Official S65 Rod Bearing Condition Example Thread

[IamFODI]

Originally Posted by Scharbag

For sure, apples to apples would be a better comparison. It is just really hard to find photos of GOOD bearings as most people post photos of BAD bearings.

As for all of the variables it all boils down to 1 thing: a properly designed hydrodynamic bearing IS NOT A WEAR ITEM in passenger cars. Even in race engines, the bottom end is not designed to wear. Sure, some race teams in uber competitive classes will minimize clearances and run minimal oil flow to reduce parasitic losses in the engine. This will reduce useful life as there is no safety margins at all.
Also, race engines live at full throttle all-the-time. But that is not how engines are designed for road use. And think, the average M3 spends what percentage of its life at WOT? What percentage of its life above 6000RPM? Typically, on the streets, WOT has limited applications.

What would be great is if we had photos of good bearings from 5.2L Audi V10s, 2.0L Honda F20c, Porsche GT3 and Ferrari F136 engines as they are high revving, high HP examples to say the least. I would bet real money that those factory bearings typically look just like Clevite/King/ACL intended.

The ONLY time bearings do not look like they should is due to a problem. Period. To properly beat the dead horse: at no time should anyone accept the notion that rod and/or main bearings are wear items in a passenger car.

Cheers,

Well yeah. Looking different from how it should is a problem by definition, no?

Completely agree that it could be helpful to see how those other engines wear their rod bearings. But we'd also have to know a ton more about those engines for any comparison to be meaningful. That's the point.

Like, just to pick one small example: I did the same super-rough rod bearing area approximation for the F20C, and the number I got (~3800 mm^2) is much bigger than what I got for the S65. The GT3 seems to land in the same ballpark, though slightly higher. That alone might explain why those engines are easier on their rod bearings -- if they even are in the first place, which I can't say (I've heard informed people comment both ways).

[Scharbag]

Originally Posted by IamFODI

Well yeah. Looking different from how it should is a problem by definition, no?

Yup - that is my point exactly. But some people still seem too think all is OK with the S65 bearing design. It is not OK. Not even close to OK. No amount of "proper maintenance" or "proper warmup" will fix the fundamental problem. If your engine is tight, it will wear the bearings and eventually break your heart. If, by chance, you got lucky and have an engine that is closer to the reccomended 0.001"/", your engine will likely last. That said, even the loosest of S65s made by BMW barely meets the 0.001"/" bearing clearance spec (based on data collected by the BE people, and only on the older copper bearings).

If any of the awesome engine builder that are part of this forum have examples of old bearings out of good Porsche, Ferrari, Honda or Audi engines, it would be great if they could share them here. Hell, a set of bearings out of a Cup car would be the shizz!!

Happy motoring!!

[HunterLee]

Here are my rod bearings that were just replaced. 2009 E90 M3 with 74k, fourth owner with very little service history. Personally I see nothing to be concerned about with the bearings that came out. I am glad that they're done and it's not something I will be worrying about any longer. Light wear and some very small places of copper showing. You be the judge

[Dpc2u]

Originally Posted by HunterLee

Here are my rod bearings that were just replaced. 2009 E90 M3 with 74k, fourth owner with very little service history. Personally I see nothing to be concerned about with the bearings that came out. I am glad that they're done and it's not something I will be worrying about any longer. Light wear and some very small places of copper showing. You be the judge

Having had the opportunity to see these first hand, I was surprised at how good they were considering the mileage and lack of knowledge about prior owners maintenance. The only sign of copper was on the edges of 3 and 7 which share the same crank journal. No real pitting other than a few small places where an oil contaminate had left a scar. Impressive! At least now you don't have to wonder anymore, you know you are good to go! Now for the Harrop you are considering.

[e92m3sf]

I changed my rod bearings about 2 years/40k miles ago with an aftermarket (forgot the brand, but I went for the more expensive one). When is the next recommended mileage to swap them out?

[IamFODI]

Originally Posted by derekc5475

I changed my rod bearings about 2 years/40k miles ago with an aftermarket (forgot the brand, but I went for the more expensive one). When is the next recommended mileage to swap them out?

There isn't one. People generally assume that aftermarket bearings will fix the problem for good, there hasn't been remotely enough data from the field to see if that's true, and no one has done (or is even likely to attempt) the required testing to figure it out without field data.

