Oil Pressure Question.
Thread Starter
Race Director
Joined: Jun 1999
Posts: 14,924
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From: Merritt Ils Fl
Oil Pressure Question.
For all you SBC oil pump guys a hypothetical question: Say a person overfilled a SBC by 1 to 1 1/2 quarts of oil, would that make a difference in the observed oil pressure? Would it make the observed pressure erratic, normal then fall to zero? To make it simple assume there are no outward signs of the overfill.
Racer
Joined: May 2009
Posts: 421
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From: van buren ar
i wouldnt think the extra oil would have any effect on oil pressure,until entrainment caused so much air bubbles in the oil that it washed out the bearings.oil doesnt compress,that how moving parts "ride on it" when the crank starts dipping down into the oil in an over full situation,well picture a blender.and on second thought if it got over full mysteriously it could be leaking water into crank case.
Thread Starter
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
You and I see this in the same light. No water leaks, excess oil was accidentally added but not to the point it was obvious, ie. no foaming or oil blowing out the dip stick or excessive smoke. The only way it was found was erratic oil pressure. Pressure would appear normal, suddenly drop to zero with no change in engine performance or sound. Pressure would remain at zero for a distance then return to normal. A restart after a zero pressure would be normal. The oil was changed, new filter and 5 quarts of oil, now it is completely normal. I first suspected cavitation but that would bring oil starvation and bunches of noise. Don't know but am glad it is back to normal. Not my car but I have a 700 mile road trip in this thing in a few weeks.
