Unresponsive oil gauge
 

I know I have oil pressure cause the light goes out and the gauge SLOWLY goes up to 20/25. Even when I rev it it won’t go higher than that. I looked and I have a slight leak where the tee is for the light and the gauge. I am going to fix it tomorrow but could that be my problem? This is the second gauge I tried cause I thought the first was defective. When the engine was on the machinists stand it was holding 70.

Is this a electric gauge?

No mechanical

Is the needle slow to drop back down when you shut it off?

Clay

I haven’t paid attention, what could that mean?

Kink in the line or one of the ends not fitting right. Restricted..

Clay

Well the copper line is about a million miles too long so it’s coiled up under the dash. Anybody know of a shorter copper line kit for Stewart Warner green lines

Try hooking up an external mechanical gauge. If it works you have a problem somewhere else.

That's what thumb cutters/mini tubing cutters is made for.

Clay

Never mind I found one

With any mechanical gauge you need to purge the air out of the line by leaving the fitting at the gauge end a bit loose while the motor is running until you get a good steady bleed of oil coming out with no sputtering which indicates air.

Just like bleeding a brake system.

My gauge came with a preterminated line that I couldn’t shorten. I found a kit that uses compression fittings. I am gonna use one for my oil and vacuum gauge

Except that with the oil gage, a pound of oil pressure is also a pound of air pressure. The air in the line actually helps subdue pulsating if present. Air in the line would not be responsible for an extremely slow gage movement. I suspect that one of the ends was pinched almost totally shut when it was assembled. Think a heavy hand on a crimp ferrule could squeeze the tubing closed.

There's a small restriction inside the back of the gauge. They do this to dampen oscillations. You probably have a piece of dirt. or Teflon tape, clogging the restriction. Take a needle, bread tie, torch tip cleaner, etc. and poke the crud out of there.

Well it went up to 40 today very slowly and it did not immediately drop when I turned the engine off

Did you confirm no kink in the line? Coiling it under the dash is not good.

I ordered a line kit that you cut and put a compression fitting on it so I don’t have a mile of line under the dash.

Regardless of what others have posted here you have a lot of air trapped in all of that extra coiled up line and It may take a few minutes of bleeding to get all that air out.

You can get this out of your hair now if you do this.

Ream out the ends of the line then bleed the line. Air compresses, oil doesn't.

So when your air compressor gauge reads 80 pounds, it's not accurate because air is compressed to reach that level? Your 6" of trapped air might compress down to 2" with the oil pushing it, but it will be at 80 PSI when it equalizes with the input pressure. I've installed a lot of mechanical oil pressure gauges and never worried about trapped air.