Official S65 Bearing Specification/Clearance Wiki

[BMRLVR]

Originally Posted by swamp2

Wow, interesting thread. I've been spending too much time over at the new M4 forum section recently...

To me it would be very interesting and relevant to know what the real failure rate is, even just an order of magnitude estimate. Let me give that a go...

It seems like about 25 failures are mentioned in the aforementioned "registry thread" not counting the "many more" ones on youtube.

The production numbers are:

~26k units (E90, E92 and E92) US and Canada
~58k units worldwide

We have the exact production numbers for E90 and E92 just the E93 had not quite wrapped up final production at the time we got the other numbers. So these numbers with rounding are correct/exact, not guesses.

I would guess the 25 in the registry thread are almost all in NA (US and Canada). That makes the NA "internet reported" failure rate 1/1000 or 0.1%. Pretty high considering that maybe this is perhaps 1/2 or 1/3 of all of the cases (not all cases end up here nor on youtube or anywhere else online). Let's say there are another 50% more cases known by forum members here but not reported. Let's also go with the 1/3 estimate above. This is admittedly pretty crude, but I have no idea how to get a better estimate. That gives about 100 failures (113 to be exact but again this is order of magnitude work). That then gives us a 0.4% failure rate to date in NA. For nice easy rounding let's say it's a nice even 1/2 of 1%, 0.5%. Said another way 1/200 cars have failed. Extrapolating this to world wide would mean about 300 cars total. Again this is an order of magnitude estimate. Maybe that number is 100 or 200, maybe 500, however it is certainly not just 50 and probably not 1000 either!

Some other key questions then are:

1. What percentage of these have been modified (most interesting what % were supercharged or had other major mods making power output changes)?
2. What percentage followed BMWs oil change recommendations?
3. What percentage exceeded BMWs oil change recommendations?
4. What percentage were driven on the track (strip or road coarse)? Of course not saying that the cars should not take that kind of use and come through shinning...

Is 0.5% of cars a real problem? I don't really have an answer for that question either. It is somewhat subjective. It's certainly not a huge problem in my evaluation. It becomes an even smaller problem when the cases with very early mileage problems covered by warranty and those cases with red flag answers to the above four question are eliminated. Heck we don't even know for what mileage/lifetime (mean time to failure, MTTF, specifically) BMW M intended for this engine.

The next question then is about design intent vs. manufacturing errors vs. manufacturing tolerance stack up. These are in order a systematic problems, random or systematic problem and lastly random. Sure, I respect the expertise of the quoted engine builders and other experts here posting on this topic but we simply cannot discount the engine engineering expertise at the OEMs, BMW M in particular (obviously...). In general I would rate them as more up to date, access to better testing and measurement equipment, more capability for simulation, immensely larger budgets, better contacts into academia, etc. I can only believe that BMW M had good reasons for the clearances and oil combination they selected, regardless of a differing opinion from the other experts here. I also can't see that they did not observe the same exact emperical bearing and rod heat/wear/lubrication issues which are being pointed out here. It is without doubt that they ran many engines very hard in the real world and on testing machines and subsequently torn those engines down and went through them with a FINE TOOTHED COMB. If a simple doubling of a few key clearances would have completely eliminated this "problem" how in the world could BMW M not also be aware of that? If the bearing suppliers have/had certain recommendations and they are more "in the know" than BMW M engineers wouldn't they have almost demanded BMW M use different clearances?

The problem inherently seems more like a variation issue rather than one of a fundamental design issue (i.e. a random issue). Although also a bit speculative, the belief stated prior that if a car makes it past some key mileage like 10-20k, then it won't fail also indicates a random problem rather than a systematic one. That would also support the idea of an improper control over manufacturing variations (some might commonly call this a tolerance stack up issue but that is really a different issue).

Similarly there is the (already partly discussed) fact the the S85 in the prior M5 and M6 engine was designed in the 2003-2004 time frame, has an "identical" bottom end (less one cylinder bank) and we are lead to believe that BMW have learned nothing from any design issues there. Is it reasonable that they did not know anything about "premature" failures in that engine? Could it be they did know and also made absolutely no changes in the S65?

