Classic/Antique Car Repair: Packard 120 vibration damper, vibration damper, center bolt

Question
Hi Brad
I have a 1938 Packard 120 (282cu in) and was wanting to know how can you tell when the crankshaft vibration damper is no longer doing it's job.  The engine has developed a vibration at mid-throttle onwards and is slowly getting worse.  The vibration occurs when driving and free revving out of gear.

Answer
The only test that I know of a visual test once the damper is off the car. Make sure that the rubber has not dried out and is coming apart. Make sure that the rivet holding it together are tight and not loose. And make sure that it fits the crankshaft snugly and that the center bolt was not loose.