This safety valve has a thread of 1/4'' 26TPI. This is the same thread as the Standard Safety Valve but has a shorter body. It was originally made for the Minor engine and also for the Meccano (SP3) engine. Mamod no longer make this item but we have sourced excellently made high quality spares for older engines. These carry our normal no-quibble guarantee so you can buy with complete confidence. If you are in doubt about anything in connection with this item or the model it is intended for, why not email us with your question before you make your purchase. We will be very happy to help you - and we always respond quickly!
Useful information:For early Traction and Steam Roller engines (say pre 1970's) you will need this particular valve as the new ones (longer body) don't seem to thread in fully. It's all to do with very slight machining differences although both are supposed to be 26 tpi pitch.
So to summarise, you can use this valve for any of the current engines (despite it being shorter than today's valves) and any of the older engines with 1/4 inch thread diameter. If you have MM1, an MM2 or any other lovely oldie, this is the right valve. They all release at 15 psi. Got it!
