High oil pressure

[Lakota]

Hey guys, I'm back from the dead and back in the garage (back injury). Picked up an '80's 350 Chevy engine and fired it up. I got high oil pressure (meter pegs at max) but the lifters are getting plenty of oil (no clatter). The sender and meter worked fine with another engine. This ones a head scratcher. Any ideas?

 

[zzrodder]

Hmmm, I'd try another sender and gauge.

 

[Sniper]

Relief in the pump stuck in the closed position?

 

[Old Iron]

Relief in the pump stuck in the closed position?

Or some brainiac stretched the oil pump relief spring [S

 

[bob w]

Welcome back Lakots. It has been a long time. I'd borrow a mechanical pressure gauge and recheck it.

 

[sneakysnake]

Do you know the history on the motor? Might check the oil make sure they didnt put 90# in to keep it from rattling.lol

 

[donsrods]

Welcome home, Lakota ! Well, there are only two possibilities:

1) The gauge is giving you a false reading, or

2) The gauge is giving you a true reading and you do have high oil pressure.

To rule out the gauge or sender (even though you swapped them already) put a $ 15 mechanical pressure gauge screwed right into the port on the block where the sender goes. You might have to use some hardware store 1/8 inch npt brass parts to make it fit, but it will tell you exactly what pressure you have.

If you have high oil pressure it is probably because the relief valve is stuck from sitting, or some modification. Someone may have put a high pressure pump in there, thinking they are better. I would start by replacing the pump with a standard pressure and volume Melling pump and then change the oil and filter and see what happens.

At least you don't have the opposite problem, low oil pressure.

Don

 

[Lakota]

Today I went out to the garage to work on it. After sitting for twenty minutes staring at it, I remembered I had two oil switches on the old engine. One was the variable oil pressure sending unit, and the other was a simple switch used to turn on/off the electric fuel pump. It was eight months since I last worked on it, and the old memory tends to forget. Switches swapped, and oil pressure running at normal. Thanks guys for the input.

Wait until I tell you what happened with the old engine. Make sure you have a crying towel nearby, it's a real tear jerker.