Cracked flywheel

[cgmg]

Checked the timing on my 503, and it needed adjustment. Could not get the fan pulley to come off the flywheel, so ended up pulling them both off at the same time.

Once we got the flywheel off, I found the problem. The flywheel was cracked from the keyway all the way out on the inner ring. That ring had expanded enough to wedge itself into the fan pulley, preventing it's removal.

Got extremely lucky and found a replacement on Ebay for 1/3 the cost of a new one, the same day.

My question, has anyone else had this happen to their flywheel? When we changed the points last time, we used a torque wrench to tighten the flywheel nut, so I am hesitant to think we over-tightened the flywheel. Any other possibilities, or am I just seeing the result of metal fatigue?

Thanks,

Mark