oil pressure relief system

[30U sedan]

Thanks, I will also check that.

[TodFitch]

The last time that happened to me it was a clog in the line going to the oil pressure gauge: The engine had plenty of oil an pressure but the dash gauge wasn't seeing it.

[30U sedan]

Thanks Bill, this helps alot. After changing oil, cleaning oil pump, and pressure valve I was not getting any oil pressure at the oil gauge. I had primed the pump and replaced the gaskets so I should have had pressure. After loosening the outlet from the oil pump and making sure that the pump was indeed pumping when the engine turned over. I figured the problem had to be with the valve pressure adjustment.? ?I will try the adjustment in the morning.

[Bill James]

The Plymouth master parts list shows the same pressure relief valve on the, U, 30U, PA, and PB. My 1st ed. Motors Manual only goes back to the 1931 PA. It lists the following, Lubrication, Oil pressure adjust, 1931-32  Normal pressure should be between 30 and 40 pounds. Remove oil pressure relief valve cap at left side of crankcase. Remove lock wire and turn spring retainer inward for greater pressure. When I adjusted mine, I found the oil pressure very responsive to the adjustment. Hope this helps, Bill James

[30U sedan]

Thanks for the info. I have removed the cover on the oil pressure valve and what I see is a threaded stud with a slot in the end for a screwdriver. The stud also has a locknut. What I was wondering is should the stud be run down tight or what. How does this thing work?

By the way, Tod I love your website. It is a great source of info and has been a big help in my restoration project.

[TodFitch]

The 1928-33 Master Parts book shows the same oil pressure relief used on 30-U, PA and PB. In the text they also list U (but not on the diagram) as having the same oil pressure relief valve parts.

Perhaps someone with those models can chime in . . . In the meantime I'll hazzard a guess based on looking at the parts book.

In the later 6 cylinder engines the pressure is set by using different springs but there is only one spring listed for the 4 cylinder engines so if the pressure relief can be set to different values it must be by adjustment. . .

It looks like the relief valve should be pretty easy to get at: It is on the outside of the engine on the left side. There is a cover, under the cover is a retaining wire. Then under that is the valve spring retainer. My book is a reprint and the cut-away illustration is hard to decipher. It looks like the valve spring retainer might be threaded. If so then you could probably adjust the pressure by how deep the retainer is threaded in.

[30U sedan]

Does anyone know how to correctly set the oil pressure relief system on the 1930 Plymouth??