Oil Pressure Relief Valve?

Dan1950

Dan1950

1974 MK II Roadster
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I'm going to have time to investigate my oil pressure loss problem.

Thread 'Good Thing I Have an Oil Pressure Gauge!' https://www.accessnorton.com/NortonCommando/good-thing-i-have-an-oil-pressure-gauge.37683/

All indications point to it being something to do with the components involved with the AMR anti-wet sump mod, be it improper assembly on my part or something to do with the modifications done by AMR.

I learned long ago to investigate the simplest, easiest to correct factor first so the OPRV seems to be the best place to start.

I'm familiar with how an OPRV works, but have never had the one on my Commando MKII apart. Since it was modified by AMR I want to check that it was assembled and shimmed properly.

Does anyone have a drawing of how the components should be assembled.

What us the best way to establish proper shimming?
 
Dan1950 said:
Since it was modified by AMR I want to check that it was assembled and shimmed properly. Does anyone have a drawing of how the components should be assembled.
Click to expand...

Exactly as drawn (Does AMR modify the OPRV?):
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk

Dan1950 said:
What us the best way to establish proper shimming?
Click to expand...

With a pressure gauge.
 
L.A.B. said:
Exactly as drawn (Does AMR modify the OPRV?):
andover-norton.co.uk

Andover Norton Parts Drawings - Genuine Andover Norton Factory Parts - Commando Parts

Andover Norton Parts are the only Norton spare parts in the market manufactured to original drawings, within the factory-approved tolerances, from the correct materials, and with the correct finish.
andover-norton.co.uk



With a pressure gauge.
Click to expand...
I'll check the drawings on my laptop when I get home. The AN drawings are my go to when checking assembly. The drawings are all jumbled together on my phone screen.

AMR offers the OPRV mod so it discharges to the sump rather than the oil inlet line.

I have an oil pressure gauge but thought there was a rule of thumb on assembly to get the pressure to a certain range.
 
Dan1950 said:
AMR offers the OPRV mod so it discharges to the sump rather than the oil inlet line.
Click to expand...
Do you have any documentation on this? I can't imagine what they could do to the OPRV (not saying they don't do something).
 
Dan1950 said:
AMR offers the OPRV mod so it discharges to the sump rather than the oil inlet line.
Click to expand...
Into the timing case.
Yes, that's what I thought but I don't think there's any modification to the OPRV.
 
L.A.B. said:
Into the timing case.
Yes, that's what I thought but I don't think there's any modification to the OPRV.
Click to expand...
I think it requires the disassembly of the OPRV.

I spoke with AMR about my oil pressure problems and he did say that he had OPRV apart and did not make any notes as to anything suspicious.
 
Dan1950 said:
I think it requires the disassembly of the OPRV. I spoke with AMR about my oil pressure problems and he did say that he had OPRV apart and did not make any notes as to anything suspicious.
Click to expand...

The OPRV would require removal to drill the new vent and I would expect them to inspect it but I don't think they modify it.
 
I copied the AMR mod as on wrong side of Atlantic and I have all the tools.

This is the Timing cover mod to redirect the drain of OPRV excess oil.

Oil Pressure Relief Valve?


You need the OPRV out of the cover to drill the new hole but no change to the OPRV was needed.
 
I would say once the timing cover comes off....all will be revealed....

I very much doubt that AMR did anything to the OPRV except remove it to machine the cover. (as mentioned)
I recently fitted a mk3 cover and plunger to my 74 (instead of amr mod)
along with a new pump and the correct oil seals etc...the one thing I noticed is the pressure is higher now on a cold start...I don't think I can attribute that to the new pump...but rather disturbing the srm oprv (fitting it to new cover)..that used to relieve at about 50-55...now its starts off at 60 psi plus...the plus i don't know as the needle hits the stopper now.....and the gauge only goes to 60 untill the oil starts to warm...I use the same liquid engineering as you ...look forward to your findings 👍
 
kommando said:
I copied the AMR mod as on wrong side of Atlantic and I have all the tools.

