MRF Engineering: Rod Bearings, Teardowns, Failures & Replacements. **PICTURE Diary**

[Malek@MRF]

As we all know, rod bearing issues have become a prominent weak link in the beloved E9x chassis M3's. While the S65B40 is one of BMW's best engines in its history, it doesn't come without faults.

Many on this forum have done an excellent job of documenting these issues/failures and posting their findings for the greater good of the community. Out of respect for other vendors, I will start a separate diary of E9x M3's that come into the shop with rod bearing concerns and/or failures. As more M3's come in for this, I will post my findings with pictures and background history of the vehicles for the community.

I will start it off with this M3.

Vehicle:

2009 BMW M3 (E92)
6-Speed Manual Transmission
35,000 miles on engine.

Modifications: (only engine modifications will be listed)

VF-620 Supercharger tuned by BPM

Maintenance History:

Always used 10W-60 Oil + OE BMW Mahle Oil Filter
Oil services have been done more frequently than BMW recommended intervals.

Vehicle Driving Habits and Usage:

Street driven vehicle with spirited canyon usage. This particular car has only seen 2 track days in California. Oil services have always been done right before track days to ensure fresh oil was in the engine before the events. Owner diligently maintains vehicle as recommended by MRF and BMW's guidelines.

Work performed: (Engine work will only be listed)

OE BMW 702/703 Connecting Rod Bearing Shells treated by WPC
OE BMW Connecting Rod Bolts (Stretch bolts)

As seen in pictures, the rod bearing shells are showing what we have all began to see in the other threads. Excessive wear at only 30,xxx miles on the engine. A little difficult to see in the pictures of the bearing shells, some of them have began to have severe pitting where parts of the bearing are missing.

[s85e90]

Those looked pretty good

[aussiem3]

Originally Posted by s85e90

Those looked pretty good

+1

I'll ask this question again ... what's the accepted wear for an engine with this mileage? Until we have that, this discussion is going to be subjective. One has to accept some wear on the shells. I am no engine expert but from the provided pictures one can conclude the wear is even, and cannot see the layer underneath.

Also you cannot strap on a SC and then expect the engine to wear and tear normally. It's not fair.

[e92zero]

eh, the OP said:

"Excessive wear at only 30,xxx miles on the engine. A little difficult to see in the pictures of the bearing shells, some of them have began to have severe pitting where parts of the bearing are missing."

is that good or bad then?

[surlynkid]

I would like to know what the Blackstone reports were for the motor as another data point when we are diagnosing these one by one.

[gobuffs]

Agree that those look pretty good, especially being a SC motor.

[Malek@MRF]

For the most part they look good, but the wear is a bit on the accelerated side for only 30,xxx miles.

As for oil analysis, this individual opted not to do one and wanted the bearings replaced for peace of mind. On a side note, the engine did become less noisy with the new bearings in place according to the owner.

[ilikebmxbikes]

they look way better than the bearings out of my Non-Sc 09 motor with 28k miles.

[DLSJ5]

Good work Malek, thanks for sharing.

[s85e90]

Originally Posted by Malek@MRF

For the most part they look good, but the wear is a bit on the accelerated side for only 30,xxx miles.

As for oil analysis, this individual opted not to do one and wanted the bearings replaced for peace of mind. On a side note, the engine did become less noisy with the new bearings in place according to the owner.

Accelerated side compared to what though?

[MilehighM3]

IMO, they don't look bad at all given the fact that the car is pushing ~50% more power than stock, I've seen way worse on cars that ran completely normal with no noise. Pull them in 35k more miles and see what they look like, then comment on "accelerated wear rates".

I understand piece of mind in this situation based on the Internet buzz, sure. Mandatory, not by any stretch of the imagination. This bearing buzz seems to be generating a nice amount of income for the sponsors of the forum.

[Hujan]

First of all, there's no indication how long the car has been SC'd, so saying that they don't look that bad for a blown motor is somewhat speculative. For all we know, 30k of those 35k miles might have been NA.

