Sounds like the cam belt just by what you have described. Some engine have what you call run free which means when the belt snaps the different parts of the engine don't contact and it can save the valves and pistons but not sure on these ones.
Like said earlier you need to remove the cam belt cover and see if it has snapped.
It's not too bad if it has at least you can get the head ported and polished/gas flowed and put a stronger head gasket on and even change the cam any valves whilst you have it all off to increase the performance.
Sounds like a good idea to use uprated parts and moddify while it's all in pieces cause it won't be much if and dearer than the parts you will have to use anyway.
Like said earlier you need to remove the cam belt cover and see if it has snapped.
It's not too bad if it has at least you can get the head ported and polished/gas flowed and put a stronger head gasket on and even change the cam any valves whilst you have it all off to increase the performance.
Sounds like a good idea to use uprated parts and moddify while it's all in pieces cause it won't be much if and dearer than the parts you will have to use anyway.