[martin417]

Rather than try to duplicate the KOP solenoid, just pick out a legal one that is available. We are using this one from SMC:


VQZ2120K-6G1-N7

This is a vqz2000 series valve with a metal seal, Cv is .3 in one
direction, .32 in the other. Max pressure 145 PSI. It has 1/4" one touch
fittings on the work ports, 1/8" NPTF on the pressure and exhaust ports
and can be mounted on a manifold. It operates on 12 volts, and has lead wires attached to the coil (no plugs)


The K indicates high pressure, or a 145 PSI rating.

Finding this exact part may be a challenge, so look for one that is close. Ours is coming from Japan, with expediting, it takes a minimum of 10 days to get here