Valves are an integral part of the gas distribution mechanism of the vehicle. It should be noted that these devices are quite important, since it is they that ensure the release of exhaust gases, create compression during ignition and injection of fuel in the engine cylinders. Modern engines provide different variants their settings.
1. How valves work
valves are enough simple device, so the principle of their work will not be difficult even for a beginner. They are driven by a camshaft located at the top of the block head. With this device, the valves open and close. The camshaft spins up and presses the valve with special ovals, which eventually opens. When the shaft stops pressing, the valve closes. The camshaft runs on a chain or belt drive, which is guided by the work crankshaft car.
The crankshaft and camshaft go through a mandatory stage of synchronization. This is done so that the movement of the piston and the opening of the valves coincide in the same sequence: when the piston goes down, the valves open, and when the piston rises, the valves close. Thus, pressure is created in the combustion chamber. Thereafter air-fuel mixture is ignited, and the piston under the influence of pressure goes down. This cycle is repeated many times.
2. The reason why the valves are bent
It is important to note that the situation when the valves are bent does not depend on how many valves the engine has. The cause of the malfunction is quite simple: an open circuit or timing belt occurs. The chain itself breaks quite rarely, since in most cases it stretches, and the hook sprockets simply jump.
The camshaft will stop abruptly when a break occurs. the same will continue to push the pistons. Thus, those valves that burn in the combustion chamber and those pistons that go up will meet at the top point, and pistons with enough energy will break and bend the valves. Eliminating this breakdown will be quite expensive, since it will be necessary to pull out all the bent elements from the motor. In addition, the block head itself may suffer, in which case it will be necessary to replace it.
3. Why the belt breaks, and how to protect yourself from it
The most common cause is a simple non-compliance with the instructions in accordance with the replacement of the belt from the manufacturer of the device. Often when vehicle under warranty, the replacement will be successful, but when a motorist wants to independently ensure the performance of his car, big troubles can arise if you save on replacing this device.
The pump may also fail. Some car models provide for the engagement of the device in the belt, and when it fails, the system simply jams, as a result of which the belt is worn out in a matter of hours. A poor-quality belt is also the root cause of a malfunction. That is why it is necessary to take high-quality, albeit expensive parts. The camshaft may also become unusable. If it is made of metal, you can immediately say that such an element will be faulty after a certain period of time, which, of course, is almost impossible to predict. Plus, they can fail and tension rollers gas distribution systems. They simply fall off or jam, as a result of which the belt comes off or breaks, and the valves bend.
There is only one way to avoid this. You simply need to follow the instructions and change the belt, tension rollers and other elements of this system in time, which manufacturers prescribe according to the regulations. All parts must be purchased only in high-quality automotive stores and services that are official dealers.
4. Are there valves that cannot bend?
Such options exist in modern automotive world but they are very rare. Previously, there were domestic devices that did not know such a disaster before. Unfortunately, there are practically none now. However, you can resort to solving the problem with tuning power units. The gist is quite simple: instead of conventional pistons, options with notches on top are installed. The method is quite effective, since in the event of a break, the valves will fall into these holes, and a breakdown will be prevented. The motorist only needs to install a new belt, as well as synchronize the camshaft and crankshaft of the car.
However, this method is not always effective. The thing is that such pistons will contribute to the loss of part of the engine power internal combustion, because such a piston will be heavier than a conventional piston, which will affect the compression force. That is why not all motorists recognize and resort to using this method.
5. How to know if the valves on the engine are bent
Many motorists are wondering how to distinguish a bending valve from a non-bending one, or how to determine the valve's performance. Unfortunately, there is no answer to this question, since valves are not subject to visual identification of a malfunction. Nowhere are there any mentions and inscriptions, notes that would lead to the comprehended truth. Of course, you can stop by the official workshop, where the masters will check the equipment, which, of course, will be quite expensive. It is advisable to do diagnostics of your vehicle every 20-30 thousand kilometers, where the inoperability of such elements will be determined.
