engine knock when running m20 90 525i

i have a 1990 525i m20 engine. i have a terrible knock when the engine is running i checked in the cylinder head and no rocker arms are broken. i have the oil pan off right now and there is nothing in the oil pan that would lead me to anything. i pulled the screen out of the oil pump and found the remains of a rocker arm from my last cylinder head which must have got sucked up in there when it broke. i have no idea what could be wrong.. any ideas?

Connecting rod bolts loosened off, crankshaft out of round, a piece of metal filing inbetween the cylinder wall and piston ring...anything really.

Loose timing chain (shrug) ...good luck.

car doesnt make any noise when just cranking with coil not attached. only when coil is attached and car is firing is when the knock occurs. all spark plugs are good and compression is good in all cylinders so no detonation. any other ideas what can i check while i still have the oil pan off?

found my problem.. flywheel bolts are loose. i can wiggle the triangle looking plate. is there any way i can tighten them without pulling the motor fully out or tranny out?

Grinded down a tappet wrench and was able to fit right up in there to fix the problem. Thanks