A couple months ago I pulled the engine oil pan on my Y Block for the third time to install a new rear main oil seal. I bought a new expensive retainer and seal kit on Ebay which did the trick, not a drop of oil has leaked since. After running it I noticed that the oil pressure was much higher than before, but I didn't feel it would harm it, about 70 psi highway and 45-50 at idle. I did a rebuild on the pump a couple years ago. Last week the pressure shot up to over 100 psi when I revved it up, so I pulled the bottom of the pump off and took the threaded cap off where the plunger goes and removed the plunger and spring assembly . It moved real smooth in the bore so I felt it was okay. Put it back together and ran it with it even getting higher pressure. It was so high it pumped 4 quarts of oil all over the floor. I found that it blew the gasket apart under the oil filter conversion bolt that fastens the plate to the block. I won't be doing any thing to it until next week, so I need some thoughts as what put the pressure up after putting in that new seal and retainer. It has me baffled. I did loosen all the main caps to get the upper half of the seal out and didn't turn the engine after loosening them. Thanks in advance for you input. The engine is a 1956 Y Block with that style oil pump. The 57 pump is different.
Regardless of what year or style pump they all work on the same principle. I can't see anyway it can produce that much pressure unless the relief valve is sticking.
I tend to agree with you. I will be removing the pump Monday and I ordered a new Melling pump yesterday. It is weird the way that all took place. Thanks for your input.
Ditto on the oil pump relief valve. Had one stick on a rebuilt motor a while back. The motor sat for a number of years without being run. same symptoms.
New Melling oil pump installed today and all is well with 60 psi highway and 30 psi hot idle. Thanks for all he comments.
Thats good news, glad that fixed it..