Cj3a oil pump

1945 - 196*, Willys CJ series, questions, discussions, regarding anything related to the post war jeep.®
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Cj3a oil pump

Post by chucks_toy » Sun Mar 11, 2018 12:55 pm

I have a cj3a engine that has high oil pressure when revved up, 80 to 90. I believe the oil pump pressure relief valve is stuck. What can I do to remove this valve? Thanks for your help.
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Re: Cj3a oil pump

Post by bantamj » Tue Mar 13, 2018 11:57 am

First check if the spring is really stuck.
You can let the engine run @ high idle (high oil pressure) and carefully unscrew the cap a couple of turns while someone is watching the pressure gage.
If the oil pressure drops as the cap is turned out, you know the plunger is not stuck but the spring shimm'd to far.
The PRV cap on an original CJ oil pump is on the pump body, it is facing toward the engine and is not so easy to reach if the plunger is stuck.
I would remove the pump for easy acces to the plunger, but the pump is driving the distributor.
So if you are planning to remove the pump...first discuss the do's & don'ts.


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