I have been having a problem with my oil pressure after I rebuild the engine. I think I put a sealed pro high volume pump in it. The oil pressure drops down to zero when the car in under acceleration. I also have an oil leak coming from the back 'wall of china', I do not think it would be causing the pressure drop though. It only drops to zero when I am under acceleration or sometimes when I turn a corner.

Idle pressure seems really low as well @ about 25 (after warm up).

Any insight would be appreciated

pre-86 block
.60 over
TPI
Milodon stock replacement oil pan
sealed power high volume oil pump (SLP-224-4143 I think its this one)

 

Did you check the gap between the oil pick-up screen and the bottom of the oil pan? I believe the high volume pumps are a little taller.
If it's too close, you will lose oil press at high rpm.

The only way I know to check it is to have eng upside down on eng stand, place a large clump of modeling clay on oil screen and install oil pan with gasket. Torque down bolts, then remove pan and measure clay thickness.

BTW; 25 psi at idle on a hot eng isn't too bad.

 

I didn't check the clearence on the oil pump screen when it was on the stand with the clay. I believe I used the eye-ball method at the time, or compared it to the stock one...I can't remember

I forgot to mention that i have the matching pickup for that oil pan.

 

I dug up my old reciept and it turns out I got the summit brand oil pump. Part # SUM-121155

If the screen was too close to the pan wouldn't I have the same zero pressure when I just rev the engine parked as I do under acceleration/corners?

 

Seems like you would. Maybe when you rev the eng sitting still you don't keep it at high RPM long enough for the oil pump to starve.

Are you using the factory oil press gauge or a direct reading aftermarket unit?? The reason I ask is if you using the factory elec gauge, maybe you have a short somewhere that only occurs when the car is under accel or in a corner.
Does it happen only going around left or right corners??

 

Kinds sounds to me more like the pickup has fallen out of the pump.

If the pickup is too low, most often it will have good oil pressure up to some RPM, and then will start falling off - drastically - above that. And, it doesn't account for the cornering problem. Having the pickup point 1" or whatever above where it's supposed to be however, DOES account for all the symptoms.

25 psi idle and 50-55 psi cruise is fairly typical for the std vol high pressure pump; so if that's about what you've got, you're in the ballpark you need to be in. Probably not a bearing problem or anything real tragic like that.

 

I am using the factory gauge. It has never gave me a problem before the rebuild

I don't remember if it occurs on both left/right, but I do know that under right hand turns it does. I haven't turned left yet (that i remember anyway).

 

I was afraid about a pickup falling out.....

I guess I'll have to take off the oil pan and check it out. I mine as well put in a M55 melling pump with #26 spring while I'm at it.

Does anyone know how hard it is to change the oil pump with the engine in the car?

 

First drain the oil and stick a coat hanger in through the drank plug and swing it back and forth - you may need to bend and rebend it a few times. If the pick up has fallen off, you will feel it at some point.

 

Thanks for the tip Stekman... I tried it and it turns out that it's has not fallen out.

Turns out that the pickup was so close to the pan that i could barely get the coat hanger under it.... So I'm gonna have to reposition the pickup at the very least .

Has anyone been able to get the oil pan off while the engine is still in the car?? I've been looking at it and it doesn't look like it can happen.

 

It can be done, on a stock pan anyways. You have to remove the bolts from the motor mounts, take the cap/rotor off the dizzy (to make sure it doesn't get broke against the firewall), and jack up on the motor enough to wiggle it out. As you jack, the rear of the motor will move towards firewall (thus the caution with the dizzy), and you can usually wiggle the pan out. Getting it back in with the gasket in tact is trickier - especially when your alone, it's 10pm, dark outside, the driveway is wet, and your work light plug gets wrapped around your foot and you pull it from the wall lol.