Chevy BBC 396 427 7.000" Internal Balanced Harmonic Damper Balancer SFI 18.1

Speedmaster Harmonic dampers are manufactured from forged K1045 low carbon steel and tuned elastomer between the two layers of steel. These dampers feature a bonding process which adheres the elastomer to the i.d. of the inertia ring and the o.d. of the hub, utilizing a strong adhesive along with an improved elastomer to create a much stronger bond. They also feature clear, white, easy-to-read timing marks against a painted black background. The steel inertia ring rotates harmonically with the engine and absorbs the torsion vibration from the rotating assembly at any frequency and RPM. It extends the life of crankshaft and bearing which allows the engine to produce more power and torque.

This damper is internal balanced; the term internal balanced damper refers to the lack of any built in weight or offset in the casting. When identifying your existing damper, (balancer) you must look on the backside. This is not visible if the damper is mounted on the engine. If your damper has no offset in the casting or weight, then you have an internal, (neutral) style damper. If you do see the offset in the casting or a weight, you have what is classified as an external damper. They are perfectly balanced, hence the term neutral.

All dampers are tested to withstand 15 tons press force without separation or deterioration.

What SFI 18.1 Certified Means
Section 18.1 refers to Crankshaft Hub Harmonic Dampers. Article 3.0 Construction, dictates that the damper shall be constructed in such a manner that the inertia devices shall not become disengaged during use For inertia disc style dampers, the containment device must cover a minimum of 50 percent of the cavity containing the disc. The thickness of the containment material must be a minimum of 0.062 inch steel or 0.180 inch aluminum.Article 5.1.3 B Testing Procedure mandates that The damper shall be driven to a rotational speed between 12,500 and 13,500 rpm and maintained at that level for one hour. Furthermore, the steel of a SFI certified Fluidampr housing must meet a minimum 40,000psi yield strength and 60,000psi tensile strength under testing.