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Old 10-25-2003, 08:39 PM
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low engine pressure

my engine pressure is around 40-50 when i start it up the it drops to about 35 while its heated,and im driving...but when im at an idle im around 10-20...
and if i do a fat burn out after the burn it will drop to almost 0 and it will sometimes stall out.
wat would cause this?
could it be my oil pump?
the engine was just built and im not to shure what it is?the mains should al be good and stuff so im so out of the loop on this...
could t be cause if i have a leak in the intake manifold?

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Old 10-25-2003, 08:45 PM
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Sounds like you have too much clearance in some of your bearings. If your clearances are too wide, you will have low oil pressure. Did you replace the cam bearings when you rebuilt it?
I have similar pressure in my 350, but it has many miles on it,
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Old 10-25-2003, 08:47 PM
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i wasnt the one who built the engine but suposedly the guy who built it did all that stuff...so if it wasntany bearnings then would it be anything else??
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Old 10-25-2003, 08:48 PM
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Lots of things can contribute to low oil pressure. however, most gauges aren`t accurate below 10 PSI, some aren`t accurate below 15 PSI. you should at least have 10 psi oil pressure per 1000 RPM. Oil gets thinner as it gets hot, this is why it`s higher at start up when it`s cold. I`ve been driving my car a long while now and when it`s hot it`s often the oil pressure goes to 0, but I keep a ear on the engine, if I don`t hear any lifter clattering, or any death rattles, I don`t worry about it any, as I keep in mind it`s not accurate below a certain point. and no, a intake leak wouldn`t cause low oil pressure. 20 psi at idle is fine.
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Old 10-25-2003, 08:49 PM
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Use 20W 50 oil
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Old 10-25-2003, 08:52 PM
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so what would cause it to stal after my huge burn out,,,i kept it going for about 45 sec...

i have 10w 40 i there right ow......royal purple
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Old 10-25-2003, 08:52 PM
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Probably cus you were beating the crap out of the poor thing.
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Old 10-25-2003, 08:56 PM
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if it couldnt handle the burn out then chevy has a prolem...
lol
jk are you shure there isnt anything else that could have caused that?
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Old 10-25-2003, 08:59 PM
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When you abuse it like that, it puts all kinds of different pressures on it. The vacuum goes all out of wack cus it isnt used to run this way. If you lose vacuum, it stalls.
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Old 10-25-2003, 09:06 PM
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It is not because you are abusing the engine on a burnout. It could be too much jet, float level, or idle mixture. It's ,most likely carb related.
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Old 10-25-2003, 09:32 PM
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hey that sounds pretty good cause i would rather have a carb problem then haveinf to ripp down the engine again.
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Old 10-25-2003, 10:11 PM
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Do a compression check if you are concerned. If they are within 10% keep lighting them up. It souds to me like too much jetting, but go through you carb one thing at a time untill you find it.
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Old 10-25-2003, 10:42 PM
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oil pressure

Well, I would start with a manual gauge. Look along the side of the engine block and you well find a plug that goes in to the oil passage (make sure it is the oil and not the water passage) If you can't find one remove the oil sender unite and screw a flex line into it and attach a pressure gage (0 to 60 lbs.) to the other end. start the engine and check the oil pressure in this manner. You know at idle and then reve it up to say 1500 rpm. and so on. If the oil pressure is more to the liking or it has a big deference, then may be the sending unit is bad. Also it could have a small chip from the overhaul in it. And that would make for a faulty reading.
Here are a few other thing that I seen happen: New Short block and OLD oil pan. When the old engine let go it knocked the baffle plat lose in the oil pan. So they welded it back in place before they reinstalled it. After reinstalling the engine it would have oil pressure at idle and then when you revved it up and held it there for a very short time the oil pressure would full to almost 0! After about third. R/R of the oil pan they discovered that the baffle would hold the floating oil sump up when installed, just at the top of the oil level. At idle it would get enough oil to show pressure on the gauge, But at high RPM's. it couldn't keep up and showed a very low to 0 oil pressure.
This one was almost the same thing but it had a fixed oil sump pipe and screen. They somehow had bent the oil sump pipe up just enough that it would not pick up the oil and so it had 0 oil pressure. Someone said DID YOU PUT ENOUGH OIL in it? The answer ----Y! but then he put two more quarts of oil in the crank case, and it had real good pressure.
Any way just thought I would shear them with you. Check it out never know what will work! -------------------Gene Neal

Last edited by Gene Neal; 10-26-2003 at 11:50 AM.
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Old 12-24-2005, 05:30 PM
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More of the same answers that you already have, I have an old beater truck that has a oil pressure gauge instead of idiot light. When it's cold,the oil pressure is great but when it's warmed up, goes to near zero at idle. I was kinda concerned at first, but I was told by gearhead much smarter than me if I had any pressure at all at idle, no rattle and it picked up with RPM not to worry. That has been at least 4 years ago. 45 second burnout? Anything is possible with that kind of thrashing. Good luck
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Old 12-24-2005, 07:49 PM
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Doc here,

Like Gene Neal said..

In a Deep pan (or any for that matter) Without Baffles oil will slosh away from the pump pick up...

As far as the stalling..

That much abrupt Change in G force, could be anything in the Fuel delivery system or induction system..Also too, remember too, the throttle mechanism is slamming home everytime you do it..you may need a vacuum assist dash pot. (or run a real high idle..)

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