Car owners encountered the problem of bending valves even on the first G8 models. The engine installed on them, with a volume of 1300 cc, bent the valves when the belt broke.
This problem is associated with several reasons, such as jamming of the pump and tension rollers, wear or poor manufacturing of the timing belt (timing).
At the moment the timing belt breaks, the camshaft stops in the position in which the break occurred, and the crankshaft, continuing to rotate, pushes the pistons towards the open valves. As a result, they collide, leading to damage to the valves and pistons.
In such a collision, it can damage not only the pistons, but also the cylinder walls and connecting rods. In this case, car repair will be very expensive and time-consuming.
On some types of VAZ car engines, this was avoided. In such engines, special recesses for valves are cast on the pistons, so when the belt breaks, a collision does not occur.
Several types of engines were installed on the Lada. Let's look at which of them are dangerous and which are safe and why the valve bends on Kalina when the belt breaks.
Types of engines affected by this problem
- Eight-valve, model 21116, 1.6 liters, equipped with a lightweight piston group. Due to the relief, the pistons became very thin and there was simply no room left for casting under the valves. When such pistons collide with a valve, the entire piston group usually suffers.
- Sixteen-valve, model 21126, with a volume of 1.6 liters, is installed on a more expensive class of Kalina cars. On this engine, the collision of pistons with valves is also inevitable.
- Sixteen-valve, model 11194, with a volume of 1.4 liters, is one of the most economical, but, unfortunately, is also prone to this problem.
- Sixteen-valve, model 21127, 1.6 liters. This new engine, based on the previous model 21126. Recently installed. It is more powerful, but also remains on our list of "dangerous".
Engine types not affected by this problem
- Sixteen-valve, model 21124, with a volume of 1.6 liters, is considered one of the most reliable. Installed on the twelfth model Zhiguli. With this motor, you will not have any problems with the gas distribution mechanism.
- Eight-valve, model 11183, 1.6 liter, proven engine, distinguished by its reliability, ease of maintenance and availability of spare parts. It also falls into the category of safe.
A few tips on how not to find out if the valve is bent on Kalina and not get into expensive repairs
In order to try to avoid damage to the gas distribution mechanisms, it is necessary to replace the timing belt in a timely manner.
In this case, it is not enough to change one belt. Be sure to change the tension rollers with it and monitor the condition of the pump. If necessary, it must also be replaced.
Never skimp on spare parts. Choose your timing belt carefully. It should not have any bumps, stripes and seams.
When buying a water pump and idlers, choose only well-known and trusted manufacturers.
By following these simple rules, you will never know if the valves on the Kalina car are bent, and how much the engine bulkhead costs.
I would like to hope that this article will help to avoid problems, as a rule, associated with an oversight of the technical condition of the car. With the right attitude to the operation of the elements of the gas distribution mechanism, such problems should not arise.
Every time before buying a car, we think about what engine size it has, how many “horses” are under the hood, what fuel consumption, we compare the car by color, interior trim, as well as various exterior elements. Of course, these issues are important, but no less important is such a parameter as the drive of the gas distribution mechanism, in short, the timing belt.
Reference!
The timing belt is an engine element that acts as a link between the crankshaft and camshaft on any modern car.
Renault Logan engine options
Consider the option that you are going to purchase, loved by everyone people's car Renault Logan. The designers of the Renault concern equipped cars (except for the top-end configuration) with two types of engines that have passed all kinds of technical tests and have the indices K7J, K7M, which indicates engines with a volume of 1.4 and 1.6 liters 8V (valves), respectively. A luxury car has a 1.6-liter engine with a 16-valve “head” with the K4M index. In each of them, a belt acts as a drive for the gas distribution mechanism. And about which engine to choose in the material:
Now we will consider each engine separately and figure out which of them will bend the valves when the timing belt breaks.
K7J - 8-valve engine with a volume of 1.4 liters (valve oppression)
The most popular engine in the domestic consumer valve oppression
The four-stroke four-cylinder gasoline engine K7J has evolved in our time straight from the 80s of the XX century. Due to the fact that the motor is a continuation of the line of engines of the previous generation, it has a clearly prominent feature in the form of an outdated design with increased consumption fuel. However, this does not prevent him from being one of the most maintainable engines in the line.
