I have seen guys damage the threads using normal bolts due to the bolts not being wound in to the same length
Well, that or some dumbazz following the previous's dumb azz's lead'n tryin' to thread a coarse thread bolt into a fine thread hole. It'll only go so far ... Oh well that's why God invented taps'n thread chasers?
Tbh I've had purty good luck popping the flywheel(s) off with my slide hammer/dent puller.
CAUTION! Remove nut on crankshaft before attempting to remove flywheel ...