Timing belt

La Timing belt It is the element that transmits the circular movement of the crankshaft to the camshaft(s) (camshafts), through which the intake and exhaust valves are actuated. Some timing belts also drive other parts of the engine such as the water pump or mechanical fuel injection pumps.

being so many connected elements by the timing belt these must be perfectly in sync, the intake and exhaust valves must be actuated at the right time, in the same way that the (mechanical) fuel injection must also work in time with the other elements.

This synchronization is called fine-tuning of distribution, phasing or timing of the distribution. Each moving element driven by the belt has to be at a certain point before placing it, so that in this way all the elements of the engine can work without interfering with each other. A poor timing belt can lead to a loss of performance if the offset is small. If this is large, it is likely that the valves and pistons could collide, causing serious internal damage to the engine, which according to the car will not be worth repairing.

There are the so-called non-interference motors, in which the valves and pistons would not collide and where the breakage of the belt would have no more consequences than a new timing of the distribution.

Timing belts have two sides. The internal is toothed and is the one that drags the elements They have to be perfectly synchronized. The external one is smooth and the tensioning rollers are supported on this face, which make the belt stay in place, and other elements such as the water pump, which do not have to rotate in absolute synchrony.

The timing belt is an element of Preventive Maintenance more, although their changes take longer and are one of the most expensive maintenance operations on the car. The time or mileage for change timing belt is determined by the manufacturer and ranges from 90.000 and 160.000 kilometers about. Respecting the time (without the need to reach the mileage) is important to avoid breakage of the strap, which deteriorates over time.

There are a number of conditions that make it advisable to pay more attention to the condition of the timing belts and change them ahead of time if necessary. Those who make many short trips and in the city, for example, must take extreme precautions, as well as those who live in extreme climates (because of cold or heat) or who park the car on the street or move in very dusty environments, rains or with mud.

With a visual inspection of the belt we can detect problems. If it shows cracks, obvious discoloration, detachment, slight breakage or marked wear, it is advisable to change it to avoid greater evils. In the same way, if we buy a car and we are not sure of the maintenance that has been carried out on it, it is advisable to change the strap, as well as fluids and filters, to ensure proper maintenance of the vehicle.

When changing the timing belt, it is important to spare no expense and replace all peripherals. Thus, we will have to change all the tensioners and the water pump if it is driven by the belt. It is also advisable to replace the camshaft and crankshaft seals to avoid possible leaks due to their deterioration in the future. In the case of having counter-rotating shafts (used to balance the motor and reduce vibrations), it is also necessary to change their drive belts (if they are independent) and the necessary bearings.

Skimping on these elements may mean that some present defects a posteriori, which would imply repay the cost of all labor, which is the most expensive part of a timing belt replacement.

The cost of a timing belt change is very variable depending on the vehicle and the necessary spare parts, but it is normal for it to range between the 250 and 600 euros.

Removing and installing the timing belt is a complex task and that it is advisable that it be carried out by specialized staff. It requires some technical knowledge and proper tools. Not following the steps properly can lead to breakdowns and breakages that can easily reach four figures.

List of cars without a timing belt

There are many brands that have abandoned the use of Timing belt in favor of chain for some of their models. However, not all have been carried away by the benefits of this last element to the same extent, often by extra costs that it supposes or by the noises that it generates.

However, there are brands that traditionally use the distribution chain a lot for a matter of prestige or to give your engines a plus of reliability and reduce the wear items. This is the case, for example, of Infinity, Nissan's luxury brand, which manufactures all your models with timing chain. BMW, Kia-Hyundai, Mazda, Mercedes, Nissan or the brands of the Volkswagen group also use it in many of their vehicles.

Cars without chain or timing belt

In addition to the chain, there are other systems that allow the timing belt to be eliminated. For example, the FreeValve technology from Koenigsegg directly removes the camshaft, so does not require a strap or chain to synchronize it with the crankshaft. An electronic system activates the valves and controls their operation to reduce consumption or maximize performance depending on what is needed at all times.

The Free Valve system has been adopted by one of the Chinese brands What has been the most push in recent years? Qoros. At the end of 2016 this brand presented its qamfree motors with the Koenigsegg system at the Guangzhou Motor Show.

The supplier and manufacturer of components for vehicles Valeo also developed an engine that used electromagnetic solenoids to remove the camshaft and timing belt. Although the development of this technology was done in collaboration with Lotus Engineering, it has not shown signs of reaching any of its production models.

Lastly, Fiat also toyed with a similar idea with its Multiair engines. But, contrary to what many believe, the fiat system did not completely remove either the camshaft or the timing belt. These items were still needed for exhaust and hydraulic pressure. It only removed one of the camshafts, as we could see in the in-depth review of Fiat Multiair engines.