On the this engine there are no hydraulic lifters, so every 15-25 thousand kilometers it needs a valve adjustment procedure. And periodically there are oil leaks at the crankshaft oil seal.
Bent 3 out of 4 valves
Some "logans" prefer this engine to a more powerful version of the K7M.
K7M - 8-valve engine with a volume of 1.6 liters (valve oppression)
Less popular 8's valve engine 1.6 liter - K7M
The K7M motor from Renault, structurally with its predecessor K7J, is practically no different. , the same liquid cooling and combined lubrication system. The same problem remained with oil leakage and the absence of hydraulic lifters - we adjust the valves.
bent valve
However, if you look at specifications, then this engine has an increased piston stroke by 10.5 mm (due to the fact that the height of the block has been changed), as well as the largest engine volume and flywheel.
However, all of the above advantages did not help in any way to save the engine valves; when the timing belt breaks, they are oppressed.
K4M - 16-valve engine with a volume of 1.6 liters (valve oppression)
Bent valves on the K4M engine
A distinctive feature of this "top" engine from the previous ones is two lightweight camshafts in the cylinder head and a new piston system. From this, the power increased by 20 hp compared to the K7M, while at the same time increased efficiency and stability in operation. On the K4M motor, there is no problem with adjusting the valves after a certain mileage interval, since the aforementioned hydraulic compensators are already present there.
The timing drive is still carried out using a belt and, in the same way as on previous engines, when it breaks, it bends the valve.
Causes!
The timing belt can break for various reasons.
From the foregoing, we realized that on all types of Renault Logan car engines, when the timing belt breaks, the valves bend. And below we will describe the reasons why cliffs occur at all and how to avoid it.
- Timing belt wear (poor quality or technical wear), oil ingress, etc.
- The ingress of various foreign bodies under the belt
- The pump is stuck
- Idler roller(s) stuck or loose
- Stuck crankshaft or camshaft
In order not to worry about the condition of the timing belt, it is necessary to constantly monitor its external condition, the degree of tension, replace it according to the regulations or change it immediately if it has any damage. Make sure that oil and other liquids do not get on the belt (is the beginning of premature wear).
It was once a piston and part of an engine
If, when the timing belt broke, only the valves bent, we can say that this is great luck. In some situations, such a breakdown may damage the pistons themselves, the surfaces of the cylinders.
Symptoms and behavior of the car in which the timing belt needs to be replaced
As a result of increased loads or wear of the connecting rod and piston group, the timing belt may jump one turn, as a result of which,. This phenomenon is a symptom of checking the condition of the belt and the correct installation.
Repair cost
Specifically, in each situation, depending on the condition of the engine, after it stops due to a broken timing drive, auto mechanics will calculate the cost of repairs strictly individually.
Considering the usual example of a broken belt in a K7J engine, the average repair cost (with materials) will be approximately 10-15 thousand rubles.
I welcome you friends to the DIY auto repair site. Experienced motorists know that a broken timing belt can lead to sad consequences. In particular, there is a high risk of “meeting” of valves that have already left their seats and pistons rising by inertia.
The result is the deformation of the vital elements of the motor, as well as the urgent need to visit the service station and carry out major repairs. But does the valve always bend when the timing belt breaks? Is it necessary to be afraid of it?
There are so-called non-interfering engines, in which valves and pistons will not collide and where a belt break will not have more consequences than a new distribution setting. The drive belt belts have two sides. The internal jagged and is the one that drags the elements to be in perfect sync. The outer surface is smooth and on this surface are supported tension rollers that force the belt to be exposed, and other elements such as a water pump that do not need absolute synchrony.
A bit of history
On the new “dozens”, 8-valve engines with volumes of 1.5 and 1.6 liters were immediately installed. The first power units (from the position of the problem we are describing) were ideal, and the valves did not bend. Although on earlier models like the figure eight, nine with a volume of 1.3, this problem was. The reason was that the piston structurally could not "meet" the valves.
