Official S65 Bearing Specification/Clearance Wiki

[thekurgan]

Originally Posted by MWM3

so does this mean that my car is going to blow up in the near future?

Tomorrow, it will blow up.

[swamp2]

Originally Posted by BuckRodgers

What will or will not happen at this point is pure speculation until real world data is collected over time. The only facts we have is that bearings were changed to provide a more durable surface ...

Agree on the speculation part. However it also sounds a bit speculative to say that the bearing change provides a more durable surface. Keep in mind that the crank and bearings should actually never touch, there should always be a complete film of oil. I suspect (following others statements/suspicions) that the bearings were changed primarily to go lead free.

[thekurgan]

Originally Posted by swamp2

Agree on the speculation part. However it also sounds a bit speculative to say that the bearing change provides a more durable surface. Keep in mind that the crank and bearings should actually never touch, there should always be a complete film of oil. I suspect (following others statements/suspicions) that the bearings were changed primarily to go lead free.

My paranoid nature would suspect too many UOAs showing lead/copper, with these new bearings, now we're looking for tin/aluminum? The side effect being of a harder compound. It will be curious to see some of the new bearings pulled with severe wear, as well as the crank examined.

[Ronnydashore]

I still have no heard anyone give a good reason why M decided to change the crank and bearings after 08 (or whenever the last change was)?

Also given a few posts that showed the bearings with the most clearance had more wear than those with the least brings into question the clearance issue as being the problem does it not?

To me it seems like a much more simple option. They designed all the past M cars to beat on the track or the ring where testing is done. In those locations and conditions I imagine the temps are kept much higher than the vast majority of daily drivers around the world in their M cars. At the higher engine temps the oil is probably absolutely fine as a light 60 weight TWS. With the temp needle at 210 or higher which M probably designed the car for, all is well. You get people driving normally or babying the car, the oil doesn't get warm and thin out enough and causes problems as discussed.

But in the end M has to design an engine for something. They chose to design it for the all out performance. Most want them to be more hardcore and stick to their heritage which is a racing heritage and this engine is designed as such. Beat on the engine once warmed up and the oil stays nice and thin as designed. Slug it around town like a high-revving car is not meant to do, and you pay the price.

To me this makes a lot of sense as does not buying an m3 if you are not going to live above 5k rpms.

[Leonardo629]

I'm not surprised with Malek's latest track testing/finding, M1 0W40 has some of the most robust chemistry and certifications, I have strong confidence that the product will serve our S65s well.

[speedaddictM3]

Originally Posted by Ronnydashore

I still have no heard anyone give a good reason why M decided to change the crank and bearings after 08 (or whenever the last change was)?

Also given a few posts that showed the bearings with the most clearance had more wear than those with the least brings into question the clearance issue as being the problem does it not?

To me it seems like a much more simple option. They designed all the past M cars to beat on the track or the ring where testing is done. In those locations and conditions I imagine the temps are kept much higher than the vast majority of daily drivers around the world in their M cars. At the higher engine temps the oil is probably absolutely fine as a light 60 weight TWS. With the temp needle at 210 or higher which M probably designed the car for, all is well. You get people driving normally or babying the car, the oil doesn't get warm and thin out enough and causes problems as discussed.

But in the end M has to design an engine for something. They chose to design it for the all out performance. Most want them to be more hardcore and stick to their heritage which is a racing heritage and this engine is designed as such. Beat on the engine once warmed up and the oil stays nice and thin as designed. Slug it around town like a high-revving car is not meant to do, and you pay the price.

To me this makes a lot of sense as does not buying an m3 if you are not going to live above 5k rpms.

Have you seen car companies do their testing? They test them under all conditions, including wet, cold weather, and high mileage daily driving. As much as some people refuse to believe it, the M3 is not a race car. One glance at the cheapo monopiston brake calipers should convince you of that. I strongly doubt BMW expects M3 owners to spend most of the time setting record laptimes at their local track. BMW made this car to widen the appeal of M cars to attract posers, magazine racers, and those who prefer to own nice things but not use them the way they are meant to be used. That is more apparent given how the E9x M3 is so much softer, more luxurious, and more numb than the E46.

Besides, the problem doesn't seem to be oil viscosity per se as much as it is tight bearing clearance. A thinner oil may be a bandaid solution to prolong bearing life, but it seems with such tight clearances excess bearing wear is unavoidable.

[swifty]

Ok, so I just bought a brand new M3 2013 and tried to read through this thread as much as I could.

What steps should I follow for breaking the engine in ... I'm assuming that the information gleaned from past 5 years has changed the original view on how to break this engine in.

Also another thing I noticed is how some M3s go thru oil at a much higher rate than other M3s.

Last should be sending my oil in for analysis regularly so a base can be established? If so at what mileage and how often should I get the oil changed.

Thanks in advance for all the info you guys have provided to current and future owners.

[thekurgan]

Originally Posted by swifty

Ok, so I just bought a brand new M3 2013 and tried to read through this thread as much as I could.

What steps should I follow for breaking the engine in ... I'm assuming that the information gleaned from past 5 years has changed the original view on how to break this engine in.

Also another thing I noticed is how some M3s go thru oil at a much higher rate than other M3s.

Last should be sending my oil in for analysis regularly so a base can be established? If so at what mileage and how often should I get the oil changed.

Thanks in advance for all the info you guys have provided to current and future owners.

There may be additional factors for you, depending on how you drive the vehicle, the ambient temperatures, travel distance, etc.

