Oil pressure
Thread Starter
3rd Gear
Joined: May 2019
Posts: 3
Likes: 0
Oil pressure
I just finished a big block transplant in my ‘73. All is good except for my oil pressure gauge. Right from start up, it zooms to 70 lbs and stays there as long as the engine is running. It was suggested to me that a different gauge is required for a 454 compared to the 350, but there is only one gauge offered by my parts supplier. Other than using copper instead of the stock plastic line, it’s plumbed like it would have been from factory. Any suggestions?
Race Director
Joined: Jan 2000
Posts: 13,013
Likes: 2,253
From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
First, I'd ck the actual oil pressure with another gauge to make sure it's not a gauge issue.
If it's that high all the time...I would start to look at the oil pump itself for having a sticking or blocked pressure relief valve. A HV pump can easily go that high at low RPM...but should drop off as oil warms up. Do you have any idea of the clearances in the motor on the bearings? What oil weight is in it? Is it a new build with assembly lube still in it?
JIM
If it's that high all the time...I would start to look at the oil pump itself for having a sticking or blocked pressure relief valve. A HV pump can easily go that high at low RPM...but should drop off as oil warms up. Do you have any idea of the clearances in the motor on the bearings? What oil weight is in it? Is it a new build with assembly lube still in it?
JIM
Race Director
Joined: Nov 2006
Posts: 13,147
Likes: 7,761
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
I agree, I'd get my shop oil pressure gauge on her and double check the actual pressure before proceeding.
Perhaps your gauge is fine. Perhaps not.
I recently changed out my pump for exactly that reason, A sticky pressure relief valve.
Improper clearance on main or rod bearings can also affect pressure.
Check the pressure with your shop gauge first.
Perhaps your gauge is fine. Perhaps not.
I recently changed out my pump for exactly that reason, A sticky pressure relief valve.
Improper clearance on main or rod bearings can also affect pressure.
Check the pressure with your shop gauge first.
1st Gear
Joined: Aug 2023
Posts: 1
Likes: 0
Oil pressure
I’ve got a 454 in a 79 Chevy and I recently installed all new gauges as some of them were not working. I replace the oil pressure sending unit and wired directly to the gauge. At cold start it read 60-65 psi. After driving it it to normal temp it’ll read 40-45 psi at a light. But after driving it for awhile when I get home it’ll read 18-20 psi. Is this normal for it to fluctuate this much?
when it’s hot it idles at 20 psi then when put into gear it’ll go up
im unsure if this is normal as I’ve never owned an older truck besides a 2004 1500 which would never drop below 30psi
when it’s hot it idles at 20 psi then when put into gear it’ll go up
im unsure if this is normal as I’ve never owned an older truck besides a 2004 1500 which would never drop below 30psi
