[Jack Ferris]

Upon a routine bearing inspection on my bracket 455 I found the #4 main bearing, on the cap side, to be showing a small amount of copper. What puzzles me is it looks like it flaked off rather than wore off. The block side bearing as well as all the rods and the remaining main bearings showed minimal wear. Has anybody had this happen to them?

[Jack Ferris]

Upon a routine bearing inspection on my bracket 455 I found the #4 main bearing, on the cap side, to be showing a small amount of copper. What puzzles me is it looks like it flaked off rather than wore off. The block side bearing as well as all the rods and the remaining main bearings showed minimal wear. Has anybody had this happen to them?

[Will]

I have heard a couple engine builders complain about this problem with the Clevite bearings. Take that FWIW.

[PONTIAC DUDE]

Any time you get flaking on the bearing, your putting the bearing under more load or stress then the bearing was designed for.
Example, lugging an engine or trying to work it at a low rpm will cause this.
Heavy vehicle at low rpm under a load
Excessive rpm under a load.
Bearings that have been handled then not installed. Acid in your hands corrodes the bearing and you don't notice it. That's why you never take back bearings that have been opened and handled.
Timing to high, check the top of the rod brg's for a small wear pattern. As it will transfer to the mains as load.
Changing to a synthetic oil will help transfer the heat and help control wear.
There's probably more but hope this helps.

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