Second, I think this just shows how de-sensitized we've become to rod bearing damage. People saying they don't look that bad are comparing these to the absolutely obliterated bearings that have been spit out of a good number of relatively low-mileage engines. IMO, these are what I would expect to see out of 100k motor, not 35k. Rod bearings should look pristine at 35k and show some wear at 100k, not be worn at 35k and shredded at 100k.

[s85e90]

Originally Posted by Hujan

First of all, there's no indication how long the car has been SC'd, so saying that they don't look that bad for a blown motor is somewhat speculative. For all we know, 30k of those 35k miles might have been NA.

Second, I think this just shows how de-sensitized we've become to rod bearing damage. People saying they don't look that bad are comparing these to the absolutely obliterated bearings that have been spit out of a good number of relatively low-mileage engines. IMO, these are what I would expect to see out of 100k motor, not 35k. Rod bearings should look pristine at 35k and show some wear at 100k, not be worn at 35k and shredded at 100k.

they may wear in and never get worse at all. They may stay looking like this. "People" (myself included) are saying from pics they don't appear bad cause they don't. Bearings shouldn't look brand new but shouldnt be eaten up either. But they def should look worn. As to how much and how soon, I don't think we have concrete answers. Here's a good visual indicator though >

http://www.bobistheoilguy.com/bearin...aranalysis.htm

[BPMSport]

Originally Posted by s85e90

they may wear in and never get worse at all. They may stay looking like this. "People" (myself included) are saying from pics they don't appear bad cause they don't. Bearings shouldn't look brand new but shouldnt be eaten up either. But they def should look worn. As to how much and how soon, I don't think we have concrete answers. Here's a good visual indicator though >

http://www.bobistheoilguy.com/bearin...aranalysis.htm

+1, those look good to me (comparatively speaking to others I've seen with similar mileage). Thanks for sharing, Malek. Looking forward to seeing the other ones you do. Will you be doing a post on your car? I'm interested in seeing the bearings from a 0w-40 car that failed, as yours is the first instance I've heard using that weight oil.

[aus]

Are the new bearings going to be the newer, harder bearings?
I think I'd prefer the old soft lead ones. At least an oil analysis is more useful with those bearings- or at least seems more usefuly since they seem to have high lead or copper levels when worn.

.

[mj89h]

Originally Posted by Hujan

First of all, there's no indication how long the car has been SC'd, so saying that they don't look that bad for a blown motor is somewhat speculative. For all we know, 30k of those 35k miles might have been NA.

Second, I think this just shows how de-sensitized we've become to rod bearing damage. People saying they don't look that bad are comparing these to the absolutely obliterated bearings that have been spit out of a good number of relatively low-mileage engines. IMO, these are what I would expect to see out of 100k motor, not 35k. Rod bearings should look pristine at 35k and show some wear at 100k, not be worn at 35k and shredded at 100k.

Let me clarify this situation and explain the logic behind my decision for doing this rod bearing replacement.

I recently purchased this car from a forum member who had a motor go out on him... he ended putting in a motor with ~5k miles from a salvaged M3 (which is fair to assume was N/A). An additional 20k miles have been put on this motor which were supercharged. Bringing the grand total to ~25k miles on the engine. This mileage included 1 track day at streets in august and a few runs through ortega canyon.

Given this circumstance I wanted to take the conservative route and replace the bearing and not need to worry. There were no real symptoms of rod bearing failure... just some odd vibrations at idle (which is to be expected with a s/c charge).

Clearly from the pictures Malek posted you can see there were no major issues with the bearings.... and from my pictures you can see how clean the crank/motor is.

I was expecting to see more wear but it looks like frequent oil changes and proper warm up go a long way in reducing the wear on the bearings. I may have also been lucky that the tolerances of this motor seem to be looser than other S65 motors.

All in all I am happy with my decision to replace the bearings. The car feels much smoother throughout the rev band and doesn’t vibrate like it used to at idle.