The timing belt is an optional element of preventive maintenance, although changes to it will last over time and will be one of the most costly vehicle maintenance operations. Respect for time is important to avoid breaking a belt that deteriorates over time.
There are a number of conditions that make it worthwhile to pay more attention to the condition of timing belts and, if necessary, to change them at an early stage. For example, those who make many short trips and in the city should take extra care, as should those who live in extreme climates, or park their car on the street, or move in very dusty, rainy, or muddy environments.
Over time, a more modern VAZ 2112 model appeared in the “ten” family, equipped with a one and a half liter engine, with a 16-valve engine. It was from that moment that the problems began. Many motorists and specialists could not figure out why the valve bends.
In fact, the reason was in the design of the power unit. On the one hand, the appearance of a 16-valve head made it possible to increase the car's power to 92 "horses", and on the other hand, a broken timing belt invariably led to a collision of pistons and valves, as well as deformation of the latter.
When replacing a belt belt, it is important not to waste or replace all of the peripherals. So we have to change all the tensioners and the water pump if it is belt driven. It is also recommended to replace the camshaft and crankshaft seals in order to avoid possible leakage due to deterioration of the camshafts in the future. In the case of countershaft shafts, it is also necessary to change the drive belts and the necessary bearings.
After that, I had to go to the service station and hand over the car for expensive repairs. Structural fault lay on the pistons themselves, which lacked the necessary recess. As a result, a broken timing belt always ended the same way.
Updated car engine
A similar oversight was adopted and more advanced 16-valve 1.6-liter engines were installed on new VAZ 2112 cars. Structurally, the power units did not differ much, but one feature was still present. In the new motor, the pistons had certain notches, so the problem described above was eliminated.
Bypassing these items could mean that someone has defects a posteriori, which would imply reimbursing the cost of all labor, which is the most expensive in a timing belt replacement. The disassembly and assembly of a toothed belt is a complex task and it is desirable that it be carried out by specialized personnel. This requires some know-how and appropriate tools. Failure to follow the steps correctly can result in breakages and breakdowns that will easily reach all four digits.
Mechanical valve problems begin to occur when the engine is subjected to overheating, lack of lubrication, or kink. Bent valves not only damage pistons, but also valve guides, camshafts, and camshaft components. If your engine drive belt breaks while driving, serious damage to the internal engine can occur. This is especially true if your vehicle is equipped with a jamming motor. Interference motors have tight tolerances between valves and piston caps.
Over the next few years, motorists began to forget about bent valves and got used to the reliability of the new 16-valve engines. But the updated Priora model with a 1.6-liter power unit was unpleasantly surprised - the valves also bent when the timing broke.
However, the final repair was much more expensive. On the other hand, the developers have made the belt as wide as possible to minimize the chance of belt breakage. Only those motorists who got a defective belt or those who did not follow their “iron horse” at all were not lucky.
Engine overspeed
Once the timing belt is damaged, the engine continues to rotate long enough for the pistons and valves to touch. Damage can include bent valves, broken pistons, and damaged engine heads. Depending on the engine your vehicle is equipped with, the maximum RPM that your engine can safely run. When the maximum RPM is exceeded, even for a short time, engine damage can occur, including bent valves.
Unfortunately, even on the new 1.4-liter Kalina engines with 16 valves, repairs cannot be avoided if the belt breaks in motion. So monitoring the state of this node is mandatory.
On which VAZ engines the valve bends, and on which it does not
Let's draw intermediate conclusions, as well as highlight the most "dangerous" and "safe" models from the position of probable deformation of the valves in case of damage to the belt:
When the engine is over-accelerated, the valves can "stretch" and come into contact with the pistons. With excess speed, the engine cannot keep the right time and allows the valves to contact the top of the pistons and cause serious damage to the piston and valves to bend.