This is the Timing cover mod to redirect the drain of OPRV excess oil.

Oil Pressure Relief Valve?


You need the OPRV out of the cover to drill the new hole but no change to the OPRV was needed.
Click to expand...
But the fact remains that the OPRV was removed and reassembled. Perhaps there is a small chip of aluminum causing it to stick or leak by.

It's the easiest thing to check. If it doesn't resolve the issue I will remove the timing cover and investigate further.
 
Dan1950 said:
But the fact remains that the OPRV was removed and reassembled. Perhaps there is a small chip of aluminum causing it to stick or leak by.

It's the easiest thing to check. If it doesn't resolve the issue I will remove the timing cover and investigate further.
Click to expand...
On ya...opening up the timing chest...gets to the "heart" of the matter...😉
 
Opened up the OPRV and this is what I found!

Oil Pressure Relief Valve?


Oil Pressure Relief Valve?


Oil Pressure Relief Valve?


No shims and a manky looking plunger.

I was able to push the plunger past the relief holes in the assembled OPRV with very little finger pressure on the end of the plunger.

Can anyone tell me the thickness of the shims so that I might see if I can substitute something to see if it makes any difference?

I am definitely going to order the OPRV kit but it will take some time to ship.
 
I found a thin washer the same OD as the spring and put it under the spring. Now carrying 40 PSI hot at 2500 RPM. 55 PSI max.

I ordered the pressure release valve assembly kit from AN.
 
I know this is an older thread but perhaps someone can jump in without me posting a new one. I am in the midst of sorting out what I have to assume is too high oil pressure in my 750. I've got multiple leaks in the head, seems to be mist or weeping rather than drops. I cleaned the pressure relief valve once and buffed the piston with some 1200 grit and I think it may have bound up again. I cleaned the valve again and buffed the piston again and it now moves freely in the valve body. I have not sprung for a gauge yet and may jury a pressure gauge to the oil feed into the head with a double banjo just to confirm or refute my perception. All of that to say both the Andover and another parts blow up show the two shims as being inside the domed cover, not inside the piston. The shims fit perfectly inside the piston and seemingly would be confined there, unable to move around by being kept in place by the spring. The domed cover is somewhat rounded in the center and to me would seem like those could move around slightly because there is nothing to keep them centered. except for the spring pressure. I am fairly certain it isn't dirty oil and I place a rare earth magnet in the bottom of the crank drain plug. What am I missing?
 
Gnalk said:
I know this is an older thread but perhaps someone can jump in without me posting a new one. I am in the midst of sorting out what I have to assume is too high oil pressure in my 750. I've got multiple leaks in the head, seems to be mist or weeping rather than drops. I cleaned the pressure relief valve once and buffed the piston with some 1200 grit and I think it may have bound up again. I cleaned the valve again and buffed the piston again and it now moves freely in the valve body. I have not sprung for a gauge yet and may jury a pressure gauge to the oil feed into the head with a double banjo just to confirm or refute my perception. All of that to say both the Andover and another parts blow up show the two shims as being inside the domed cover, not inside the piston. The shims fit perfectly inside the piston and seemingly would be confined there, unable to move around by being kept in place by the spring. The domed cover is somewhat rounded in the center and to me would seem like those could move around slightly because there is nothing to keep them centered. except for the spring pressure. I am fairly certain it isn't dirty oil and I place a rare earth magnet in the bottom of the crank drain plug. What am I missing?
Click to expand...
You are missing critical data.

Oil pressure reading.
 
Oil Pressure Relief Valve?


If you had one of a Triumph , and put the outer bits on your Norton one , youd have a Thing , that stuck out .
running. So youd know if youd left the rubber grommet of the timingt cover / oil pump .

PLUS ; its not as easy to ' Kick the indicator button into gear ' on a Norton ! .

Oil Pressure Relief Valve?

Freds right on . all the bits to the right .
 
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