Official S65 Rod Bearing Condition Example Thread

RSV Atelier wrote

....

All are ok , and all measured 0.51 with the new bearings.
I just want to say , i am not a "professional garage " . It is something that i do in my spare time .

Have you got a photo of your old bearings?

higgins2613 wrote

2013 with 45600 miles. Replaced with ACL and ARP2000’s.

Fancy carrying out a little experiment on 1 or 2 of your old shells?

2008 E93 M3 with 156,522 Miles (Factory Bearings)

The car has always been on a 5K mile OCI using factory BMW 10W60 oil change kits. No damage to the crank considering the condition.

I replaced them with ACL Custom Clearance Rod Bearings and ARP2000 Bolts

Stevenglan wrote

2008 E93 M3 with 156,522 Miles (Factory Bearings). The car has always been on a 5K mile OCI using factory BMW 10W60 oil change kits. No damage to the crank considering the condition.
I replaced them with ACL Custom Clearance Rod Bearings and ARP2000 Bolts

It was definitely time. You can sleep better now. I'm interested to know what ACL Custom Clearances you went with?
.

It was! I can definitely sleep better now haha. Here is the link to the set that I put in:

https://europowermotorsports.com/product/acl-race-series-rod-bearing-set-bmw-m3-e90-e92-e93-s65-v8-engine-with-custom-mixed-shells/

They created their own customized set that will achieve .0023″ to .0025″ bearing clearance, similar to the BE Bearings. Mine measured a little under .0025" on all journals with plastigague. It was right at $490 with bolts.

Stevenglan wrote

It was! I can definitely sleep better now haha. Here is the link to the set that I put in:

https://europowermotorsports.com/product/acl-race-series-rod-bearing-set-bmw-m3-e90-e92-e93-s65-v8-engine-with-custom-mixed-shells/

They created their own customized set that will achieve .0023″ to .0025″ bearing clearance, similar to the BE Bearings. Mine measured a little under .0025" on all journals with plastigague. It was right at $490 with bolts.

Excellent price. Thanks for posting that.

Stevenglan
Wow! Yea those on 3 & 4 were shot! Very lucky they didn't pick up!
Amazing mileage you got from those though! lol

Btw, unusual to see the lowers just as bad as the uppers, are they in their correct position?

For sure! And I was honestly surprised as well as I expected the top bearings to be in worse condition. I marked them with a paint pen on removal to ensure I kept the order.

2012 e92 M3 - 96,000km Car was in dealer network under full warranty for 10 years so had OEM service schedule. Clean as a whistle. really dont see much wrong with these at all.

uk215m3 wrote

2012 e92 M3 - 96,000km Car was in dealer network under full warranty for 10 years so had OEM service schedule. Clean as a whistle. really dont see much wrong with these at all.

They do show some wear, but compared with many other examples in this thread they’re in relatively decent shape for an S65 engine at roughly 60K miles. What brand of bearings and bolts did you use to replace them with?

uk215m3 wrote

2012 e92 M3 - 96,000km Car was in dealer network under full warranty for 10 years so had OEM service schedule. Clean as a whistle. really dont see much wrong with these at all.

........

Some mild surface wear and some flattening of the microgrooves it seems, yea not bad.

2011 E92 47,000 miles

Looked good, definitely some wear, more so on uppers. First picture better represents how they all looked…2nd picture was dealing with shadows and I tried to brighten it up a bit.

Al Bundy's Dodge wrote

2011 E92 47,000 miles

Looked good, definitely some wear, more so on uppers. First picture better represents how they all looked…2nd picture was dealing with shadows and I tried to brighten it up a bit.

Fancy carrying out a simple experiment on 1 or 2 of your old shells?

Assimilator1 wrote

Fancy carrying out a simple experiment on 1 or 2 of your old shells?

PM me…have a lot going on over next month including some travel, so just depends what you are after, time available, etc…

MAHLE's S65/S85 replacement Rod Bearing research paper:
https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf
I can’t imagine buying S65 Rod bearings from a company that reached this conclusion regardless of the empirical evidence in the market place all over the world.
The rod bearing photo below is only an example given to illustrate the failure mode and taken from this thread:
https://www.m3post.com/forums/showpost.php?p=29218232&postcount=2615
.

Work completed @ MPORIUM BMW, LLC
Fantastic folks over there.

2010 M3 sedan DCT
147,852k miles on original bearings.

DrFerry wrote

MAHLE's S65/S85 replacement Rod Bearing research paper:
https://marmotorsport.com/wp-content/uploads/MAHLE-Motorsport-High-Performance-Engine-Bearings-for-the-BMW-S65-S85-Iss.-2.pdf
I can’t imagine buying S65 Rod bearings from a company that reached this conclusion regardless of the empirical evidence in the market place all over the world.
.

