I'm sure this has been discussed, but please humor me. I have a problem with oil pick up when hot. After a hot start up, the engine emits a noticable main bearing knock for three seconds, but takes as long as twenty to show any oil pressure. At idle, hot, the guage reads about 1/8" to the right of the "zero" mark. At 2500 rpm hot, the guage is well over half. The engine exhibits NO noise when cold, even after sitting for days. Engine is VERY fresh, and every clearance was measured with a dial bore guage or plastiguaged. It has a high volume oil pump with the race springs installed. Could the oil pressure relief valve in the block oil filter boss cause this? Any thoughts? Thanx.