Timing belt and timing chain

A vehicle’s engine is an assembly of numerous parts put together, accomplishing different tasks while staying synchronized to achieve an efficient and smooth result. Dividing those parts into three main engine elements:

·         The Cylinder head: Contains the spark plugs, the camshafts that are responsible of controlling the intake and exhaust valves, and have a direct relation with the fuel injectors. It is the upper part of the engine.

·         The Cylinder block: As the name shows, it contains the cylinders. It forms the middle sector of the engine

·         The Crankcase: carry the crankshaft that rotates around itself to move the piston rods up and down. It constitutes the bottom part of the engine.

*To be noted that the number of cylinder heads depends on the engine’s shape and how many cylinders it has.

Figure 1: The main parts of an internal combustion engine (Military.com, 2019)

To operate the engine, all those components must function with great harmony and high precision. To guarantee this, all those parts are connected with timing chains or belt. An engine with bad timing can cause huge mechanical damages to inner parts such as valves, pistons, roads and even the engine’s body generating major problems such as misfire, lack of power, stalling...

Timing chain vs Timing belt:

The timing chains and belt rotates on the camshaft and crankshaft pulleys. The timing chain is made of metal, used in the first decades of the internal combustion engines; it is located inside the engine and lubricated by the engine oil, lasts for a long time depending on many aspects of the engine.
However, the timing belts are cheaper and quieter than the timing chains. They are made of reinforced rubber, first used in the 1960s, placed outside of the engine, and lasts for a shorter time than timing chains. In general, it is recommended to change the timing belt every 90000 - 120000 Kilometres or every 7 years.

It is important to note that in the recent decade, the manufacturers brought back the timing chains into their engines with noticeable improvements in noise and vibration.

Figure 2 (Left): Internal combustion engine’s timing belt. (Sun Auto Service, 2019)

Figure 3 (Right): An internal combustion engine with timing chains (Sellén, 2019)

                                      

Conclusion:

The timing belt is a softer version of the timing chain that connects and makes sure that all the engine parts are working with high precision and harmony. A timing problem in an engine may causes big damages to its various components. Therefore, it is essential to maintain and change your vehicle’s timing belt/chain according to your vehicle’s service manual.

References:

• Military.com. (2019). Auto Repair: Major Engine Components. [online] Available at: https://www.military.com/off-duty/autos/auto-repair-major-engine-components.html
• Sun Auto Service. (2019). What Is The Difference Between A Timing Belt & A Timing Chain | Sun Auto Service. [online] Available at: https://www.sunautoservice.com/timing-belt-vs-timing-chain/
• Sellén, M. (2019). Timing chain vs. Timing belt: Which one is the best? - Mechanic Base. [online] Mechanic Base. Available at: https://mechanicbase.com/engine/timing-chain-vs-timing-belt-differences/