waddisme

Does it measure a flow pressure as it goes by, or does it measure constant pressure? The reason I am asking is I have been monitoring my oil pressure since my accusump is down. I have 3 ports off my valve covers running into 2 small breather cans (crankcase pressure issues). It is not a closed system. Would that affect my pressure reading?

0Randy@DRM

The oil pressure gauge works from the pressure in the oil galleys. Your breather should not change the oil pressure.

Randy

Mark2009

It's not a flow meter, so it reads instantaneous pressure (well, it's too slow to read instantaneously, but it reads it faster than the eye could on a gauge).

What Randy said on the breathers. Your oiling system is a closed system with a set of calibrated leaks -- these leaks are the small holes that supply the lifters, the cam bearings, and the crankshaft bearings. Once the oil 'leaks' thru those holes it is no longer pressurized until after it falls into the oil pan and is sucked up by the oil pump which again pressurizes it into the system (the oil galleys or galleries). Anything between the leak and the suction side of the oil pump is not pressurized (not intentionally, anyway). Rinse and repeat

Interesting roundtable on crankcase pressures/drainage: http://speedtalk.com/forum/viewtopic.php?f=1&t=37170

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waddisme

Great explanation. Thanks. The linked thread is pretty technical plus lots of people who definitely have some hands on experience.

travisnd

And as a motor wears out and loosens up those "leaks" become bigger and bigger and the engine can lose the ability to maintain the same oil pressure.

varkwso

My experience with LS motors the leaks become mortal soon after the first strange sound you hear in the crankcase.