Official S65 Rod Bearing Condition Example Thread

[BimmerMan33]

2011.5 E92 M3 manual transmission, changed rod bearings last week at 74,000 miles using BE bearings & BE-ARP bolts.
I would recommend Performance Eurowerks, Buffalo Grove, IL for those looking in Chicago area.
I shall continue using Redline 5w50 eve though BE bearings are extra clearance but I am concerned about main bearings whose clearance is also tighter that industry standard & 10w60 could have flow issues during cold starts in winter weather.

[Helmsman]

Originally Posted by BimmerMan33

2011.5 E92 M3 manual transmission, changed rod bearings last week at 74,000 miles using BE bearings & BE-ARP bolts.
I would recommend Performance Eurowerks, Buffalo Grove, IL for those looking in Chicago area.
I shall continue using Redline 5w50 eve though BE bearings are extra clearance but I am concerned about main bearings whose clearance is also tighter that industry standard & 10w60 could have flow issues during cold starts in winter weather.

You discussed that with your shop, run with a lighter oil even with increased clearance? Would def not do that but thats me.

[pbonsalb]

The clearance is increased to closer to the industry standard, but the industry standard is not 10W60. Other weights can work fine.

[IamFODI]

Originally Posted by BimmerMan33

2011.5 E92 M3 manual transmission, changed rod bearings last week at 74,000 miles using BE bearings & BE-ARP bolts.
I would recommend Performance Eurowerks, Buffalo Grove, IL for those looking in Chicago area.
I shall continue using Redline 5w50 eve though BE bearings are extra clearance but I am concerned about main bearings whose clearance is also tighter that industry standard & 10w60 could have flow issues during cold starts in winter weather.

Is it me or do those look completely fine for the mileage?

[Scharbag]

Originally Posted by IamFODI

Is it me or do those look completely fine for the mileage?

For an S65 they look good. Lucky tolerance stack.

They still show wear which is unacceptable at such low mileage.

Sucks there is no way to know if you are lucky and have adequate clearance without opening up the engine. And once you are there, you might as well replace them anyway.

Cheers,

[IamFODI]

Originally Posted by Scharbag

For an S65 they look good. Lucky tolerance stack.

They still show wear which is unacceptable at such low mileage.

Sucks there is no way to know if you are lucky and have adequate clearance without opening up the engine. And once you are there, you might as well replace them anyway.

Cheers,

How bad is the wear, though?

Asking honestly. It doesn't look any different from "normal wear" pics of similar bearings I've seen in other contexts, and it certainly doesn't look anywhere near worn to the point of imminent seizure or crank damage. But I'm an amateur. Interested to hear from a better informed party.

[Helmsman]

Originally Posted by IamFODI

Is it me or do those look completely fine for the mileage?

Tend to agree, comparing the piles of shells we've seen coming out they look great for the mileage. Which is yet another reason I'd personally would stay to 10W60.
And possibly even stick with 702/703 clearance but maybe a VAC or ACL lead tin shell. Easy to say though as the shells typically already are delivered once the old comes out.

[BimmerMan33]

Originally Posted by IamFODI

Is it me or do those look completely fine for the mileage?

I felt they looked fair for an S65 but on few of the shells the top layer at some places was worn enough to start showing minimal glimpses of the underlying metal surface.
For 74,000 miles in general, they definitely look worn more than expected.
Like others have said, it's difficult to guess but most people that have changed rod bearings around 75K miles have similar bearing wear.
It's around $2300 for peace of mind , especially if you are planning to keep the car long term/over 100K miles. I would suggest using a lighter oil 5W50 which would flow better and might slow down the bearing wear while you decide if/when you want the bearing service done.
Maybe we should consider rod bearing service as part of routine Maintenence on these cars at 75-100K miles, just like cooling system refresh on older BMWs...

[pbonsalb]

I would do the next change interval based on what is seen at the mileage when the bearings are removed. Probably very very few will drive the cars enough to do more than one change. I changed at 60k in 2014 and the bearings were excessively worn but not on the verge of failure and was thinking about changing again at 120k. My car is at 95k now so at the rate I drive, that will be in 2022. Unless I get really bored before then and decide to pull the motor for fun and change the main bearings — something I am considering if my free time opens up.

[IamFODI]

Originally Posted by BimmerMan33

Maybe we should consider rod bearing service as part of routine Maintenence on these cars at 75-100K miles, just like cooling system refresh on older BMWs...

That's my approach, until/unless a field-proven long-term fix emerges.

[Scharbag]

Originally Posted by IamFODI

That's my approach, until/unless a field-proven long-term fix emerges.

