I know what it does by definition, but how does it work? What would happen if just a regular pulley was in its place?

I know what it does by definition, but how does it work? What would happen if just a regular pulley was in its place?

The Harmonic Balancer is a steel center, bolted to the crankshaft, surrounded by a rubber element, which has a steel ring around it. Its purpose is as follows; as the crankshaft is pushed by the connecting rods, some bending occurs, and as a result it tends to oscillate; these oscillations can cause fatigue and failure, so the harmonic balancer absorbs them by dissipating vibrations in the rubber element.
If you were to place a solid pulley in its place vibrations in the crankshaft would not be dissipated and the fatigue life of the crankshaft would be dramatically reduced. You would probably also hear a lot more noise coming from the engine.

The Harmonic Balancer is a steel center, bolted to the crankshaft, surrounded by a rubber element, which has a steel ring around it. Its purpose is as follows; as the crankshaft is pushed by the connecting rods, some bending occurs, and as a result it tends to oscillate; these oscillations can cause fatigue and failure, so the harmonic balancer absorbs them by dissipating vibrations in the rubber element.
If you were to place a solid pulley in its place vibrations in the crankshaft would not be dissipated and the fatigue life of the crankshaft would be dramatically reduced. You would probably also hear a lot more noise coming from the engine.

Powerlabs, would that additional vibrations trigger off any sensors in the car?

Powerlabs, would that additional vibrations trigger off any sensors in the car?

Unlikely. The only sensor that could sense vibrations would be the knock sensor, and that sensor uses noise filtering to detect only the frequencies specifically associated with knock.

The Harmonic Balancer is a steel center, bolted to the crankshaft, surrounded by a rubber element, which has a steel ring around it. Its purpose is as follows; as the crankshaft is pushed by the connecting rods, some bending occurs, and as a result it tends to oscillate; these oscillations can cause fatigue and failure, so the harmonic balancer absorbs them by dissipating vibrations in the rubber element.
If you were to place a solid pulley in its place vibrations in the crankshaft would not be dissipated and the fatigue life of the crankshaft would be dramatically reduced. You would probably also hear a lot more noise coming from the engine.

:goodpost: Powerlab, great post!

Here is what Wikipedia had to offer also:

"Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in synch with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance causes stress beyond what the crankshaft can withstand, resulting in crankshaft failure.

To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber/clutch/fluid) element absorbs the vibrations.

Additionally the energy transferred from the piston to the crankshaft can induce as much as 2 degrees of twist in the crankshaft, which has many follow-on effects on all engine elements that require adequate timing such as valve opening, cam timing, ignition timing etc.

Over time, the energy dissipating (rubber/clutch/fluid) element can deteriorate from age, heat, cold, or exposure to oil or chemicals. Unless rebuilt or replaced, this can cause the crankshaft to develop cracks, resulting in crankshaft failure.

Performance enthusiasts have been known to remove harmonic balancers, usually when the balancer is attached to the crank pulley, deciding that they aren't necessary and their mass reduces the performance of the engine. However, this is unproven and potentially very risky because the danger of damage to the engine from the vibrations the damper is intended to prevent is too high.

Certain cars, however, do not come equipped with an external balancer on the crank pulley, and as such, can have the pulley replaced with a performance oriented product which counter-act these resonance frequencies."