If you want to feed the public knowledge base on this topic, run yours to 60k-80k+ (recommended interval for stock bearings) and then pull 'em out so we can see.

[2bits]

2009 e90 M3, 59k miles. Castrol 10w60 till 54k. Redline 5w50 last 5k. Car has been autocrossed but not tracked. Not too bad I think.

[kevin @ eas]

50k miles on a 6mt with a supercharger

[HunterLee]

Originally Posted by kevin @ eas

50k miles on a 6mt with a supercharger

Not too bad at all. Wonder how many rod bearing failures we'd have if people actually let their cars warm up before full send

[Scharbag]

Originally Posted by HunterLee

Not too bad at all. Wonder how many rod bearing failures we'd have if people actually let their cars warm up before full send

Those bearings do not look very good as they look like 702/703 bearings. Also have a lot of scoring.

And why are you focused on warm-up? Some who are religious about warmup and short OCIs have removed bearings that look totally thrashed.

Clearance is the issue. Some people get lucky. Some do not. Yes, not thrashing a cold engine is wise but letting a tight engine warm up fully will not solve the clearance problem.

Cheers,

[G80indy]

Originally Posted by HunterLee

Not too bad at all. Wonder how many rod bearing failures we'd have if people actually let their cars warm up before full send

It is with a supercharger after all !

[pbonsalb]

Originally Posted by HunterLee

Not too bad at all. Wonder how many rod bearing failures we'd have if people actually let their cars warm up before full send

The warmup theory has been around for years, like the sulpher in the gas theory and the oil change interval theory, but don’t have much following as the cause for premature rod bearing wear on the S65 because cars that have always been warmed up and always ran other gas and that had short OCI have also suffered premature bearing wear. A simple, common-sense explanation would be great, but it should explain all the examples.

I would agree, though, that a few owners have abused their cars on cold starts and added to bearing wear that may or may not have otherwise occurred depending on the actual clearance in the particular motor. And likewise that some owners have used low octane or bad gas and suffered detonation that caused wear. And that some did not change their oil even within BMW’s 15,000 mile or 1 year spec and that might have caused added wear.

[HunterLee]

Originally Posted by pbonsalb

The warmup theory has been around for years, like the sulpher in the gas theory and the oil change interval theory, but don’t have much following as the cause for premature rod bearing wear on the S65 because cars that have always been warmed up and always ran other gas and that had short OCI have also suffered premature bearing wear. A simple, common-sense explanation would be great, but it should explain all the examples.

I would agree, though, that a few owners have abused their cars on cold starts and added to bearing wear that may or may not have otherwise occurred depending on the actual clearance in the particular motor. And likewise that some owners have used low octane or bad gas and suffered detonation that caused wear. And that some did not change their oil even within BMW’s 15,000 mile or 1 year spec and that might have caused added wear.

I agree with you completely. I'm not saying there isn't an issue with the factory bearings, clearance or tolerances. But to say that none of the failures that have been reported weren't self inflicted would be absurd. I appreciate your logical and unself-absorbed response to a theory that can't fully be proved since you can't predict human behavior. It would just be nice to see, in a perfect world, how many engines failed that ran proper fuel, ran proper oci, allowed cold start before driving.

Correct me if I am wrong but BMW would have issued a recall on this if the number of motors blowing was much higher? That being said, the amount of cars with these particular rod bearing issues is too limited vs the production number of cars produced? Trying to better understand, not meant in a smart-a$$ way

[IamFODI]

Originally Posted by pbonsalb

The warmup theory has been around for years, like the sulpher in the gas theory and the oil change interval theory, but don’t have much following as the cause for premature rod bearing wear on the S65 because cars that have always been warmed up and always ran other gas and that had short OCI have also suffered premature bearing wear. A simple, common-sense explanation would be great, but it should explain all the examples.

I would agree, though, that a few owners have abused their cars on cold starts and added to bearing wear that may or may not have otherwise occurred depending on the actual clearance in the particular motor. And likewise that some owners have used low octane or bad gas and suffered detonation that caused wear. And that some did not change their oil even within BMW’s 15,000 mile or 1 year spec and that might have caused added wear.

Second paragraph sounds more like my thinking.

Being mindful of things like cold running, fuel quality, oil change intervals, etc. is clearly valuable -- not because it'll guarantee long engine life and the opposite will guarantee early failure, but because it's all just good practice and can improve the odds for any engine.

