Official S65 Rod Bearing Condition Example Thread

[///M Power-Belgium]

Here is more => http://www.m3post.com/forums/showthr...8#post21019178

[drrust]

In this thread there is only one post of the main bearings (first post on second page). Most reports of failed mains seem to super charged motors.

Had my rod bearings replaced about 2K miles ago with 109K on motor. Will keep an open mind on the mains but in my mind there is not enough hard data out there. However, it is HARD to see such a mangled rod.

Right now I'm planning (but not yet saving) on having the motor rebuilt at 200K or so. It would seem that having mains replaced would be better performed with engine out of the car. But if gas prices jump to the $4 level, my plans will likely change.

[hank90m3]

2009 E90 M3 127000 Km

[MikeHawk7]

2013, 63K miles (purchased the car at 62K), preventative, no prior symptoms, BMW's 10W-60 its whole life. Replaced with BE/ARP.

No particular order (randomly threw them in a bag and cleaned them off at home):

[doogee]

After seeing 3 dismantled S65's over the past two weeks, I'll be pulling my motor to replace the main bearings.

On all three engines, they showed the same, if not more wear than the rod bearings.

One motor with 40K, 120K miles and the other unknown.

I think replacing the mains is now just as important as the rod bearings. Unfortunately no aftermarket alternative. But new OEM is better than nothing.


One of these engines in particular, had its rod bearings replaced. The engine blew up after 2 laps at Mosport. No installation error, just really bad luck. Main bearing failed.

2 of the 3 motors had a main bearing failure and both blocks cracked.

No, none of them were supercharged.

[SDPLV]

Originally Posted by doogee

After seeing 3 dismantled S65's over the past two weeks, I'll be pulling my motor to replace the main bearings.

On all three engines, they showed the same, if not more wear than the rod bearings.

One motor with 40K, 120K miles and the other unknown.

I think replacing the mains is now just as important as the rod bearings. Unfortunately no aftermarket alternative. But new OEM is better than nothing.


One of these engines in particular, had its rod bearings replaced. The engine blew up after 2 laps at Mosport. No installation error, just really bad luck. Main bearing failed.

2 of the 3 motors had a main bearing failure and both blocks cracked.

No, none of them were supercharged.

First we are hearing of this on the 'rums.
RBs swapped, not SC'd, nuked mains.
That 40k car barely even lived.

Now the important Q: Which aftermarket rod bearings?

BE you hearing this?
We demand a main bearing alternative!

[doogee]

Originally Posted by SDPLV

First we are hearing of this on the 'rums.
RBs swapped, not SC'd, nuked mains.
That 40k car barely even lived.

Now the important Q: Which aftermarket rod bearings?

BE you hearing this?
We demand a main bearing alternative!

This isn't new. Malek from MRF has had a few crankshafts out and they all showed main bearing wear as well.

The aftermarket bearings were BE Bearings but they were not the problem.

Yes an aftermarket replacement would be good.


Just an FYI, the main bearings VAC is currently selling are coated OEM bearings. Only their rod bearings are a custom made bearing.

Currently have a friend looking for a suitable bearing that can be used, from Porsche, Mercedes etc.

[deansbimmer]

Originally Posted by doogee

This isn't new. Malek from MRF has had a few crankshafts out and they all showed main bearing wear as well.

+1. I've had a few as well with failed mains. Some SC'd some not. Did a couple other preventative main bearing jobs and their old bearings were poorly worn but not failed yet. I suspect all mains are wearing like rods, just not failing as much.

[SDPLV]

Originally Posted by deansbimmer

+1. I've had a few as well with failed mains. Some SC'd some not. Did a couple other preventative main bearing jobs and their old bearings were poorly worn but not failed yet. I suspect all mains are wearing like rods, just not failing as much.

Preventative mains are a thing?

[tom @ eas]

Latest casualty on OEM bearings, @ 120K miles. Unfortunately, it was too late by the time we were able to service:

[deansbimmer]

Originally Posted by SDPLV

Preventative mains are a thing?

...If you have the means [/Ferris Bueller]

But really...the job isn't anywhere near "thing" status since it's so involved.

[///M Power-Belgium]

Originally Posted by tom @ eas

Latest casualty on OEM bearings, @ 120K miles. Unfortunately, it was too late by the time we were able to service:

Game over ,shavings on the crank with aluminum bearings!

[BanjoPaterson]

Originally Posted by hank90m3

2009 E90 M3 127000 Km

Almost exactly as mine, a 2009 model too; but at 85000km

[oldmanstyle]

Originally Posted by doogee

I think replacing the mains is now just as important as the rod bearings. Unfortunately no aftermarket alternative. But new OEM is better than nothing.

What about machining the crank if it's making the clearance too tight?

[TheMidnightNarwhal]

Well damn. Mains are actually a bigger issue than it was now??

You know what. I'm really feeling going with a warranty instead... maybe only 4 years and in that time saving a small amount every month to build up enough for a main + rod job when warranty goes out.......

[Green-Eggs]

Originally Posted by oldmanstyle

What about machining the crank if it's making the clearance too tight?

Originally Posted by TheMidnightNarwhal

Well damn. Mains are actually a bigger issue than it was now??

You know what. I'm really feeling going with a warranty instead... maybe only 4 years and in that time saving a small amount every month to build up enough for a main + rod job when warranty goes out.......

This was all documented in the bearing wiki some time ago. Mains are smaller clearance than industry standard too. There's no aftermarket main bearings available, and if you believe too little clearance is the real issue, then adding a coating on top of factory bearings is the wrong way to go.

[TheMidnightNarwhal]

Originally Posted by Green-Eggs

This was all documented in the bearing wiki some time ago. Mains are smaller clearance than industry standard too. There's no aftermarket main bearings available, and if you believe too little clearance is the real issue, then adding a coating on top of factory bearings is the wrong way to go.

I don't know what the issue would be. But at least replacing them with new ones in like 5 years would be better than nothing right.

This is making me crazy. Lmao, makes me remember what a seller told me when I was looking for a 330ci and his car was sketchy AF, "Don't listen to the forums it'l make you crazy".

[GORDON.M3]

Originally Posted by tom @ eas

Latest casualty on OEM bearings, @ 120K miles. Unfortunately, it was too late by the time we were able to service:

What model year? Looks like the new 702/703 bearings.

[tom @ eas]

Originally Posted by gordon@

What model year? Looks like the new 702/703 bearings.

Production date is 2/08.

[GORDON.M3]

Originally Posted by tom @ eas

Production date is 2/08.

[MidLifeM3]

2008 E92, 85k miles. Replaced preventively by me upon buying the car. As far as I'm aware the car's history is stret only no significant track history. my pics look much like many others in this thread, nothing new here besides another datapoint.

the tech at the shop I used said his opinion all S-series motors should replace rod bearings about every 80k miles, not only S65 and its V10 big brother.

https://photos.app.goo.gl/2v8si5SVpQzOa3il2

[pbonsalb]

You can see how successive layers have been worn through. Also some copper at the parting lines and a little bit down the side from the line. Mine were in this range at around 60k. Not imminent failure but you don't know until you look. Only a few bearing sets have been posted that show what might be normal wear. At least you know you should be good for another 80k.