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Oil pressure at idle with a stock oil pump?

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evil666

Active Member
Joined
Dec 4, 2004
Messages
545
If the motor is very hot, lets say after an hour of city driving, what is the lowest the oil pressure should be at idle with a stock oil pump?

Thanks for any replies,
Marco

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver.
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BESTmph=114
 
Hi,
I'll bet 5 to 8 psi is possible. I remember a campaign in the mid 80s which dealt with a flickering oil warning lamp on vin A 2 bbl G bodies, hot at idle,in drive. The turbo cars, which idle a little higher, weren't included in the recall.
Anyway,the GM fix was to install a recalibrated oil pressure switch, which didn't close until something like 4psi.I never heard any tappet noise or other indications of oil problems from these motors.The bottom line is that our motors don't need a whole lot of oil pressure at low idle. Don't sweat it. Just an opinion....
 
5psi is very normal. My 85 with 140,000 miles on it had around 5 at idle, with no ticking. The bearings in still looked fine. Keep it blow 5500, which is all the stock bottom end can handle reliably, the stock oil pump is just fine.
 
5 psi would scare me!! 15psi? OK, I could live with that. Something is wrong if a turbo motor is that low. Turbo engines received the same front covers as the carbureted engines. Buick sorted the front covers and installed the best covers on turbo engines.

Either your bearing clearances are too big or the oil pump is worn out. My stock motor with tight clearances and a blueprinted stock pump holds 30-35 psi at a hot idle with 10w-30 mobile one.

Oiling is one area you don't want to get wrong on these engines. You're not just oiling the bearings, you're oiling and cooling a turbo too.
 
hmmm, maybe I need a new oil pump then...i DO have a leak somewhere, guess I should check on that as well :)
 
How old is your oil? What weight? Everyone says ~10 hot idle is fine, but that makes me nervous. After a few hard runs getting TLink data mine will hover at 10-12 idling. :redface:
 
Get the $11 booster plate from AdvanceAuto. It'll help out with hot idle pressure.
 
8-10 psi. at idle would be normal after that kind of driving on a stocker.

I'd look into the Kenne-Bell booster plate and the RJC oil filter mod.s. myself.

They work well on my 2 drivers. :cool:
 
On my car when the motor is really hot the oil pressue at idle is between 10 and 12 psi. My oil pump is still the stock original one.

Marco

86 Grand National t-top (59900km)
stock long block,stock suspension, red stripe convertor, te44, smc alk injection, 24lbs boost, 94 octane, hooker cat back with dyno max ultra flow muffers, tomco 30lbs injectors, dynotech stage 4 street chip, thdp, mease 24 row IC, Ron Custom max boost brake module, MT drag radials (275/50/15) 3800lbs race weight with driver.
BEST E/T
60FT=1.52
1/8= 7.38
I/4= 11.74
MPH=113
BESTmph=114
 
On my 54k original mile motor, 6-8psi is normal after running it for a while. It has 12-15psi before it gets hot at idle. Immidiately when the gas is tapped it goes right up to 30-40psi. WOT is has around 55-60psi.
Its been this way for many years and I do have the KB booster plate.
 
The KB (well actually it was Jim Ruggles' idea) booster plate requires mods (drilling) to the timing cover. The $11 AdvanceAuto booster plate accomplishes the same thing without any drilling.
 
Actually the Kenne Bell booster plate requires NO mods. to the front timing cover.

It requires some simple dremeling or machining of the oil pump cavity that comes off when you install the plate.

Get the RJC biggie oil filter adapter at the same time, saves on work and oily mess. :)

Assuming it and the filter will fit on your car however.
 
The oldtimers have told me that you need 10# of oil pressure for every 1000rpm. I think 8-10# at idle would be fine. What would worry me is 30# at 5000 rpm.
 
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