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Poor oil pressure???

I'm in the process of changing the valve cover gasket on my 258...it leaks...shocker I know. I took the cover off and cleaned the crap out of it with Simple Green. The inside is very dry now. So I put a new gasket on. I fired it up for about 2 minutes and found yet another small leak. So today I take it off and noticed that the top inside of the valve cover doesn't have any oil on it at all...bone dry like the day I put it on. Wouldn't you think that two minutes of running would be enough to get the oil out of the pan and splash the top of the cover?? It got enough oil up to show a leak from the bottom of the cover. My gauge is reading low...around 20-25 PSI. I just recently bought the jeep (was a project) and the entire dash was out of it..so I'm not sure if this is a guage/sender problem or not. Allen

83 CJ7
Reply to
<ABanks5
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snipped-for-privacy@columbus.rr.com did pass the time by typing:

Was there oil on each of the rockers? The stuff that accumulates on the valve cover gets there by condensation, not usually by splash. Although I think there should be some by the rockers.

Reply to
DougW

This really isn't an issue. Some engines (the 258 included) take a while to get the oil flowing at the top end. Even then it may or may not splash the valve cover at idle. Some engines will spray oil all over the place when the lifters are being adjusted with the valve cover(s) off. As for having 20-25 PSI oil pressure at idle, that is perfectly fine. A good rule of thumb is to have 10PSI pressure for every 1000RPM that the engine is turning, so at

4500RPM you should have 45PSI as a minimum. The gauge is easy to test. Just ground the lead that goes to the sending unit and the gauge should max out. The sending unit is a bit more difficult to test. You can hook up a mechanical gauge and verify the sender is working properly, or just replace the sending unit if you aren't sure about it. They aren't very expensive. This is why I really prefer mechanical oil pressure gauges. They are much more reliable than the electrics, and also respond to pressure changes faster.

Chris

Reply to
c

Odds are if the cover leaked then there is oil present. Next time you seal the cover, use the gasket sealer on both sides of the gasket and let it sit a good 24 hours before starting the engine. That should stop the leaks.

Reply to
Joe

I heard that! A Slant 6 will splatter quite well at 600 RPM. And my Toyota Celica would splatter something awful out of the oil filler hole if you left the cap off.

Fortunately, I've never had to take the valve cover off either of my Jeeps!

Regards,

DAve

Reply to
DaveW

4500 rpm on a 258 is way to high. I barely get to 3000 when I am running it through the gears hard. The Chiltons manual says that you should be at 50 psi at 2000 rpm.
Reply to
econof

I think you misunderstood me. I was using the RPM as an example and wasn't implying that everyone is spinning their 258 at 4500 RPM. Also, if you notice, I said that was the minimum pressure required for that RPM. The "minimum" required for an engine to survive at 2000 RPM is 20PSI. If you've got 50PSI at 2000 RPM, even better.

Chris

Reply to
c

My 86 will pull hard and fast up to 4500 rpm since I dumped the governor out of it (emissions computer).

Meanwhile, they don't spray oil at idle up top. You can see it running out the rockers, but no splashes.

As the main bearings wear in that engine the oil pressure drops. Mine was down to 25-30 hot and at speed, but still had tons of power and good compression at 145000 miles.

I went to one with 40K on it and the highway oil pressure is about

45-55.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's
Reply to
Mike Romain

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