Problem is, this is not just a mileage thing. The probability of failure is based on how tight your bearings are. Some peoples will never blow up and others are dusted at very low mileage.

Rod bearings are not wear items.

Purchase some properly designed BE bearings and do it once. BE-ARP bolts make it easier but new factory bolts work too.

Cheers,

[IamFODI]

Originally Posted by Scharbag

Problem is, this is not just a mileage thing. The probability of failure is based on how tight your bearings are. Some peoples will never blow up and others are dusted at very low mileage.

Rod bearings are not wear items.

Purchase some properly designed BE bearings and do it once. BE-ARP bolts make it easier but new factory bolts work too.

Cheers,

Has anyone actually characterized the relationship between tolerance stack-up and bearing lifespan, or are you inferring that relationship from the idea that the clearances are the problem?

Already had my rod bearings done and won't be doing them again for a while. By the time I'm due to revisit this issue, I'm sure it'll be pretty clear which route I should go.

[Scharbag]

Originally Posted by IamFODI

Has anyone actually characterized the relationship between tolerance stack-up and bearing lifespan, or are you inferring that relationship from the idea that the clearances are the problem?

Already had my rod bearings done and won't be doing them again for a while. By the time I'm due to revisit this issue, I'm sure it'll be pretty clear which route I should go.

This has been covered in great detail. Bearings need clearance to operate. If there is too little clearance, then the bearings will not operate as intended. The that happens, wear occurs. This is bad...

Cheers,

[IamFODI]

Originally Posted by Scharbag

This has been covered in great detail. Bearings need clearance to operate. If there is too little clearance, then the bearings will not operate as intended. The that happens, wear occurs. This is bad...

Cheers,

Interesting -- I think by missing the point of my question, you actually answered it.

[Solo_M_Tech]

This is the best thread on any forum, on the entire internet. It's full of people who think they got lucky and dodge an S65 grenade.

It's also full of internet experts who think they truly understand the issue and it's technical attributes.

Also it's got a dash of actual engine experts familiar with this engine.


ALL OF WHICH STILL HAVEN'T COME UP WITH A SOLUTION!

Here's why...... ( In my opinion based on 100+ bearing replacements done over the last 2 years)

Not every S65 suffers from tolerance stacking issues. Not every S65 suffers from improperly torqued rod bolts. Not every S65 suffers from out of round rod end bores.... All of which cause the typical wear patterns we see posted here.

Each engine is a special combination of issues. Some worse than others. Best practice is to replace the bearings and bolts with a combination that has been shown to work..... but we still don't have any real evidence that the current line up of solutions actually prevent wear accross a WIDE RANGE OF ENGINES. I emphasize that because one or two people who have had the service done a second time and post their specific results doesn't lend a large enough evidence pool to be conclusive.

Summary: change your bearings for piece of mind. We don't yet know if it's a solution to the problem, or just a band aid. I lean toward the latter....

[BimmerMan33]

Agree with Solo M Tech's post above, changing rod bearings is probably a band aid but with increased clearance bearings the band aid might last to 175-200K miles, at which point this platform would be quite old and most people might move on to other cars/newer M3s.
For those who still hang on to their cars, might then consider an engine out rebuild and refresh/upgrade a bunch of other engine components as well, including main bearings, maybe make it a stroker motor or other etc...

[Solo_M_Tech]

Originally Posted by BimmerMan33

Agree with Solo M Tech's post above, changing rod bearings is probably a band aid but with increased clearance bearings the band aid might last to 175-200K miles, at which point this platform would be quite old and most people might move on to other cars/newer M3s.
For those who still hang on to their cars, might then consider an engine out rebuild and refresh/upgrade a bunch of other engine components as well, including main bearings, maybe make it a stroker motor or other etc...

Unfortunately there isn't any evidence that the increased clearance really extends service life, since like I said before, each engine is different. I've pulled bearings at 22k miles and they were wiped, and I've pulled bearings out of a 113k mile 1 owner that were in almost new condition with minimal wear. I've pulled bearings with minimal wear but the parting lines were down to the copper, indicating the rod bore is out of round due to improper torque. While the extra clearance may be beneficial for the first candidate, it may not be for the latter. Same can be said for changing OE bolts for ARP, it might be the perfect solution for one engine and cause an out of round condition for the next. Ideally you should look at the wear on your OE bearings, take clearance measurements, install new bearings and repeat. Adjust until you obtain the proper clearance. Also anytime you replace the rod bolts you should check the rod end for an out of round condition with the bolts torqued. This requires an engine out experience. While we can all agree that changing your bearings out for any of the available kits ( BE, VAC, WPC, ACL, KING etc) is a very smart idea, it's not a cure all for every engine. Just the majority.

