Official S65 Rod Bearing Condition Example Thread

2013 M3 DCT @ 42,456 miles:

tom @ eas wrote

2013 M3 DCT @ 42,456 miles:

Cheers Tom. With the 088/089 shells one can have an idea when they have been close to spin, i.e. crazy wear down through the copper. The 702/703 seem to look pretty much the same when coming out, what would your opinion be on for instance these with regards to "close to death"?

Thanks

Helmsman wrote

Cheers Tom. With the 088/089 shells one can have an idea when they have been close to spin, i.e. crazy wear down through the copper. The 702/703 seem to look pretty much the same when coming out, what would your opinion be on for instance these with regards to "close to death"?

Thanks

In reality nobody can really know what "close to death" bearings look like, because they would obviously need to know what failed ones looked like just before they failed. We can all make guesses though.

deansbimmer wrote

In reality nobody can really know what "close to death" bearings look like, because they would obviously need to know what failed ones looked like just before they failed. We can all make guesses though.

I hear you, and was thinking you guys with significant experience could make qualified guessing. Again, on the old shells its seems more obvious when they have been close to go just from the nasty looks, but maybe the LCI ones never develop that bad look but just go boom. Or they hold up better, the way they where intended to?

The later shells are harder metal. There's not as much of a "grace period" as with lead/copper. Harder shells won't keep wearing down like the softer copper/lead when there's repeated journal contact, they'll just gall and seize up. I believe that's why we don't see as many 702/703 bearings worn down as much as the 088/089 tend to.

deansbimmer wrote

The later shells are harder metal. There's not as much of a "grace period" as with lead/copper. Harder shells won't keep wearing down like the softer copper/lead when there's repeated journal contact, they'll just gall and seize up. I believe that's why we don't see as many 702/703 bearings worn down as much as the 088/089 tend to.

Sounds like a good guess, interesting, thanks Deansbimmer.

2011 M3 DCT @ 51,246 miles:

tom @ eas wrote

2011 M3 DCT @ 51,246 miles:

So these have worn through a layer the previous - and most 702/703 - hasn't, yes?

Helmsman wrote

So these have worn through a layer the previous - and most 702/703 - hasn't, yes?

Appears that way, these are in pretty bad shape.

tom @ eas wrote

Appears that way, these are in pretty bad shape.

Tom,

You have to stop cherry-picking only the bad bearings to post on this forum. Please, share the 100s of good shells that are being removed from S65 and S85 engines for no reason.

tom @ eas wrote

Appears that way, these are in pretty bad shape.

That might suggest that the discoloration we've seen on previous 702/703 bearings might not indicate severe wear as most people assume, no? It looks like that discoloration is visible on some of the shells, and it looks very different from the parts where a layer has completely worn through.

IamFODI wrote

That might suggest that the discoloration we've seen on previous 702/703 bearings might not indicate severe wear as most people assume, no? It looks like that discoloration is visible on some of the shells, and it looks very different from the parts where a layer has completely worn through.

This is where I am heading at too. Assumingly plenty of life still in all those 702/703 shells coming out with "only" discoloration, while some comes out - still without issues - with layers worn off. The latter much closer to end of life.

Not saying there is still good reason to change well in time, and even go for an aftermarket shall to avoid metal to metal all together. But the paranoia over that it has to be done regardless of mileage and treatment I personally think has gone way too far.

Another aspect that I think is being overlooked is the characteristics of the bearing material. While the worn thickness of 088/089 and 702/703 shells is generally similar in their centers, the early style shells appear more dramatic because of their softer makeup. The lead top layer flakes off. You can feel the ledge with your fingernails. Later style bearings, being of a harder material, have edges that 'feather' better, leading to similar wear shape and dimensions, but less dramatic visual cues.

I touched on this in one of my threads here: https://www.m3post.com/forums/showthread.php?t=1486113

Helmsman wrote

This is where I am heading at too. Assumingly plenty of life still in all those 702/703 shells coming out with "only" discoloration, while some comes out - still without issues - with layers worn off. The latter much closer to end of life.

Not saying there is still good reason to change well in time, and even go for an aftermarket shall to avoid metal to metal all together. But the paranoia over that it has to be done regardless of mileage and treatment I personally think has gone way too far.

That's where I'm leaning, too.

Also thinking BE's statement that these are bimetal aluminum bearings needs to be taken down, because it seems untrue and I know I'm not the only one guilty of spreading it uncritically.

I have half a mind to try to crowd-fund a real metallurgical analysis of 702/703 bearings...

I'm not sure how folks arrive at the above conclusions. Bearings are not brake pads. There is no acceptable wear. The fact that the engine may not immediately seize because the crank journal contacts the bearing does not mean it is okay or, somehow, there is a formula for acceptable bearing wear like brake pad wear. I have seen *1* set of bearings posted that had no wear. One. All of the others had wear. That's unacceptable.

A question for those who think this is blown out of proportion: if you have your bearings taken out and they are not into the succeeding layers of the bearing, are you going to put them back in because they are not yet worn out? If the answer is anything but yes, then you are not fully believing what you are saying.

serranot wrote

I'm not sure how folks arrive at the above conclusions. Bearings are not brake pads. There is no acceptable wear. The fact that the engine may not immediately seize because the crank journal contacts the bearing does not mean it is okay or, somehow, there is a formula for acceptable bearing wear like brake pad wear. I have seen *1* set of bearings posted that had no wear. One. All of the others had wear. That's unacceptable.

A question for those who think this is blown out of proportion: if you have your bearings taken out and they are not into the succeeding layers of the bearing, are you going to put them back in because they are not yet worn out? If the answer is anything but yes, then you are not fully believing what you are saying.

