The damper’s rubber ring will naturally decay with age, mileage, exposure to hot chemicals, vibration, ozone, and ultra-violet light, and become unsuitable for even a stock engine, let alone high performance or racing use.
Visible signs of damage and potential failure include:
» the rubber is partially missing
» the rubber is discolored gray or “chalky”
» the rubber has surface cracking
» the rubber has been partially extruded
» the damper rim is dented or bent
» the damper is loose on its hub or on the crankshaft nose
» the damper rim has excessive run-out (“wobble”)
» a “squeaking” noise that defies detection