RayJ

Need some advice just rebuilt entire engine and can't get oil pressure back to where it was (30 lbs) before the rebuild. Here is the series of events
Block was honed, new camshaft bearings, heads refrubished, new freezeplugs.
New cam, new rod and main bearings, new piston rings.
new camshaft had a "painted surface on the lobes and bearing surfaces that the machine shop told me was OK to assemble that way.
Put it all together and started it up. Oil pressure went to 30 then dropped to 20 at idle. Drove car around to seat the rings and pressure continued to drop to 20 under full acceleration. Parked car for the night and next day started it and the pressure gauge spiked at 80 then dropped to 30. Changed oil and filter (10W30). Pressure again 30 when cold dropped to 18 when hot and about 22 under acceleration. Changed oil and filter again (10W30) same results. Engine runs very smooth, no noise just no pressure, changed oil again to 10W40 still the same. I am using a Stewart Warner mechanical gauge, I blew out the plastic line to make sure it wasn't clogged. Question, could the oil pickup tube be clogged from the painted surface on the cam, can this be reverse flushed without taking off the pan. Will a High Volume Oil pump solve the problem? Forgot, I also took out the pressure relief valve and cleaned that area, the valve had alot of scratches on it. Help, need advice!

Ozzie

Be sure that the gauge is accurate. A spike to 80+ PSI at low RPMs seems unlikely with a stock pump. Normally a rebuild won't lower oil pressure if everything is done correctly. I'm a bit suspicious about the "painted" surfaces on the cam. It probably was to stop corrosion during storage. I probably would have removed it before installation. This material may be partially clogging the pump's pickup screen. If the pieces are too big to pass the screen they will only reclog the screen even if you removed them by backflushing. You could look in the first batch of oil and inside the filter for evidence of the coating material. Or you could try the backflushing and then drain the oil without running the engine and again look for the coating material. If the pressure seemed normal before the overhaul you probably should be able to get back to that condition without changing the pump. I'm wondering if you noticed any unsmoothness in the pressure relief valve when you cleaned and inspected it. The scratches could have meant something.

RayJ

What could the scratches on the pressure valve mean? There are alot of scratches around the outside near the front of the valve.

Ozzie

I am uncertain. Usually when a part is unused, I would not expect to find the scratches. When it gets the scratches during use it's often due to some abrasive crud or a burr on an adjacent piece which it touches during operation. I suppose the question now becomes do the scratches (or the cause of scratches) interfere with the valve performing it's job or not. I suppose that a close inspection with attention to functionality would be a good thing. Best wishes.

RayJ

Does anyone have a method to backflush a oil pickup screen on a 63 215 engine?