johnhanson

I have a 61 with a 350 crate motor, which runs around 60# oil pressure at 2000rpm and above, since I bought the car 3 years ago. Suddenly today it is well beyond 60# and burying the needle at 2500rpm. I am concerned this will ruin the oil pressure gauge, I am running the stock 1961 corvette oil gauge in the gauge cluster. Any ideas what could have happened/changed?

midyearvette

i would be more concerned of the motor than the gauge, if the gauge is accurate.......so step 1, verify the gauge with another one, hopefully the unit is bad.....

pull the dipstick to see if its milky

DZAUTO

For over 30yrs, all the engines that have been in my 56 have had a hi-press oil pump. My original, stock 56 oil pressure gauge is pegged most of the time. When cruising with the rpm below 2000, the gauge sits at about 55psi. Never a problem.

rich5962

I agree with Tom......In 1995 I rebuilt the 270hp 283 in my '59. A year before I installed a high pressure oil pump. I re-used the same pump during the rebuild and went from 15 psi hot idle to 60+ psi hot idle and pegged when cold. Obviously the engine needed a rebuild with the lower pressure.

I've put about 30k miles on the car since the '95 rebuild and it's still the same. No problem with the gauge or any other effects whatsoever.

Right after a oil change the pressure reacts a bit higher at all conditions until it wears in. Also runs a bit higher in cool weather startups here in Florida in winter.

John, Your engine must have the high pressure pump installed by a PO. It'll run a little higher when colder temps and right after a oil change. The gauge has a internal stop in the mechanism behind the needle and the needle still floats without applying pressure to it. It won't hurt the gauge if pegged.

If nothing else has changed you might have a relief valve issue in your pump or the gauge has weakened a bit. Check this thread about a similar issue......Here. Confirming your readings with a known good gauge would help.

Frankie the Fink

My original 283ci in the '61 runs just like that. Rebuilt in 2004 by the Amick Racing Team engine guy in North Carolina, I'm sure he put in a hi-pressure oil pump. I think you are fine and this is quite common. My gauge is original and has been fine like this.

For my '67 Chevelle, several companies offer original looking oil gauges that are calibrated for hi-pressure pumps.

FTF

midyearvette

guys, the op said this issue just happened....not really enough info for a complete diagnosis.
but this is a new condition.....

OC-1

Tom,

Some say the hi oil pressure generates problems for the FI distributor seals.

Apparently this has not been the case in your situation.

Any insight into this theory?

Thanks,

Recent rebuilt 283 to spec hi perf specs, gave builder a low mileage stock pump and he instead installed a hi pressure hi volume pump because he didn't like the condition of the stock pump. No rationale given relating to bearing clearance.

I'm using a 62 fuel injection unit.

Was going to remove the pump after breakin but you got me thinking.

Joe

63split63

Why would high pressure cause the oil to be milky ?

Bill

Westlotorn

Is it cold out today for the first time this year?
For those running a high pressure pump in cold climates I have seen the oil filters blow right off a cold engine on start up. We are talking below 20 degree's outside. I think most of our cars do not even go outside in that weather, except for Jack up in Maine. He always posts pictures with snow around the car.
I would think any engine with a high pressure pump is safe in 40 degree weather or warmer. Or if you switched to thinner oil for winter.

midyearvette

water in the oil from a coolant internal leak makes the oil much thicker, milky, if run long enough and there fore more oil pressure, especially if suddenly, like the op stated he saw a dramatic rise in pressure......hopefully he changed to a heavier viscosity oil or his gauge is on the fritz or he really does not know his own car.....

w1ctc

High pressure oil pumps can be a substantial user of HP.

http://www.carcraft.com/techarticles...s/viewall.html

DZAUTO

FROM THE FACTORY, The 64-65 375hp/327 FI engines got a hi-press pump. The seals in those distributors are the EXACT same seals as used in the earlier FI distributors.

Jebbysan

The SBC had the most efficient oiling system of any small V8 built until the LS series was introduced.
A High Pressure or High Volume pump is simply not necessary...and this is a hang on to the old days when they didn't know any better.
If the bearing clearances are correct....a stock pump is good to 600 horespower and/or 7000rpm.....or as good as the stock block can sustain volume anyhoo.....
A friend in Michigan who has been racing Stock Eliminator for 30 years in a 358ci 67' Camaro runs a braced Stock Volume Melling pump.
He makes 630hp and shifts from first to second while in a wheelie....

The Big Blocks are the same way......just not necessary for 90% of the stuff people do with them.

Sure they had High Volume pumps on them back in the day.....but they didn't have Spintrons back then either and glass windowed oil pans.....

To answer the OP's question......I believe your gauge is shot.

Jebby