Oil Pressure Relief Valve Mods

[spmdr]

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:

Oil Pressure Regulator Questions

My dad's '65 has some oil issues...specifically the oil pressure regulator is junk. He was planning to modify it with the screw but it got a bit damaged during disassembly. After looking at it, I see why it was made the way it was but that reason (low price at high volume) doesn't much matter...

forum.sunbeamalpine.org

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.

DW

 

[alpine_64]

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]

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.

 

[hartmandm]

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.

Based on the pictures, DW's setup is adjustable.

Mike

 

[alpine_64]

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

 

[hartmandm]

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?

Thanks,
Mike

 

[RootesRooter]

Has galling been found on the earlier, brass OPRV's that most Series Alpines have?

 

[alpine_64]

Has galling been found on the earlier, brass OPRV's that most Series Alpines have?

Believe so.. the rootes oprv design in general didn't seem to be great for longevity. I had 2 of the early ones stick

 

[Scotty]

Are there any plans out there for someone to make a batch of these?

 

[spmdr]

After countless cold starts, street drives and 2 performance events,

The mods are working flawlessly.

DW

 

[hartmandm]

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?

Thanks,
Mike

 

[spmdr]

Mike, I drilled a 7/16 hole in the center of the OPRV

to be able to remove the piston.

I used a lathe to drill the hole on center and

still needed to play with the hole with a file

to get the piston out.

I tapped the valve head with 1/2" fine thread.


I didn't put any sealer on the 1/2 bolt, it may

weep oil in the long term, but not much,

plus, IF I sealed it, it would only force me to take

it back apart.

With no sealer, chances are I'll NEVER need to touch

it again....

DW