Problems such as lack of lubrication and overheating of the engine can also lead to bent valves. If you keep working on the engine while it's overheating, the engine's internal tolerances are reduced to the point where the valves can stick to the valve guides, causing the valves to contact the pistons. Likewise, when lubrication is insufficient, it can cause the valves to stick to the guides, causing the valve to bend when it hits the pistons. In engines with overload valves, lack of lubrication and overheating can cause the lifters to stick, resulting in two bent valves and bent pushrods.
1. Which VAZ engines bend valves? This category includes car engines of the following model range - 21127, 21116, 2112, 1194.
2. Which VAZ engines do not bend valves? More reliable are the engines of such VAZ models as 1183, 21114, 21083, 21124, 21126 (bent until 2013, but now not), 21128.
The current problem has caused a lot of controversy among motorists. Many owners of "problem" VAZs are interested in what to do so that the valve does not bend. In fact, there are several recommendations.
When rebuilding an engine, care must be taken to ensure that proper clearance is provided between the pistons and valves to ensure that the valve reliefs on the piston covers are properly aligned with the intake and exhaust valves. Be careful when milling the heads to ensure that the valve is supported in the direction of the piston. Check valve lift specification before exhaust valve assembly. If any of these specs are incorrect, you can cause the valves to bend when the engine is rebuilt first.
Find out that a modern car has several hoses that can stick or clog and even terrible pressure when opening the tank cap. Previously, a carbureted car needed one hose to feed the engine, but nowadays the engine needs at least two, and any defect in them can cause your car to fail, stop, or even consume more fuel, to say the least. leaks. The tank is an example of this question, as it clearly shows the existence of most hoses and their fundamental functions for the good operation of the engine and the admission of gases that were previously released into the environment.
They are the following:
1. First, try to periodically assess the condition of the timing belt and replace it at the first sign of damage. Cracks, engine oil getting on the surface, excessive stretching, peeling edges - all this is a reason to install a new timing belt and not wait for a break.
2. Secondly, if the engine is expected to be repaired, then you can change the pistons, and in some cases the crankshaft. In addition, some experts recommend (as a way out) the installation of a new camshaft.
The main hose is the fuel pressure that picks up pressurized fuel to the groove that feeds the injector jets, but pay attention to the filter that stays in that line and its maintenance because if it gets clogged the fuel won't reach pressure and flow properly into the nozzles. In addition, it is important to evaluate the general condition of the pressure hose for possible folds or wrinkles that impede the flow of fuel, but we cannot help but point out possible leaks that often occur even inside the tank, since there is a small hose that directs the fuel collected by the electric pump, on the cap, and that cracks or leaks in the clamps are often found, which ultimately create a pressure loss in the system.
But here, of course, one cannot do without the advice of specialists. After that, you may need to flash and remove the catalyst.
If you got a car where the valve bends, then do not despair ahead of time. The ideal solution would be maximum attention to the engine and more frequent timing belt replacement. Even this will be enough to minimize the risks.
When there is a loss of the necessary pressure for the correct operation of the engine, the vehicle may fail or deteriorate, the fuel consumption will be high due to low pressure because the electronic injection module will have more nozzles, and at low pressure - the fuel flow will be changed and poorly controlled.
The return hose is responsible for the waste fuel to start the engine that is released by the throttle, but be careful as this regulator also has a screen that can get dirty and this can prevent proper fuel flow and create a defect in the system. Fuel feedback has been used in the past to boost fuel pressure in unofficial methods that allowed a gasoline engine to run with alcohol, and it's always worth checking if there's an external component in the return hose that was used for this function, or even if for some reason the hose is not bent or obstructed.
As for the replacement of components and expensive repairs, these costs, as a rule, do not justify themselves. Good luck on the road and of course no breakdowns.
Often, in the conversations of motorists, the phrases flash: “I got in for repairs, the belt broke, the valves bent”. Of course, in such cases we are talking about the timing belt. In order to understand the causes of the “catastrophe”, let us consider in general terms the interaction of the connecting rod and piston group and the gas distribution mechanism.
