Crankshaft wobble & knocking noise while in Drive

[pajojama]

I have a 93 lwb 4.2 and it started knocking while n drive but in park there seems to be no knocking noise. i took the top part of the engine apart and the oil pan and saw a peice of the old piston that broke on the block. I got it off and cleaned it off. It was on piston 8 and i hear a rattling noise, do you know if this means. i checked the camshaft bearing and also the main bearing to the crankshaft and the seem to be fine. The crankshaft is wobbling when the truck is running but not loose when it seems like it will break. It has a new timing chain but the gears are the same, the woodkey is worn, replaced all 16 lifters but i dont know whats rattling?
Thanks Paul

[57loboy]

I have never seen that combination before - if your crank is walking out the front of the engine, you have big problems. The cam could walk if the button on the front got chewed, but again, that still equates to a new engine or rebuild if nothing structural is damaged.

[pajojama]

TY for replying. The crank isnt walking out that i can tell just the pully is wobble. if i take the front cover off and rest the camshaft do u think that would help. I also plan on looking at the key to make sure its not worn. Thats how my pulley broke about 2months ago and i had to replace the front cover the timing chain along with the crankshaft pulley.

[57loboy]

I'd check the integrity of the harmonic balancer and whether the threads in the crank snout are intact. If the key isn't the right size, you could have symtoms like this too...