Crankshaft Vibration Damper

Ford crankshaft vibration dampers (also known as harmonic balancers) are identified by basic part number 6316. A damper is a heavy, circular device mounted on the snout of the crankshaft to help balance the engine's reciprocating assembly. OEM dampers are constructed of a cast iron hub and a steel outer timing ring with a layer of vulcanized rubber between the hub and ring. The hub is keyed for proper location when mounting on a crank, ensuring that the timing marks present on the ring line up where they're supposed to be. The front of the hub has three mounting holes to secure the crankshaft pulley. The correct original color is semi-gloss black.

The 428 CJ and 428 SCJ used different dampers, each of which can be identified by the engineering number found on the hub. When compared side-by-side, the SCJ damper is obviously wider and thicker than the CJ damper. Thanks to Jim Kruse for letting me borrow his SCJ balancer for these pictures.

Front view of 428 SCJ damper (left) and 428 CJ damper (right)

Rear view of 428 SCJ damper (left) and 428 CJ damper (right)

Application Chart

The timing ring on the 428 CJ damper has timing marks from 10 degrees after top-dead center (ATC) to 30 degrees before top-dead center (BTC). The SCJ damper has timing marks from 10 degrees ATC to 46 degrees BTC. A letter-digit date code, such as "B8" for February 1968 or "K8" for October 1968, is present just to the right of the "BTC" mark.

If you have an original damper that you'd just hate to toss, know that they can be rebuilt and made better than new! See the registry forum (registration required) for details.

Images Provided by Members and Friends

Thanks to Bill Upham of Mansfield Restoration Parts for these images:

C8AE-A1 CJ engineering number detail
C8AE-A2 CJ engineering number detail

Thanks to Jim Kruse for the damper loan that allowed me to take this picture:

C8AE-C SCJ engineering number detail