Too many possibilities ... a blown head gasket could have this effect - but knowing what the noises actually were would help, too. Combustion pressure in the water jacket will sound like a snall pistol being shot in a well. (OK ... I tried! )
"Slipped" timing chain is not likely. Cracked head or block would more than likely have drained the water and overheated the engine. I'll put my wager on head gasket. What color was the exhaust smoke? White? Or black?
)
