They can leak at the front thread reducing overall pressure apparently.
Oddly enough I got a mail out from SRM last night on the same subject and now have one on the way.
Oil Pressure Release Valves | SRM Classic Bikes
shop.srmclassicbikes.com
It looks nicely made (externally) for under $100 to the door.I keep thinking I should get one of those. How is the quality?
If this is the SRM valve with a stainless steel piston in a stainless steel bore, that is (at least theoretically) a bad choice of materials.I have one they look fine but someone somewhere complained about rapid wear. Not enough miles on mine to say...
Dry it would be a poor choice. Immersed in oil, no problem.If this is the SRM valve with a stainless steel piston in a stainless steel bore, that is (at least theoretically) a bad choice of materials.
It looks nicely made (externally) for under $100 to the door.
I would need to have a look inside and check the pressure setting at release to be sure but would be surprised if it sealed any better than the stock unit at the forward thread area.
It screws nicely but still has clearance even if slightly less that the OEM unit.
A test fit shows the passage in the timing cover is sitting about this position so there are not many threads in front of that 'hole.
(I could machine the timing cover pad to move the unit inward so the hole is in the channel but the front thread might still need some Wellseal)
I guess only a pressure test with the cover being used would show if there is leakage past the front thread, the OEM sealing/design is a little hit and miss as is .
View attachment 20309
Maybe the shuttle body will need some moly paste from new and then periodically after that but in theory when it opens oil should get to that area . (Any wear will have to be an ongoing check)
I will get another one for the 750.
It looks nicely made (externally) for under $100 to the door.
I would need to have a look inside and check the pressure setting at release to be sure but would be surprised if it sealed any better than the stock unit at the forward thread area.
It screws nicely but still has clearance even if slightly less that the OEM unit.
A test fit shows the passage in the timing cover is sitting about this position so there are not many threads in front of that 'hole.
(I could machine the timing cover pad to move the unit inward so the hole is in the channel but the front thread might still need some Wellseal)
I guess only a pressure test with the cover being used would show if there is leakage past the front thread, the OEM sealing/design is a little hit and miss as is .
View attachment 20309
Maybe the shuttle body will need some moly paste from new and then periodically after that but in theory when it opens oil should get to that area . (Any wear will have to be an ongoing check)
I will get another one for the 750.
I tested one of the SRM units for a local club member to determine it's characteristics .Have been running the SRM unit for several years now, consistently levels off pressure at 50psi on cold start, I should probably get in there and check for leakage past the front threads though
The exit passage for the vented oil is dependent on the NHT engine series . valid for 6 of NHT 26 years
It vents to the oil inward passage on both my 850 and all the 20M3S cases I have, 20M3/ Mk111 850 I do not know
Within all commando series they vent as you say except the MKIII which reverted to early style and vent inside the timing chest. There were a few pre MKIII mongrel commando engines also using MKIII type .It vents to the oil inward passage on both my 850 and all the 20M3S cases I have, 20M3/ Mk111 850 I do not know (This is a Commando specific forum on the website so applied to that )
Its a moot point now as Peridon never returned to the thread he posted.