oil pressure disappeared.

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Kent mosby

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I replaced my oil pan gaskets and windage tray due to a leak. I went with a windage tray/gasket combo that is much thinner. The pan was off for a week or so. After completion, I cranked and got no oil pressure even with the distributor off and a hex rod in a drill motor going CCW.. I then loosened the oil filter a bit and used a hex rod to prime the pump and got it to burp and then oil pressure was back. Fast forward a week and I started it and I got nothing again. This time I took off the oil filter completely and tried cranking (without the ignition disconnected so it would not start) I get nothing. Filter was new, oil fresh. Pump has less than 1000 miles on it. The only thing I can think of is the pickup has an issue.

Could it be that since I removed the gasket and windage tray and used a thinner one that it is hitting the bottom of the pan and preventing it from sucking up oil? Is there a one way valve stuck open somewhere that is supposed to prevent oil from draining from the pump and causing it to lose prime? I would think that if I cracked or broke the pickup that it would not have worked after the first incident. Is the pump bad. Is there a check valve?

Help, I need this fixed so that It never gets driven without oil pressure by anyone.
 
Let's discuss what method of oil pressure reading you are using. A "master guage" or the one in the vehicles dash? If it's the vehicles guage, check the wire.
 
Analog gauge. Copper line down to under dash. This has been working for 2 years
image.jpg
 
How much oil pressure was it running? Any change from before changing the windage tray?
 
You really can't guess what is wrong, it could be any of the things you mentioned - pickup tube, pump, etc. Don't assume a pump with under a thousand miles will not have failed already. Pumps can have a pressure relief valve, that surely can stick open - even intermittently. You'll need to tear down and inspect further.
 
Garrett Ellison said:
How much oil pressure was it running? Any change from before changing the windage tray?
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It was always at 75 psi at 2500 rpms. At idle 25-30psi at 950 rpm. It was the same after I fixed it last week. It just seems to lose prime or cannot get going. Last week when I loosened the oil filter a bit. It only took 2-3 seconds of drill rotation to get suction from the pan and pressure reading.
 
I'd check the pickup, it sounds like an air leak. Tube could be cracked at the threads.
 
B pumps just unbolt. Take it off and check out the bypass valve. While your at it, pack it with vaseline to prime it. It draws the oil in by suction and a dry pump take a while to pull it but a packed pump will pull it almost at once. The vaseline will thin out in your oil.
 
royslead said:
You really can't guess what is wrong, it could be any of the things you mentioned - pickup tube, pump, etc. Don't assume a pump with under a thousand miles will not have failed already. Pumps can have a pressure relief valve, that surely can stick open - even intermittently. You'll need to tear down and inspect further.
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Any way to test the pressure relief valve?
 
I’m going to say one of two things.
1- you broke pickup and it is sucking air
2- pressure relief valve in pump is sticking.
 
I can drop the pan and check the pickup. That is just bolts. How do you check the pressure relief valve? Do you just replace the pump or cam the valve be repaired?
 
You can remove the relief valve with the pump in the car. But I would remove the pump and place it on the bench so you inspect the relief valve and any foreign material that might be causing it to stick.
 
pishta said:
B pumps just unbolt. Take it off and check out the bypass valve. While your at it, pack it with vaseline to prime it. It draws the oil in by suction and a dry pump take a while to pull it but a packed pump will pull it almost at once. The vaseline will thin out in your oil.
Click to expand...
Don't "just" do that. Take the pump apart, it might have cracked an O ring, and makes sure proper gaskets and O rings are in place. Seems to me there is one on the snout where it goes into the block, plus the block to pump gasket, and a large dia. O ring where the cover mates. ALWAYS remove filter when trying to prime as it relieves the head pressure on the pump and makes it easier to pick up and prime.

Any possibility the hex is damaged?

YOU MAY HAVE cracked the pickup tube and it's suckin air
 
Max1196 said:
Let's discuss what method of oil pressure reading you are using. A "master guage" or the one in the vehicles dash? If it's the vehicles guage, check the wire.
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He removed the filter off the engine and got no oil. I don't think it's a gauge issue.
 
Kent mosby said:
I can drop the pan and check the pickup. That is just bolts. How do you check the pressure relief valve? Do you just replace the pump or cam the valve be repaired?
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The pickup is supposed to touch the bottom of the pan. That's how it's designed, so that's not going to stop it from drawing oil into the pump.
 
Sounds kinda messed up.

What exactly is "thinner gasket's" and a windage tray? Never heard of such!

Must have sucked something in the pump or broke the pickup.

Seems if your pickup was hard bottomed to the pan you have noticed such when re-installing it!

