PART NUMBERS: 13811PY3000 & 13810PY3003Acura Legend Crankshaft Pulley Damper Harmonic BalancerFITS: 1991 1992 1993  1994  1995  ACURA LEGEND 3.2LTR ENGINEWHAT DOES IT DO?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, a device fitted to the free (accessory drive) end of the crankshaft of an internal combustion engine. It is essential in engines with long crankshafts  and is present on most engines as it reduces torsional vibrations that tend to peak at certain speeds. Torsional vibrations can greatly reduce crankshaft life, if not cause instantaneous failure, if the crankshaft runs at or through resonance. Because of this, dampers are designed with a specific weight and diameter to reduce mechanical Q factor, or damp, crankshaft resonances. Factory dampers are often re-sized in the same basic engine with any factory modification of crankshaft material, thickness, weight, or throw