my fully rebuilt motor started to knock. went to check it out and i seen that the crank pulley had got loose. will this cause the motor to be off balance and knock. i'm praying that it's still good. help me out here.

 

using a long flathead stethiscope method (SP), try and locate where the sound is coming from. Is it coming from the pan or the valve cover. a loose crank pulley would make a vibration noise. why dont you fix it and see before you ask.