STUCK CYLINDER SOLUTIONS
Here are some links to products that may help: Aerokroil Gibbs
Muriatic acid and 50/50 mix of ATF & acetone have been used successfully, and/or you may prefer John Aylor's method:
Note: 750 requires 3/4 tap
This works pretty good for ones that are stuck real bad. Tap the stud holes with a bottoming tap. 3/4" fine works good on h2.
dill and tap 3/4" bolt with a 3/8" fine. Use at least two of the tools, but use of all 4 holes will get an even pull.
Sometimes a bit of heat really helps, too.
Here is another approach, especially good when the piston
rings are seized to the cylinder: