Why Some Cars Use A Timing Chain Vs. A Timing Belt

Why do some engines use a timing chain vs. a timing belt or timing gear? Each has its strengths and weaknesses, and automakers and engine builders balance these.

· Timing belts are light and quiet, but they don’t last very long, relatively speaking. Because they’re rubber-based, they degrade over time and must be replaced. Oil and coolant leaks speed up this deterioration. Most automakers recommend replacing the timing belt every 60,000 to 105,000 miles.

· Timing chains are heavier and more complex than timing belts, but they also last much longer. Really, unless there’s a problem, timing chains don’t have a replacement interval. Regular oil changes prevent premature wear, stretching, and failure.

· Timing gears are the heaviest and noisiest, with a distinctive whine some liken to a supercharger. Like timing chains, timing gears are strong, accurate and last a long time.

At first, automakers used timing chains and timing gears because that was all that was available. Later, timing belts came around and were found to be quieter, but problematic. Broken timing belts have damaged many interference engines due to valve crash.

Interference designs help engines breathe better by improving engine efficiency, power, fuel economy and emissions. More recently, automakers have been moving back to stronger and longer-lasting timing chains to prevent premature failure and valve crash.