OK, let's for a minute assume that MAHLE are incorrect. From the data I have seen (admittedly UK biased) actual engine failures are pretty rare. I'm open to be corrected on this. I'm not party to the origin of the bearings MAHLE have historically checked, it would be a reasonable assumption that they originated from BMW. The bearing picture in the report is from a set I submitted. These were used at my suggestion so any claims of selected samples to fit the conclusion could be disproven.

So what would be your theory / conclusion for the condition of the bearings we often see posted? Do you have data that I have possibly missed? Do you have any questions you would like me to pose to MAHLE on the subject? Company rules forbid them participating in forums / social media in any official capacity, but I can act as a go between.

My issue with the tight clearance theory is mainly centred on 4 points.

1. Early life failure would be normal with too little clearance, yet we are seeing bearings with 50,0000, 60,000, 70,000 + miles with no failure yet visually "worn" bearings.

2. Although the substrate is visible, it generally shows no signs of seizure or distress. The exception would be on engines that HAVE suffered catastrophic failure.

3. A number of these bearings have overlay no longer present / damaged in the counter bored area by the parting line. This is the part of the bearing with the largest clearance, so why the wear here? Excessive crush has been checked for and discounted as the steel backing had not distorted / yielded.

4. The actual drawing clearances have been made public and been shown to not be as tight as initially believed at 0.046mm nominal.


If you check back on posts, BE have conceded that this information is from a known and reputable source and should be trusted. I have personally met with Robert and so has the engineer who wrote the MAHLE report.

These are genuine questions, I have an unhealthy obsession with finding answers to problems. I spend a disproportionate amount of time on S65 bearings not because it generates a lot of turn over (it doesn't we have bearings that sell 100 times any volumes the S65 ever could) and bearing sales in total are around 10% of our business.

But, it is still a problem without a definitive answer so I keep digging. I genuinely don't believe there will be a eureka moment as I don't believe there is a single reason for all issues. But I do believe that collective minds sharing ideas and information openly have a far greater chance of piecing together the failure mode on these parts than any individual.

If all information is out in the public domain then that allows people to make an informed choice with full facts. If they then choose to not purchase MAHLE Motorsport then that is OK (for the S65 it's one of 3 brands we offer ) as long as that choice is made with full facts.

PaulGros wrote

OK, let's for a minute assume that MAHLE are incorrect. From the data I have seen (admittedly UK biased) actual engine failures are pretty rare. I'm open to be corrected on this. I'm not party to the origin of the bearings MAHLE have historically checked, it would be a reasonable assumption that they originated from BMW. The bearing picture in the report is from a set I submitted. These were used at my suggestion so any claims of selected samples to fit the conclusion could be disproven.

So what would be your theory / conclusion for the condition of the bearings we often see posted? Do you have data that I have possibly missed? Do you have any questions you would like me to pose to MAHLE on the subject? Company rules forbid them participating in forums / social media in any official capacity, but I can act as a go between.

My issue with the tight clearance theory is mainly centred on 4 points.

1. Early life failure would be normal with too little clearance, yet we are seeing bearings with 50,0000, 60,000, 70,000 + miles with no failure yet visually "worn" bearings.

2. Although the substrate is visible, it generally shows no signs of seizure or distress. The exception would be on engines that HAVE suffered catastrophic failure.

3. A number of these bearings have overlay no longer present / damaged in the counter bored area by the parting line. This is the part of the bearing with the largest clearance, so why the wear here? Excessive crush has been checked for and discounted as the steel backing had not distorted / yielded.

4. The actual drawing clearances have been made public and been shown to not be as tight as initially believed at 0.046mm nominal.

If you check back on posts, BE have conceded that this information is from a known and reputable source and should be trusted. I have personally met with Robert and so has the engineer who wrote the MAHLE report.

These are genuine questions, I have an unhealthy obsession with finding answers to problems. I spend a disproportionate amount of time on S65 bearings not because it generates a lot of turn over (it doesn't we have bearings that sell 100 times any volumes the S65 ever could) and bearing sales in total are around 10% of our business.

But, it is still a problem without a definitive answer so I keep digging. I genuinely don't believe there will be a eureka moment as I don't believe there is a single reason for all issues. But I do believe that collective minds sharing ideas and information openly have a far greater chance of piecing together the failure mode on these parts than any individual.

If all information is out in the public domain then that allows people to make an informed choice with full facts. If they then choose to not purchase MAHLE Motorsport then that is OK (for the S65 it's one of 3 brands we offer ) as long as that choice is made with full facts.

