02 Civic si (ep3)
not even sure how to call this phenomenon but the crank pulley/harmonic balancer(whatever you want to call it) pretty much demolished itself is the best way I would describe it. Im completely unsure what caused it but have ideas, seeing a lot of things about the plates being worn down and maybe its sitting too close to the timing cover but upon removal i saw little to no rubbing, it does seem to sit close to it but not enough to completely remove almost an inch of it's diameter. I assumed my compressor was the problem because I heard squealing here and there for a while and would see rubber shavings in the engine compartment(i assumed from the failed bushing in the compressor pulley was rubbing the belt away) i didnt look too closely because i had done the belt and tensioner a while back and noticed how close the crank pulley sat against the timing cover but made sure there was enough clearance and assumed there were no issues.
Now honestly it could just be because it was still the oem pulley, and the car has 182k so maybe it just got old and rubbed itself away. Havent had the car long so i havent done much preventative maintenance but after my battery light came on and i pulled off the freeway to see my car smoking and then find my belt missing I'm just trying to rule out any possible causes so that doesn't happen again. thankfully i stopped driving immediately and didnt kill the battery or overheat the car, no coolant leaks visible as of now so i should be good. any ideas or suggestions would be appreciated.

pictures below, but like i said it may have just been old asf, maybe it was a wrong part cause it does seem smaller, who knows. Im not too sure about anything the last owner has done to this car but its been fine up until this point..

 

The rubber dampening ring failed and the outer steel ring either broke apart or fell off. It happens. Buy another crank pulley, install it and you will be fine.