On startup, my oil pressure gauge shows around 80 psi.

For a few minutes as I drive at cruising speeds it will hit around 60 psi.

After 10-15 minutes the pressure dips to around 40 psi or so.

After say 30 minutes of driving, the car struggles to hit 30 psi, and sometimes at idle will drop below 10 psi.


The oil was drained, and there was ZERO metal in the oil leading my mechanic to believe that there wasn't any bearing damage...


What could be causing this pressure drop as the motor warms up?? Are there O-rings or gaskets that when heated up are causing me to lose pressure?

Any other ideas?


The car will not go into VTEC, and I know this because if I rev to say 7,000 RPM's my A/F guage is showing 10.0 FLAT, when it should be 12.x...


My mechanic is baffled, and I am at my wits end...

Thanks,
Matt

 

How much oil have you got in the thing? what kind too along with weight and are there any CELs getting chucked at you??

 

Running EMS, so no codes...

Was running Mobil1 10w30... Now, we are trying Mobil1 15w50 to try to help keep the pressure up.

 

More information:

I've had an oil pump fail 6 months ago, and then had main bearings fail a couple of months later...

I am starting to think that the new oil pump may have been damaged when the bearings went bad.

Does this sound like a possibility?

Like maybe on cold starts I've got good oil pressure, but once the oil warms up the poor flowing oil pump becomes evident...

 

possibly the pressure relief valve is not functiong properly? maybe its not holding any pressure and that could be why your pressure keeps dropping.

 

Oil pressure will drop considerably after the oil heats up. That's just the basic physics of oil viscosity (resistance to flow) as it heats up. If you want more oil pressure when the oil is hot, then you will have to switch to a higher viscosity oil. Try 5W-40.

 

It does lower the pressure with heat obviously but would it be this dramatic?? What is the optimum pressure level that the f20 should be producing?

 

I don't have a pressure gauge in my car, but my truck pressure drops about 30-40% after warming up. I don't know the normal operating temperature pressure range for the F20. Maybe someone with a manual can help you.

 

The service manual says 70 psi at 3,000 RPM.

I am seeing 30-40 psi.


I am starting to believe that the shop's decision to machine the stock crankshaft down and use oversized bearings was a bad one.

I have been told after the fact that this is frowned upon...

I was told that this "MIGHT" work on a stock motor, but shouldn't be done to one with forced induction -- putting down 360 hp.

Anyone have any input on this?

 

Sorry can't help you on that, maybe moving or creating another topic in the forced induction section could maybe help you???