Originally Posted by ForceFed86
Tore down a cheap 5.3 motor tonight. 2 of the mains have copper showing at the upper edges of the cap. Is this normal? I see no abnormal wear anywhere else. Crank looks good. Is this typical of a 100k mileage motor? Anything to worry about? Should I just replace them? What would cause one are to wear like this?
Local had mentioned that some of the tri-metal bearings would wear this way over time (high mileage) and that it was normal. He suggested I just slap it back together and run it.
You're looking at the hard working (lower) half of the bearing . These look super good especially considering the mileage. Given the surface layer (babbit overlay?) isn't even penetrated I think you're looking at some waviness in the bearing's plated surface what wear there is has got to be in the millionths of an inch. This shows damn good machining and straightness in the block and crank.