If the engine was broken/worn the pressure would still increase with rpm. A gauge that always reads 20 PSI indicates a faulty gauge.
1973 454 oil pressure problems
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8th Gear
Joined: Jun 2017
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1973 454 oil pressure problems
Hi ,the oil pressure gauge on my !973 Excalibur ,with has a 454 Corvette engine ,reaches up to 20 on the gauge when i start it ,doesn't move from there ,nor even when accelerating ,when i turn it off it goes back to almost zero,never gets to zero.
I've just did the motor flush because i had noisy lifters ,i filled with 1 gallon of regular 15/40 and 2 quartz of diesel 15/40 and 1 quart of lucas stabilizer ,now the engine runs completel
y silent,i've noticed that the plastic tube of the oil pressure gauge ,has bubbles o air when
is engine off ,is that normal???
I've just did the motor flush because i had noisy lifters ,i filled with 1 gallon of regular 15/40 and 2 quartz of diesel 15/40 and 1 quart of lucas stabilizer ,now the engine runs completel
y silent,i've noticed that the plastic tube of the oil pressure gauge ,has bubbles o air when is engine off ,is that normal???
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Moving this to C3 Tech for a possible answer.
Le Mans Master
Joined: Mar 2001
Posts: 5,738
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From: Lincoln, CA
Hi ,the oil pressure gauge on my !973 Excalibur ,with has a 454 Corvette engine ,reaches up to 20 on the gauge when i start it ,doesn't move from there ,nor even when accelerating ,when i turn it off it goes back to almost zero,never gets to zero.
I've just did the motor flush because i had noisy lifters ,i filled with 1 gallon of regular 15/40 and 2 quartz of diesel 15/40 and 1 quart of lucas stabilizer ,now the engine runs completely silent,i've noticed that the plastic tube of the oil pressure gauge ,has bubbles o air when
is engine off ,is that normal???
I've just did the motor flush because i had noisy lifters ,i filled with 1 gallon of regular 15/40 and 2 quartz of diesel 15/40 and 1 quart of lucas stabilizer ,now the engine runs completel
y silent,i've noticed that the plastic tube of the oil pressure gauge ,has bubbles o air when is engine off ,is that normal???
Bubbles in the tube are normal.
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From: Plano TX
Safety Car
Joined: May 2001
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From: Fairfax Virginia
Check your sending unit!
I had an issue on a boat engine that is very similar. I saw that my gauge was only reading a specific number when running. I found that there were two different sending units, 1 for a vehicle with "dummy lights" and the other sending unit sent a variable signal to work with a oil pressure gauge.
I put the correct sending unit back on and I had somewhat accurate pressure readings again at my gauge. The difference between the two sending units was that one was twice the price of the other......
If that is not the problem this might help. My 1968 Corvette came with a nylon tube connecting at the engine near the oil filter going to the gauge on my dashboard. If that tube gets kinked or blocked you gave issues.
I upgraded mine to a braided stainless hose made for this application so now the chance of having hot oil shooting out of the dashboard is reduced.
Enjoy your Corvette Engine and may your gauge function as it was designed!
I put the correct sending unit back on and I had somewhat accurate pressure readings again at my gauge. The difference between the two sending units was that one was twice the price of the other......
If that is not the problem this might help. My 1968 Corvette came with a nylon tube connecting at the engine near the oil filter going to the gauge on my dashboard. If that tube gets kinked or blocked you gave issues.
I upgraded mine to a braided stainless hose made for this application so now the chance of having hot oil shooting out of the dashboard is reduced.
Enjoy your Corvette Engine and may your gauge function as it was designed!
Team Owner
Joined: Jan 2006
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From: Crossville TN
Two things:
1. It doesn't matter if there is air or air bubbles in the oil pressure gauge line. Air will compress to the same pressure as the oil almost instantly.
2. The only way to know if your pressure gauge is reading reasonably well is to tap in another [more accurate] gauge in the same line so that you can compare them. You CAN disconnect the gauge line from your engine and hook it up to your air compressor, then set it at different air pressure levels to see if your oil gauge is performing properly.
1. It doesn't matter if there is air or air bubbles in the oil pressure gauge line. Air will compress to the same pressure as the oil almost instantly.
2. The only way to know if your pressure gauge is reading reasonably well is to tap in another [more accurate] gauge in the same line so that you can compare them. You CAN disconnect the gauge line from your engine and hook it up to your air compressor, then set it at different air pressure levels to see if your oil gauge is performing properly.
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Joined: Sep 1999
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From: Plano TX
Air compresses, but it is still the same pressure. You can have nothing but air in the line from the motor to the gauge and the gauge will read the exact same thing as if the line is filled with oil.
I did what 7t1vette says above to calibrate my gauge. Set my air compressor to 35 PSI, verified with a tire gauge, then calibrated the oil pressure gauge to show exactly half sweep. Worked great.
I did what 7t1vette says above to calibrate my gauge. Set my air compressor to 35 PSI, verified with a tire gauge, then calibrated the oil pressure gauge to show exactly half sweep. Worked great.
Last edited by zwede; Jul 9, 2017 at 10:13 PM.