I would for sure, let the oil warm up/hot before I let the rpms climb and consider a different weight for Canadian cold weather.

[kawasaki00]

Has Longwong re-entered the thread?

[dparm]

Originally Posted by klammer

Would it make sense to switch oils depending on the season? Am in Chicago so winters get pretty cold, but in the summer its hot and I track quite a bit...also, is there any risk in preventative switching out OEM for OEM of the bearings?? Am worried I've had no problems, replace the bearings, and the new ones don't match as well or they create a clearance issue where one never existed before...does that make sense? Also, haven't heard enough about the statistical probability of these events and how much tech and engineering improves and that clearances may or may not be changing over time...I plan on doing a winter refresh with the car and am just running down the checklist and looks like this will be added...the beauty of science and engineering is that almost nothing is set in stone (thinking larger concepts, not math) , just greater degrees of understanding...thanks for continuing to add to that level of understanding to all

You can run M1 0w40 year-round. It's basically a streetable race oil.

These cars are not air-cooled (they're water-cooled) so there is no reason to run thicker oil in the summer.

[thekurgan]

Originally Posted by kawasaki00

Has Longwong re-entered the thread?

Who?

[Yellow Snow]

Originally Posted by kawasaki00

702 .07855
703 .07875
Measurements are pretty much in line with what others have documented up until they get polished.
.

That doesn't concur with my sizes. Can you explain why my measurements were .07844" for both bearings? I was using a much more accurate measuring process.

It makes no sense at all that one of your measurements makes the bearing thicker than 2mm unless quality control is that bad.

Also, why the 50% price difference between top and bottom shells? Both shells are exactly the same in size and appearance. There must be a difference in material?

[FogCityM3]

Lots of evidence to prove that what BMW did was wrong, but as someone stated earlier what is the hypothesis for BMW making the decisions of a) original bearing clearances, b) changing the crank 3x and bearing materials 1x, c) keeping same clearances in new cars vs changing them with increased clearances when they decided to change bearing material and the crank d) the ease of changing bearings/clearances like they did for the E46 m3. Something just seems really weird in that given the opportunities to change the clearances and cranks, they consciously decided not to

An alternative hypothesis is probably pretty important here to provide a rational argument for BMW taking various actions/decision points as well as establishing plausibility as to why a mistake was made in the first place (or was it a conscious, yet ultimately erroneous decision)?

[swamp2]

Originally Posted by FogCityM3

BMW making the decisions ... b) changing the crank 3x ...

It was not clear to me at all that we have 3 part numbers with 3 different nominal sizes for the crankshaft. Did I completely miss that. Were any measurements provided to establish this?

[Yellow Snow]

Originally Posted by swamp2

It was not clear to me at all that we have 3 part numbers with 3 different nominal sizes for the crankshaft. Did I completely miss that. Were any measurements provided to establish this?

Exactly.

No actual evidence of BMW changing clearances, just guesswork.

Is there any actual evidence that the s54 bearing change gave more clearance? Or is it guesswork again.?

[FogCityM3]

Don't know and another question that needs to be answered... basing it on what others said in the thread in making claims that there were different part numbers (and as yet unknown measurements and whether were same or different with each part number).

Originally Posted by swamp2

It was not clear to me at all that we have 3 part numbers with 3 different nominal sizes for the crankshaft. Did I completely miss that. Were any measurements provided to establish this?

[FogCityM3]

This is the 4th reincarnation per my count.

Originally Posted by kawasaki00

Has Longwong re-entered the thread?

[regular guy]

Originally Posted by swamp2

It was not clear to me at all that we have 3 part numbers with 3 different nominal sizes for the crankshaft. Did I completely miss that. Were any measurements provided to establish this?

You are correct, I have no data to support three different sets of crank journal sizes with different part numbers. I have multiple cranks to choose from, but so far can't even find any different markings on them to know which one is an earlier or later part number. I know somebody who has about 50 S65 cranks. Maybe when I get some time, I'll go over there and ask to inspect them. But getting time is a big "IF" with my current schedule.

EDIT: I personally assume the journal sizes haven't changed in spite of three different crank part numbers. Instead, I assume the manufacturing process might have changed, but the specs stayed the same.

[thekurgan]

Originally Posted by FogCityM3

This is the 4th reincarnation per my count.

I count 5.

[swamp2]

Originally Posted by regular guy

EDIT: I personally assume the journal sizes haven't changed in spite of three different crank part numbers. Instead, I assume the manufacturing process might have changed, but the specs stayed the same.

Sounds like very solid speculation to me.

I'm trying to do my small part to quell the rampant rumors and false conclusions on this important thread...

[bigtracing]

I have been working on finding parts to rebuild my motor with and found a guy with a 2011 s65 with only 1400 miles that came out because the lady drove it through a puddle and it hydro locked. he pulled down the motor for me and sent me pics other then one cylinder the rest of the motor looks fine. I am just interested in the crank and oil pump possibly heads. What I will be intrested to see is the bearings. since the car was just out of break in I want to see what they look like after they break in.

I have been working on a new thread as I tear down the motor. it will be up soon.

[qtrlifecrisis]

Fantastic read. I just picked up an 08 m3 with 75k miles.

It's going to dual purpose as a daily/track rat and of course one of the first preventative(hopefully) maintenance issues that I want to address is the rod bearings.

I'm curious if you guys have any recommendations for this yet? I noticed that some of the bearings are different sizes for different manufacturers. And then there's the different types of oil.

Can an oil analyses help me sleep a little easier about this until I replace the bearings?

Thanks again to everyone for this amazing write up!