Thimble drome .49 engine from a Mercedes-Benz w-196 car is stuck

Back in march I found this car in my dads bedside table drawer, it might've been from my great grandfather and he found it when he died, I quickly found out that the car was covered in 60 year old oil. So I took it apart and saw that it had a mini engine in it, me and my dad attempted to clean the body of the car, but quickly gave up because of how much oil was in the car. So we put it on a shelf for later. Fast forward to last week and I remembered about it. I took it off the shelf, disassembled the engine, cleaned it up and it looks so much better than it did when I found it, But the engine didn't want to move. I remembered that I'm taking an auto shop class at my school, I talked to the teacher about it and learned that the glow head could be screwed off, he also mentioned that the reason it wasn't moving was probably because the piston is stuck. He told me so find a lubricant called "PB B'laster" and soak the piston assembly in it. I've been soaking it in the oil for almost a week now and there's no progress seeming to be made. Would anyone know what else to do, or do i just have to wait for a longer amount of time to get results?

The oil in the engine will be castor oil which does not easily disolve in solvents like mineral oil does. It will usually, however, disolve in alcohol but that still doesn't guarantee a result. Just one caution, please don't try to turn the engine over by force. They can easily be damaged.
Gentle heat is probably what's required. Sometimes the engine can be heated by boiling it in a pot on the stove, or maybe even using a heat gun, but be careful not to overdo it or burn yourself. Don't use a torch and please don't use pliers to try to turn it by grabbing the front of the engine. Turn it by attaching the original flywheel, a propeller or even just a stick with a hole in the middle for the mounting screw.

Good luck.

Oldenginerod