Thread: Oil Pressure

Tweet

Cranked up the 327 small block today after rebuild. Reved engine up around 2000 or so I think. Don,t have a tack so just guessing at that. Could have been around 1500 or 2500. It,s the oil pressure that I,m worried about. The gage reads all the way up to the top. Is there a such thing as to much oil pressure? If so what would be some causes of that.

where is it at idling?

Mike, did not let the motor idle. Kept the rpm high. Did'nt run it to long. It was late. I left the vale covers off to see the rocker arms to make sure they were getting oil. They got oil in about 30 to 45 secons. And the oil was comming out so hard it went over the fenders on to the driveway. Smoke everywhere. This morning I'm going to ajust the vales by buming to motor. Get them as close as I can. Put the vale covers on and let the engine run for a while at high rpm. Then take the vales covers back off and ajust them while motor is hot. Will at that time check the oli pressure at idle. The oil gage I,m going by is the stock gage found in all the old chevy trucks 67-72. It has no numbers on it. But I guess the top is 80. I don,t know how reliable the gage really is. It ofcourse has a copper line that gos to the engine. So I think it,s right.

sounds good, i wouldn't trust that gage, as for the oil going over the fender thats ok to. once you get it adj. up and get the valve cover on i think it will be ok. get an old cover and cut the top out of it, sure would help in adj. the valves.

My stock guage in my 76 truck goes to 60 psi. I have the Melling Z-28 oil pump which is a stock volume pump, but has a 60 psi spring. It pegs my guage when cold. At temperature on the highway, I make about 45 psi and 25 at idle while hot.

Originally Posted by 76GMC1500

My stock guage in my 76 truck goes to 60 psi. I have the Melling Z-28 oil pump which is a stock volume pump, but has a 60 psi spring. It pegs my guage when cold. At temperature on the highway, I make about 45 psi and 25 at idle while hot.

you got enough oil pressure for sure, but if it was mine I'd want to know just how hi it was going.

yeah.... tooo much oil pressure can be bad as well.... i had a faulty high pressure pump that was putting out 100 PSI when hot..... my valve covers, timing cover, and oil pan were always leaking..... finally i got fed up with the oil leaks and putting oil in it and regasketed the motor and put a stock pump in

What pressure does the oil filter bypass valve lift at? I've been meaning to ask and don't feel like starting a new thread for it.

Originally Posted by 76GMC1500

What pressure does the oil filter bypass valve lift at? I've been meaning to ask and don't feel like starting a new thread for it.

the bypass pressure is dif. on each filter brand, it runs from 15 to 25 lbs. on most cars, but its not the free flowing oil pressure from the pump that makes it work, its how restricked the filter is or how backed up the oil gets from dirt or thick oil.
Most engines incorporate a bypass valve across the inlet and outlet of the full flow oil filter within the lube oil system. The valve is designed to open and bypass oil around the filter and/or element when the restriction reaches its opening pressure
The bypass flow circuit ensures oil flow to the engine when there is a significant restriction across the filter due to element plugging or cold start conditions. Typically, engine manufacturers design bypass valves to open at a pressure differential of approximately 10 to 30 psid with some as low as 4 psid and others opening as high as 75 psid.

SBC's have the bypass on the filter adapter, not in the filter. But, if it works off PSID, then I'm not worried. I was worried about it lifting due to just too much pressure.

I had one of those high pressure springs in freshly rebuilt 350. It registered 80-90 lbs during the cam break-in...2000 rpm. Oil pressure was great, but as mentioned above I had leaks all over the place.

To the original question, I would check with the another mechanical gauge...warm and idling.

i will second that 80psi with no leaks... well after I installed a proper pcv system anyhow