Engine was rebuilt 4 or 5 years ago. I didn't drive my car last year much due to transmission issues - but I recall hearing a noise at certain rpm last summer. I recently got it on the road again and resumed looking into the noise. I also noticed the oil pressure is low. Just warmed up to operating temp in the garage it had less than 10# at idle with new 10-40 Royal Purple Synthetic. I also verified my electric gauge with a mechanical gauge. I put in 20-50 conventional and with same conditions had 20 psi and raised at least 10 psi per 1000 rpm. Thought it was good so hit the street. However after maybe a 15 mile drive once back at home noticed down under 10 psi again. I also had reset valves prior to drive. After some reading I decided to pull the oil pump apart. There is some what I would call minor scratching on the oil pump filter housing, not very deep at all. I was kind of hoping it would be chewed up a bit and low oil pressure could be causing some valve train noise. How much wear would it take on the oil pump filter housing to lose pressure? Tonight a friend stopped by and suggested we cut the oil filter apart which he did with a cut off wheel. There were filings in the filter - some brass colored and some silver. Most of which are metallic - and stick to a magnet. If it was bearing material it wouldn't stick to the magnet. So I thought perhaps the cut off wheel was a bad idea as it could have put the filings into the filter. So I drained the oil into a white pail and let it settle for a while - then drained it off slowly. I couldn't see much for debris in the oil. I'm looking for directions or opinions on where to go next. Drop the pan, inspect the bearings? Re-surface the housing, put it back together and run it, then re-examine oil filter - cutting it apart cleaner? Engine has hydraulic roller cam. Not too many miles ago I checked crank and cam end play. Crank was bang on, cam was tight at .002" if I remember correctly. Was chasing hi rpm knock readings. Could be related... Is it trying to eat itself?