Well, in short, I think this issue is far from settled...

The thing is that there are potentially more problems but people just wont know about them until they either disassemble their engines or they have a failure. Approaching this issue from a statistical standpoint is exactly what BMW will do. Basically it all comes down to dollars and cents and they are gambling with the fact that most of these engines will last beyond the warranty period and they are then off the hook.

The thing about the S65 is that it uses the exact same journal diameters, same rods and same bearings as the S85 so there were in fact no changes made to the S65 main and rod bearings and clearance specifications. The majority of the development for the S65 was most likely done side by side with the S85. Since the S54 bearing issue was not known or addressed till MY03 it is very likely that the majority of the S85/S65 development work was done before they knew there were clearance/bearing issues in the S54. Since the S85 was released for production in 2005 with the final engine R&D being done at least 2 years before, once the problem surfaced in the S54, BMW most likely decided not to spend big money on the S85 to change the clearance specs. This would involve having new cranks and bearings made, and test this stuff all before the release date of the E60 M5......... All this equals big $$$$$ and most likely the bean counters would have just said NO!

Clearances are not a mystery and are not something that has been played with a lot in engines over the last 50-60 years. the 0.001"/inch of journal diameter is a well accepted rule, and on the tight side 0.00075"/inch of journal diameter is also a number that is used quite often too. BMW is assembling some engines that are much tighter than even the latter quoted number above. The engines you mentioned that were tested for R&D were most likely hand assembled and blueprinted engines (as we have all seen from the videos of the gentleman assembling the S65 and all of the numbers being recorded for the particular engine right down to torque numbers on the head bolts) once the S65/S85 went to mass production there was no way to control or know if one bearing was 0.00025" tighter than the rest since measuring to this tolerance is no longer feasible. Having only one size of STD bearings available for an engine makes it damn near impossible to dial in clearances to exactly what you want. Even the lowliest civic or corolla will be assembled with multiple main and rod bearing sizes to dial in clearances to what QA wants. Even a GM small block has numerous bearing sizes available to allow the clearances to be dialled in from journal to journal and keep them within spec (even if they are not assembled as such the sizes are still available and with the relatively loose tolerances they are built with [roughly 0.002"+ mains and rods] a few ten thousandths don't matter anyway). Machine work is often out a few ten thousandths and when you are extremely tight like the S65 that can account for a 20-30% difference in total clearance....... With different bearing sizes one could hand fit every journal and cancel out minute machining differences.

I am 100% confident that the clearances in this engine (and the S54 and S85) are too tight. As soon as I heard the numbers I was horrified since I knew I would have to disassemble my S65 at some point to measure and confirm/adjust clearances if I wanted my engine to last for the life of the car. I have fit hundreds of sets of bearings and I have also seen many failures. The failures are virtually always either tight clearances or an oil starvation issue resulting from a failed oil pump, blocked oil passage, blocked pick-up tube, or low oil level.

Hopefully many people will not have any issue with their S65's and S85's and this may be the case......... What I fear is that the majority will see bearing issues, or at least accelerated wear. It is virtually impossible to build an engine this tight and not have the variation between bearings bite you in the butt without multiple bearing sizes to allow you to fine tune the clearances.

[swamp2]

Originally Posted by BMRLVR

I am 100% confident that the clearances in this engine (and the S54 and S85) are too tight.

If that is your literal and exact belief I'd go out on a limb and say you are 100% incorrect. If I may, let me reword this statement a bit, my wording seems to be in line with your thinking anyway:

BMW chose small bearing clearances in the S85 and S65 by design. It is unknown what advantage(s) or the design intent from BMW M was. Due to manufacturing variations in both bearings and cranks journals these clearances can and will become smaller the desired design point (this will happen in all engines, obviously). These smaller clearances are causing oil starvation issues in some engines/some bearings which can lead to catastrophic engine failure or accelerated/premature wear.

I still wouldn't even go that far primarily because of this, straight from the OP in post #108:

Originally Posted by regular guy

... the first thing I notice are the worst looking bearings coming from the cylinders with the largest bearing clearance. I've got to be honest, I don't quite understand that; but this is also the only engine I know that has correlated the clearance to the actual bearings.

