Catastrophic Failure of the Camshaft Bearings

Check the oil galleys that feed to that cam bearing and use a straightened wire coat hanger to make sure that the passages are not blocked.

have them measure the cam bores with a micrometer and make sure that they are the proper size.

I can think of five causes for the cam bearing to fail.

1. Improper (oversize) bore for the cam bearing.

2. Blocked oil passage feeding the bearing.

3. Dirt behind or on the bearing surface when the cam was installed.

4. They misinstalled the bearing, then removed it and reinserted it. Once you press in a cam bearing and then remove it, junk it. Do not reuse it, get a new one and install it.

On the block machining line that I worked on, once a cam bearing was installed and then removed we didn't reuse them, we replaced them with another one.

5. Bad surface finish on the bearing and/or cam journal itself.