Low oil pressure

fred56 · #1 (**permalink**) 10-04-2003, 03:39 PM

I looked in the knowledge base first but with so many articles I must of overlooked what I was looking for. I have a 66 sbc that the crank was turned .010 under. Ever since I have had low oil pressure. I used another manual oil pressure gage with similar results so I pulled the pan and all clearances seem ok. Since I put in a new oil pump could I have a bad one? Can I just shim the bypass spring to increase pressure? What about a high volume oil pump will it raise my oil pressure? I here no sounds of distress(noises) from the valve lifters. The oil pressure is about 5-10 lbs at idle and 20 at 2000 rpm.

Pony · #2 (**permalink**) 10-04-2003, 04:05 PM

It's quite possible that the crank went slightly more than .010 on a throw or main and your losing pressure there. You can check the clearance with what's called Plastic Gage. It's a spaghetti looking material that you put on the bearing and torque the cap down and measure how much it flattens out against a gage that comes with it and get your clearance that way. It comes with complete directions and is fairly accurate. You could always run a high pressure, high volume racing pump but you would'nt know what your problem was until it caused problems. Good Luck..

fred56 · #3 (**permalink**) 10-07-2003, 05:33 PM

Thanks for the info I will pull the pan off and check it out. By the way, any idea on what the clearance should be between the oil pick up and pan? My pan looks like it was dented in a little.
Thanks

DoubleVision · #4 (**permalink**) 10-07-2003, 05:58 PM

there`s other areas also that can cause low oil pressure, they are, trash in the oil gallery`s, a leaking gallery plug or plugs, worn cam bearings, oil pump tube not staked tight enough to pump, worn oil pump, trash at the sending unit, trash in the sending unit, worn rod and main bearings. however, if the clearences are on spec, and the pressure is still low, then trash is likely in the gallery`s or the plugs are leaking. run a can of Sea Foam from your nearest car quest right before your next oil change, pour it in, let it idle for 15 minutes, then change the oil, you`ll see all kinds of crud come out with the oil. Keep in mind most gauges are not accurate below 10 PSI, some as much as 15 PSI.

fred56 · #5 (**permalink**) 10-08-2003, 02:19 PM

Thanks for the information. I will try the Sea Foam and see what happens.

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