Classic/Antique Car Repair: Oil Pressure Relief Valve, pressure relief valve, valve question

Question
QUESTION: Brad,

I have a 1939 Dodge D11 4dr that I am restoring.  The car sat for 20 years in storage so I have had many hurdles to cross but I am doing well.  The current hurdle is excessively high oil pressure, well over the 80 lbs the gauge is designed for, it fully pegs the gauge and in fact broke the gauge.  There is no oil flow to the oil filter canister, yet both lines are clear.  Everything seems to be pointing to the pressure relief valve being stuck.  I removed the cap screw, the spring comes out, but the plunger inside must be stuck, as I cannot get it out.  I need to remove the plunger and clean it up, how can I get it out?  
Any experience with this?

Dan

ANSWER: You assumption that the pressure relief valve is stuck appears to be correct. When the valve is in all the way this is the same as seeing no oil pressure and the flow back to the pan is blocked as well as the flow to the oil filter. The oil filter only gets oil when the valve is seeing high or normal pressure. Now, if 80 pounds of hydraulic pressure will not budge the valve then it is really stuck. A good penetrating oil, Marvel or such, squirted in the end hole and dropped in through the oil filter line. Let is soak a bit, a couple of days. Then put the cap back on without the spring and start the engine. If the valve breaks loose the oil pressure will drop. If this does not do the trick, then it is take apart time.
Brad

---------- FOLLOW-UP ----------

QUESTION: Brad,

I appreciate the help.  I have it soaking right now.  I tried starting it this morning without the spring but no luck, still stuck.  I tapped it lightly with a tiny hammer and a punch and I felt it move backwards.  Any ideas on how to get a hold of the plunger to pull it out?  Also, do you know if there is access to the plunger from the inside if I drop the oil pan?

Thanks again,

Dan


Answer
Good, it moves. I know it is a pain but put the cap back on, start the engine, then shut it down and tap and see if the plunger had moved. If it does it should move a bit further each time. I don't remember if the passage is blind or has a plug inside the block. So I can't answer that. If the plunger is hollow you might get a tap started in it that you can then use as a lever. But remember that the plunger is hardened and you don't want to break the tap off in it. Keep me posted.
Brad