Official S65 Rod Bearing Condition Example Thread

[Scharbag]

If high revs on a cold engine caused fast bearing destruction, every rental vehicle on earth would spin bearings monthly.

The rotating assembly in an S65 follows the same laws of physics that a Honda/Toyoya/Mazda/Ford/Chev/Volvo does. If bearings are properly designed, they are not fragile. If the oiling system is designed properly, then cold running will not damage bearings because all you need is flow to make the bearings work.

No, I do not propose that you flog your engine while cold. It is good practice to warm it up. But BMW limits the cold RPM redline to a value that will protect the engine so there is no way that the damage we see can be consistently attributed to cold engines at high loading.

Cheers,

[----Flyin-High----]

Rod Bearings at 85k honestly the looked fine

[Helmsman]

Originally Posted by ----Flyin-High----

Rod Bearings at 85k honestly the looked fine

Yeah, they look great!

[IamFODI]

Originally Posted by ----Flyin-High----

Rod Bearings at 85k honestly the looked fine

Wow! Pretty much perfect!

[pbonsalb]

Very nice! I wish more looked like that, but 90% posted here look much much worse and that is one of the reasons people worry.

[Helmsman]

Originally Posted by Scharbag

If high revs on a cold engine caused fast bearing destruction, every rental vehicle on earth would spin bearings monthly.

The rotating assembly in an S65 follows the same laws of physics that a Honda/Toyoya/Mazda/Ford/Chev/Volvo does. If bearings are properly designed, they are not fragile. If the oiling system is designed properly, then cold running will not damage bearings because all you need is flow to make the bearings work.

No, I do not propose that you flog your engine while cold. It is good practice to warm it up. But BMW limits the cold RPM redline to a value that will protect the engine so there is no way that the damage we see can be consistently attributed to cold engines at high loading.

Cheers,

Well now we're kind of back to the - race/high rev engines is tight hence need light oil and/or well warmed up a'la old F1s they poored pre heated oil into - story. Sure the S65 is not one if them but half way there and I def will continue my warm up procedure...

[IamFODI]

Originally Posted by Scharbag

No, I do not propose that you flog your engine while cold. It is good practice to warm it up. But BMW limits the cold RPM redline to a value that will protect the engine so there is no way that the damage we see can be consistently attributed to cold engines at high loading.

They couldn't "properly" design a rod bearing, but they could figure out how to set a foolproof cold rev limit?

Even if they could, why would they then advise keeping it under 3500 RPM when cold?

The cold rev limit was most likely a compromise between limiting engine damage and allowing short bursts of high RPM in case the situation demands it. I agree that cold revving can't explain the rod bearing issue on this engine, but nor should we suggest leaning on the rev limit to protect the engine.

[Scharbag]

Originally Posted by Helmsman

Well now we're kind of back to the - race/high rev engines is tight hence need light oil and/or well warmed up a'la old F1s they poored pre heated oil into - story. Sure the S65 is not one if them but half way there and I def will continue my warm up procedure...

The list of differences between an S65 (idle at ~600RPM) and a modern (V10, V8, V6) F1 engine (idle at ~4000RPM for the V6 - old V8 idle of near 10,000RPM) would fill a very large sheet of paper.

The S65, while a nice piece of engineering for the street, is not really a race engine. The rotating assembly in the S65 follows the same laws of physics that Mercedes, Ferrari, Audi, Lexus, Honda, Suzuki, Toyota, Yamaha, Ford, Chev etc. all have to follow. Yes it revs high, but no higher than a number of other similar displacement-per-piston NA high revving engines. We do not see the Audi R8 V10 forums inundated with spun bearings and premature bearing wear (the Audi V10 has a higher redline, higher mean piston speed and a larger HP/L output than the S65). Nor do we see complaints in forums for Honda, Ferrari, Porsche etc. Search for Audi R8 v10 spun rod bearing and you find a single post from 2011 that sounds like a bad luck bear bit the guy in the ass while the car had full warranty.

BMW screwed the pooch on the bottom end of this engine. Most of their problems would likely have been avoided if they had simply hand built the engines from "binned" assemblies that guaranteed their design tolerances were actually maintained. Since they did not do this, we get to play the German lottery - where winners are really losers.

I bet you, that somewhere, there is a German engineer that works(ed) for BMW that has a memo that he/she drafted advising management that the S65 rotating assembly design is compromised - but for fear of getting fired, they just filed it somewhere safe.

Oh, to be a fly on the wall some days...

[Scharbag]

Originally Posted by ----Flyin-High----

Rod Bearings at 85k honestly the looked fine

Those are very nice. You chose your M3 wisely.

[mgmarsh39]

MY 13 with 21k miles. Super glad I had this done.

[Helmsman]

Originally Posted by Scharbag

The list of differences between an S65 (idle at ~600RPM) and a modern (V10, V8, V6) F1 engine (idle at ~4000RPM for the V6 - old V8 idle of near 10,000RPM) would fill a very large sheet of paper.

