When my cams were remove during engine disassembly, we noticed some wear "grooves" on the bearings. This appeared to be more than expected for <10K mi. Has anyone had experience with this before? This was the first time these have been removed. They were deep enough to feel with my finger.

yikes, I hope that is a fluke. I can imagine some serious wear by 50k miles.

Myself as well. I was hoping someone would have some input, as I am at a loss.

Was the motor 100% stock before? Meaning were those the original cams?

Yep, all stock.

What oil were you running?

Mobil 1 5W30

Oil change intervals? What filter?

That def looks like foreign particles may have contaminated your oil, or your oil was dirty and it caused this premature failure of the cam bearing. Dirt/Foreign Particle contamination contributes to almost 50% of all bearing failures seen in the field. Though I find it quite strange how uniform the wear looks on both sides of the bearing (minus that its more apparent on the bottom bearing, in comparison to the cap side bearing). I would def like to know what filter you were running as it seems it didn't do a very good job at filtering. How do the rest of the bearings look? Is it localized? More info may be a bit more helpful in determining why you have a premature failure.

I've seen that before. Even tried polishing them and moving to a looser bearing from mitsubishi. Improper timing chain tension could be the cause or being a tooth off.

~2500/6months. I get back to you on the filter, don't remember right now.



My rod and crank bearings look fine.


The wear is more apparent on the back side of the bearings, this may be hard to tell from the phots, but the front has no wear marks at all. Almost like it was being pushed toward the back by something.