ORIGINAL: juxy2
You may be right PE - I really hadn't thought of that, but it seems like a lot of trouble to go to - and to achieve what? Surely all new engines from such a manufacturer would have fairly consistent good fits - or am I being naive? Anyhow, I'm stuck with the problem. The engine is 52 years old and in this condition, with box and docs, is worth repairing. I just need to find somebody who has the facilities to machine a new piston, I guess ...
I have done just that with Veco engines. Buy 5 cylinder sets in order to get two excellent sets, one so-so, and discard two. I never would consider selling the loose fits.
The hurrican normally has very tight fits when sold, and this trick is normally not needed.
The cast iron piston is made of meehanite, which is sort of malleable cast iron. You can take the piston out, and make a punch that fits theinside closely. place thepiston bottom on a flat steel surface, and use the punch to hammer (expand)the piston bottom. A few microns (0.001mm) can be gained that way, enough fora re-lap fit. Do not use diamond grit on a cast iron piston though. It is hardly impossible to get the grit out of the iron pores later. So better use grit that dulls quickly if you lap the piston together with the cylinder.
The heat cycle growth of the iron is dearly needed during the running in process, so I would prefer to not use it to get thepiston to fit in the first place.