Timing belt - what is it? Why change the timing belt?
Certainly some novice drivers do not knowsuch thing: the timing belt - what is it, what is it for. Therefore, you should conduct a small introductory course to understand how important an element in the engine it is. It starts with how it looks, where it is located, and also examine its internal device. Well, finish better with a small guide to replace the belt and related elements. But first things first.
Appearance and composition of timing belt
But it is worth thinking about: Timing belt - what is it, what advantages can it give? Note that it is flexible. This is one of its advantages. Appearance - a small width of the belt, the outer part is smooth, the inside of the teeth. But hardly anyone thought about what gives him such strength. After all, its life on most cars is about 60 thousand kilometers, and this is about 2 years of operation in normal mode.
The outer part is the base. It is smooth, able to provide reliable protection against any liquid - antifreeze, water, oil. Internal - it's teeth, their profile can be of three types. Simple curved or modified, as well as trapezoidal. The teeth ensure a reliable grip on the crankshaft pulleys and camshafts. But the most important is inside the belt - there are filaments of fiberglass. The winding of these yarns is made in a spiral, which makes it possible to provide excellent elasticity and the ability to withstand the tensile load.
Purpose of timing belt
Now that we have sorted out more or less whattiming belt, that this device is, you can move on and on - determine for what purpose it is needed. Current cars have a system of valves driven by a shaft on which the cams are located. This mechanism is called "gas distribution". The fact is that with its help the combustion chamber opens and closes during the cycles of intake and exhaust. Consequently, during the combustion of the air-fuel mixture, the maximum tightness of the combustion chamber is ensured.
This way you can achieve more power. Indeed, if you compare it with engines that do not have valves, you can see not only increased power, but also efficiency. The timing belt "Ford" is also made of elastic materials. Previously, only chains were used for the drive, but they have exactly the same resource, and the noise is produced an order of magnitude more. That's just the valves in the engine can be a different number, but you need to control all. And so that they worked in time with the pistons. Some engines use two belts. True, it's on very powerful and expensive cars.
How important is it to place labels?
To understand whether it is necessary to accurately expose shafts tojust imagine how the engine will work if an imbalance occurs. Presented? Yes, not a very beautiful situation. Suppose, in the first cylinder, the fuel injection stroke must occur. But because of incorrect installation of a belt the inlet valve appears completely closed, and the final one is opened. Consequently, all fuel simply does not enter the combustion chamber, nor does it ignite in a timely manner.
Then the working cycle takes place, at whichthe mixture ignites. She had to catch fire, but she did not, she stopped at the entrance and was separated by a valve. If the timing belt marks were set correctly, then there would be no problems. And now a spark rushes, but it illuminates a dark and empty combustion chamber. During the exhaust stroke, the intake valve opens and a certain amount of fuel is supplied. Provided that it does not spill back into the ramp or carburetor. At the next bar, a small part burns, and everything else goes into the exhaust system. With this operation, the engine will never start, so it is extremely important to accurately position the marks.
How correctly to put labels?
So we got to the most important question, onwho needs to know all the answers. What tags are there and where to look for them? Knowing the construction of one car, it's easy, acting by analogy, to replace the belt on any other. If you know how to replace the timing belt "Renault", then for you it will not be a problem to install a new one on the "nine" or even the "top ten" 16-valve. The main thing is to know where to find the tags you need.
First, there are marks on the flywheel and the engine block. Secondly, on the camshaft, or more precisely, on the drive gear, there is a mark.
Now we should consider the most popularengine models. If 8-valve, then they have one camshaft. If 16-valve - then two, but there is one more tensioning roller. It is not needed for adjustments, with its help the timing belt "Chevrolet" is held in a normal position. There are no significant differences in the procedure for installing pulleys according to the marks, it is only necessary to put them against each other.
Replacing the belt
On different cars, a replacement is made withsome features. For example, on some Renault models, in particular, on the popular in our country Logan, you need to hang out the engine, since you need to remove his pillow. Without this, it is impossible to remove the belt and put a new one. Owners of these cars know what the timing belt is, how to deal with it, so they can carry out a replacement very quickly, without resorting to the services of car-care centers.
But in most cases it is enough to raiseright side of the machine, then remove the wheel. Remove the protective cover from the plastic, which covers the drive. Also dismantle the drive belt of additional hinged mechanisms - power steering, generator, air conditioning, depending on the equipment of the car. Then remove the pulley drive additional mechanisms. The crankshaft pulley, which drives the timing belt, is not necessary to remove, it is enough to release it. Now it remains only to loosen the tension of the tension roller and pull the belt to remove it from the pulleys.
What happens if a break occurs?
Many people are asking themselves what is dangerousbelt timing. In this case, you need to turn to experienced auto mechanics who know the device of the piston group specifically your engine model. If we take as an example domestic cars, then in the model range of engines 2108 there are many differences. On some, a belt break is painless, while others can bend the valves and even damage the cylinder head.
Pay attention to whether there are any cycles onupper surfaces of the pistons. If they are present, then you will not get to expensive repairs in case of breakage. But if they are not, then inevitably there will be damage to the valve system. Do you plan to use the car for a long time? Turn to the turner, which will make the notches on the pistons. This can really protect the engine. And the only thing that will be required from you in the future, is to carry a spare belt with you to quickly replace. Of course, after the cliff, you will find out what the timing belt is and how to change it in the field. But a bitter experience is a lesson for you, and very useful. For sure, every motorist faced with such an occupation away from home.
Roller and Pump Replacement
And now it's worth to talk about what's onMost cars use a drive scheme for the gas distribution mechanism, which has already become a classic one. The belt also rotates the pulley of the pump, which is necessary for the cooling system for normal operation. Looking at the resource of the pump and belt, you can see that the first it is not much more. And the cost of this unit is not that big, so it's worth replacing the pump simultaneously with the timing belt. Of course, the videos always need to be changed, since they have the same resource as the belt.
True, this requires completely drainingliquid from the engine cooling system, allowing it to cool for a while if the motor has been muted recently. In all models, there are practically two drain holes - in the block and in the bottom part of the radiator. Again, pay attention to the fact that the resource of the antifreeze is not very large. Its additives evaporate, and properties change after 60 thousand kilometers of run. Is it not better to replace and antifreeze? Therefore, having understood the timing belt - what it is, you need to determine what else to replace when installing a new one.
What can be replaced at the same time?
Depending on which car, you canchange the various drives. In particular, very often the car owners, together with the timing gear, change the belts of the generator, the air conditioning compressor and the power steering. This is quite reasonable, since the service life of them does not always exceed the one that is provided for the timing drive. And the external influences on these belts are much greater, since they are not covered by protective covers in most cases.
And if for a gas-distributing mechanismit is important that the timing belt marks are correctly installed, then for other drives this condition is irrelevant. Installation is arbitrary. All dust and drops of water immediately settle on the surface of the accessory drive belts. Here and before the appearance of cracks not for long. Of course, if suddenly the generator belt or air conditioning compressor breaks, the engine will not suffer, it will not need to be repaired. Only becomes less comfortable or just starts to discharge the battery.
So you figured out why change the timing belt. Now you can safely proceed to this simple matter, having familiarized yourself with the design features of the mechanism on your car. The main thing is to correctly set the tags and make a quality repair. For example, with a strong wear of the pump, the belt begins to crawl, its edge rubs against the roller, and the surface width gradually decreases. This can cause a breakage, which can easily lead to the repair of the cylinder head.