The returning fuel is directed to the pump bowl or housing so there is no shortage of fuel to the last drop inside the system, but unfortunately the pump bowl or reservoir is not well handled by some unsuspecting professionals who may break or give a damn about its proper assembly. which can allow fuel to run low or curve because fuel can roll and the pump is holding air instead of fuel.
The most common fuel leakage occurs at the seal of the fuel pump assembly, especially after replacing the primer of the pump, due to the common practice of not replacing the pump lining, which can provide a leak when the tank is filled to the maximum or even a constant smell of fuel that is exhaled by the pump seal. Fuel couplings on the pump cover are also often abused when moving and are always evaluated.
This interaction is strictly coordinated, otherwise it is impossible to provide normal work engine.
The principle of operation of the valve-piston system
Let's take the compression stroke as an example. When the piston, squeezing combustible mixture, approaches the top dead center, it almost comes close to the combustion chamber (on diesel engines - to the surface of the head). If at this moment any of the valves is not closed, then the loss of compression will be the lesser evil. Most likely, the valve, the core of which is rigidly held by the rocker (or camshaft cam) from above, will take the blow of the piston.
The gases absorbed by the container will be incinerated by the engine, and this process is controlled by an injection module that controls a valve that allows these gases to be absorbed by the engine. Fuel hoses that direct fuel from a bottleneck to a reservoir are victims of drying and road objects, often thrown around the wheel and requiring a visual inspection whenever the vehicle passes the view or when a fuel smell is detected.
A strong fuel smell can also come from the fuel cap or bottleneck as this cap is not indestructible, therefore timeless as it is one of the busiest components thanks to stock. The cap seal is in most cases located in the neck itself, and this neck can break or the rubber seal fails. The fuel tank cap still needs to be replaced, allowing the fuel to evaporate through the key entry slot, and this is very common.
The valve bends in the event of a collision between the valve and the piston
In very rare cases, the manufacturer provides recesses in the piston crown to avoid collision. From the foregoing, I hope it is clear why the valve bends when the timing belt breaks: the camshaft stops rotating, some of the valves remain in the open position, being a “convenient target” for the pistons moving by inertia.
Now that you know the function and the main disadvantages of fuel lines, it's interesting that you interact with your mechanic in reviews to evaluate these important components. Existence had brought us there at this moment, now it was up to us to look and understand. He came to the end of the laboratory visits, even those that were reserved earlier, in the days when he worked on earthquakes with other laboratory machines. We were there for two days, but he stayed there after we left. In general, on the phone made later, we realized that we had been working on it for almost a week.
The coherence of the timing with the crank mechanism is ensured by the precise installation of gears or sprockets. To do this, alignment marks are made on them and at certain points of the engine.
According to the type of torque transmission, the gas distribution mechanism drive can be:
- Belted
- chain
- gear
Consider their common malfunctions that can lead to valve bending.
Timing drive device
The consequences of a broken timing belt
Some inquisitive motorists are interested in the question: is it possible to bend the valves with a starter? The answer is easy! Just do not install sprockets or gears "by marks" - and the key is to start! If the engine starts, you will immediately learn to recognize the symptoms bent valves. Although, if you don’t “miss” much, then everything can be fixed by assembling the timing drive according to the rules.
If only one valve is bent, the engine will run unevenly. Even if it is a V-shaped "six" - hear.
If, after restoring the camshaft drive, the engine runs smoothly and develops the same power, then you are lucky and the manufacturer prudently installed pistons with sufficient recesses in the bottoms. But, unfortunately, this is not always possible. First of all, when designing a motor, the designer achieves a combination of many seemingly contradictory qualities of his “brainchild”. For example, such as efficiency and power. This can, to some extent, justify the fact that on 16-valve engines, the valves often bend when the timing belt breaks.
Such problems are especially acute for the creators diesel engines, in which the compression and the necessary swirl of the fuel mixture determine the power characteristics. Therefore, the combustion chamber is located in the bottom of the piston and often has a whimsical shape.
