Oil pressure performance question
Thread Starter
Advanced
Joined: Mar 2012
Posts: 81
Likes: 0
From: Dallas
Oil pressure performance question
I recently bought a '80 which I'm fixing up. It's obvious the engine's gone through some performance upgrades... Just don't know what!
Anyway, is there any reason why the previous owner would have intentionally increased the oil pressure? It's sitting between 70-80psi.
I replaced the oil filter & did an oil change... So the next thing I know to do is to replace the oil pump. But I'd hate to replace it if I don't need to.
Anyway, is there any reason why the previous owner would have intentionally increased the oil pressure? It's sitting between 70-80psi.
I replaced the oil filter & did an oil change... So the next thing I know to do is to replace the oil pump. But I'd hate to replace it if I don't need to.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Id just leave it be, wont hurt anything just use a good quality filter that doesnt have a flimsy shell like fram or cheap innards that collapse.
I swear by Wix pieces. Delcos are junk made overseas unfortunatley.
NAPA brand are wix also
I swear by Wix pieces. Delcos are junk made overseas unfortunatley.
NAPA brand are wix also
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
No need to change the oil pump altogether. Replacing the pump's pressure relief spring to a lighter one will reduce your oil pressure.
Thread Starter
Advanced
Joined: Mar 2012
Posts: 81
Likes: 0
From: Dallas
I'm running 10w30... The manual says the engine should run fine @ this weight.
Would it not be hard on the engine seals to run at high pressure? Is it not likely to blow a gasket?
I've been trying to find a pump rebuild kit, but so far can't. Where would I find a different spring?
The pump for the '80 is $30 from LPS. There are higher $$ ones too; would I need one of the expensive ones?
Would it not be hard on the engine seals to run at high pressure? Is it not likely to blow a gasket?
I've been trying to find a pump rebuild kit, but so far can't. Where would I find a different spring?
The pump for the '80 is $30 from LPS. There are higher $$ ones too; would I need one of the expensive ones?
Race Director
Joined: Jul 2001
Posts: 15,892
Likes: 42
GM determined long before many of us were born exactly how much oil pressure an engine would require to live a long and happy life- and also figured that anything higher would be waste. Being conservative and adding in a fudge factor for wear and tear, owner abuse, unusual operating circumstances and a bunch of other factors resulted in the pressure the engines were delivered with to the customers (us). 60 years of history has proven they were right.
Bubba comes along and figures he knows better so starts farquing around with 'racin' pumps and racin' oils causes that's what he done seen on Speed Vision. Yee Haw!
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
If it runs OK then leave it alone don't play with it like my dear ol' dad used to say 
Is it at that pressure at idle ? Mines around 40psi at idle as soon as I give it some gas it goes to 70psi. The engine is not a balloon it won't blow up or blow out anything ( I know someone is gonna say they blew there dipstick out from an improperly vented lower end). Sounds to me like it runs OK because all your worried about is the oil pressure.
Is it at that pressure at idle ? Mines around 40psi at idle as soon as I give it some gas it goes to 70psi. The engine is not a balloon it won't blow up or blow out anything ( I know someone is gonna say they blew there dipstick out from an improperly vented lower end). Sounds to me like it runs OK because all your worried about is the oil pressure.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Thread Starter
Advanced
Joined: Mar 2012
Posts: 81
Likes: 0
From: Dallas
Tranny's shot. So I can't drive far or long. But after valve stem seals & springs, new plugs & wires, coolant sender & flush, power steering fluid, oil & oil filter.
Car starts easy, idles well, drives around the block in first gear well, temp stays put @ 200F, no smoke, cylinder pressure @180psi +\- 2psi, new plugs look clean.
The only remaining problem (other than oil pressure) is after the car is turned off it makes odd fluid sounds like a washing machine slowing down. I'll make a second post about it.
