What would cause a wrist pin to loosen??

[Warp6]

Been trying to diagnose a skip. Thought it was electrical so I tried a few things there. Car would run great until fully up to temp, then it would just start skipping. Did a compression check..160 across the board except #3, 140lbs. Noticed plug was oil soaked too. (I never saw it smoking) I thought it was probably a bad ring. I yanked the engine yesterday and began the teardown. #3 didn't want to come out of the hole. Now I know why...the pin was bound up against the side of the cylinder which left a nasty gouge about an inch wide along the wall. It was built about 5 years ago. Std bore TRWs with stock pins, stock polished rods, TTA crank, RJC girdle. I thought I had a solid bottom-end....WRONG! What could have caused this?

 

[gossamer]

I saw it once in an engine that was pinging alot... It didn't slide the pin sideways, but rotated the pin in the rod about 1/4 turn. It sounds like the small end of your connecting rod was resized a little too large and eventually, the pin worked it's way out. Sorry to hear.