Grinding, " diesel " noise under valve covers
I listened again and you guys should too. It's a grinding noise like if a bolt were rubbing on the flywheel or the cam gear. Like I said before, it's a whirring noise. Twice the engine rpm at least. With the cam and slow idle you can damn near hear every cylinder fire. If it was piston slap that would have the same rhythm as the cylinders firing. This noise is double that rhythm.