This what I call my Mk 2 engine the only difference from the engine in the above picture is the ignition, on this engine the sensor magnet is fixed in an extra timing gear this moves the sensor away from the crankshaft area and oil splash.
The piston on both engines are aluminium with cast iron rings I make my own rings, crankshaft bearings and big end bearing are bronze
The spark plug is a miniature NGK - CM6
All governor and valve gear components are case hardened
Building these engines was a learning curve for me, but I got them built and running and I know what to expect if I decide to build another model internal combustion engine of this type