Empirical evidence from the market place for blown engines is given in the "Blown Motors, Rod Bearing Failure" catalog thread linked below. It is a 123 page thread started in 2012. I joined the forum in 2010 and am familiar with it.

https://www.m3post.com/forums/showthread.php?t=786615

Scientific evidence for "Why do the motors blow with rod bearing failure" is given in the BE Bearings article linked below. Tolerance stacking, tight clearances and oil starvation due to thick oil are the main points of the study article.

https://www.bebearings.com/Overview.html

Early failures were seen and some are shown in the BE Bearings article linked above. There are too many failure mode factors to list, but here's a few that may have been overlooked: The advent of start/stop technology and its adoption by BMW around 2010 (I think) places more strain on engine components. The S65 has a 12:1 compression ratio. Reports of detonation are not uncommon. Some areas of the USA require different gasoline additives for smog reduction (CA for one) and lower octane (RON) gasoline blends which can exacerbate detonation. The S65 uses an ionic detonation detection system which employs the spark plugs and coil pack chip set to monitor detonation. The S65 uses a 10W60 multi-viscosity motor oil - in spite of tight rod bearing clearances and even in cold climates such as the northern states and Canada. The too 'thick oil' for tight clearances subject is discussed in the BE Bearings article linked above. The S65 crank journals appear to be too narrow to my eye. Admittedly this is speculation on my part, but even a BMC A-Series engine has wider crank journals (more surface area to spread the load).

You asked:
So what would be your theory / conclusion for the condition of the bearings we often see posted? Answer: OEM Bearing clearances that are too tight (especially in cases of tolerance stack up), and oil starvation at cold start up as well as high RPMs due to the OEM choice of 10W60 oil. This is the same oil viscosity spec used in the E46 S54 M3 which also suffered from rod bearing failures. My conclusion stems from the empirical market place observation that we do see rod bearing failures using the OEM bearings but we do not see bearing failures (yet that I know of) using increased clearance bearings - such as those which are - and have been for some time - available from B.E. Bearings.

Do you have data that I have possibly missed?
Answer: Yes, please study the information contained in the links I provided above.

Do you have any questions you would like me to pose to MAHLE on the subject?
Answer: Yes. Did MAHLE consider the empirical evidence from the market place showing hundreds of blown motors with OEM rod bearings and yet no blown engines with extra clearance bearings when coming to the conclusion the OEM bearing specs were "entirely satisfactory"?

DrFerry wrote

Empirical evidence from the market place for blown engines is given in the "Blown Motors, Rod Bearing Failure" catalog thread linked below. It is a 123 page thread started in 2012. I joined the forum in 2010 and am familiar with it.

Would have been great with one thread Doc (3 posts?), much easier to follow and organise questions/answers in one (not the least for Paul who then only need one flame suit...) Interesting topic and surely lenghty, maybe use Pauls original thread instead of clutter a perfectly good general RB wear catalog?

Helmsman wrote

Would have been great with one thread Doc (3 posts?), much easier to follow and organise questions/answers in one (not the least for Paul who then only need one flame suit...) Interesting topic and surely lenghty, maybe use Pauls original thread instead of clutter a perfectly good general RB wear catalog?

Paul addressed me specifically in this particular thread. Hence, only one reply by me here. My other post(s) (including this thread I thought I only made two) are in more obscure thread(s) and for information only. Those thread(s) are possibly less subscribed too. There is nothing about my post to Paul that would require a flame suit IMO. Hopefully you can understand my logic now.

DrFerry wrote

Empirical evidence from the market place for blown engines is given in the "Blown Motors, Rod Bearing Failure" catalog thread linked below. It is a 123 page thread started in 2012. I joined the forum in 2010 and am familiar with it.

https://www.m3post.com/forums/showthread.php?t=786615

Scientific evidence for "Why do the motors blow with rod bearing failure" is given in the BE Bearings article linked below. Tolerance stacking, tight clearances and oil starvation due to thick oil are the main points of the study article.

https://www.bebearings.com/Overview.html

Early failures were seen and some are shown in the BE Bearings article linked above. There are too many failure mode factors to list, but here's a few that may have been overlooked: The advent of start/stop technology and its adoption by BMW around 2010 (I think) places more strain on engine components. The S65 has a 12:1 compression ratio. Reports of detonation are not uncommon. Some areas of the USA require different gasoline additives for smog reduction (CA for one) and lower octane (RON) gasoline blends which can exacerbate detonation. The S65 uses an ionic detonation detection system which employs the spark plugs and coil pack chip set to monitor detonation. The S65 uses a 10W60 multi-viscosity motor oil - in spite of tight rod bearing clearances and even in cold climates such as the northern states and Canada. The too 'thick oil' for tight clearances subject is discussed in the BE Bearings article linked above. The S65 crank journals appear to be too narrow to my eye. Admittedly this is speculation on my part, but even a BMC A-Series engine has wider crank journals (more surface area to spread the load).

