One poster suggested that nothing firewall forward is rated to take the weight of the airplane while rolling it from teh front yard to the back yard on the rotisserie.  This is actually not correct.  The engine mount and firewall should be sized for the weight of the engine at the maximum G limits of the airplane, acting at the CG of the engine/prop.  I would not be worried about the bending moment on the engine mount or firewall, but I would have to run the numbers to make sure.

 

On the other hand, putting a huge bending/shear load into the crankshaft scares the crap out of me.  Call the engineering department of your engine manufacturer and tell them what you propose and ask what they think.  When they regain consciousness they will probably have many colorful words to suggest that it's a bad idea.  However, I'm just speculating since I have not run thse numbers either.

 

I appreciate your plight, but it would be better to find another way.

 

- Rob Wolf