To me this is DIRECT proof that for this particular engine the tighter clearances are a benefit, not a problem.

For all of those thinking that this story is done and a firm conclusion has been obtained I strongly advise to rethink this. A ton of data is vastly different than a firm and justifiable conclusion.

[swamp2]

Originally Posted by aus

Good post.
Also keep in mind, that the registry only includes blown engines, mostly on this board. There have been a LOT more engines with worn bearings in the other 2-3 threads here with pictures showing worn bearings. There have also been a few members here with high lead and copper levels on oil analysis, so those are problem engines too; just like all the youtube vids with ticking noises. Even then, I think it's still a small fraction of all the failed engines out there.

Thanks, if you would like to try to revise my "back of the envelope" estimate of the failure rate, please contribute by doing so. My estimate was very hasty and admittedly not based upon a complete examination of all evidence. Cheers.

[aussiem3]

But BMW has unofficially acknowledge there is a bearing issue. Now they are recommending a thinner oil.

[BMRLVR]

Originally Posted by swamp2

If that is your literal and exact belief I'd go out on a limb and say you are 100% incorrect. If I may, let me reword this statement a bit, my wording seems to be in line with your thinking anyway:

BMW chose small bearing clearances in the S85 and S65 by design. It is unknown what advantage(s) or the design intent from BMW M was. Due to manufacturing variations in both bearings and cranks journals these clearances can and will become smaller the desired design point (this will happen in all engines, obviously). These smaller clearances are causing oil starvation issues in some engines/some bearings which can lead to catastrophic engine failure or accelerated/premature wear.

I still wouldn't even go that far primarily because of this, straight from the OP in post #108:

To me this is DIRECT proof that for this particular engine the tighter clearances are a benefit, not a problem.

For all of those thinking that this story is done and a firm conclusion has been obtained I strongly advise to rethink this. A ton of data is vastly different than a firm and justifiable conclusion.

I know I am not 100% incorrect, many years of experience and many hundred sets of bearings don't lie!

As for the particular engine you referred to, I think there is an issue with concentricity of the rod bores and also possible fastener stretching due to the added wear near the parting line.

One thing you are 100% correct about is the more data we collect, the better off we will be to developing a solution. I will be building a stroker next summer and opening up the oil clearance on the mains and rods and adjusting the side clearance on the rods to something I am more comfortable with! At that point my low mileage S65 will be measured, pictures snapped and the info added to regular guy's data so as to benefit the entire community!

[OM VT3]

Originally Posted by BMRLVR

I know I am not 100% incorrect, many years of experience and many hundred sets of bearings don't lie!

As for the particular engine you referred to, I think there is an issue with concentricity of the rod bores and also possible fastener stretching due to the added wear near the parting line.

One thing you are 100% correct about is the more data we collect, the better off we will be to developing a solution. I will be building a stroker next summer and opening up the oil clearance on the mains and rods and adjusting the side clearance on the rods to something I am more comfortable with! At that point my low mileage S65 will be measured, pictures snapped and the info added to regular guy's data so as to benefit the entire community!

what oil do i use next!?

[BMRLVR]

Originally Posted by leigh

what oil do i use next!?

You can use the BMW recommended 5W30 and not have to worry. According to Kawasaki00 it is relabelled German Castrol 0W30....... An oil that I have used in all of my stuff for years now! Alternatively the M1 0W40 is great oil to use too and it has very similar properties to the GC.

[L4ces]

Lol!
But +1
Although I know no better, I am changing mine tomorrow and it's likely going to be either M1 0w40 or 5w30 OE.

And the answer is?

[BMRLVR]

Originally Posted by L4ces

Lol!
But +1
Although I know no better, I am changing mine tomorrow and it's likely going to be either M1 0w40 or 5w30 OE.

And the answer is?

Both good oils, if you are under warranty then go for the 5W30 OE.

I guess this throws the "S65 was designed for 10W60" guys for a loop now doesn't it!?

[gatorfast]

I'm confused about this BMW revised oil listing. Does this mean 5w-30 is ok for use in all current and previous M models or just recommended for current models (ie turbo cars)?

[PandaM3]

I'm confused too... In the bulletin it says that we can use 5w30 or 10w60 depending on what the climate is in the region we are in.

I'm in California... Does this mean I can use 5w30?

As far as warranty is concerned... Can I get away now with different brand oils now? Such as Mobil 1 0w40? Or motul 300V 5w30 or 0w40?

[L4ces]

Just something I read on Blackstone's site. It is not in response to anything, just more info and I hope it is not misinformation.

"The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase."

[CSL_E36]

Originally Posted by L4ces

Just something I read on Blackstone's site. It is not in response to anything, just more info and I hope it is not misinformation.

"The heavier oils provide more bearing film, and that's important at the lower end. If your oil is too light, the bearing metals can increase. If the oil is too heavy, the upper end metals can increase."

Strong info supporting BMW original recommendations from an Oil ANALYSIS company. I certainly would take that info with more then a grain of salt.....

[L4ces]

Originally Posted by 96LTWM3

Strong info supporting BMW original recommendations from an Oil ANALYSIS company. I certainly would take that info with more then a grain of salt.....

Link is attached for us newbies.
Since context is everything, I am posting the link

http://www.blackstone-labs.com/oil-viscosity.php

[aus]

Originally Posted by Moxie

Part # 07 51 0 037 195 is LL04 & not LL01. It's the same oil I run in the 335d.....the recommended oil list BMW put out listing it as LL01 is confusing.

From the manual - The 335d’s engine oil is different than for BMW gasoline engines. Use only “low-ash” fully synthetic oils meeting BMW’s long-life rating LL-04. One such oil is Castrol SLX Professional OE SAE 5W-30 (Castrol #06070). This oil is also available at BMW Centers under BMW part number 07 51 0 037 195.

http://www.bmwusa.com/Standard/Conte...ngineOils.aspx

Good info. Thanks.
I was wondering what BMW oil the 07 51 0 037 195 was for.
Anyone have any idea how it's different than the regular 5W30?

BMW Long-life rating LL-01 Synthetic Oils for BMW M vehicles equipped with S54, S62, S65 or S85 engines

Castrol EDGE Professional TWS Motorsport SAE 10W-60 Synthetic Engine Oil, BMW part number 07 51 0 009 420 or Castrol Edge Professional OE 5W30 Synthetic Engine Oil BMW part number 07 51 0 037 195

The following is a listing of synthetic oils recommended and approved for use in the BMW B7 ALPINA in the US market: BMW Genuine Oil SAE 5W-30 Synthetic Oil BMW part number 07 51 0 017 866

Originally Posted by dreamspeed

So to clarify, BMW is now saying regular old 5w30 oil like Castrol Edge or Mobil 1 is ok to use now?

That makes oil changes like a 3rd to a 4th of the cost as before with the TWS

So what would be the best oil to use? Reading through this post it seems like Mobil 1 0-40? Thanks

No exactly. You want the above BMW diesel oil, or Mobil 1 0W40.
NOT the standard Mobil 1 5W30.

.

[swamp2]

Originally Posted by BMRLVR

I know I am not 100% incorrect, many years of experience and many hundred sets of bearings don't lie!

To be fair your personal experience is with large, low rpm diesel engines, correct? It is also entirely devoted the the repair and remanufacture as opposed to the design or the engineering? Look, I'm not trying to beat you up here at all. You are a wonderful contributor to this forum and have plenty of knowledge and experience I don't. I have personally learned from you and thank you again for that. The statement above simply does not seem to be supported by your experience.

Also, your statement I criticized as incorrect was fairly easy to do so because it is so absolutist. Is every clearance on every engine too small? I think not, that's why I offered a rewording of the statement that seems to be more in line with the direction both you and the OP have taken already in prior posts.

Agree or disagree, my rewording of your statement is more accurate accounting of your hypothesis? Note I use the term hypothesis because that is about all we have thus far. This has not yet graduated to the status of a theory.

