Prepping for rod bearing replacement on 01 M3 with replacement engine through BMW

[sapote]

Here are the pictures of the road bearings they took out, glad I decided to get these done.

These bearings still have 60 to 70% life, with 0% as showing copper.

[bigjae46]

Just to be clear, that was 150k kilometers, not miles. I do agree with you, 100k miles seems like a good interval

5 years ago, I’d be OK with that with S54 prices being relatively low.

Now, prices are just going up. I probably wouldn’t take the chance and do them before 60k. The oil pan gasket likely won’t survive that long anyway.

[Arith2]

Seems like a waste of parts, time and $. With regular oil changes and warm up procedure, these bearings easily see 80-100k with non-track use. On the post above, that is pretty standard wear and nothing was failing even at ~100k miles, which is double the miles you are suggesting. Almost every bearing replacement done now won't need another replacement until the entire engine needs a full rebuild.

To me, I'd rather replace a good bearing rather than a worn one. When bearings wear, material goes throughout the engine. The oil filter does it's job well however there's oil passageways and other bearings that could be affected. The oil pump also is before the filter. Why wait until there's copper? The goal is prevention, and quite frankly, bearings are cheap compared to the $5000 engine I had to put in because I had bearings fails. Oil analysis is a scam. The only true way to know the health of the bearing is to look at and that's what I intend to do.