You asked:
So what would be your theory / conclusion for the condition of the bearings we often see posted? Answer: OEM Bearing clearances that are too tight (especially in cases of tolerance stack up), and oil starvation at cold start up as well as high RPMs due to the OEM choice of 10W60 oil. This is the same oil viscosity spec used in the E46 S54 M3 which also suffered from rod bearing failures. My conclusion stems from the empirical market place observation that we do see rod bearing failures using the OEM bearings but we do not see bearing failures (yet that I know of) using increased clearance bearings - such as those which are - and have been for some time - available from B.E. Bearings.

Do you have data that I have possibly missed?
Answer: Yes, please study the information contained in the links I provided above.

Do you have any questions you would like me to pose to MAHLE on the subject?
Answer: Yes. Did MAHLE consider the empirical evidence from the market place showing hundreds of blown motors with OEM rod bearings and yet no blown engines with extra clearance bearings when coming to the conclusion the OEM bearing specs were "entirely satisfactory"?

I'm happy to put your points to MAHLE, my intention is to collate questions and submit them all at one time so please bear with me.

I will however, comment on some of your points.

1. OEM bearings theoretical clearance is 0.029 - 0.062mm with nominal 0.046mm – source OEM drawing.

2. They have commented on bearings seen (more than 1 set, see later post) as well as using the development data from their archives

3. I'm not familiar with US petrol (gas) but I would agree it is an interesting area that should be considered. Could the additional additives used in CA contribute to the bearing corrosion MAHLE reports? How can we prove / disprove this?

4. I'm not sure the A series would be a good comparison, The engine design is some 70 years old and was unique at the time due to the gearbox being located in the sump meaning the engine oil also lubricated the gear box. If you look at the Ford 1.6 EcoBoost engine (4 cylinder turbo, 200hp factory) we see a bearing width of 15.4mm with a 44.00mm shaft. Certainly in the UK in modified form these engines are regularly seen with 350hp +

5. I'm not convinced the oil viscosity is part of the issue. Now, I am far from an oil expert, but available technical papers suggest the opposite is true - the higher viscosity gives a thicker oil film. Example here https://www.substech.com/dokuwiki/doku.php?id=effect_of_oil_viscosity_on_hydrodynamic_friction_of_engine_bearings&s=oil%20viscosity

PaulGros wrote

I'm happy to put your points to MAHLE, my intention is to collate questions and submit them all at one time so please bear with me.

I will however, comment on some of your points.

1. OEM bearings theoretical clearance is 0.029 - 0.062mm with nominal 0.046mm – source OEM drawing.

2. They have commented on bearings seen (more than 1 set, see later post) as well as using the development data from their archives

3. I'm not familiar with US petrol (gas) but I would agree it is an interesting area that should be considered. Could the additional additives used in CA contribute to the bearing corrosion MAHLE reports? How can we prove / disprove this?

4. I'm not sure the A series would be a good comparison, The engine design is some 70 years old and was unique at the time due to the gearbox being located in the sump meaning the engine oil also lubricated the gear box. If you look at the Ford 1.6 EcoBoost engine (4 cylinder turbo, 200hp factory) we see a bearing width of 15.4mm with a 44.00mm shaft. Certainly in the UK in modified form these engines are regularly seen with 350hp +

5. I'm not convinced the oil viscosity is part of the issue. Now, I am far from an oil expert, but available technical papers suggest the opposite is true - the higher viscosity gives a thicker oil film. Example here https://www.substech.com/dokuwiki/doku.php?id=effect_of_oil_viscosity_on_hydrodynamic_friction_of_engine_bearings&s=oil%20viscosity

This goes round and round.

BMW nominal clearance is less than recommended by EVERY DAMN PROFESSIONAL ENGINE BUILDER ON EARTH!

The failure mode is diagnostic of flow starvation based on available literature (low flow due to tight bearings).

Not one single engine has blown up with properly sized bearings to date (due to rod bearing failure alone).

Many properly sized bearings have been pulled showing pristine shells after many hard miles (search, you can find them).

There is so much good hard data available - I am disappointed that this is still being “debated.”

Scharbag wrote

This goes round and round.

BMW nominal clearance is less than recommended by EVERY DAMN PROFESSIONAL ENGINE BUILDER ON EARTH!

You are a bit behind the curve there buddy.
Part of the original Glacier Vandervell drawing has been recently released showing the OEM bearings nominal clearance at 0.046mm.
A clearance in line with previous generations of M cars and the Clevite white paper.
Anything you ever read about S65 tight bearing clearance can be disregarded.