Caught valve maybe? She was fairly scorching…
Pulling the top off you may see the scuff within the bore very clearly:
The rings had been OK, aside from the truth that the second ring was tight in it is groove. Hardly shocking actually:
Rightly or wrongly, I polished this out. Probably somebody will inform me I ought to have changed the piston.
I constructed this software to carry the barrel whereas I honed it – it is simply a few bits of plywood:
You’ll be able to mount it within the vice both manner, however that is probably the most handy for honing. I mounted it vertically to grind the cylinder head to barrel joint.
I used a cylinder hone to wash up the bore. Hopefully these honing marks will retain a bit extra oil…
I additionally changed the inlet valve which was very free – the brand new one had an interference match within the bore however was the older bore measurement – the inlet valve stem diameter modified from 5 1/16″ to three/8″ someplace round 1941 I believe…