A harmonic balancer (also called crank pulley damper, crankshaft damper, torsional damper, or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts. Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, wh...