Is 1/4" end play on oil pump OK?

[eastbay]

So I had no oil scavenge going on in a newly built motor.

It would fire up and run fine but oil pressure would drop from 50psi to 7 or 8 psi after running about a minute or so. Verified with a mechanical gauge.

Hmmm, oil tank was empty. OK, drain crank case of 12 quarts of oil, pour back in oil tank, repeat. Same outcome.

Thought I had lost or crimped an oil pump oring, on tear town, no such luck, all orings virginal and accounted for.

Examined oil pump and the scavenge side has roughly a 1/4" of end play



What do you guys think?

[stownsen914]

Nope, that's not right. Sounds like the scavenge portion of the pump can't draw a vacuum to suck out the oil, probably due to the gap. Was the oil pump disassembled when the engine was apart?

[eastbay]

right, 2-4 thousandths is industry standard for oil pumps.



So I am 100 times what the clearance should be.


This is a pump I sent to Glen Yee for the GT1 mods and was fresh from his shop. More slippery slope money pissed away.



I will be doing a forensic tear down of this pump once I get the motor back together with a different pump and have the time.


Look for it, I have a feeling it will be entertaining.

[stownsen914]

Strange and a total pain for you. Sorry that happened. Sounds like it got assembled with the wrong gears.

[Trackrash]

^ +1 . Send it back and see what they say. Are the end bolts on the pump tight?