After changing my oil pump on my newly rebuilt 1966 442 engine because I was getting a oil pressure reading that was jumping up and down (when at first start up 50lbs. and about 30 seconds then drops down to less than 5lbs. then back up to about 15lbs and at idle below 0 to 5lbs and above idle maybe as high as 10lbs.) I still have the same problem with after installing a new high volume pump. What could the problem be? Am I running out of oil in the oil pan? Could it be a spun bearing (I have no bearing noise)? I also checked the oil pick up and it was clean.

Thanks for your help.

John

 

Did you check it with another oil pressure gauge? And did you cut open the oil filter to see what was inside?

 

The first thing I would check is the gauge. Is the line ok? Is it grounded correctly? Looks like f-85 and myself replied at the same time. Electric or mechanical?

 

Have a new oil filter and I also check the oil pressure with an another oil pressure gauge that I know is good and I get the same oil pressure readings. I have mechanical oil pressure gauges.

John

 

The problem on mine was a Fram oil filter. Changed the Fram to a Wix and pressure has been fine.

 

But did you cut open the old filter to see what is inside of it?

 

No, I sure didn't. I was so happy the problem was solved I didn't think to try and find out what was wrong with the filter.

 

I installed an new oil filter when I changed the the oil pump.

John

 

Well do you still have it around? Cut it open to seee whats inside. If you have alot of glitter inside of it, then you have a bearing problem.

 

I'm not sure if the last post was for me or Cessna? I do not have the Fram oil filter that was removed from my car.

 

Fram filter???? That is why.

 

Yes, it was because of a Fram filter! I had problems with the oil pressure on my rebuilt 66 442 also and Rickman48 said he had heard of problems with Fram filters and suggested I change it. Sure enough I changed the filter and the pressure has been fine. Other suggestions were, wrong weight oil, maybe the oil relief valve? Wish I could help more but I am not a mechanic just posting what others told me.

 

If you've changed the filter to something other than Fram, it actually sounds like the oil pump pick-up is too high off the botton of the pan, and not picking up the oil.
Measure the pan depth from the rail, then measure the pickup from the block - should ony be about 1/2 inch difference.
You did 'tack-weld' or braze a spot to hold it in the correct position, didn't you??