Pistons are still stuck. 24 hours in diesel plus carb cleaner; have already tried regular penetrating oil. Was hoping to get the Gibbs Brand oil around here somewhere, but no luck as yet.
I decided to go ahead and pull the engine out and open it up. After all, it spent at least a decade, maybe two without its plugs… no telling what’s in there. So I put a dolly under the engine, and put in enough blocks to support the engine when it comes out, and got down to loosening things.
Well, the upper bolts (attaching the head to the frame) loosened easily. Of course, I left them in place until I could get the others loose also; and therein lies the rub.
I started, naively, trying to loosen the bolts in the rear mounting holes from the outside, but I couldn’t budge them, even with a breaker bar. After cleaning more of the crud from the inside of the frame, I found the nuts and washers heavily rusted, but amazingly I broke them loose with an ordinary wrench and removed them; they are pretty buggered up, though, and I expect to have to replace them.
With the nuts off, I assumed it would be easy to remove the bolts. Nope. They are in there tight… I still can’t move them, even with a breaker bar. So I convinced myself that they must be threaded into the holes in the crankcase, and rusted in place. However, a question asked online resulted in the answer that, no, there are no threads in the case holes. Now I’m going to have to figure out how to get them out without breaking the upper engine case in the process.