hey guys, need your help

i have a 88 turbo, now the crank pully was vibrating something terrible. i got the clutch fan off, pulled off the belts, lossened the nut on the crank pully and it fell off. on closer examanation, i found that it took a good chunck off the crank and the pully . if i had drove the car, i think i would have snaped the crank. the motor i had in the car before this did just that. i want to know if this is a common problem or if i did somthing wrong. i did use the same crank pully. any help would be great.

first I've heard on a Z31, sounds like the pulley was either not installed all the the way or the woodruff key was left out, I know the Z32's had a problem with this early in production, and a lot fo the miata's had a similar problem where the crank snout would snap but the pulley bolt would retain it, it just allowed for the cas to dance back and forth casusing it run very poorly

hey guys, does anyone know where to get a new crankpully. i found a crank kit for 200, but no pully. nissan wants 400 for a new one....thanks

junkyard?