The timing chain is responsible for engine control in the four-stroke internal combustion engine. In concrete terms this means: It connects the crankshaft with the camshaft in the cylinder head and thus drives it. The crankshaft rotates twice as fast as the camshaft, which in turn must open and close the intake and exhaust valves of the engine at the right time. The valves ensure the gas exchange from the fuel-air mixture to the exhaust gas. Intake valves allow the air-fuel mixture to enter the combustion chamber, where it ignites and burns. Exhaust valves let the exhaust gas out of the combustion chamber. The combination of crankshaft, timing chain, camshaft and valves creates the synchronous flow in the engine.
First of all, it can be said that both drive trains have the same task in engine control and can cause great damage in case of failure. A timing belt is inherently quieter and can achieve a higher speed due to its lower weight. It is also more flexible than a timing chain and does not need to be oiled. However, timing belts need to be serviced or replaced more often, as they are mostly made of plastic. The replacement intervals for timing belts are specified by the vehicle manufacturer.
Control chains are more resilient and can withstand high forces. They are virtually maintenance-free and only require regular oiling and retensioning. However, the chain drive makes the car more expensive in production. For this reason, many vehicle manufacturers opt for the timing belt instead of the timing chain. Both drive trains must be checked for wear and tear during inspection. The timing belt only shows optical changes, such as small cracks or breaks in the profile. The timing chain usually makes itself felt acoustically when problems occur.
An overview of the advantages and disadvantages of both drive trains for engine control:
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The timing chain therefore drives some units in and on the engine. If the chain breaks, however, the engine is in most cases dead. Lengthening of the chain set can also lead to engine damage, as the chain then jumps (skips) over the sprockets of the gear wheel. The result is that the valve timing is no longer correct, the engine does not run properly and can be seriously damaged when valves and pistons touch. Rattling noises from the engine compartment after starting or even while driving can be a sign of a worn timing chain and should be taken seriously. If there is any suspicion of damage to the chain drive, the engine must be switched off immediately and a workshop must be contacted!
A workshop can also rule out other causes for the noise, such as an insufficient oil supply or similar. Even though the majority of cars today are equipped with a timing belt, some manufacturers such as BMW and Mercedes-Benz continue to install timing chains in part or even exclusively. The reason for this is the higher load capacity of this drive train. It is therefore the first choice for vehicles with high performance.
All too often it is claimed that a timing chain lasts forever and does not need to be changed. This is not quite true. Often the change interval is between 100.000 - 400.000 km. You can find the exact intervals in your board manual. When buying a used car, you should also pay attention to what has been done with the timing chain in terms of maintenance. It is worth taking a look at the service booklet here.
Please note that the chain tensioner and guiding elements are also wearing parts and can also cause problems. In all cases, an inspection or replacement should only be carried out by experts.
If it should be necessary to replace the timing chain, there are large price differences depending on the motor. The timing chain set itself is generally inexpensive compared to the cost of labour. This is because access to the timing chain is usually very difficult and special tools are required for adjustment and tensioning.
The higher the quality of a timing chain, the longer its service life. For this reason it is worthwhile for the engine control to rely on brand quality. We carry timing chains from well-known manufacturers such as BGA, Febi Bilstein etc. As a special feature, you will also find ready-made sets in which the chain set and the corresponding wear parts are included together. Here you can really save money. If you have any further questions about our products, please do not hesitate to contact our customer service.