However, behind this is an accurate calculation and simulation of vortex flows on a computer. Such chambers are called undivided and it is not advisable to make recesses for the valves from the point of view of high-quality atomization and the most efficient combustion of the fuel mixture. The piston is almost very close to the head of the block. Therefore, it is not yet known for certain whether there are diesel engines on which “valve does not bend”. Although, perhaps, the human genius coped with this disaster.
Repair
bent engine valves
Never attempt to repair bent valves in any way!
Replacement, and only replacement!
If you straighten the valve “by eye”, then you risk getting yourself more trouble. A valve restored by handicraft is unlikely to be coaxial with the guide sleeve and tightly pressed against the seat. And if you want to “slightly” trim the rod, then it will work like a pump, pumping oil into the combustion chamber - no cap will hold it.
It would be prudent to make troubleshooting of other parts as carefully as possible. After all, a blow can damage the guide bushings, valve seats. There are cases when the connecting rods were bent. Breakage of rocker arms is also not uncommon.
Models of VAZ engines, the valves of which are not "afraid" of a broken timing belt:
VAZ 2111 1.5l; VAZ 21083 1.5l; VAZ 11183 1.6l (8 valves); VAZ 2114 1.5l and 1.6l (both 8 valves)
It is known that the old 8-valve "Opel" engines (such as those on the DAEWOO Nexia and Chevrolet Lanos) also calmly endure this trouble.
As a rule, if a person on his beloved car has bent at least one valve, even once, such a person is already beginning to understand that even the “piece of iron” does not have iron patience and will try to become a good owner of his “horse”.
In conclusion, it would be useful to add - watch your car, do not hesitate if there is a reason to “look under the hood”.
"Stick" - the meeting point of the valves and the piston cannot be changed.
There were no problems with valve bending when the piston and valve met on VAZ engines - it did its job perfectly. But the appearance of front-wheel drive models required new engines, since the Zhiguli engine had a chain in the block, its dimensions were not suitable for transverse installation. With the help of Porsche specialists, a 1.1 liter engine was developed. with a belt in the timing drive and an aluminum block mounted transversely. It all started with him.
With the use of the timing belt, there was a risk of its breakage, which means that it could happen " stick". But on the first engines corresponding to Euro 2, there was no such problem - the belt happened to break, but without consequences. The distance between the valves and the piston was sufficient, and when out of sync, the piston did not reach the valve.
With the advent of Euro 3 standards, a broken belt began to lead to a “meeting” of valves and a piston: a motor “strangled” by eco-standards needed to compensate for the loss of power. This can be achieved by increasing the compression ratio. The piston at its top dead center (TDC) has become closer to the valves. It turns out that as a result of the race for better ecology and power, almost all cases of belt breakage began to lead to valve bending.
This happens as follows: the timing belt breaks - the camshaft stops, but not immediately, but rotates in the same mode. The piston goes up and meets a stuck valve at TDC. Impact - the valve is bent into weak point, under the "plate". The car cannot move on.
At best, 1-2 valves suffer, but at worst, everything. Repair involves and. The pleasure is not cheap, and most importantly - unpleasant, because who likes to open a generally serviceable engine?
How to avoid
Often " plug-in» is achieved by using non-standard pistons with special milled areas on the bottom of the piston to fit the valve shape. VAZ has such engine modifications. As a rule, these are eight-valve. Also, third-party milled pistons are used.
The inevitable increase in the combustion chamber, which can cause the engine to blunt due to a decrease in the compression ratio, is compensated by the stamping at the bottom of the piston. However, as practice shows, this measure does not always save from the “meeting” of the piston and valve. We list those motors that, according to the manufacturer, are free from the risk of a collision between the piston and valves:
VAZ 2111;
VAZ 21083;
3;
VAZ 21124;
VAZ 2113;
VAZ 11183;
.
But the only reliable means is timely. It’s just that in the case of a VAZ, it’s worth doing this more often than the manufacturer recommends. By the way, in foreign cars there are also “risky” internal combustion engines, but correct operation and timely service nullify the negative statistics of "plugs".