Changed out my Rod Bearings - 08' E90 M3 Supercharged

[SenorFunkyPants]

I didn't think the bearings looked too bad considering the outer lead layer is only ~0.0005" thick....the one that is showing cooper - any idea which cylinder # that came from?

[DrakeKemper]

Originally Posted by EvenSteven

That still seems extremely excessive. That would be like every 6-8 weeks, way too much hassle. There are plenty of high mileage blowers out there, so the additional wear can't be THAT bad? Does it really stress the components 3x more than normal (assuming a more reasonable 7500 intervals for NA engines rather than BMW's 15000 recommendation)?

Makes the whole blower thing seem like a terrible idea if you are right.

Well normal people driving normal cars change their oil every 3,000 miles.
Just because BMW says that I don't have to change it for 15,000 miles doesn't mean anything to me personally.
Whether it's blown or not, it's out of warranty, time to take better care of it to last a long time.

[regular guy]

Originally Posted by DrakeKemper

I recently had my 2008 E90 M3 supercharged, and before doing that I thought it would be a great idea to swap out the rod bearings.

It's about time! I've been waiting for your car to get done for months!

Overall, it was a good idea to replace them.

Yes, it looks to me like 6 of 8 were in pretty sad shape for 47000 miles.

I believe we went with the 2013 OEM bearings with a High performance coating? I don't know, ask Autotalent lol.

Auto Talent used WPC treated (not coated) bearings on your engine. The ones I measured for the Bearing Wiki thread were originally supposed to go in your engine.

Good luck, enjoy your supercharger in good health.

[EvenSteven]

Originally Posted by DrakeKemper

Well normal people driving normal cars change their oil every 3,000 miles.
Just because BMW says that I don't have to change it for 15,000 miles doesn't mean anything to me personally.
Whether it's blown or not, it's out of warranty, time to take better care of it to last a long time.

"Normal" people are using "normal" oil, not this pricy synthetic stuff. It's your money to piss away.

[BMRLVR]

Unfortunately the bearings show signs of the rod bores distorting or not being true...... Hence the wear on the part lines and on one side of the bearing or the other, not even all the way across.

Good that the OP changed the bearings, the WPC bearings are going to add a few tenths of clearance and the ARP fasteners should address any fastener stretch if any was occurring. The engine will definitely be better off now than if it had been left alone.

[regular guy]

Originally Posted by EvenSteven

If you're going to supercharge, swapping the bearings is probably a good idea. Doesn't coating the OEM bearings make the problem worse though?

Yes, but these aren't coated bearings. They are treated bearings. The WPC treatment actually increases clearance by 0.00042 inch where the coated bearings decrease it by 0.00030 inch. This will help the clearance, where coated bearings will hurt it.

Originally Posted by speedaddictM3

One such Honda engine is that in the S2000. Remember it? Made more hp/L than the S65, and also revved to a whopping 9000 rpm. And I'm sure it was built to very close tolerances. Yet it can still keep going on and on without eating up its bearings.

In the bearing wiki thread, one S2000 owner reported a very large number of miles without bearing issues. I think he said it was very common to get 250k to 300k from the S2000 engine. The S2000 bearing clearances are very hard to find; if anybody has official numbers, please post. As best I can tell, the S2000 main clearances are 0.00075" per journal-inch diameter, and the rod clearances are 0.00085" per journal-inch diameter. Compare that to the S65 of 0.00061" per journal-inch diameter.

[rev9k]

Here's a question:

Everyone is posting pictures of all the bearings and/or caps out at once.. Shouldn't the bolts be changed 1 at a time to prevent any misalignment of the rod cap ( I know it's a fractured cap but still).. Additionally, ARP says rods need measuring/possibly re-sizing w/ new bolts//

????


Anyone

[BPMSport]

Question for the bearing experts: I have a new s65 on the way and have had the VAC coated bearings/ARP bolts sitting here on a shelf for some time. I was thinking about replacing only the bolts and leaving the new stock bearings alone. Would this be of benefit or should I leave it as is? Any input here is much appreciated. I'd hate to open a baby fresh motor but if it serves a valid purpose I'm not opposed to it.

I'm also excited about sending the oil from the 1,200mi service to Blackstone. Would be extremely interesting to see what the results are on a brand new motor. I don't recall seeing any break-in oil reports from the S65.

[W///]

Originally Posted by FogCityM3

Exactly. Remember seeing a video with Steve Dinan saying that BMW designed these engines (S65/85) to last about 150k miles. He also said that modifying the engine with typical bolt ons, tune, rpm limit raise, etc would likely reduce its life by about 25k miles. For this type of engine, I'd be happy with 125k-150k miles. No such thing as a free lunch.

Would love to see that if you can find it

[rev9k]

Originally Posted by Mike Benvo

Question for the bearing experts: I have a new s65 on the way and have had the VAC coated bearings/ARP bolts sitting here on a shelf for some time. I was thinking about replacing only the bolts and leaving the new stock bearings alone. Would this be of benefit or should I leave it as is? Any input here is much appreciated. I'd hate to open a baby fresh motor but if it serves a valid purpose I'm not opposed to it.

I'm also excited about sending the oil from the 1,200mi service to Blackstone. Would be extremely interesting to see what the results are on a brand new motor. I don't recall seeing any break-in oil reports from the S65.

IMO not worth either of those things. A break in oil analysis will prob just show elevated levels of metal as things break in

[FogCityM3]

at 4:00 min:

Also talks about life expectancy of modded N/A and FI engines in Dinan's experience:

Finally, not directly related some interesting info about bearing loads when building a stoker motor

Originally Posted by W///

Would love to see that if you can find it

[EvenSteven]

That interviewer is retarded, for reals.

[L4ces]

FogCityM3
Thanks frosting that. It was good viewing.