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Oil Pressure Relief Valve Mods


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This could go in the Stock world.... but NEEDS to be done to a Race Engine.

In the past, there has been quite a bit of discussion

about the problems with the Alpine engine Oil Pressure

Relief Valve.

Here is one thread:

The problem is, the end result was a bit inconclusive.

So I am picking up the subject.

I too have had the OPRV stick open and closed!

...too many times!

Time to try something different.

upon disassembly, I found the piston was galled.


I wanted to try a ball bearing to replace the piston.

Looking closely at the valve refreshed my memory about some

unexpected details.

I concluded the OEM valve is a bit of a controlled leak,

even when closed, it does not seal very well.

The piston does not seal against it's face.

The inner sleeve of the valve housing has notches.


And the piston diameter (.435 Dia) is not a real snug fit

in the valve housing.

The replacement Ball bearing (.4375 Dia ) is a better fit.

The original spring is too long to use with the ball.

I found a shorter, stiffer spring at the Hardware Store.

The spring is a #136, with 10 turns of .056 wire.


I put the new ball and spring together with a single flat washer

to give a little more pressure.


so far it works correctly.

Time will tell.

Last edited:


Donation Time
Steve Silverstein and Jarrod Gross both loomed into a ball OPRV many moons ago .. iirc some were made .. maybe touch base with JG and see what the longevity was

todd reid

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Tiger Tom had an update that made the OPRV adjustable. I can probably dig that out of my files if you can't find it.


Donation Time
Tiger Tom had an update that made the OPRV adjustable. I can probably dig that out of my files if you can't find it.
Toms was adjustable, but the update in Dan's is the ball which should stop the galling of the moving component and allow pressure adjustment


Diamond Level Sponsor
What sizes did you use for the drilling and tapping the bolt head?

And did you need to add a seal for the adjustment bolt?