All vehicles on the road today have either a timing belt, or a timing chain assembly.

The timing belt or chain rotates the engine’s cam and crankshaft in sync so the cylinders fire at the right time. It controls the action of the pistons and valves inside the engine cylinders to ensure the valves open in synchronized time with the pistons. The combustion process of a modern four-stroke engine has four “strokes” or steps: intake, compression, combustion, and exhaust. Throughout an engine’s four-stroke process, the camshaft rotates once and the crankshaft rotates twice. The rotational relationship between the camshaft and crankshaft is called “mechanical timing.” It’s what controls the combustion cycle –pistons and valves moving in sync within the engine cylinders. The valves have to open at a precise time in conjunction with the pistons, and if they don’t, the engine won’t work properly, if at all. If this timing is off, the engine will run unreliably, or might not run at all.

We created the JE Performance Essential® Timing Belt or Chain Service, just for you.

Higher torque engines that do a lot of heavy work, such as towing, are usually equipped with timing chains. Trucks, utility, and heavy-duty vehicles are usually equipped with timing chains, as their engines are regularly subjected to higher stress and have to deliver more power and torque on a consistent basis. Rubber timing belts are found in the majority of small cars and SUVs, particularly 4 cylinder engines that have lower torque. But more and more modern cars are being manufactured with timing chains purely for the durability, and ease or elimination of maintenance or replacement.

To identify which your vehicle might have you can look in your owners manual, or contact us and we can help you determine which engine design you have.

Timing Chain Engines:

• A timing chain looks much like a bicycle chain. Metal chains serve the same purpose as belts, but last longer. Some manufacturers recommend changing the chain at certain intervals, but those intervals are longer than for rubber timing belts. Though it might seem hard to believe, some manufacturers say that the chain doesn’t even have to be replaced and will last as long as the lifetime of the vehicle. Chains do stretch, however, and should be checked to ensure tension is set properly and the chain is not stretching. If you have to change the timing chain due to stretch or any other damage, it is necessary to also replace the timing gears, as the teeth on the sprockets will have worn to match the stretch of the chain.

Timing Belt Engines:

• Rubber belts are easier to replace and usually come in a package that includes a new water pump (the water pump is usually the same age as the belt and will wear out at the same time). Replacement intervals for rubber timing belts vary from 60,000 to 100,000 miles. How long a timing belt lasts depends on a number of factors, such as the type and quality of materials used in manufacturing, driving habits and environment, miles driven, engine temperatures, and exposure to dirt and contaminants. When a timing belt fails, the risk of damage is similar to a timing chain breaking – pistons, valves, and cylinders can be severely damaged, as well as other engine parts. At worst, the engine has to be replaced, or you buy a new car.

Timing belts and chains are susceptible to the same forces and suffer the same stresses. Either one can break when the tension is greatest – at startup or shutdown of the engine, or at acceleration or deceleration. For rubber timing belts and non-interference type engines, you can usually just install a timing belt kit to maintain the system.

If you have an interference engine, there is going to be some damage no matter at what point in the engine’s operation the belt breaks. How bad that damage is will depend on the engine speed at the time the belt snaps. If it breaks at startup or shutdown, there will probably be some bent or broken valves and valve guides. If the belt breaks while you’re speeding down the highway at high rpm, then there will be more catastrophic damage – valves will shatter and bounce around inside the cylinders, bending the connecting rods and destroying the pistons. As the pistons and rods disintegrate, the damage will expand to the oil pan, the engine block, and other parts of the engine, basically cutting holes throughout the other systems. This sounds bad, and it is, because damage of this magnitude can’t generally be repaired and needs replacement.

This answer varies drastically, as all vehicle’s timing components are different in level of complexity for labor, and the overall part cost.

Smaller 4 cylinder engines can be as inexpensive as a couple hundred dollars. Larger, more complex engine can be $1,000 or above, again depending on complexity and labor required to do the service.

We are more than happy to help you research any information you may need about your vehicles’ timing components, and also build you an estimate at any time.