[IamFODI]

Originally Posted by HunterLee

Correct me if I am wrong but BMW would have issued a recall on this if the number of motors blowing was much higher? That being said, the amount of cars with these particular rod bearing issues is too limited vs the production number of cars produced? Trying to better understand, not meant in a smart-a$$ way

Technically, the trigger for a recall would be running out of ways to weasel out of issuing one. Companies will do everything they can to bury problems unless or until they calculate that it's less costly to get out in front of them.

I'd imagine excessive rod bearing wear isn't much of a risk in terms of legal liability, but it's certainly very high in terms of cost to fix. If that's correct, the bar for a recall is going to be fairly high vs., say, a loose battery cable that might cause a fire.

To be clear, I share your implicit suspicion that the rod bearing issue would clear that bar easily if it were as bad as some people made it out to be. That's just a hunch, though.

[GoodTime]

Mine at ~108k.

2008 M3 with zero maintenance records.

[pbonsalb]

Originally Posted by HunterLee

It would just be nice to see, in a perfect world, how many engines failed that ran proper fuel, ran proper oci, allowed cold start before driving.

Correct me if I am wrong but BMW would have issued a recall on this if the number of motors blowing was much higher? That being said, the amount of cars with these particular rod bearing issues is too limited vs the production number of cars produced? Trying to better understand, not meant in a smart-a$$ way

My take, simply from following the issue for years, is that the majority of premature wear and failures are due to a very tight clearance spec plus tolerance variations that made the clearances on some motors simply too tight. This is the prevailing theory and it makes sense to me, but we won’t know for sure until a bunch of motors with increased clearance bearings have their bearings replaced again so we can see how they look.

I replaced mine when my extended warranty ran out in 2014. I used stock bearings with wpc treatment. Increased clearance bearings were not yet available. I have 40k miles on the new ones and will change them sometime in the next 20k miles. I removed my originals at 60k miles and they weren’t disintegrating and about to fail but had excess wear.

[Helmsman]

Originally Posted by GoodTime

Mine at ~108k.

2008 M3 with zero maintenance records.

Good time indeed.

[GoodTime]

Originally Posted by Helmsman

Good time indeed.

Lol, yup. Glad to have it done.

Rest of the car feels spectacular for the mileage, so I don't get the sense it was neglected, but with no records you just don't know.

[Green-Eggs]

Originally Posted by pbonsalb

The warmup theory has been around for years, like the sulpher in the gas theory and the oil change interval theory, but don’t have much following as the cause for premature rod bearing wear on the S65 because cars that have always been warmed up and always ran other gas and that had short OCI have also suffered premature bearing wear. A simple, common-sense explanation would be great, but it should explain all the examples.

Did anybody else notice that all of those "alternate" theories were promoted by the same guy? Whereas the simple, common-sense explanation and the one that does seem to fit all of the wear, failure modes, and all of the examples is bearing clearance too small. That is, I'm talking about the 99.5% cases, not the 0.05% of driver abuse and driver neglect. Driving off when cold is not driver neglect -- it's the recommended procedure in the BMW owner's manual! There's a cold-start RPM limiter that already prevents the overrev when engine is cold.

[Helmsman]

Originally Posted by Green-Eggs

Did anybody else notice that all of those "alternate" theories were promoted by the same guy? Whereas the simple, common-sense explanation and the one that does seem to fit all of the wear, failure modes, and all of the examples is bearing clearance too small. That is, I'm talking about the 99.5% cases, not the 0.05% of driver abuse and driver neglect. Driving off when cold is not driver neglect -- it's the recommended procedure in the BMW owner's manual! There's a cold-start RPM limiter that already prevents the overrev when engine is cold.

Hey Green-Eggs, just curious, you go all 6k isch allowed shortly after start?

Cheers

[Green-Eggs]

Originally Posted by Helmsman

Hey Green-Eggs, just curious, you go all 6k isch allowed shortly after start?

Cheers

You'd have to ask Bert. But yes, I think that's the whole point of his oil flow testing on BE Bearings is to test oil flow at various engine oil temperatures up to redline. That means when the engine is cold, it hits the cold-start limiter at various RPMs until the engine is fully warmed. This is what the oil flow graphs show IIRC.