All You Ever Wanted To Know About Timing Belts And Chains

The timing belt (also called a cam belt) or timing chain play a big part in your engine's valve timing. A timing belt or timing chain is what synchronizes all the engine's operations. It creates the timing intervals the engine runs from. Most modern gasoline and diesel-powered engines use a timing belt or a timing chain to accomplish this.

The Main Difference Between Timing Belts And Timing Chains

toyota Timing Belt

Whether an engine has a timing belt or a chain, the setup is the same. The belt or chain's rotation determines the engine's timing.

There are several differences between timing belts and timing chains. For instance:

  • The timing chain is slightly louder than a timing belt.
  • You can find the timing belt outside of the engine. The timing chain is on the inside, where it’s lubricated by the engine oil.

  • The timing chain has tensioners that are controlled by the engine oil pressure. The timing belt tensioner uses either springs or hydraulic pressure from engine oil to create pressure on the timing belt.

The main difference between a belt and a chain is its construction.

  • The timing belt is made of synthetic rubber, fiber cords, and other components.
  • A timing chain is made of metal and has a design very much like a bicycle chain.

Each design its own advantages and disadvantages. Many older Toyota models have timing belts. All newer Toyota models have timing chains. Toyota did away with timing belts for several good reasons.

Why Timing Chains Are More Reliable Than Timing Belts

Timing belts have a few disadvantages that timing chains do not. First, timing belts experience stretching over time and will wear out after 90,000 miles or so. Replacing a timing belt is not difficult for a mechanic, but it is time consuming. A car owner will typically pay more than $1000 to have the timing belt replaced. 

In contrast, timing chains are much stronger and more durable than timing belts. Timing chains typically last the life of the engine. The main disadvantage of timing chains is that they cost more to manufacture.

To sum it up, let's explore the pros and cons of each part.

The Pros And Cons Of Timing Chains

  • The timing chain has one distinct advantage over a timing belt: durability.
  • Timing chains rarely go out of service. There's no replacement interval or wear and tear under normal operations.
  • In most engines, the timing chain will last the lifetime of the engine itself.
  • Timing chains are expensive to build and install.

The Pros And Cons Of Timing Belts

  • Timing belts are fairly cheap to construct, lightweight and operate quietly.
  • They require regular replacement. They can fail if not properly cared for or installed.
  • Most vehicles require a timing belt change every 60,000 to 100,000 miles.

How The Timing Belt Or Chain Works

Timing belt timing chain

Timing belts and chains are designed differently, but they function the same way. The crankshaft powers the timing belt or chain. There's a pulley or gear at the front of the engine, mounted to the crankshaft.

From the crankshaft, the belt or chain extends upwards to the camshaft pulley(s) or gear(s). There's one pulley/gear if it is a single overhead, inline camshaft configuration. There's more than one pulley/gear if it is a V-style or multiple overhead camshaft configuration. Between the crank and camshafts, the belt or chain often powers other critical engine components. For example, the oil and/or fuel pump, depending on engine configuration. Often, the tightness of the chain or belt is regulated by a tensioner pulley as well. It's a small pulley that pushes or pulls on the chain/belt to provide the tension.

What The Timing Belt Or Chain Does

The timing belt or chain links the rotation of the crankshaft to the rotation of the camshaft(s). This, in turn, dictates when the valves open and close. The valves control the flow of fuel or exhaust into or out of the combustion chambers (cylinders). It is critical that the crankshaft and camshaft(s) be in perfect time for the engine to run at optimum.

How To Find Quality Replacement Timing Belts And Chains

It's pretty easy to replace the timing belt by yourself. There are plenty of model-specific tutorials available on the web. For example, here's a timing belt replacement tutorial for the Toyota Highlander.

But first, you need a replacement timing belt or chain. Quality matters a lot. OEM timing belts and chains are generally better than aftermarket ones. It's because they are designed to be the exact same size and type as the original equipment. Aftermarket timing belts generally cost less because they have a universal design. Like with many car parts, you get what you pay for. Aftermarket timing belts and chains rarely last as long as OEM ones.

OEM timing belts and chains tend to be more expensive than aftermarket ones, but not always. You can find pretty great deals online. For instance, we carry genuine OEM Toyota parts, including timing belts and chains, at deeply discounted parts. Check out our inventory of OEM Toyota timing belts and chains here!