sounds like your cam chain tensioner failed.. timing may have jumped. The fact your cam chain is lose is a tell-tale sign the cct failed. Timing jumped a little, wont' run. Jumped a lot, the valves are all bent as the pistons hit them.
yes that's what's happening. the piston is hitting the valves.
if the timing is off 1 tooth it will turn over. I never tried it 2 teeth off.
cct=cam chain tensioner.
you will need to put the timing back in right before you can test the compression of the engine to see if you did in fact bend some valves. that is if the motor will turn over by hand with it in time.
you can pull the tensioner out to inspect it. there is also a pretty expensive guide in there as well. you should replace them both if you have to do one.
First, the tensioner is now garbage and needs to be replaced. That is the least of your worries. I don't think there is anything you can do now but pull the head and inspect the damage.
It's not clear weather you have been turning the engine by hand or with the starter, but a sudden stop and freezing is very bad news. Yes, it can still turn when the timing is off a little bit, but when the chain is freely skipping over teeth it will be likely to end up with pistons colliding with valves. At this point you may even have valves that are permanently open because they got bent or some other significant damage like that. You won't know how bad it is until you look inside.