oiling problem/mystery

[JRODHOTROD]

Over the life of my engine, I noticed that the oil pressure seemed a little high at idle. 50 psi. At full throttle it would touch 80. After two years, all of a sudden it went 8-10psi at idle and 75psi WOT, all of which with a high pressure high flow pump. What happened. BTW it still runs fine. Am I OK

[apex69]

The gage may have been at fault on the high reading, or now a piece/ chunk of something is blocking passage to the gage. What the type of pump/part number? Same oil used over the two years? How many miles do you have on this. Was it a fresh rebuild? What do you idle at

I have seen in one instance where the pressure spring in the pump broke and the two halves clocked allowing them nest into each other effetely reduced the spring height thus reducing the pressure. But that is a lot of loss. Medium performance pressure at idle can be 10-15 +/- 2 psi with a 2500 rpm psi at 25-30. Just depends on the clearances used in the build up. What is the pressure at 3000-4000rpms?

At idle sounds like the spring but still seems ok. WOT at 80 even 75 psi seems high but with the pump it may be normal opp for it. Pump specs would help. I pummel my 383 with a 1000rpm idle at 10psi and 6500rpm wot at 45 psi. 6years and 39k miles. Been that way after break-in.

[JRODHOTROD]

well, I supose this sounds normal then, ive heard that 10psi for every 1k rpm is normal, I just cant figue out the sudden pressure drop. The pump is a melling and sits in a 7.5q milodon. Ive used mobile one syn 15w50 the entire time.

[Milow68]

Jrod
I heard the same saying about 10psi for ever 1,000 rpm
Brad

[apex69]

My 99 GMC 350cid with 65k on it at temp idles at 750rpm with a reading of 25psi. I increased it at 1000-rpm intervals up to 3750, static (sitting) and dynamic (driving) the increase in pressure went to around 45 psi.

In this case about 6.5psi for every 1k rpm increase.