Getz 1.1 – crankshaft gear wheel loose

Hello, my sister’s car has a problem with the crankshaft. As I understand it is the gear wheel, which sits on the crankshaft loosely or the screw is knocked out and thus the ignition time or the valves and the car has no more power. Now I have tried the Internet a bit and also found some forum entries for it. My question, can someone explain to me exactly what the problem is or send pictures? Is there by Hyndai The problem only seems to concern the Getz 1.1 and the Atos? Would be really great if someone could help us, because 1500€ for the Rep. is not very little. Thank you!!!!!