ok here it is...i have a 92 318i with the m42 4 cylinder motor the car was running great other then a leaking head gasket. i changed the head gasket made sure everything was top dead center. put everything back together but when i put the chain back on i believe i screwed something up (maybe), anyways...i finished putting everything back together and went to start the car and it is very loud. this happened before but not as bad when my camshaft pulley was loose. so ive taken everything off and tried to time it again and made sure everything is lined up and it is still making the same noise and the plugs are fouled (black). could it be the hyrdraulic tensioner that has to build up before it smoothens out? although that won't help the fouled plugs... PLEASE HELP!!!