DREYKO

91 oil pressure guage and sender from 88,
car is an n/a, mechanical omp

anyway, it worked fine untill a few days ago and now it goes from 30 at idle to pegged when driving.

I know its most likely the guage or sender, but lets assume its not.
what could cause it, and what will it cause?

thanks guys

scathcart

Plugged oil pressure regulator is the only thing possible... which is not really possible. Its the gauge.

DREYKO

I pulled out the sender and appied some vacuume to it and sprayed it out with seafoam, works like a charm now.

just in theory though what could running that high of an oil pressure do to the motor? 130+ psi?

pistones

iTrader: (5)

blow some oil seals, eg: front or rear main seals, oil control o rings.

scathcart

Impossible. None of these seals are ever under oil pressure.
The front and rear seals both have drain passages for oil flow back to the oil pan, so they only ever see gaseous pressure from blowby if the PCV system fails shut.
The oil control o-rings only ever see oil splashed on them after they leave the rotor bearings and the rotor through centifugal force, at which point the oil returns to the oil pan via passages in the center, front, and rear irons.

The only problems with high oil pressure is:
- higher parasytic horsepower loss to pump at higher pressure
- More oil aeration (foaming of the oil; air bubbles getting trapped in the oil) which can cause bearing failure in extreme upper rpms, generally above 9000
- higher risk to creating leaks in the oil system peripherals: the oil cooler and oil cooler lines are more likely to burst if not in proper condition, and external oil leaks at the upper dowel passage.
- increased oil temperature.

Think about it: racing cars run 100+ psi of oil pressure all day, with no internal modifcations. The engine handles it fine. The modifications typically associated with running higher oil pressure are to improve oil flow.