My buddy has I think an MT55 in an Ultimate biplane. Today the spark plug blew out of the cylinder and stripped the threads. Is there a fix for this short of buying a new cylinder? Can a heli-coil be installed sucessfully? Matt

Clarence Lee does them for glow engines. He likely could do them for a gasser. Or maybe just a well equipped auto engine rebuild shop. A friend blew out all four plugs from his Mazda GLC and had them fixed with Helicoils. If the plug was a 10mm, maybe the head could just be drilled and retapped for a 14mm plug, or a 14mm to 10mm plug adapter could be used.

Sincerely,

richard

what size is the plug? Local auto stores carry helicoil kits for most sizes

I do it all the time, easy as pie.