a simple count from the proponents of the "clearance hypothesis" of how many engines fit the "pattern" of not modded, no outward signs of problems, then torn down, bearing wear noted and documented. My latest best estimate of this number remains at 0.02% (10 out of 50k)...

[regular guy]

Originally Posted by swamp2

Excellent post.

However, I'm not ever quite sure we have a case of the first bold statement above. regular_guy keep mentioning a focus on those engines with no outward signs of any problems. Again, why so many of those have had their bottom ends torn down, I can't quite figure out.

I think this thread is what really kicked off the topic:
http://www.m3post.com/forums/showthread.php?t=824004

From that thread forward, people started changing their rod bearings as "maintenance items." Many of them began posting photos when they got the service done. There are maybe 6-10 different threads of people doing this, and some posting photos. Some threads contain multiple cars, so it's not always easy finding them.

Now as to your statement in red, I couldn't agree more. Since there will almost for sure be no actual testing, I don't think there is much that anyone can post that will magically make the requirement testing as a necessary condition for "proof". Of course if a BMW M engineer came along, identified himself and admitted they botched it big time (perhaps with some reasonable explanation how that could actually happen) then we might have something concrete.

Correct. None of us have the funds (or time) to do this type of testing. Going from hypothesis to theory will be impossible IMO. But we can rule OUT certain possibilities.

Heck we can't even get a simple count from the proponents of the "clearance hypothesis" of how many engines fit the "pattern" of not modded, no outward signs of problems, then torn down, bearing wear noted and documented. My latest best estimate of this number remains at 0.02% (10 out of 50k)...

I don't believe anybody other than BMW will have these numbers, and I'm not a fan of guessing at statistics. I never thought of my photo database as anything but emperical evidence, and I never meant it to be anything else. I never thought of the photo database as "proof of anything" and I always thought of them as more pieces of data.

[swamp2]

Originally Posted by regular guy

I don't believe anybody other than BMW will have these numbers, and I'm not a fan of guessing at statistics. I never thought of my photo database as anything but emperical evidence, and I never meant it to be anything else. I never thought of the photo database as "proof of anything" and I always thought of them as more pieces of data.

BMW clearly won't have the numbers I'm looking for, they will have some related numbers for in warranty cars I guess.

Making reasonable and justified order of magnitude estimates, or similarly attempting a bracketing min/max estimate are both way more powerful "techniques" than guessing.

Also based on your input that cars meeting this particular criteria I have mentioned are in about a half dozen or dozen threads I'd immediately revise my 0.02% figure to be a lower estimate. I think 0.5% is still probably a reasonable upper estimate.

Come on, throw us a bone. How many cases do you believe you have uncovered that fit this general set of criteria I've mentioned. Let me nudge you along, 10 cases, 50 cases or 100 cases. See how powerful a ROM (rough order of magnitude) estimate can be.

[swamp2]

Originally Posted by gatorfast

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.

I'll bite... As it seems largely aimed at me and a few I strongly agree with.

There has been consistent praise for the effort put forth by RG, the OP. I'd never posit that I have spent anywhere near the time the OP has spent on this endeavor. At the same time I've spent a great deal of time simply thinking critically about this problem. I've posed many "tough" and legitimate questions and almost all of them still have no answer let alone a good answer. Many others have taken a similar approach in the discussion.

Other than kawasaki00, many of us (even perhaps the OP) now believe that we really won't ever have a firm, proven, causally connected answer to many of the questions posed here. Part of the reason we are in this "bind" is due to healthy skepticism (even perhaps a bit of unhealthy skepticism and even some barking up the wrong tree as well...). Being uncertain sucks but ultimately it is better than having a belief for the wrong reason and it's also better than being right for the wrong reason.

Also don't confuse measurements, rules of thumb or rash statements from experts (some of whom refuse to post their qualifications as an expert) to be the equivalent of an investigation. That term brings us full circle - a (scientific) investigation should have some form of testing... If the investigation is non-scientific then it pretty well means by definition that the conclusions are not proven.

Trust me if the numbers I've been trying to estimate here to "size" this potential problem were substantially larger, say even just 5% or so, I'd be a lot more prone to supporting some sort of class action effort. BMW would still of course never admit any mistake but we could get a redesign, an extended warranty, some free maintenance, etc. and we would have a much stronger hunch that BMW did make some error/mistake.

I guess you are perfectly welcome to (and probably will continue to do so despite this post) continue to believe my contribution here is worthless until I grab a rod and micrometer and post up some numbers...

[SenorFunkyPants]

So given that Clevite recommend a minimum rod bearing clearance for a "2.000” shaft diameter [of] .0015".
On page 1 of this thread...The only measurements taken with *new* bearings gave a range of .0014 to .0015".
The other (tighter) measurements were taken with a used set.
Does that really count as tight clearances?