Hi. I recently overhauled the NRV on my Primus 96, (1931 vintage), and was unable to locate the old sealing washer around the valve. I had a good look down the pump tube with a torch/flashlight but nothing was found. I’m guessing that the valve assembly hasn’t been replaced since production? And all I could see was a leather/grease/oil mix The valve pip looks to be made from cork. Does anyone know if these stoves left the factory without any form of seal?
The cork is very likely the original, give it a soak in oil and there is a good chance you'll get a few more decades service from it. If it doesn't seal, you can reverse it. A lot of older No.96s seem to have left the factory without a sealing washer for the pump valve body. And a lot of stoves which did were reassembled without one after overhaul. Reassemble with a lead or HDPE washer and a smear of copper grease on the threads and you shouldn't have any problems now or in years to come.
Thanks @Blackdog I used a “viton” pip and an HDPE seal from Fettlebox. Had visions of struggling with a stuck NRV so relieved to hear loud click upon release. Alas original cork pip was damaged by me removing it with a pin. regards Nick
Commiseration @Sizzler670- Viton does the job perfectly but it's always depressing when the original cork can't be salvaged. Well, I think so!
