Early stage - testing the nearside cylinder using steam from a Mamod stationary engine boiler. The engine has piston valves and i use Fluorisint for the bobbins, which is  a type of PTFE, but harder wearing with less expansion. Testing on compressed air does not work very well as the air tends to blow past the piston valves which must be left with some room to expand when heated by the steam.

 

Testing at a later stage under its own steam

 

Nearing completion in the workshop

 

Completed engine. it took about 4years and approx. 1000 hours construction. Credit to John Swarbrick who helped with construction of the boiler.

 

1st running day