I have an LS6. I've had a cam bearing walk out on me twice in about 1000 miles each time. The block has been checked by a reputable machine shop and found to be true. The bearings have been professionally installed. I've heard of this happening before but I've never heard of a solution. Any input?

 

Same one both times? If so which one?

 

Define how the machine shop determined they were “true”. If the bore diameters are within spec, the correct bearings are used along with adequate clearances, and there are no oiling problems, then they shouldn’t he coming out.

There are some endurance racing applications where this can happen when there are legitimately no issues, the block just gets really hot, expanding the bearings bores and loosening the press fit of the bearings, but I don’t think thats the case is it? If so, pinning the bearing seems to be the solution.