Originally Posted by BMRLVR

As for the particular engine you referred to, I think there is an issue with concentricity of the rod bores and also possible fastener stretching due to the added wear near the parting line.

Pure, unadulterated speculation. And speculation so that the data will fit your premature conclusion. Really I expect better especially from you! One might be able to make loosely related statements about other tolerances anywhere in the system to explain away most of the observations already made.

Last but not least, I think someone should chime in here with an attempt to understand BMW M's DESIGN INTENT. If doubling of this clearance would have absolutely no downside and 100% pure upside then they would have done it. They chose the nominal clearance for a reason.

[dreamspeed]

Ok, so after scouring the board for all the posts about these bearing problems i went from just dismissing the issue to accepting that it could legitimately be an issue.

I plan to send in my oil for analysis when I do my next oil change and if there are elevated levels of lead I'll switch to a lighter oil. If not, I'll just stick with the TWS

[regular guy]

Originally Posted by swamp2

Last but not least, I think someone should chime in here with an attempt to understand BMW M's DESIGN INTENT. If doubling of this clearance would have absolutely no downside and 100% pure upside then they would have done it. They chose the nominal clearance for a reason.

We will never know BMW's design intent, but we can infer it from the Mahle-Clevite white paper on the subject of bearing clearance. That part's been mentioned here and in other threads. In a nutshell, tighter tolerance may give higher power, better gas mileage, and a quieter engine. The trade off is engine longevity -- which translates to engine reliability.

[regular guy]

Here's a quote from the Mahle-Clevite white paper to explain why engine manufacturers sometimes employ tighter tolerances.
http://www.mahle-aftermarket.com/C125790900540AC0/vwContentByUNID/56F6CDE0B180EF1BC12579AB00611F28/$FILE/EB-20-11.pdf (pages 25-27)
http://www.mahle-aftermarket.com/C125790900540AC0/vwContentByUNID/58A5032D3003098AC12579AB00615520/$FILE/EB-10-07.pdf (pages 09-11)

For most applications .00075 to .0010” (three quarters to one thousandth of an inch) of clearance per inch of shaft diameter is a reasonable starting point. For example a 2.000” shaft diameter would require .0015 to .0020” bearing clearance. (.00075 X 2.000” = .0015” and .0010 X 2.000” = .0020”) Using this formula will provide a safe starting point for most applications. For High Performance engines it is recommended that .0005” be added to the maximum value determined by the above calculation. The recommendation for our 2.000” shaft would be .0025” of clearance. (See figure 2.)

Remember however, that the above are only recommended starting points. The engine and its application will tell us where to go from these starting points. For example, a passenger car engine assembled at .0010” per inch of shaft diameter might turn out to be noisy on start-up, especially if the engine has an aluminum block. Most passenger car engines are originally assembled by “Select Fitting” to achieve clearances that are less than what would result from random selection of mating parts. This is because the stack-up of manufacturing tolerances on the mating parts may exceed
the acceptable level for control of noise and vibration. In addition, most new passenger car engines are now designed to use 5W-30 weight oils to reduce HP loss and conserve energy. These lighter weight oils are capable of flowing more freely through tighter clearances.

It's noteworthy that according the Mahle-Clevite (BMW's S65 bearing manufacturer) tighter tolerances must be mated with thinner oil. The above quote used the example of 5W30 oil for tighter tolerances -- which is exactly what BMW just announced may be allowed on our M engines.

[BMRLVR]

Originally Posted by swamp2

To be fair your personal experience is with large, low rpm diesel engines, correct? It is also entirely devoted the the repair and remanufacture as opposed to the design or the engineering? Look, I'm not trying to beat you up here at all. You are a wonderful contributor to this forum and have plenty of knowledge and experience I don't. I have personally learned from you and thank you again for that. The statement above simply does not seem to be supported by your experience.

Also, your statement I criticized as incorrect was fairly easy to do so because it is so absolutist. Is every clearance on every engine too small? I think not, that's why I offered a rewording of the statement that seems to be more in line with the direction both you and the OP have taken already in prior posts.

Agree or disagree, my rewording of your statement is more accurate accounting of your hypothesis? Note I use the term hypothesis because that is about all we have thus far. This has not yet graduated to the status of a theory.

