reason. Premature valve spring failure, extremely short timing chain life, continually loose oil pan bolts and erratic ignition timing are all indicators that a damper isn't damping.

Stock Dampers
     There's really nothing wrong with a stock vibration damper-- except that it's designed for the operating conditions of a typical passenger car engine- conditions that rarely include rotational excursions to the Twilight Zone that exists on the other side of 4000 rpm. At higher engine speeds, stock dampers have been known to fracture and ultimately explode. (That's precisely the reason many racing associations require use of an SFI-approved vibration damper). While such occurrences are rare, they do happen. Cast iron flywheels have the same tendency to self-destruct, which gave rise to regulations that forbid their use on race engines. With stock dampers, the inertia ring is constructed of cast iron, hence the concern. Although acceptable for low rpm applications (where a change in materials would do little besides increase costs), cast iron has a nasty habit of fracturing when repeatedly subjected to the high levels of centrifugal force generated by elevated engine speeds. Once the ring begins fracturing, pieces break off and are hurled outward and if they're spinning at high rpm, they hit like a blast from Dirty Harry's favorite handgun. A half-pound of iron on the outer ring of an 8" damper generates a force of 2779 pounds when spun at 7000 rpm. (Just as a point of interest, at 9000 rpm, the force generated by eight ounces of iron is 4593 pounds). Although the probability of a stock inertia ring fracturing is remote, it's not out of the question–especially if it has been smacked a few times with a hammer.
     Another weak point of a stock damper is the elastomer strip between the hub and inertia ring. This strip functions in the manner of a tightly wound spring. Vibrations are