83beast

when i drive my stang, after it heats up to operating temp, the oil pressure starts to drop if im revving below 3 grand. i mean it drops below a quarter pressure. over 3 grand its fine, over half. i just changed the oil a month ( 700 miles) ago. ive checked the oil level and its fine. plus it doesnt matter what gear im in, if its below 3 grand it looks bad. could it be the gauge?

posnick

could be the gauge but i doubt it. get an oil pressure tester and check the oil pressure. that will tell you for sure. if the pressure is low its either the pick up tube or the main bearings. how many miles are on it?

nhdungeonracer

Hmmm, it is an "electric" type oil gauge, so if it for some reason or another isn't getting proper voltage, it could read incorrectly. But even at 1500 rpms, you should be getting plenty of electrical current to the gauges, let alone 3000 rpm.

If it makes you nervous, invest in a good mechanical type oil pressure gauge. If the oil pressure drops below 3000 rpm with that gauge, then you have reason to be worried...

black89gt

i had a previous problem like that and the OPG was really bouncy and not steady, so, i changed the oil pressure switch and it now its really steady, but im still low.. im at about notch above 1/4 when idling but it goes up about 5/8 of the way up when on the highway after warming up. but i think my motor is bad because its starting o throw out black smoke when i floor it.

83beast

well, it has somewhere around a seventy thousand on it. the front main seal is leaking very minimally, and i never lose oil between changes. i know my motor is fine cause it has no visible, or audible signs of wear. plus im the first one under the age of 40 to own this car. the other guys babied this car, plus i know the guy who rebuilt the motor.

nhdungeonracer

Not trying to make the guy look bad, but just an experience I had when racing Pintos (remember those? )
I rebuilt a motor, and it ran like a top. In fact, I was leading the race (oval), and with 3 laps to go, it started smoking. Rather than risk losing a newly rebuilt motor, I pulled off the track. Good thing I did. When I opened the motor up, I found that either I had tighten the oil pan gasket too much, or more likely, because it was a cheap cork type gasket, or combination of both. Either way, quite a few bits off the gasket had broken off inside the pan, and had clogged the pick-up screen that that oil had a hard time getting thru the motor.
Like I said, not trying to make the guy look bad, but sometimes weird stuff happens.

I still say invest in a good mechanical oil pressure gauge. this way you can determine better if if's your stock gauge screwing up, or if something really is going wrong.

83beast

im looking into making a weekend racer next spring, and a full complement of mech pillar gauges is in the works. ive got a 351 2V C sittin in the backyard, and with gas, weekends would be cheaper. but when i say 70,000, i mean on the motor. the car itself has prob just under twice that. the guy rebuilt it back in like 88.

JD1969

You guys all realize that it is normal for oil pressure to drop after the motor warms up right? Now if at idle he has less than 10-15 psi I would worried, but since he only has a stock inaccurate gauge we don't know what the pressure is. If you do get a new gauge make sure to get a mechanical one.

83beast

yeah, we realize. but it just started this a while ago. at idle i have just about 100% pressure, but it has never, ever dropped this low. and it isnt all the time, maybe a few times a week.

JD1969

Sounds like the sending unit then. If it was somthing wrong with oil pump or a worn motor, it would do it all the time.