3-25. CRANKSHAFT PULLEY AND VIBRATION DAMPER - MAINTENANCE
a. The engine is equipped with either rigid or rubber mounted type pulleys. Rubber mounted pulleys
have a rubber insulator between the pulley and the pulley hub for vibration dampening.
b. The crankshaft pulley is keyed to the crankshaft and secured with a special washer and bolt.
A viscous type vibration damper is mounted on the front end of the crankshaft to reduce
crankshaft stresses to a safe value. The vibration damper is bolted to a hub which is on the front
end of the crankshaft.
d. A viscous type vibration damper consists of an inertia mass (flywheel) enclosed in a fluid-tight
outer case but separated by a thin wall of viscous liquid not responsive to temperature changes.
Any movement of the inertia mass, is resisted by the friction of the fluid, which tends to dampen
excessive torsion vibrations in the crankshaft. The vibration damper must be removed
whenever the crank-shaft, crankshaft front oil seal, and crankshaft front cover is removed.