My oil pressure runs at 70-80 lbs hot or cold . Engine smokes some . Using oil . The book says should run around 50-60 lbs . Using 10W30 oil . Wondering if that high a pressure is pushing oil past the rings . Engine has 78000 miles on it . Does the pressure relife valve by the filter control the engine pressure or is it just control by-pass if the filter gets plugged ? Thanks Brian
6 cyl oil pressure
- Thread starter blionl
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The oil pump has a pressure relief valve that controls the oil PSI. In the better oil filters that actually have a valve in them, this valve is used to control oil drain back when the engine is shut off so there won't be a dry start. Your smoking could be caused by bad valve guide seals or loose valve guides.
Oil pressure doesn't usually go up on a worn engine. I would suspect something has gone wrong with the oil gauge or sending unit. Hook a manual gauge into the main oil passage and get a second opinion. 70-80 lbs. pressure is good for throwing extra oil on the cam and distributor gear, but not so good for a worn ring package. If your gauge is correct you must of developed a restriction in the oil gallery or the pump it self. Bubbas right, for sure the valve guides are worn, unless you installed bronze guides. The fact the pressure doesn't change between hot and cold oil, points to the gauge. Good luck.
New valve guides, liners, are a machine shop install, knurling could be done, but in all cases the head would need to come off to remove the valves.
Question: Which 6 cylinder engine are you working on? Ford? Flathead or overhead? 226-254, 215-223-262, 144-170-200-250, 240-300? The overhead engines can sometimes have the valve umbrella seals replaced with the head on. The flathead has no seals, and the valve guides are very tight in the bores. The early G engines have split valve guides like the early (before 1949) v8 engines.
Route--66--
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blionl":13dng7h7 said:
Mine runs at a shade under 40 pretty much constantly regardless of engine hot / cold revs hi or low! ..
The relief valve to the rear of the filter controls system oil pressure. The filter is partial flow only and the oil flows through the element and through a restriction hole of about 1/16 inch and the filtered oil is dumped directly back into the crank case.
As to the oil useage, how many miles does it get per quart used? Does it oil foul spark plugs? Does it leak oil from the front or rear mail seals, leaky pan gasket, leaky valve cover gaskets or leak around the filter can? Oil puddle under the car over night? The old style rope seals that these engines used are notorious leakers even in the best of times. Some older rebuilder / rering jobs used cast iron compression and oil rings and these did not last as long as the chrome rings or later moly rings that are used now and if so, 78,000 miles might have worn them out.
Is there much blowby coming out of the oil filler tube or road draft tube?
As to the oil useage, how many miles does it get per quart used? Does it oil foul spark plugs? Does it leak oil from the front or rear mail seals, leaky pan gasket, leaky valve cover gaskets or leak around the filter can? Oil puddle under the car over night? The old style rope seals that these engines used are notorious leakers even in the best of times. Some older rebuilder / rering jobs used cast iron compression and oil rings and these did not last as long as the chrome rings or later moly rings that are used now and if so, 78,000 miles might have worn them out.
Is there much blowby coming out of the oil filler tube or road draft tube?
Route--66--
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Hi again!
My oil pressure gauge is a mechanical after market one.
Am wondering if 40psi is enough?
Engine seems to be in fine condition, no smoking.
Is that ok, if not is it likely to be a worn oil pump or a weak pressure relief valve maybe?.. (and is that hard to change?!) can't get it above 40psi even if revved
Cheers all!
My oil pressure gauge is a mechanical after market one.
Am wondering if 40psi is enough?
Engine seems to be in fine condition, no smoking.
Is that ok, if not is it likely to be a worn oil pump or a weak pressure relief valve maybe?.. (and is that hard to change?!) can't get it above 40psi even if revved
Cheers all!
Hi, if my engine had blow by and burned oil I would do a compression test. Squirting oil into the cylinders after a dry compression test can tell you if the problem is the rings or the valve guides.
40 psi oil pressure is good. Generally oil pressure is higher on start up when the oil is cold, and then the pressure will be lower after warm up. At idle the pressure will be lower, and rise as RPMs rise.
Good luck
40 psi oil pressure is good. Generally oil pressure is higher on start up when the oil is cold, and then the pressure will be lower after warm up. At idle the pressure will be lower, and rise as RPMs rise.
Good luck
Route--66--
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Great thanks for that, good to know 40 is ok.
Cheers!
Cheers!