Oil pressure pegged
 

Yesterday I took my 1969 Corvette out on a Marine's sponsored Toys 4 Tots run. Had the car up to 85 ish on the highway, running great. Had to deal with a lot of traffic getting into the event, which did not make the car very happy. Temp gauge got to 210 and she felt like it was loading up; possibly the beginnings of vapor lock.

Anyway, the ride home was uneventful but, this morning when I went to take it out for another ride I noticed that the oil pressure gauge was pegged. I was only heading down my street, maybe 15 mph. When I let off the gas and let it idle the needle sat between 35 and 70.
Normally the gauge reads 35 when I am driving and never gets anywhere near 70. I immediately brought it home. I checked the oil, it's full and clean.

Any ideas what the cause could be and/or what I should do?

Oil pressure pegged
 

Until you test the oil pressure with a mechanical gauge, it's a crap shoot/guessing game. As Snap On Tools moto goes: "Test, Don't Guess". Could be the pressure regulator valve in the oil pump has stuck or the spring broke into pieces.

Bill

Well that doesn't sound good. I am not a mechanic so I don't have the tools or knowledge to perform such a test. Is it safe to drive it a few miles to a local shop like it is?

I am an optimist. Best case is your gauge has become a little inaccurate, not sure if you have a sending unit? or directly to your gauge.However as stated you should have an independent mechanical gauge hooked up to read the actual pressure.

Oil pressure pegged
 

If it truly is 80 lbs. of oil pressure as your gauge reads, you risk blowing the oil filter off the engine with prolonged use.

Bill

Was your car up to operating temp when you noticed your pressure?? Oil pressure is always higher when the engine is cold. Once it warms up, it should come down to a lower pressure. My Camaro is always around 70 lbs. when cold and then drops down once it warms up to about 45 to 50 lbs. when driving. At idle it's around 30 lbs. when hot...

What does the gauge read with key on and engine off?

The 68-73 corvette oil gauge is very susceptible to corrosion at the pivot points. Can be fixed. Not a problem. If you are willing to pull it out send a PM and I will get you through it.

Probably won't get an opportunity to drive the car until next weekend sometime. I think I will let it warm up completely and watch the gauge. Hopefully it will come down to a normal range.
If not, I am going to change the oil and possibly replace the oil pressure gauge.

Might be prudent to pull the filter and open it up to look for metal. Probably the gauge but you never know.

My 1969 corvette 427/390 is around 35-40 when warmed up. It’s has 3:08 gears. Rob

If it is an electric gauge, make sure the lead is not grounding out somewhere ... I think if the lead is grounded ... the gauge will indicate max pressure. If I am wrong -- someone chime in ... TAZ

The gauge is a mechanical unit.

gauge
 

Sent you a PM regarding the rebuilding / clean-up of the pivot points.

Finally got around to removing the oil pressure gauge; can anyone here help guide me through the steps needed to get it working properly again? Nothing about the gauge seems broken, I can move the needle very easily and it doesn't seem to stick at all.

Of course that makes me think it's something more serious...............ugh.

Oil pressure pegged
 

Try looking at the oil filter bypass valve above the oil filter, maybe the bypass valve is clogged or stuck shut thereby raising the oil pressure, just a thought, without pulling the engine. Don.

The bypass is only supposed to open when the oil filter is clogged.

'

Have you tested actual pressure w/ a remote gauge yet also how long has the engine been operating normally - any recent rebuild etc?
Info supplied so far sounds like it may be the pressure relief valve in the pump as Bill mentioned at the beginning?:hmmm:
So, best test before going in other directions and good luck w/ everything!
:beers:
~ Pete

.

Oil pressure pegged
 

The oil pressure bypass valve also opens when the engine oil is cold so that the oil filter will not expand. Racers have been plugging off this bypass valve opening for years but are cautious about revving the engine when cold to prevent oil filter damage. When the engine is totally warmed up is the oil pressure still pegged? If so I'd check the oil pump pressure spring, cup and relief valve in the oil pump. If pressure goes up there is a restriction somewhere. Doesn't cost anything to check it out. Just my 2 cents worth. Don.

Not true. At least with sbc & bbc. The bypass valve (BV) opens @ 17-18 lbs of pressure. The engine, while running, is constantly by-passing oil from the filter. In other words, while the engine is running, a % of unfiltered oil is always going through an engine. It was designed that way and that bypass should never be plugged. The engineers that designed the oiling system felt it was better to have some dirty oil, than no oil at all.
Back to the OP. There are only 3 causes of pegged oil pressure I am aware of 1) defective gauge- get another gauge and test to rule out gauge 2) stuck pressure relief valve in oil pump- remove pump repair or replace ( 2nd option preferable) 3) oil galleys plugged with foreign matter-tear down engine.

Dang, I've got to quit commenting on things that I don't know about. I plug all of mine, except when doing a stock rebuild. I use the Wix racing filters so that I don't explode them.