Oil Pressure issue

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wirenut

wirenut

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Hi Looking for ideas;
440
solid cam

Unloading the car from the trailer and OP went to about 5psi.. So shut it down.
Pulled the valve covers, everything is in place. Cranked the engine no oil coming up top. Pulled the pump disassembled and inspected. all looks good, spring, valve, gearotors etc..
Pulled the intermediate shaft, put it in a vise to see if the gear was slipping. Its not.
Put the pump back on the engine, primed with a drill and has 75 psi steady.
Put it all back together and fired it.
20 psi then down to 5 ish..
Checked the intermediate shaft again. OK.
Primed it again. Still 75. ran the drill for 2-3 min. no pressure drop.
For the short period of time it ran, sounded fine. No lower end noise, but now I'm suspecting a bearing issue in some form? What could be moving, turning or otherwise blocking a passage while the engine is running that is not when the engine is not running.
Also changed oil and filter during the course of things.
This is not a new rebuild. No previous issues. Engine has maybe 150 passes on it.
 
Pull the plugs and while running the prime, rotate the crank, see if you lose pressure that way as well.
 
Daves69 said:
Pull the plugs and while running the prime, rotate the crank, see if you lose pressure that way as well.
Click to expand...

X2, Possible cam bearings?
You could actually turn the motor with the starter while you drill prime it.
Even with the plugs in it.
 
Daves69 said:
Pull the plugs and while running the prime, rotate the crank, see if you lose pressure that way as well.
Click to expand...

Great idea, I'm embarrassed I didn't think of it.........

Engine cranking, primer priming op is 75 psi.

I thought cam bearing as well but didn't think it would settle back into place when the engine was off. Cam thrust pushing it ?

What else ya got?
 
I was thinking rotate by hand try to find "a spot".
other.........
pickup screen clogging? cracked pickup and pump sucking air? pump rotor spinning on rotor shaft?
What's left?
 
Ummm, When you backed off the trailer, all the oil ran to the back of the pan. Is your pick-up back there?

On the flat;
The drill spins at what? 300rpm? And the idlespeed is what? 800rpm? I think the pick-up may be restricted, or its sucking air? I'm guessing here.

Oops, scooped by Dave .
 
Daves69 said:
I was thinking rotate by hand try to find "a spot".
other.........
pickup screen clogging? cracked pickup and pump sucking air? pump rotor spinning on rotor shaft?
What's left?
Click to expand...

Didn't think to check the rotor spinning on its shaft. If its a pressed piece it could be.
 
Thanks everyone for the ideas, I'm truly at a loss with this one.
 
wirenut said:
Didn't think to check the rotor spinning on its shaft. If its a pressed piece it could be.
Click to expand...

Not that its what's happening here but kind of a last resort. Seen some failures with pump gears pressed on shafts where I worked in powder metal, so I know it can happen.
 
a lot of these suggestions forget that priming gives good pressure. u did not say if the hex on the tip of the intermediate shaft is good or bad,
 
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