Been there, done that.... within the first month i had mine, 83mod 3.o engine... Got a paper cloth in between the belt and pully, belt broke, inastalled a new one, ccw'd the engine, tensioner collapsed... Had a terrible rattling noise at 1200-1500 rpms. Dropped the engine 10 inches without loosing the transmission mount, narrow workspace, but accesable.
Here you can see that the tensioner has collapsed.
Here is the slack in the chain.
I was lucky that the chain didnt jump a tooth and ruin my engine. Had a top end overhaul when i got the car, so that would hurt. Easy fix if its the same problem.
Reading the other posts, maybe its possible for the chain to jam between something and lock the engine.
Espen
