Rod Bearings 70k miles PRE LCI

[F36Baker]

Thought I would post these for reference.

Car was completely stock up until the last 5k miles.

Kind of sketch to see how bad they were! Curious if others with experience think this is normal wear??

[Denny347]

"Normal" is relative with our family of engines. Knowing that, it is still excessive for the mileage, for our engines. I had mine changed out at 65k mi and it was a HUGE weight lifted off my shoulders. I bet you feel better now.

[F36Baker]

Originally Posted by Denny347

"Normal" is relative with our family of engines. Knowing that, it is still excessive for the mileage. I had mine changed out t 65k mi and a HUGE weight lifted off my shoulders. I bet you feel better now.

I really do! My mechanic said cylinder 2 crank had a small mark on it but should be fine. Said it was a ticking time bomb.

[Davisca455]

Good on you for changing those.

"Normal" rod bearing wear seems like a relative term around here.
I used to think the whole rod bearing issue was an internet hoax.
But just about every picture of rod bearings that I saw posted on the forum showed rod bearings that didn't look normal, so I decided to do the DIY for peace of mind.
But even then, I was fully prepared to be mad at myself when I removed perfectly good bearings because of internet hysteria.
I did the work on the original owner's lift.
He also thought the rod bearing "hysteria" was overblown.
He would say "The car was never left outside, I always warmed it up, and I always had the car serviced at 6000 miles."

I had about half of the bearings replaced when the PO walks back into the garage.
He starts inspecting the old bearing sets I had left on the top of the toolbox and says "These don't look right. Good call to change the bearings."
As he turns to walk away, he slowly shakes his head from side to side and mutters "Fuckin previous owner."

"Ticking time bomb" is no exaggeration.

[F36Baker]

Originally Posted by Davisca455

Good on you for changing those.

"Normal" rod bearing wear seems like a relative term around here.
I used to think the whole rod bearing issue was an internet hoax.
But just about every picture of rod bearings that I saw posted on the forum showed rod bearings that didn't look normal, so I decided to do the DIY for peace of mind.
I did the work on the original owner's lift.
He also thought the rod bearing "hysteria" was overblown.
He would say "The car was never left outside, I always warmed it up, and I always had the car serviced at 6000 miles."

I had about half of the bearings replaced when the PO walks back into the garage.
He starts inspecting the old bearing sets I had left on the top of the toolbox and says "These don't look right. Good call to change the bearings."
As he turns to walk away, he slowly shakes his head from side to side and mutters "Fuckin previous owner."

"Ticking time bomb" is no exaggeration.

Wow that's nuts!! Ya it's kind of scary. On cylinder 2 on mine it even took a small chunk out of the crank.

[Denny347]

Originally Posted by F36Baker

Wow that's nuts!! Ya it's kind of scary. On cylinder 2 on mine it even took a small chunk out of the crank.

What the heck did that? There should be nothing on the outside of the connecting rod that would make contact.

[F36Baker]

Originally Posted by Denny347

What the heck did that? There should be nothing on the outside of the connecting rod that would make contact.

No clue.. what was weird two is on bearing #2 there was this weird indent through the whole bearing that you could feel with your nail. Like it was grinding against something.

[Z K]

That looks "normal". The stock bearings look terrible when pulled out of most M3s. No amount of babying the car will protect the bearings or guarantee it won't wear badly. I'm glad I had mine done with extra clearance bearings.

It's cheap insurance compared to the cost of a new engine!

[couchflyer]

I think it has to do with the original owners and if the let the engine oil warm up properly before getting on it.

OP good call.

[Scharbag]

Originally Posted by couchflyer

I think it has to do with the original owners and if the let the engine oil warm up properly before getting on it.

OP good call.

Warmup is insignificant compared to proper flow. When cold, the S65 protects itself with a reduced redline.

[eroobeeroo]

These look identical to my 64k mile bearings

[couchflyer]

Originally Posted by couchflyer

I think it has to do with the original owners and if the let the engine oil warm up properly before getting on it.

OP good call.

Originally Posted by Scharbag

Warmup is insignificant compared to proper flow. When cold, the S65 protects itself with a reduced redline.

You contradict your self. Warm up allows for proper flow. Proper engine oil temperature is near 195 degrees, the rev limit is based on coolant temperatures not engine oil temperatures.