The transmission system is a set of parts that works by making sure that the right amount of power created by the engine is transferred to the driving wheels, so that the vehicle can move; In other words, it is the instrument in charge of transforming thermal energy into mechanical energy, so that movement occurs.

Practically 100% of internal combustion engines in any vehicle are equipped with a timing belt or timing chain system.

In today’s article we know the particularities of those systems, the main differences of the chain and the belt, and we also talk about the auxiliary drive system, increasingly complex and in demand.



Timing chain or timing belt drive


It is possible to differentiate distribution systems depending on several factors such as the position of the camshaft and the valves (SV, OHV or OHC), according to the valve actuation or the most well-known classification that is given by the distribution control, that is: distribution by belt or distribution by chain.

Among the main functions of the timing distribution are:

  • Synchronize that engine timings are running at exact precision.
  • Make the transmission valve work as it should. As speed is gained, all parts must speed up accordingly for the engine to exert potential.
  • Starting up the vehicle’s engine.

Such is its importance within the engine gear that its malfunction can even affect the water pump or lead to a critical breakdown for the vehicle’s engine.


Timing Belt


The timing belt consists of an internal toothed part that allows the transmission of mechanical energy between a drive gear (the pinion) and another driven pinion. It is a silent transmission and requires rigorous maintenance due to being an element prone to wear.

Contrary to what happens with the chain, in this type of distribution there is no lubrication, so it is not necessary for it to be so hermetic. When the distribution is carried out by chain, this system is lubricated with oil.


Timing Chain


For its part, chain is made of links, like a bicycle chain, although more complex and robust. Among its great advantages is that it does not require regular maintenance. However, it makes more noise than the timing belt and is prone to slack, directly affecting engine performance.



Related content: All you need to know about Dolz kits



Auxiliary drive system


On the other hand, we also find the auxiliary belt transmission. An auxiliary drive system designed to transmit the power of the engine to the different auxiliary groups, some of them of vital importance such as the alternator, the power steering, or the water pump.

This need arises because current vehicles incorporate more and more electronic equipment to increase driving comfort, and these are activated through this system. Which has led to a considerable increase in the amount of torque to be transferred.

This function used to be performed by the V-ribbed belt but is no longer sufficient to drive the high output alternator and other front end accessories. 



Dolz, premium brand 


About us

With over 90-year history, Industrias Dolz is a European leader in manufacturing water pumps. In addition, we also supply timing chain kits, timing belt kits and thermostats in the spare parts industry for the aftermarket.

We have three factories in Spain (Castellón), Argentina (Buenos Aires) and China (Shouzou) and we have delegations in Argentina, Mexico, China, Poland, and Spain marketing our products in more than 70 countries around the world.


Range of Timing Distribution Kits

With a wide range made up of more than 250 references, Dolz Kits cover more than 90% of vehicle applications in the European market. 

Each kit contains everything necessary for a professional assembly and meet all OE quality standards.

Are you looking for a partner with experience in the aftermarket? Our combination of innovative technologies, industry 4.0 techniques and our in-house production, advocates for a multi-product structure, trusted renowned and qualified by the ISO quality standard.

Contact us for further information on our product range!

…yes we have!


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