Timing Gear or Chain and Sprocket Noise

Engines designed with timing gears, or those equipped with a timing chain and sprockets, can produce different noise. The most common noise is a high frequency, light-knocking sound. This sound will generally be the same in intensity whether the engine is idling, operating at high speeds, or under load. The following are causes of timing gear or chain and sprocket noise:
^ Worn timing chain and/or gears
^ Misaligned gears
^ Excessive backlash
^ A damaged tooth
^ Gear or sprocket loose on the shaft
^ Too much end play in the camshaft or crankshaft
Loose or improperly seated camshaft timing gears are usually loudest when warm. They are speed sensitive only. They are not load sensitive. Cam gear noise will usually be evident at a warm idle in neutral and sounds much like a loose timing chain noise.