4.2 LITER. Damper bolt. A Bolt which attaches the Timing Belt Tensioner pulley to it's mounting point. A threaded rod with a drive head (such as hex, 12 point, torx, etc) on one end used to secure the Drive Belt Tensioner Damper to it's mounting point. Engine Timing Belt Tensioner Bolt. Pulley. Damper. HEXAGON - HEAD.