These are not the pulleys pictured by nippymog - his problem is with a camshaft pulley. The problem with the crankshaft pulley is the retaining bolt has the wrong hand thread on it and as soon as it loosens the engine rotation causes it to unwind and like a screw jack, it burst the front cover. The offered solution is a screw with a bigger head so that it can be tightened more, together with liberal amounts of glue (loctite) in the hopes that it will not happen again - we hope! Some positive locking device would be more appropriate.
