Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Quite a few flaws of significant importance there.

I agree with Dennis, forget about that piston, and make it a new one.

In fact i think i just would have made it a fast one, running a teflonring or similar, just to see how the engine behaves with something properly sized in there.
When the bore is properly honed, there might not even be a reason for anything more in your case, as it would last decades if merely intended to be a demonstrator, rather than an all day workhorse under load.

Would be a good thing to get those bearing machined to fit a single shim, and the flywheel will tell whether it really is bent, or the bore crooked, as soon as you get it off there to attend the keyway on the shaft anyway.
If it isnīt too badly bent, those 3 cracked spokes could be brazed, and it would be back to a relatively high structural health.