When I had my auto repair shop I would occasionally get a car in for repair in which the harmonic balancer bolt was left loose on the crankshaft. These vehicles would have a destroyed crank and balancer where the pulley was pressed onto the crankshaft.
Proper repair was new crank and harmonic balancer. Needless to say the vehicles weren't worth the cost involved and in almost every case... the owners were scraping by week to week, barely paying their rent. A new or reman engine was a dream for these customers.
Long story short, I cleaned effected mating surfaces and loaded it up with J-B Weld.... Tightened the bolt securing the the balancer to crank and let it dry 48 hrs.
Of course, I informed the owners that this wasn't kosher and it's at best a patch. I also let them know that the engine crank was now welded to the balancer and they'd need a new motor. Forget about getting it off once I JB'd it.
I must have done 5 of these patches over the years.
I don't think a single one failed. One of these "repairs" was even on a diesel engine and the customer was still driving that car 4 years later. That's impressive because diesels put out incredible vibrations.
JB is impressive stuff.