I have a newly rebuilt 440 engine. I primed the pump with a priming rod and a drill. The oil filled the rocker arms and was as abundant as it should have been. I ran through the break in period. I now have some valvetrain noise. (Engine has less than 1 or 2 hours of total run time.) I removed the valve cover to see what was going on. The engine is gettinbg some oil, but it doesn't flood the rockers as it should. What could be wrong? Thanks.