Seem to be losing oil pressure when at the race track. It will drop from about 65psi to 45psi at about the 1200ft. mark. It seems to recover as soon as I lift off the throttle. Oil mods have been done to timing cover only. Bearing are TA cam and F/M rod and main. I'm using a stock pan. Could it be running dry? Or is a bearing going away. From what I can tell the oil is clean. Scott
Fellow racer I know had the same problem. His lifter galley has the titanium epoxy set-up. Seems the drain back holes were not large enough for oil to get back to the pan. All oil was in valve covers and galley area. Do you have the same set-up?
No George, I'm not using that modification on this motor. Could the oil pressure regulator valve be sticking? Thanks, Scott
I am trying to think of why the oil pressure drops. Hmmm, here are some ideas: 1. Need to confirm oil pressure gage is accurate 2. Is oil being aerated causing cavitation? 3. Is oil pressure relief spring correct? Possible bad spring? 4. Possible you have a cracked oil pump housing? Oil is bypassing normal oil flow at higher pressure since something is cracked or leaking. I think you have a oil path problem. I don't know of a way to confirm it without tearing the engine apart. Maybe someone else has an idea.
I would guess you have some oil drain back problems. George might be on to something too. I'm guessing the motor is buzzing pretty high. It is possible that the oil pump case is deflecting under the high load. the gears could be pushing the case around. 65 psi is not a whole lot of pressure though. I bet the sump is getting uncovered. Maybe a high capacity pan should be in your future. Doe sthis happen if your just revving the motor with no load? if it did then you have some problems....
Pressure only drops under load. And not all the time. Since I've got nothing better to do, looks like it's time to do some wrenching! Thanks, Scott
If you have the stock pan... I'd look for a deep one.:bglasses: I recall seeing a used TA one on ebay, not sure if it ended though.o No:
I remember a few years ago I ran into this problem on an engine for which I had built the oil pump. Turns out that the customer was running a roller cam with a lot of lift mated with BBC roller mech lifters running approx .030" clearance. At upper rpm's the lifters would tend to float the radial oil channel of the lifter out of the lifter bore dumping oil to the lifter valley. I think he ended up using a different brand lifter with a narrower channel to fix the problem. Don't know what your particular set-up is but it is definitely something to look for.
