long

I picked up a used 6.0 iron short block this week. I checked the rod bearings before I puchased it but not the mains. During the tear down I found that the number 1 main bearing had spun. The first thing I looked for was a pinned crank thinking it was from a supercharger. It was not pinned. I removed the bearing and torqued the main cap and check the diameter. It is in spec but at the high end of the spec. Has anyone seen this before and is this a common problem? I have no history on the engine. It had been painted so I am assuming it was not just pulled out of a truck.
Thanks

American Heritage

Line Bore/Hone time

long

You are correct. I have seen spun cam bearings and rods on these engines but never mains. That's why I'm concerned.

Johnny wangwang

Why would you automatically think supercharger? A spun bearing can be from a few things. Supercharging wouldnt be close to my first guess.

And im gonna go with not very common unless the driver just wasnt watching the oil press. My oil pump died and then my mains rod, and cam bearings became worn. I didnt know any of that and just swapped the oil pump out and kept it moving. Oil pressure was low though. After parking it and tearing it down... The cam ITSELF was worn down on some lobes, lifters were pitted, and metal had gone through out the motor. I was shocked to see that no bearings had been spun. Im guessing it was because I constantly was changing the oil and never took it over barely idling while driving it after I saw the low oil press.

Yo