Pure, unadulterated speculation. And speculation so that the data will fit your premature conclusion. Really I expect better especially from you! One might be able to make loosely related statements about other tolerances anywhere in the system to explain away most of the observations already made.

Last but not least, I think someone should chime in here with an attempt to understand BMW M's DESIGN INTENT. If doubling of this clearance would have absolutely no downside and 100% pure upside then they would have done it. They chose the nominal clearance for a reason.

You are just now entering this discussion and telling me that you expect better of me?!

I am not speaking from total lack of experience here nor am I going off of speculation. If I had the parts here in front of me I could measure the rods with the excessive wear and prove to you that there was an issue with the boring of those particular rods and show there is an issue there. I actually work on high and medium speed diesels mostly. (Low speed diesels are largely reserved for large power generation facilities and ships). Your statement stating that my experience is unrelated is not correct either. A bearing and the principals of hydrodynamic lubrication and clearances are the same regardless of the engine. We still use the same 0.00075"- 0.001"/ inch of journal diameter during assembly and what we lose in RPM we more than make up for in the mass of the parts and forces exerted. The end result is the same regardless of the engine you work on.

Your comment regarding not being involved in engineering and development of engines is not entirely true either. Our mine has been use as a testing ground for most of the new products that came on the market in the mining industry! We had the first development (Field follow as the manufacturers call them) CAT 797A truck in operation, one of the first two development Komatsu 960E's in the world. One of the first two CAT 797F trucks in operation. In fact, right now we are helping Komatsu in developing their Autonomous (operator less/fully automated) 930E haul truck for oil sands usage at our mine as we speak. All of these units have been new prototype units and have had developmental engines and transmissions/diesel electric propulsion systems in them, which we, the local dealers, and the manufacturers have worked together on to work out the bugs and come to a production ready product. In mining equipment the only way to develop a product is to put it in service at a mine where it will be working once it is in production. Real world testing of large mining equipment is hard to do unless you own a mine......... None of the manufacturers own mines big enough to accurately test their largest equipment ...... Just smaller proving grounds. I interact with development engineers on a daily basis so you are incorrect in your statement.

I highly respect your opinion and you make huge contributions to the forum. I wish you would give me some more credit in this area since I do this on a daily basis and have seen failure after failure. Based on all of the photos that have been posted and measurements that have been taken I am quite confident in my diagnosis since I have seen these conditions many, many times before.

You say that you wish someone would enlighten us on the "M design intent". Unfortunately, there probably was a design intent but there was also one with the original S54....... One that was flawed and they changed their intent along with bearing clearances, bearing shells, and even rods and rod bolts. This goes to show that even with their "design intent" there are still mistakes made. I personally think that in light of the previous acknowledgement of the S54 bearing issue, BMW is going to be highly reluctant to admit there is an issue with the S65 and S85 since it would damage their credibility. Acknowledgement of an issue here would show the customers that they obviously didn't learn from the S54 so it is most likely that engine issues will be handled on a case by case basis with the S65 and S85. Their latest recommendation of the lighter oil (Castrol Edge OE 5W30) also shows that they are acknowledging that there is a potential issue at hand....... Just a few months ago a lighter oil in an NA M engine was strictly Taboo..... M engines were designed for 10W60...... Right!?

I apologize for any grammatical or spelling errors, I replied from my I phone.

[VtecforV8]

To sum up the oil recommendations, M1 0w40 seems like a safer (and significantly cheaper) bet than the TWS 10w60. Is that the consensus here?

[kawasaki00]

Originally Posted by VtecforV8

To sum up the oil recommendations, M1 0w40 seems like a safer (and significantly cheaper) bet than the TWS 10w60. Is that the consensus here?

Yes, directly from the website

•BMW Long-life rating LL-01 Synthetic Oils for BMW M vehicles equipped with S54, S62, S65 or S85 engines

Mobil 1 0-40 has LL01 approval on the bottle. Therefore according to the new recommendations it is ok to use. Also because it says LL01 on the bottle you will also retain warranty.