The S65, while a nice piece of engineering for the street, is not really a race engine. The rotating assembly in the S65 follows the same laws of physics that Mercedes, Ferrari, Audi, Lexus, Honda, Suzuki, Toyota, Yamaha, Ford, Chev etc. all have to follow. Yes it revs high, but no higher than a number of other similar displacement-per-piston NA high revving engines. We do not see the Audi R8 V10 forums inundated with spun bearings and premature bearing wear (the Audi V10 has a higher redline, higher mean piston speed and a larger HP/L output than the S65). Nor do we see complaints in forums for Honda, Ferrari, Porsche etc. Search for Audi R8 v10 spun rod bearing and you find a single post from 2011 that sounds like a bad luck bear bit the guy in the ass while the car had full warranty.

BMW screwed the pooch on the bottom end of this engine. Most of their problems would likely have been avoided if they had simply hand built the engines from "binned" assemblies that guaranteed their design tolerances were actually maintained. Since they did not do this, we get to play the German lottery - where winners are really losers.

I bet you, that somewhere, there is a German engineer that works(ed) for BMW that has a memo that he/she drafted advising management that the S65 rotating assembly design is compromised - but for fear of getting fired, they just filed it somewhere safe.

Oh, to be a fly on the wall some days...

Scharbag, we didn't discuss bearing design but reasons to warm the engine up. All engines/oil should be allowed warming prior being loaded, period. And comparing an S65 with 10W60 oil with an Toyota on 5W30 or whatever oil is simply not relevant. And yeah, why would you trust the rpm limiter? Finally, do you rev to the initial 6k rpm from start Scharbag?

Cheers

[Helmsman]

Originally Posted by mgmarsh39

MY 13 with 21k miles. Super glad I had this done.

Looks like mine at 34k miles. Would have run for another ton of miles but yeah might as well get them done early than late.

[Scharbag]

Originally Posted by Helmsman

Scharbag, we didn't discuss bearing design but reasons to warm the engine up. All engines/oil should be allowed warming prior being loaded, period. And comparing an S65 with 10W60 oil with an Toyota on 5W30 or whatever oil is simply not relevant. And yeah, why would you trust the rpm limiter? Finally, do you rev to the initial 6k rpm from start Scharbag?

Cheers

This got off topic.

Sorry bout that everyone. We should discuss cold engine care elsewhere.

[deansbimmer]

Originally Posted by ----Flyin-High----

Rod Bearings at 85k honestly the looked fine

Do you know the history of the engine to be assured that those had not been replaced prior to your ownership? Those look almost a darker color, like they may be WPC treated bearings. Condition-wise, they look great, better than any S65 I've ever seen if the mileage is true.

[deansbimmer]

Some recent ones. The last one came in with a slight knock and metal in the oil.

[Helmsman]

Originally Posted by deansbimmer

Some recent ones. The last one came in with a slight knock and metal in the oil.

Last one wasn't pretty. The other three sets looked quite fine on picture though, would you agree?

[deansbimmer]

Originally Posted by Helmsman

Last one wasn't pretty. The other three sets looked quite fine on picture though, would you agree?

Fine? No. Typical of the poor wearing S65 bearings we see most? Yes.

The engine from the last picture has to have a full teardown and rebuild now.
Definitely not good.

[tdott]

Originally Posted by deansbimmer

Do you know the history of the engine to be assured that those had not been replaced prior to your ownership? Those look almost a darker color, like they may be WPC treated bearings. Condition-wise, they look great, better than any S65 I've ever seen if the mileage is true.

I feel the same, if the mileage is true that is probably the best looking bearings I've seen removed.

[G80indy]

Originally Posted by ----Flyin-High----

Rod Bearings at 85k honestly the looked fine

Wow
What oil ?
What OCIs ?

[----Flyin-High----]

Originally Posted by deansbimmer

Do you know the history of the engine to be assured that those had not been replaced prior to your ownership? Those look almost a darker color, like they may be WPC treated bearings. Condition-wise, they look great, better than any S65 I've ever seen if the mileage is true.

I honestly dont, I bought the car used a couple weeks ago. I am skeptical as you guys are as. The car had 90k miles when i purchased it. The seller was a mechanic at a high end tune shop, he provided me with the invoice for the work along with the photos. I called the shop with the invoice number to confirm the work was completed. Short of pulling the pan off and checking myself, I dont know a good way to verify.

I took the car into my mechanic and he says all the motor mounts, throttle actuators are new. Which lines up with what the seller said.

As far as being the original bearings or having been replaced I have no Idea....

If anyone has seen that photo posted before I would really like to know. I want to give the guy the benefit of doubt.

Edit: Just for clarification the photos came from the seller, I have not seen the rod bearings for myself.

[----Flyin-High----]

This is the car purchased

https://www.ebay.com/itm/2011-BMW-M3...72.m2748.l2649


I was going to install a supercharger, I am nervous about the rod bearings. My shop mechanic said its one of the cleaner M3s he has seen, hopefully i got the unicorn, and not a fraud.

[tdott]

Originally Posted by ----Flyin-High----

I was going to install a supercharger, I am nervous about the rod bearings. My shop mechanic said its one of the cleaner M3s he has seen, hopefully i got the unicorn, and not a fraud.

The Ad lines up with what Deansbimmer suspected:
Maintenance items within last 2k miles:
WPC Coated OEM Bearings w/ OEM Bolts

Looks like it was well taken care of then, I wouldn't worry about it too much. Enjoy it.