[IamFODI]

Well said, Solo.

[rantarM3]

Originally Posted by Solo_M_Tech

Adjust until you obtain the proper clearance.

But what exactly is that clearance? Has BMW published any guidance, or are installers shooting for what is being referred to as "industry standard recommended clearance"?

I read a few articles on engine building, and they had sections dealing with bearing and clearance selection. I'm no expert but based on what the articles stated, there are a plethora of factors that go into determining what the clearance should be for a given engine. My impression was that this "industry standard" was a starting point and nothing more. You would then make clearance adjustments (either looser or tighter) depending on your build and goals (although you certainly might end up not needing to make adjustments). They even mentioned crank material as relevant in making that determination. Perhaps I've missed it but it seems that no one has published a comprehensive S65 clearance analysis that takes into account the multitude of factors mentioned in the articles. Maybe there's a reason for that - who knows.

I'm in no rush to crack open my engine to replace the bearings. I'm the original owner, broke-in the engine strictly following BMW's instruction (to 3,000 mi.), always keep the engine below 3k rpm with low throttle while warming up the engine, never "beat" on the car, and frequently change the oil + filter. But more importantly, like you, I don't believe anyone has actually identified the cause of the exhibited abnormal wear on this engine (and perhaps there's no single cause).

[Solo_M_Tech]

Originally Posted by rantarM3

But what exactly is that clearance? Has BMW published any guidance, or are installers shooting for what is being referred to as "industry standard recommended clearance"?

I read a few articles on engine building, and they had sections dealing with bearing and clearance selection. I'm no expert but based on what the articles stated, there are a plethora of factors that go into determining what the clearance should be for a given engine. My impression was that this "industry standard" was a starting point and nothing more. You would then make clearance adjustments (either looser or tighter) depending on your build and goals (although you certainly might end up not needing to make adjustments). They even mentioned crank material as relevant in making that determination. Perhaps I've missed it but it seems that no one has published a comprehensive S65 clearance analysis that takes into account the multitude of factors mentioned in the articles. Maybe there's a reason for that - who knows.

I'm in no rush to crack open my engine to replace the bearings. I'm the original owner, broke-in the engine strictly following BMW's instruction (to 3,000 mi.), always keep the engine below 3k rpm with low throttle while warming up the engine, never "beat" on the car, and frequently change the oil + filter. But more importantly, like you, I don't believe anyone has actually identified the cause of the exhibited abnormal wear on this engine (and perhaps there's no single cause).

I tend to believe the bmw specified oil clearance was engineered correctly given the intended rpm range of the engine, but due to tolerance stacking and inconsistent torque on the bolts, the majority of the engines exhibit excessive wear. For one reason or another, or both. This is my running theory.

Even though you're the first owner, and been super meticulous ( bravo if I can say so) I'm willing to bet you have some wear on the upper bearing and or at the parting lines. To what degree? Won't know till you crack it open.

I have a friend who's 2013 E92 is in search of a new heart because is 22k mile, only owned and maintained by him, weekend toy spat out 2 rods at sebring last fall.

[pbonsalb]

Originally Posted by rantarM3

But what exactly is that clearance? Has BMW published any guidance, or are installers shooting for what is being referred to as "industry standard recommended clearance"?

I read a few articles on engine building, and they had sections dealing with bearing and clearance selection. I'm no expert but based on what the articles stated, there are a plethora of factors that go into determining what the clearance should be for a given engine. My impression was that this "industry standard" was a starting point and nothing more. You would then make clearance adjustments (either looser or tighter) depending on your build and goals (although you certainly might end up not needing to make adjustments). They even mentioned crank material as relevant in making that determination. Perhaps I've missed it but it seems that no one has published a comprehensive S65 clearance analysis that takes into account the multitude of factors mentioned in the articles. Maybe there's a reason for that - who knows.

I'm in no rush to crack open my engine to replace the bearings. I'm the original owner, broke-in the engine strictly following BMW's instruction (to 3,000 mi.), always keep the engine below 3k rpm with low throttle while warming up the engine, never "beat" on the car, and frequently change the oil + filter. But more importantly, like you, I don't believe anyone has actually identified the cause of the exhibited abnormal wear on this engine (and perhaps there's no single cause).

Which means your bearings might be fine or might be excessively worn or might be on the verge of failure. Which condition are yours in?

[davesaddiction]

The Mporium BMW (DFW area) Fb page has lots of examples of worn bearings, different years/miles.