Harmonic Balancers

Many harmonic balancers, also known as vibration dampers or torsional dampers, have V-grooves on their circumference to engage the accessory drive belt, but this component is far more than just a pulley. As the name implies, the harmonic balancer helps to balance the engine, and some balancers have weights that work with the crankshaft counterweights to offset the weight of the piston and connecting rod assemblies. The balancer also dampens the torsional distortion and vibration in the crankshaft that is created by the combustion process, which could break the crankshaft if not otherwise dissipated.

The typical harmonic balancer consists of a metal hub that mounts to the crankshaft snout, with a thick metal inertia ring surrounding its circumference, separated by a rubber ring. The rubber flexes, allowing the inertia ring to counteract the crankshaft’s twisting motion. With a functioning harmonic balancer, your engine will operate smoothly and reliably. However, age and the environment can conspire to diminish the balancer’s effectiveness. Heat and exposure to road salt and fluids like oil can cause the rubber to soften and deteriorate. In some cases the rubber can harden and crack and lose its flexibility.

Regardless of whether the rubber softens or hardens, the harmonic balancer will no longer be able to function as designed, possibly leading to excessive vibration and crankshaft damage. Our replacement harmonic balancers are the solution. They’re made of superior materials for increased durability, and many come complete with a new crankshaft Woodruff key, for a complete repair. And since exposure to oil is often the cause of harmonic balancer failure, a front crankshaft seal oil leak should not be ignored. If your leak has been caused by a hardened seal and grooved harmonic balancer hub, we have repair sleeves that will create an effective sealing surface, and replacement seals to make your engine oil tight.

Unfortunately, standard original equipment harmonic balancers are only designed to dampen torsional vibration at magnitudes and frequencies common to an engine in the original factory state of tune. Typical modifications made to an engine to increase horsepower output can increase vibration and/or change the RPMs where it is most critical, in which case the OE balancer will leave the engine virtually unprotected. In contrast, we offer performance harmonic balancers that will protect your heavily modified engine at all RPMs.

Our performance harmonic balancers are available for most popular engines. They will eliminate the vibration that could destroy your expensive crankshaft and other components. We have balancers that are of traditional construction, viscous fluid balancers, and multi-piece balancers that are tunable and rebuildable. All have been tested to ensure safety at extreme RPMs, and meet or exceed SFI 18.1 specifications, which is a requirement for most racing organizations. Most also feature 360 degree timing marks, to facilitate engine tuning.