So I am having oil pressure issues. I rebuilt the top amd bottom end with the help of a good friend. My question is this. To me it looks like the oil pump where it pushes oil into tje side cover has a spot for a sleeve. I don't remember if there was one there or not. Is it just an o ring inbetween the cover and pump or is there a little metal sleeve? I also need to find the right size o ring for it.this is hopefully the last piece to the puzzle.