Loud noise from motor

Hi all i just had a major problem with my tercel it was driving fine and than died one day after work when i started it it sounded fine but i little tapping in the front somewere. well it died again well when i started it agian there was a loud knocking-grinding noise so i shut it off and went and looked under the hood to check it out well i took off the oil cap and smoke was coming out of it so i shecked it and was a little low not to bad so i put a half a quart in it and tried to start it again well the noise is still there like by the valves if anyone could help it would be appreciated. Sorry its so long.

91 toy.

Hey,

Sounds like a bad rod bearing "rod knock". Ive seen rods go right through the block on these engines. Ive also read of a few going bad, so I guess these engines are notorious for it. So ya its time to rebuild or swap. Especially if the knock increases with rpm.