oil pressure loss

[sweetgn]

I was driving to work the other day and heard a tapping coming from the engine, like a bad lifter. I glanced at the oil pressure gauge and it read approximately 30 psi. Not normal at highway speeds for my car but I was two miles from work and figured I could baby it the rest of the way. As I got closer to work, the oil pressure slowly dropped until the gauge registered 10psi at 2000 RPMs. I was about to shut it down when the oil idiot light popped on. Luckily I was able to drift most of the way to work. I started it back up and had about 15 psi, enough to get to work. Still sounds like one of the lifters is suffering a collapse, I'm hoping from little oil pressure. Where do I start? I was thinking about checking the spring at the oil pressure relief valve and seeing if it broke or maybe a particle of dirt in the valve not allowing it to close. Could I be that lucky or does this sound like a worse problem. It seems strange the oil pressure SLOWLY dropped over a two minute period. Any ideas?? Please help! I've never taken out the oil pressure relief valve. I would appreciate any advice on that job. Thanks.

 

[tjthorson]

I don't mean to sound stupid, but did you check the oil level? You might have a hose leaking or something. When you turned it off, enough oil drained down to start pumping again?

How old is the timing chain? Only other thing I can think of is something blocking up the pickup screen (like pieces of a nylon cam gear).

I don't think the spring is going to be of any use. Sorry!

 

[sweetgn]

Yes, the oil level is fine. There are no leaks. The timing chain has to be fine as the car runs. It was replaced in '98 at time of the rebuild. I failed to mention the car used to produce about 80 psi at startup now it is 20 psi at startup today. I only left it run a few seconds. Thanks.

 

[sweetgn]

BTW, It has metal timing gears now also.