After riding over a pothole engine got noisy and red sign no battery charge came on plus stop car, so I stopped and realized the alt belt is not turning.
removed right front wheel and liner and noticed the 30mm harmonic balancer nut is fallen below and the balancer now is rubbing to sheet metal in front of it,
As the four 10mm bolts on balancer where in place, it seem both balancer and sprocket behind it are shifted forward as nut fallen. The engine noise was
the balancer rubbing against side wall sheet metal.
I hammered balancer 4 corners over the 10mm bolts and it shifted back in, then I tighten the 30mm crankshaft nut over balancer again , place the
belt back on and all is fine after that.
1. Is this common? did it happen to anyone else? it seem if the metal side wall did not prevent the entire balancer plus sprocket fall away, engine
timing were to go bad and I could have had engine fail
2. What is the torque spec for the 30mm crankshaft nut?
3. Is the 30mm nut also the only thing holding the sprocket on crankshaft, how come the sprocket did not stay in place and shifted over half inch forward?
I am not expert on engine an do appreciate expert comments on above.
4. when both harmonic balancer and sprocket are seated as they should and 30mm hex nut is tighten, does the crankshaft end stick out of 30mm hex nut
and if so how much? as is on mine after hammering balancer in and tightening the 30mm nut the surface of the nut is flush with crankshaft end on mine, just
wondering if I hammered the balancer in enough or need to do more?

 

You should buy a lottery ticket - you are lucky - the timing belt did not have a problem /yet - it should be inspected very closely and the nut tightened. Make sure the serpentine belts are perfect (really just two short belts) If they get damaged and shred - the pieces can get caught under the timing belt with disastrous results.

Yes I have seen that before - when someone does not tighten that nut enough after doing a timing belt. I'm guessing your 14 year old car has had one by now.

 

That someone is me , changed timing belt, water pump . pulleys and their belts last Summer and I tighten the 30MM nut, guess it was not tight enough, I do have torque wrench
so if I find what the official torque spec is, I open again and make sure torqued to that.(Also bought a Lottery ticket as you suggested).

Found the Torque specs:
Center Nut (30mm) : 180 Nm that is 133 ft-lb
Four M10 bolts: 60 Nm that is 44 ft-lb

Will make sure they are all right this time