Whatever you call it, that big chunk of metal hanging off the crankshaft snout of your engine is essential to your powerplant’s wellbeing and performance. Its job is to absorb harmonics, so from here-on-out we’ll refer to it as a harmonic damper (its only true proper name, we believe).
Why You Need a Harmonic Damper
The crankshaft buried deep inside the engine in your car isn’t a solid, immovable hunk of steel or iron. The crank twists and bends relative to the loads placed upon it by the respective pistons and rods on each throw. General Motor’s research has shown there is considerable crankshaft deflection in a race-prepped engine spinning at 8,000 rpm.
There is also resonance to consider. This occurs when the torque an engine makes on each combustion cycle “syncs” with the crankshaft’s natural vibration frequency. Without a proper harmonic damper to dissipate the torsional vibration caused by resonance and deflection, certain crank failure and other damage will occur, including: