Originally Posted by Bosch
Are these cracks in the crankshaft rod journal? I am not a machinist, I don't really have much experience or expertise with this sort of thing. I will try to get this to a machine shop when I get a chance, but any insight would be appreciated. This is a cast crank from a Chevy 350. I had planned to put together a decent little 350 to run for a couple of seasons in a Chevelle. It is not going to be used for racing. Just a nice strong little engine to run until I can get a big block put together. I was thinking something like a 325 to 350 h.p. 350.
The pictures are not that good, but hopefully you can see the little marks on the journals that I think might be cracks. There are also lots of paper fibers on the journals, I used a paper towel to wipe the crank off.
I'm suspicious that your hunch is correct. This looks enough like early stages of fatigue cracking or is an inclusion. Are the marks on the journal in pictures 1 and 2 on the same journal as the marks on picture 3?
I’d definitely get it checked out. Do you know if this shaft was reground? That can sometimes hide a journal that got toasted by a rod failure where subsequent turning of the journals cleared the burnt metal, but this could be remaining heat check cracks that scarred deeper into the metal beyond the burn.
Hard to tell by a picture but something's there that's worth investigating further.