supldys Posted March 6, 2003 Report Share Posted March 6, 2003 im still having the same problem i had on my old motor, with my oil pressure, not the problem with my piston tongue.gif what happens is at idle, warmed up, my oil prssure gauge (autometer) will sit around 25. when i rev up anywhere between 1000-2000, whether moving or not, it will go up to about 40psi. when im between 2000-4000 the oil will stay right below 40psi and wont move. anywhere above 4000 my oil pressure will actually drop. how fast it drops depends on how far up in the revs i go, and for how long it drops depends on how long i stay in the high revs. it dosent seem dependent on boost or throttle or anything like that, just on the revs. at first i was thinking internals, but i have gone through two blocks, each with new rings, and three different sets of bearings and it hasnt affected the oil pressure much at all. the only thing that has really stayed the same on the car is the oil cooler, but i dont know if that would cause that. if you have any ideas, itd be really appreciated!! -Jono Quote Link to comment Share on other sites More sharing options...
slow4now Posted March 6, 2003 Report Share Posted March 6, 2003 Well isn't the oil pump run off the crank? So the higher you rev it the more pressure it will build. A lot of it also depends on how much oil the pickup can get from the oil pan.So you may have low pressure at higher revs because there isn't much oil in the pan. How far away is the oil pan from the pickup? Make sure it isn't too close or the pickup won't be able to suck up much oil and could leave to seized bearings. I take it what your car is doing isn't normal? Just some things to think about, I am not too knowledgable about oil pumps so maybe there is something special about yours. Quote Link to comment Share on other sites More sharing options...
supldys Posted March 6, 2003 Author Report Share Posted March 6, 2003 you're right, it does run off the crank. but ive been through two different oil pumps, pans, and pickups, and it hasnt changed at all tongue.gif Quote Link to comment Share on other sites More sharing options...
Akula Posted March 6, 2003 Report Share Posted March 6, 2003 We have a titan on the Altered, it runs 80psi off of idle, keeps that the whole time. I think you might be getting some kind of pump cavitation at high RPM, seems to me the pump isn't getting enough oil to keep the volume up, pickup not in the right place, low on oil, or something restricting the flow back to the pan. If you rev to 5000 rpm and keep it there, does the pressure continue to drop or will it stay at say 35 psi on 5000 and go to 34 psi at 5100... Quote Link to comment Share on other sites More sharing options...
slow4now Posted March 6, 2003 Report Share Posted March 6, 2003 What kind of oil pump are you using? I take it the screen on the oil pickup is free of debris? I would try by-passing the oil cooler, it may be clogged...That's all I can realy think of that may help diagnose the problem. You said you've been through a coulpe of oil pans so a dented oil pan doesn't seem likely. Strange problem. Quote Link to comment Share on other sites More sharing options...
supldys Posted March 7, 2003 Author Report Share Posted March 7, 2003 if i keep it at 5000, the pressure will continue to drop. the oil pressure got real low today, like 20 psi cruising, it didnt drop any lower at idle, like it didnt move from there at all. scared me though my buddy dwayne at work whos been drag racing awhile says hes heard that happening and so to overfill the oil by a quart, i did 3/4 of a quart, but it didnt change a damn thing at all either. I tried checking my oil as soon as i turned the car off and there was plenty of oil in that pan. -jono Quote Link to comment Share on other sites More sharing options...
Dave1647545494 Posted March 7, 2003 Report Share Posted March 7, 2003 rule of thumb we follow on oil pressure is 10psi for every 1000 rpm(minimum engine hot) drops in oil pressure at higher rpm can be caused by lifters too as the increased pressure can cause them to bleed off. I'm not sure what kind of motor your working on. does the oil pump mount down in the pan like a chevy or a chrysler or in the timing cover like a buick/ford if its a pan mount cavitation is possible if you didn't get the new pump primed good they need to be dipped into a bucket full of clean oil and spun till all the air comes out. the cover mounted ones are a little easier you can pack them with grease or vaseline and they prime up in the car. HTH Quote Link to comment Share on other sites More sharing options...
supldys Posted March 7, 2003 Author Report Share Posted March 7, 2003 im working on a little 4cylinder, the pump is a lot like a hondas. mounts on the end of the crank (which turns it) and has a pick-up that goes down into the pan. im gonna try moving my sensor first, since it actually screws into the adaptor for my oil cooler, and then im gonna try running without the oil cooler if i can get the non-oil cooler adaptor off of my non-turbo motor. then we'll see from there whether or not some new oil pump stuff is in order or not, thanks for the help guys -Jono Quote Link to comment Share on other sites More sharing options...
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