3 Things to Know About Timing Belts vs. Chains If You're in Auto Repair Training

At the front of a car’s engine rests either a timing belt or a timing chain. They both serve to connect the crankshaft to the camshaft, making sure the valves and pistons of the engine stay in time to keep everything running. The crankshaft of the engine could be likened to the pedals of a bicycle, which turn the bike chain (timing belt or chain), which in turn rotates the back wheel (the camshaft). But while they fulfill the same purpose, there are differences between timing belts and chains that you will want to know if you’re interested in pursuing automotive service technician training.

Functions of Interest to Students in Auto Mechanic College

Without the belt or chain, an engine’s timing can be off, which means it can’t run properly to power the vehicle. As the pistons work with the intake and exhaust valves to take in fuel and air, compressing it for combustion with the spark plug, and finally pushing out exhaust gases, the timing belt or chain keeps everything on schedule. That means the crankshaft is able to change the up and down motion of the pistons and turn the camshaft to control the valves, by way of the belt or chain.
Of course, the valves must open and close at the perfect time to coordinate with the pistons, so timing is important.

The Difference Between Timing Belts and Chains

Learning about vehicle engines is a large part of auto mechanic college, where you prepare to work in a hands-on environment. As you might soon discover, timing belts are often made of reinforced rubber and are closed belts, while chains are actual metal chains. Belts are located outside of the engine, while chains are found on the inside where the engine’s oil can act as a lubricant. Before rubber technology made belts a possibility in the mid-60s, chains were the only option.
Timing belts make less noise and are less costly. However, as chains often last the lifetime of the vehicle and belts often do not, chains have become the preferred choice since the 90s. It’s rare that you’ll encounter an issue with a timing chain, as they are strong and durable. You may just see an oil leak from the cover over the chain, a result of an aging gasket.

Replacement of Belts and Chains for Students in Auto Repair Training

A big part of auto repair training is understanding problems that may arise and how they can best be addressed. When tackling this part of the car, you will need to check the owner’s manual to determine whether the car has a timing belt or timing chain. It’s not something that can be determined by simply looking, as this part is hidden from view. Some people are misled by the serpentine belt, which runs the alternator and air conditioning compressor. It is a rubber belt under the hood, but it is not a timing belt.

Maintenance is often not required on chains, but in very old vehicles, they may need to be replaced. In the case of timing belts, it’s important for them to be replaced before an issue is apparent. It’s difficult to examine the part for wear and tear, but if the belt breaks it can cause the pistons and valves to meet—which creates very expensive damage, possibly totalling the engine itself.
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