What pan? Correct pick-up for it? What thinner gaskets and windage tray?
 
1969383S said:
Sounds kinda messed up.

What exactly is "thinner gasket's" and a windage tray? Never heard of such!

Must have sucked something in the pump or broke the pickup.

Seems if your pickup was hard bottomed to the pan you have noticed such when re-installing it!

What pan? Correct pick-up for it? What thinner gaskets and windage tray?
Click to expand...

I previously had 2 cork gaskets and a metal windage tray. Now I have a windage tray rubber gasket combo. Probably a 1/8-3/16" shorter. Since I use studs and the gasket is rubber and no RTV is used, I am tightening the pan up and it could press up against the pickup and either plug it or crack it. No way to feel that happening. I should have remeasured the drop of the pickup but I did not. The pan and pickup were used for many miles. The pickup is a 440 source pickup designed for stroker motors. It is narrow at the threaded end so that is does not hit the crank..
1271017b.jpg

Many pickups are welded by the threads and the flange hits the crank. I cannot see the bottom end of this pickup to see if there are stops, say 1/16-1/8 inch to prevent it from sealing against the bottom of the pan. If I measured before to get it close, I could have had it 1/16" away.
 
Kent mosby said:
I previously had 2 cork gaskets and a metal windage tray. Now I have a windage tray rubber gasket combo. Probably a 1/8-3/16" shorter. Since I use studs and the gasket is rubber and no RTV is used, I am tightening the pan up and it could press up against the pickup and either plug it or crack it. No way to feel that happening. I should have remeasured the drop of the pickup but I did not. The pan and pickup were used for many miles. The pickup is a 440 source pickup designed for stroker motors. It is narrow at the threaded end so that is does not hit the crank..
View attachment 1715813509
Many pickups are welded by the threads and the flange hits the crank. I cannot see the bottom end of this pickup to see if there are stops, say 1/16-1/8 inch to prevent it from sealing against the bottom of the pan. If I measured before to get it close, I could have had it 1/16" away.
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Ok, so it's an aftermarket pickup. WHERE is the opening? On the bottom? The factory pickups are designed to hit the bottom of the pan. If that pickup has the opening on the bottom and is resting against the bottom, that could be your issue.
 
Just a thought, you could loosen the oil pan bolts to allow it to drop down just a little then try and prime the oil system. This might tell you if the pan is against the pickup and sealing it off?
 
SGBARRACUDA said:
Just a thought, you could loosen the oil pan bolts to allow it to drop down just a little then try and prime the oil system. This might tell you if the pan is against the pickup and sealing it off?
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I was thinking just that. Right now, I have to determine the most likely candidates, 1. pickup,, is it up against the bottom of the pan. If so, loosening the pan a bit would allow priming the pump.....If that doesn't work, pan has to be pulled to determine if I broke the pickup. 2. Pump is bad, either the relief valve or the pump itself.

@RustyRatRod I will check tomorrow
 
Kent mosby said:
I was thinking just that. Right now, I have to determine the most likely candidates, 1. pickup,, is it up against the bottom of the pan. If so, loosening the pan a bit would allow priming the pump.....If that doesn't work, pan has to be pulled to determine if I broke the pickup. 2. Pump is bad, either the relief valve or the pump itself.

@RustyRatRod I will check tomorrow
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If you go to the trouble to loosen the pan, you may as well take it off and check everything out with a fine tooth comb. I know I would. That's too nice an engine to be second guessing anything.....but you already know that.
 
67Dart273 said:
Don't "just" do that. Take the pump apart, it might have cracked an O ring, and makes sure proper gaskets and O rings are in place. Seems to me there is one on the snout where it goes into the block, plus the block to pump gasket, and a large dia. O ring where the cover mates. ALWAYS remove filter when trying to prime as it relieves the head pressure on the pump and makes it easier to pick up and prime.

Any possibility the hex is damaged?

YOU MAY HAVE cracked the pickup tube and it's suckin air
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Well, you gotta take the pump apart to pack it! "..O-ring cracked" ? ....sounds deeper than an O-ring. You got clearance Clarance? I dont think you cracked anything as the tube is pretty soft.


I remember on an LA we just screwed the pick up in so it was snug and still sticking up a bit and laid the pan on it with no gaskets. push the pan to the rails and that would set the distance minus the gasket. The LA had that shoe type with the built in standoff on the bottom.
 
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Kent, if your pickup is made like that one above ^^^^ and pressed to the bottom of the pan, I believe that's your issue.
 
If he has a stocker, there is no way it can be "too close" as it has the stand off bottom too.
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