Agree the rod shells preferably should not wear at all, I've replaced mine too. And yes pretty much every single shell coming out has shown some level of wear which yes, bad.

Still 90% of the S65s is running a happy life out there with original shells, most of them today reaching an healthy 50-100k miles, some more. This concludes that while they wear in a way they "shouldn't", the majority do so slow enough to still provide a long life. Hence I think its hysteric to claim they HAVE to be replaced regardless of mileage.

The only thing that every owner MUST do to address rod bearings is decide whether they will deny the issue and risk it, or go through with the preventative service based on the overwhelming evidence.

To those who believe this hysteria was made up by the repair industry, consider that we make just as much over time selling replacement engines to customers, as we do performing bearing services. Either way is profitable for us. One way is just less heartache for the customer.

With the value of these future classics nearing historical lows, having an engine spin a bearing can easily total the car. These cars are already dropping like flies. I think it's with this in mind that most enthusiasts would suggest it's a "must do" service.

Another anecdote to put things into perspective: Historically, we've seen more S65 failures than all other ///M engines past and present combined.

Two worst bearings on my street-driven ‘12 w/ 66K:

deansbimmer wrote

With the value of these future classics nearing historical lows, having an engine spin a bearing can easily total the car. These cars are already dropping like flies. I think it's with this in mind that most enthusiasts would suggest it's a "must do" service.

Wise words like always. Even being very remote I appreciate your service, to the board, and effort to keep the S65 alive Deansbimmer. For me its not a question about whether the shops are trying to squeeze business out of the market but simply curious to better understand where the threshold between "ok wear" and f@kked is, where most of the pictures of replaced shells seem to be on the ok side regardless of mileage.

Helmsman wrote

Wise words like always. Even being very remote I appreciate your service, to the board, and effort to keep the S65 alive Deansbimmer. For me its not a question about whether the shops are trying to squeeze business out of the market but simply curious to better understand where the threshold between "ok wear" and f@kked is, where most of the pictures of replaced shells seem to be on the ok side regardless of mileage.

I think that’s my point. If it has wear, it’s not ok. How is one supposed to know what “ok” is vs “not ok.” I hate to beat a dead analogy, but I’m bringing up brake pads again. I’m sensing that there is some kind of remorse if one has one’s bearing replaced and the old ones are not ground completely away. Is there a sense that perhaps one is wasting money, as one would be doing by replacing brake pads that showed little wear?

The analogy is flawed because there is a normal wear profile for brake pads. There is no such profile for these bearings. And there is substantial evidence that they might last 25K or 100K. But you just don’t know.

So as deansbimmer says, if you want to play Russian roulette over $2500, that is your choice. I think it’s a personal choice. But it’s not a case of some kind of unwarranted hysteria. The bearings wear abnormally. That is not speculation.

First photo is from an N54 with unknown miles being rebuilt and it has a big turbo. Obviously some debris in the oil but there is no sign of oil starvation. This is a 500+HP N54.

Second photo is from a 80K mile 535. Again, the bearings do not show strange starvation wear characteristics like the S65 does.

It seems that no one has shared photos of Honday F20C bearings... Or Audi R8 V10 bearings... Likely because they do not have a design flaw.

I really hope that some people start pulling out BE bearings from high milage S65 and S85 bearings to show how they look. There is one post here that shows how a BE bearing looks after 50K KM. That is how they should look. It is the last photo in this post.

Cheers,

serranot wrote

Helmsman wrote

Wise words like always. Even being very remote I appreciate your service, to the board, and effort to keep the S65 alive Deansbimmer. For me its not a question about whether the shops are trying to squeeze business out of the market but simply curious to better understand where the threshold between "ok wear" and f@kked is, where most of the pictures of replaced shells seem to be on the ok side regardless of mileage.

I think that’s my point. If it has wear, it’s not ok. How is one supposed to know what “ok” is vs “not ok.” I hate to beat a dead analogy, but I’m bringing up brake pads again. I’m sensing that there is some kind of remorse if one has one’s bearing replaced and the old ones are not ground completely away. Is there a sense that perhaps one is wasting money, as one would be doing by replacing brake pads that showed little wear?

The analogy is flawed because there is a normal wear profile for brake pads. There is no such profile for these bearings. And there is substantial evidence that they might last 25K or 100K. But you just don’t know.

So as deansbimmer says, if you want to play Russian roulette over $2500, that is your choice. I think it’s a personal choice. But it’s not a case of some kind of unwarranted hysteria. The bearings wear abnormally. That is not speculation.

I completely understand your point. It is psychological - someone goes through the process to have a faulty part replaced expecting it to come out totally trashed, and if that's not the case, they may feel concerned they wasted money, or had the procedure for no reason.

To that line of thinking, I think we should all keep the following in mind:

The bearings wear abnormally, and to varying degrees and rates across the platform when they shouldn't. We have a nice thread that evidences this point.

We are unable to diagnose and monitor bearing wear accurately without opening the engine up.

Outside of not driving the car, there does not seem to be anything we can do in terms of regular maintenance to prevent, stop, or slow bearing wear.

There does not seem to be any indication risk of failure correlating with any characteristic or metric. Wear appears to be ubiquitous across years, driving styles, mods, and maintenance patterns.

Therefore, when bearings are replaced they will come out in all different states of wear (some better some worse). But when they do come out and are replaced with better bearings, theoretically, you've inhibited the wear process and reduced risk of both wear and failure from that point forward (data for this final point is still being gathered)