correct oil pressure question
Thread Starter
Burning Brakes
Joined: Mar 2008
Posts: 1,038
Likes: 39
From: Denver, CO
St. Jude Donor '08-'09-'10
correct oil pressure question
just as the title states, what is correct oil pressure on a '79 auto?
with the engine completely off, im runnin 20.... on, i run 50-70. the car is new to me, and only know that the engine was rebuilt about 4 ears ago (have that receipt) though it doesnt say everything that was done.
i guess next question once correct is determined, is why am i running 20psi (or whatever) with the engine off.
with the engine completely off, im runnin 20.... on, i run 50-70. the car is new to me, and only know that the engine was rebuilt about 4 ears ago (have that receipt) though it doesnt say everything that was done.
i guess next question once correct is determined, is why am i running 20psi (or whatever) with the engine off.
Last edited by joshtried; Jun 21, 2008 at 11:59 PM.
Le Mans Master
Joined: Oct 2007
Posts: 7,455
Likes: 977
From: RI, Now Franklin/Nashville TN
I don't think your guage is incorrect! My 78's gauges when the ignition is turned off remain where they were when the car was running until the next time I start the car at which time they all reset to "0". I just went out to look at the gauges in the car sitting in the garage off and oil pressure shows 40, Temp about 175, and volts 14. When I start the car they all reset. Also, my oil pressure with a stock L-82 is about 40 lbs idling and 50-60 at high RPM with 20W-50 Racing Mobil 1.
Melting Slicks
Joined: Aug 2003
Posts: 2,135
Likes: 2
From: Dayton Oh
Your oil pressure will depend upon the oil pump and RPM. My 79's engine is nothing close to the original L82 and uses a HV/LP Melling. According to my oil pressure guage, it runs 40lb at idle and 50lb at cruise. I could read the real pressures by hooking up a mechanical, calibrated guage but haven't done so.
As far at the guage not zeroing when the key is turned off, then I agree that mine does not but, if you turn the key off to kill then engine and then turn it to run without starting, the guage does drop all the way to zero.
As far at the guage not zeroing when the key is turned off, then I agree that mine does not but, if you turn the key off to kill then engine and then turn it to run without starting, the guage does drop all the way to zero.
Race Director
Joined: Sep 2001
Posts: 10,560
Likes: 439
From: Wellington, FL
St. Jude Donor '11 thru '25
Thread Starter
Burning Brakes
Joined: Mar 2008
Posts: 1,038
Likes: 39
From: Denver, CO
St. Jude Donor '08-'09-'10
let me rephrase that one... my gauge NEVER goes to 0. sounds like gauge is whack according to a few of ya..
isnt there a way to test.. like ground should go one wa, and positive another.. or somethin like that
isnt there a way to test.. like ground should go one wa, and positive another.. or somethin like that
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Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
I think that you are saying the gauge reads 20 psi when the engine is not running...but the key is turned ON. I suspect that the wire terminal/connection going to the temp sensor is dirty or that someone has put teflon tape/sealant on the threads of the sensor when it was installed into the block. The threads should be CLEAN, as that is the ground connection for the circuit.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
Nevermind. You said oil pressure...and my brain is 'thinking' water temp. The only reason for the oil pressure gauge to read anything with engine off and ignition turned on is that the gauge is broken or the needle has been positioned in error (slipped or moved by someone).