Thread: Crank pulleys/ Harmonic balancers 351W

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Sensing that you don't have a large inventory of shop tools (like a bench-mounted motor with a wire wheel on it), go down to AutoZone or Checker or whatever and purchase a wire wheel to mount up in your 1/4" or 3/8" drill motor. I think they have a 2" and a 3" diameter wheel. Wire brush all the crud off the pulley and give it a fresh coat of gloss black paint.

If they have an eccentric weight of some kind either cast into them or bolted on, then they are called a balancer/damper. If there is no eccentric weight on them, then they are correctly called a damper. Their function is to dampen harmonics that are set up in the crankshaft when the piston fires and sends a shock down through the rod to the crank. If these little vibrations, or harmonics, are not cancelled in some way, they will crack the crankshaft and the game is over.

There are 3 parts to them. The inner hub that press fits onto the snout of the crank, the elastomeric material in the middle and the outer inertia ring. In the presence of ozone from the atmosphere, oil, grease and other contaminants, the integrity of the elastomeric material can degrade to the point that the inertia ring can slip circumferentially in relation to the hub. This will render the damper incapable of showing a valid top dead center location on the inertia ring, so the motor can no longer be timed with a light. You must either rebuild or replace the damper at that point or bolt on one of those covers that the aftermarket makes that is degreed in relation to the hub. A bolt-on cover still does not fix the slippage problem, but it will allow you to time the motor with a light.

These guys do a fine job of rebuilding OEM dampers....
http://www.damperdoctor.com/