Lastly I’d like to thank Malek for doing this job with meticulous attention to detail in every step. Not to mention coordinating his appointments such that I could be present for the bearing swapping


Top Shells - #6 #7 #8 (notice the pitting / chunks missing)


Bottom Shells - #5 #6 #7 #8


Top/Bottom Shells - WPC #1 and OEM #2


#8 Replacement WPC Bottom Shell


Crank #8 (dont mind the fuzz )


Squeaky clean oil pan

[SenorFunkyPants]

Recording the replacement of S65 bearings in one thread is a great idea. What might help is a little better lighting for the photos and taking an oil sample for analysis (regardless of whether the owner wants or not). For myself it would be interesting to know the US State that the cars come from (I'm assuming mostly CA) as I'm trying to follow up how climate affects the bearing wear rate.
It is hard to judge the wear from the photos but based on the feedback RG got from Clevite (during the epic bearing thread) I don't think they would be considered to have excessive wear.
Great work.

[pbonsalb]

Those bearings are way better than mine (08 with 62k). Mine had actual, visible patches of wear on 4 upper bearings. And mine were not bad or in any danger anytime soon. We have seen some pictures of sets of bearings that really do have bad wear, the kind of bearings you would obviously not want in your car based on just one quick look.

The reality is that not all these cars have a problem, but some do. Exactly why, we do not know. Most of us who change bearings are doing it for peace of mind because we do not know how ours look and we do not want to risk an engine failure, rather than because we are experiencing a problem.

To me, it was worth the peace of mind. Others may decide that less than 1% have a problem so the odds of a problem are minute and they have nothing to worry about. That was the approach I took while I was under warranty and extended warranty.

[W///]

Originally Posted by pbonsalb

Those bearings are way better than mine (08 with 62k). Mine had actual, visible patches of wear on 4 upper bearings. And mine were not bad or in any danger anytime soon. We have seen some pictures of sets of bearings that really do have bad wear, the kind of bearings you would obviously not want in your car based on just one quick look.

The reality is that not all these cars have a problem, but some do. Exactly why, we do not know. Most of us who change bearings are doing it for peace of mind because we do not know how ours look and we do not want to risk an engine failure, rather than because we are experiencing a problem.

To me, it was worth the peace of mind. Others may decide that less than 1% have a problem so the odds of a problem are minute and they have nothing to worry about. That was the approach I took while I was under warranty and extended warranty.

+1. My engine shows no symptoms of any bearing issue at 81k on the surface (ie no weird noises, oil reports look really clean). But eventually, I'll take the same route and change out to WPC treated Rb's. Unless oil reports start looking bad, the goal is at 100k miles, which will take me a while to get there.

Will also do solid bushings at the rear end at the same time. Going to bulletproof the entire car in 1 go.

[douglee25]

I think what people forget here is that bearings aren't considered a wear item. They never have and never will be. There should be zero wear on those bearings. Of course special purpose cars (ie drag cars) could be a different story. With that said, bearings should last the lifetime of the vehicle. Think 300k+ miles.

Doug

[Petros]

Originally Posted by douglee25

I think what people forget here is that bearings aren't considered a wear item. They never have and never will be. There should be zero wear on those bearings. Of course special purpose cars (ie drag cars) could be a different story. With that said, bearings should last the lifetime of the vehicle. Think 300k+ miles.

Doug

[thekurgan]

Originally Posted by W///

+1. My engine shows no symptoms of any bearing issue at 81k on the surface (ie no weird noises, oil reports look really clean). But eventually, I'll take the same route and change out to WPC treated Rb's. Unless oil reports start looking bad, the goal is at 100k miles, which will take me a while to get there.

Will also do solid bushings at the rear end at the same time. Going to bulletproof the entire car in 1 go.

I'd go with a dry sump as well, if it does come to having mine replaced, although I'm weary of these newer on-lead babbitt bearings. I'd rather have wpc treated lead bearings.