Seized engine

Head came off today. #3 cyl has rust on walls. Done some slight tapping on wood on pistons. Still solid. Will get some wet&dry tomorrow, to take to the cylinder wall.

Spray some wd40 or similar down there. So much that it floods the cylinder, then walk away for a couple of hours. It might surprise you

This is gonna sound rough, but has worked for me in the past. Touch a wire on the starter solenoid as you feel each piston crown. 3 will be going up, 3 will be going down. Once you feel some trying to move, not hard to work out which is which from the firing order and their positions.
Bash the down ones with a hammer on some hardwood, then bang the starter in repeatedly while pulling on a breaker bar on the crank nut. (don't hold the starter on, just touch the solenoid wire for half a second, or so each time) Bash the down ones again. Repeat until it gives in. Then you can easily yank them all out for a check. Likely only the one, maybe two will be rusted and easily fixed at the engine reconditioners. I usually find only the top ring is rusted in.

This assumes no stuck valves, which can also be hit (with extreme care) if need be with a drift. Can be levered up off the cam followers, bashed back down, etc.

Sometimes being a bit rougher than you would like actually works.

Jarrod.

FatBob103, I may have to take you up on the offer.
I think the engine is too far gone for my limited knowledge. ASW120, have done all the things you suggested.
I have put a mixture of kero and diesel on top of each piston. I piston allows it past the rings. Don't know if this is good or bad. When I hit this piston with the piece of wood, it sounds like it is NOT stuck. The others feel different - nothing.
Have also spread a lot of "the mixture" around the valves.
One cylinder has a lot of rust on the walls. Too much for wet and dry.
So either another engine or take it to an engine reconditioner

At least you had a go. You never know until you try

Cheers, Jarrod.