Car starts easy, idles well, drives around the block in first gear well, temp stays put @ 200F, no smoke, cylinder pressure @180psi +\- 2psi, new plugs look clean.
The only remaining problem (other than oil pressure) is after the car is turned off it makes odd fluid sounds like a washing machine slowing down. I'll make a second post about it.
Thread Starter
Advanced
Joined: Mar 2012
Posts: 81
Likes: 0
From: Dallas
Race Director
Joined: Apr 2000
Posts: 17,676
Likes: 201
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
[QUOTE=justinkscott;1581378517
Oil pressure is 75 @ idle & 85+ when I rev the engine. Engine temp is 200F.[/QUOTE]
Now that is a little odd, either your gauge is reading wrong or Bubba put in an oil pump that is way out of line that could actually be detrimental to your motor as it takes some power to turn an oil pump like that and distributor and cam gears could wear prematurely
Oil pressure is 75 @ idle & 85+ when I rev the engine. Engine temp is 200F.[/QUOTE]
Now that is a little odd, either your gauge is reading wrong or Bubba put in an oil pump that is way out of line that could actually be detrimental to your motor as it takes some power to turn an oil pump like that and distributor and cam gears could wear prematurely
Last edited by MotorHead; Jul 22, 2012 at 05:42 PM.
Cruising
Joined: Feb 2006
Posts: 11
Likes: 0
From: tx
maybe you can find or get another manual gauge and screw it in where the sender is and see if there is a difference. gauges are always off. if it not pushing oil out or "blowing your dipstick out" probably ok. easier than pulling pan. now if its alway at 70 and one day its at 40 then you might have a problem.
Thread Starter
Advanced
Joined: Mar 2012
Posts: 81
Likes: 0
From: Dallas
Yup fully warm @200F.
I noticed the OPS is wired in line with the carb's choke. Bubba replaced the original carb with a Holley which has no electric choke; just a manual one. Could this be the trouble?
I noticed the OPS is wired in line with the carb's choke. Bubba replaced the original carb with a Holley which has no electric choke; just a manual one. Could this be the trouble?
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
This topic always generates plenty of disagreement, but fact is that excessive pressure isn't insurance, rather it only puts additional heat in the oil, causes additional wear and tear on oil pump drive related parts, wastes power, and opens the filter bypass a higher percentage of time. None of these are benefits, but those who sell HP pumps won't bother to tell you that.
In a healthy SBC or BBC with proper clearances, you only need ~10 true PSI per 1000 RPM (hot) to overcome centrifugal force at the crank mains and supply the engine with sufficent lubrication. That said, it's common for pressures at idle and lower RPM's to run higher than 10/1000, as the relationship isn't necessarily going to be linear, but IMHO 75# (hot) at idle should be considered excessive.
I'm not suggesting you tear it down just now if you don't run it hard very often, but if you ever pull the pan for anything else I'd advise addressing it. However, if you do tend to thrash it regularly, I certainly woudln't be coming up with reasons to put it off. My $.02; lesson learned the hard way.
TSW
In a healthy SBC or BBC with proper clearances, you only need ~10 true PSI per 1000 RPM (hot) to overcome centrifugal force at the crank mains and supply the engine with sufficent lubrication. That said, it's common for pressures at idle and lower RPM's to run higher than 10/1000, as the relationship isn't necessarily going to be linear, but IMHO 75# (hot) at idle should be considered excessive.
I'm not suggesting you tear it down just now if you don't run it hard very often, but if you ever pull the pan for anything else I'd advise addressing it. However, if you do tend to thrash it regularly, I certainly woudln't be coming up with reasons to put it off. My $.02; lesson learned the hard way.
TSW
Last edited by TheSkunkWorks; Jul 22, 2012 at 07:28 PM.
Drifting
Joined: Jul 2002
Posts: 1,995
Likes: 110
From: Garland Texas
Turn the key to "run" position but don't start the engine. Post what the gauge reads.
Mike