harmonic balancer ??? !!!!!

[Norbie]

Given that a 2JZ crank is about twice the length of a 4A crank, I'd say that's pretty likely.

[pilot]

The damper is there to stop these vibrations

It dampens, not stop vibrations.

Imagine that when one cylinder fires, the cranks accelerates, as there is rubber in the pulley, part of it "remains" in the original state absorving part of this energy. That´s the way it works.

Sorry if my english isn´t very accurate.

[takai]

Sorry if my english isn´t very accurate.

Makes more sense than some people on the forum.
And yes, you are right, that is torsional vibration dampening. Longditudinal (for want of a better word) vibration dampening is where the crank flexes and forms in effect a standing wave. The rubber will do a reasonable job of absorbing some of this.