Why would the pulley to the block of a car not be moving?

clear as mud

pullies are normally attached to an engines crank either by being directly bolted to the nose of the crank which has a taper machined into it and is retained by the pressure exerted by the attaching bolt which screws into the nose of the crank. The other method is to fit the pulley over the crank nose which has a valley or keyway machined along about an inch or so along the length of the nose and then place the pully onto the crank nose and line up a corresponding machined keyway in the pully and insert a metal key into the space created by the keyways. pullies will remain stationary if a key fails or is sheared,or if the pully bolt has fallen out and the pully has become loose on a tapered crank or the other cause is when the rubber dampener which circles the mid section of the pulley perishes thru from contamination by fuel and oil etc the crank continues to rotate with affecting the pulley. so there,it is ,clear as mud. razmo

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