Grinding, " diesel " noise under valve covers

Yessir. The noise don't bother me like that! I ain't a quite one! These have C clips, if I remember. Is there any way to " lock down" that? After warm er up and listen? Noise Don't bother me, the thought of killing my mill real does!
Wait until you can start it up and let run a long time and get completely warmed up. If it subsides, it's piston slap. Stop this insanity until you're able to do that. Then if it doesn't quieten down some, you can go insane.