Hi,

Have my 1970 Cutlass back together. The engine was rebuilt along with many other things. I'm having very low oil pressure readings as follows and would like some feedback/suggestions. I just changed the oil and put 20W/50 in as per engine builders recommendation.

The manual gauge is connected on the front of the engine right above the temperature gauge and was also checked with another gauge to confirm accurate readings.

Cold start:
Oil 35 PSI then drops as it warms (normal). Service Manual says 7-10 PSI at idle is normal.

After 10 minutes at Idle:
Temp 215-220F
1100 RPM
Oil 5 PSI
Vacuum 18 and remained pretty steady unless I was rev'ing it.

2000 RPM
Oil 13 PSI

2500 RPM
Oil 17 PSI

3000 RPM
Oil 17 PSI

Then let drop back down to idle:
1100 RPM
Temp 220
Oil 3 PSI

Oh, and after 20 minutes of letting her run in the driveway, she just shuts off! Starts up again but doesn't want to stay running.

 

That's lower then normal. Could be a number of things. Bearing clearance, oil pump pickup to high sucking some air, Bad oil pump. Should not run it any more until you find the problem

 

Ut oh. Seems low to me too.

 

You should have more like 50 cold, 20 hot idle and 40-45 at 2000 rpm. I have that on a 2 year old $500 rebuild with 20w50 oil. Take it back, something is very, very wrong.