The timing belt , surely all drivers have heard of it. Most people also know what distribution is, what role it plays and much more, but we assure you that you don’t know everything about distribution.
In today’s article we will talk more about the distribution belt or chain so read this article to the end if you want to learn more about it.
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In this article we will answer the following questions: What is the timing belt ? What is its role? How many types are there? When should we change it ? Which timing belt brand is better?
These are some of the big questions we will answer, but at the same time we will detail each topic in order to better understand everything.
Let’s start with the first question, which is quite simple and which all drivers should know, but we will explain again so that everyone understands better.
The distribution kit is that subassembly of the engine whose role is to synchronize the components responsible for intake, exhaust and position of the cylinders, so as to respect the combustion times of the engine.
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In many vehicles, the distribution also includes the water pump which is driven by the same belt.
The distribution generally consists of: timing belt, guide roller, tensioner and water pump, if the distribution of your car is using a timing belt. If you have a distribution chain then things change and more parts come into play.
There are several types of distribution that you may not have heard of. For a start, we need to know that since the 1890s, internal combustion engines were equipped with timing chains and did not have timing belts. Only in the 1960s did Pontiac launch the first 6-cylinder engine and rubber timing belt and not the classic chain. Then followed an explosion of engines with timing belt.
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What advantages would the timing belt have? Well, first of all, it is much cheaper, meaning it is a piece of rubber, not a complex chain, so the price of an engine was lower. Also thanks to the fact that there is no iron-on-iron contact, but one rubber with iron, the vibrations and noise at idle were much lower.
But after the 1990s, the distribution chain began to be appreciated again. So the big manufacturers have even equipped the low capacity motors with timing chains instead of belts. But quite big problems have started to appear with the distribution chains, so the latest models on the market are also equipped with a timing belt and not with a chain.
What advantages would a distribution chain have over the timing belt? The timing chain in the first place does not require replacement at 60,000-100 km as the belt. Because it is made of metal, being similar to the bicycle chain, but more resistant, some manufacturers say that it should never be changed, but some recommend that the chain be changed at some point,at about 250,000 - 300,000 kilometers.
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Another advantage would be that the water pump is independent of the distribution so if you have to change it you will not have to touch the distribution kit . Both the belt and the timing chain work with a tensioner.
The belt has mechanical tensioners, tensioned by means of a spring or a shock absorber. But the chain tensioner works on the basis of hydraulic pressure, which can be a problem.
The TSI and diesel engines from BMW are known for problems with the timing chain tensioner, because the tensioner does not receive pressure immediately, the chain is wide, and because is vibrating over time the distance between the links is increasing thus creating play,leading to the engine becoming very noisy (in some cases in which the car was not taken to service on time, the chain failed).
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There are also engines that have a sprocket distribution (gears). These models are quite rare, for example Ferrari uses on its engines the sprocket distribution. This distribution is durable over time but is very complicated. VW also used this technology on several engine models (on the 2.5 TD engine that equips the VW LT 46, but also the 2.5 TDI engine that equips the 5th generation Transporter).
There are also two types of motors, those with interference and those without interference.
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What exactly does that mean? Well, if unfortunately the distribution chain or the belt breaks, there are two possibilities.
The first is the one in which we break the engine and the second in which the engine suffers absolutely no damage . Well, an interference engine is the engine in which the maximum position of the piston exceeds the maximum opening level of the valve.
The valves being synchronized with the position of the piston through the belt, they do not hit the piston, but if the belt breaks, the piston and the valves rotate independently and will definitely hit each other.
That’s why we shouldn’t play too much with the engine because we risk doing damage, or if the timing is not mounted correctly, we also risk causing major damage, because synchronization is essential and adjustments are made to the limit. An engine without interference will not suffer anything even if we have the misfortune to break our timing belt. In this case, the valve, even in the lowest position, will never reach a position where the piston rises (they will never be touched regardless of the position they have). So if the timing belt fails, you won’t have any problems, because the piston and the valve will not touch each other.
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What happens if a belt or timing chain fails?
More and more people when they sell their car will tell you that the distribution has been changed recently and you don’t need to invest any more money in servicing.
Well, the biggest mistake you can make is to believe that he serviced the car before selling it. If you believe them, you take a risk, because you do not know the age of the belt on the car and you risk that it will give way when you least expect it.
If the timing belt fails for the first time we will hear a bang on the front of the car (under the hood, ) after which the engine will stop.
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If we have an engine without interference, we put another timing kit on and we are off without too much trouble. But if the engine is one with interference, we will have to replace the pistons, valves and other parts that are affected. That means a lot of money spent on parts, labor and lost time.
For example, if we run with too little engine oil, the damage will be greater. The chain is a heavy metal part, which, once broken at high speed, can break the engine block, cylinder head and even bend the vibrochen. Usually, if our chain breaks whilst driving , we will need a completely new engine.
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Overall which is better, the belt or the chain?
Well, a distribution chain is more resistant, it lasts more kilometers than a belt, but it is much more expensive, noisier and if it fails, it will cause significant damage.
A belt will always be quieter and in case of failure it will not cause as much damage as a chain. In addition, the timing belt costs even less.
But unfortunately with the timing belt we have to change the tensioning rollers and the water pump. The timing belt must be replaced within 60,000-100.000 km.
Now we can draw a conclusion, if you cover hundreds of thousands of kilometers per year, a distribution chain is better, but if you drive a maximum of 10,000-15,000 kilometers per year, a motor with a timing belt is certainly more profitable.
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Which distribution brands are better? If we had to choose, it is best to change the timing belt in time, it is better to change it with a cheaper one, but more often (maximum 60,000 km) than to wait until we have the money for a higher quality one.
But the best brands for timing belts are Continental Contitech and Bosch. For the tensioning rollers the best company is INA and for the water pump the best brand is HEPU.
Our advice for all drivers is to do the overhaul in time and not take any risks in terms of the resistance of the timing belt.
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If you have just bought a car, the first thing you should do is change the timing belt and not trust the words of the former owner. Also, to change the timing belt, it would be best to use an authorized service, because this operation is quite complex and cannot be done by anyone.
Photo source: knowhow.napaonline.com, majormotors.co.uk, carthrottle.com