I blew the head gasket and have removed the head which is currently being rebuilt. I want to remove the carbon build up on the pistons. I have cylinder 1 at TDC and #6 is at the top too. I want to clean up the others, but I need to know if it is OK to turn the engine so the other pistons get to the top so I can clean. My worry is that with the timing chain loose if I turn the engine will it cause a major problem?