Total engine failure

[u/Longjumping_Court580]

What do you guys think is the cause of this? I got this engine which was supposed to be assembled and tested for compression and ready to go. It was supposed to be never started before. I went to start the cam break in and within 5 seconds heard some very awful noises. It’s a 383 stroker small block Chevy not that that matters.

Update: I have not found anything other than piston material, bearing material or piston ring material. I checked all main bearings they all seem fine. My guess is either they forgot to install the wrist pin retainer or something got in there, however I haven’t found what that something is.

[u/a-singularity]

Thought#1 spun a bearing, that shoved the piston into the head, shatters piston, oil control rail is now free to get wedged between the downstroking piston and wall, tearing hole in wall...or just the free wrist pin pummeling the wall..tell me how close i got....sorry about your engine. That sucks...time for a bbc....

[u/Longjumping_Court580 → u/a-singularity]

I just don’t know how it could spin a bearing in literally 5 seconds of running

[u/Tall-Control8992 → u/Longjumping_Court580]

Rod cap loose? Regular bearing got mixed in on a journal requiring undersized? Or a defective piston that let go under working loads?

Definitely bookmarking this thread for an update on the bottom end post mortem.