What to do to prevent the valve from bending. On which VAZ engines does the valve not bend? Full list

Welcome, friends, to the DIY auto repair website. Experienced car enthusiasts know that a broken timing belt can lead to dire consequences. In particular, there is a high risk of “meeting” valves that have already come out of their seats and pistons rising by inertia.

The result is deformation of vital engine elements, as well as an urgent need to visit a service station and carry out overhaul. But does the valve always bend when the timing belt breaks? Should we be afraid of this?

A little history

The new “tens” were immediately equipped with 8-valve engines with volumes of 1.5 and 1.6 liters. The first power units (from the perspective of the problem we are describing) were ideal, and the valves did not bend. Although earlier models like eight and nine with a volume of 1.3 had this problem. The reason was that the piston structurally could not “meet” the valves.

Over time, the “ten” family included more modern model VAZ 2112, equipped with a one and a half liter engine, with a 16-valve engine. It was from this moment that the problems began. Many car enthusiasts and specialists could not understand 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, broken timing belt invariably led to a collision of pistons and valves, as well as deformation of the latter.

After that, I had to go to a service station and have the car undergo expensive repairs. The design fault lay with the pistons themselves, which lacked the necessary recess. As a result, the timing belt break always ended in the same way.

Updated car engine

A similar oversight was taken into account and more advanced 16-valve 1.6-liter engines were installed on new VAZ 2112 cars. Structurally, the power units were not very different, but one feature was still present. In the new engine, the pistons had certain recesses, so the problem described above was eliminated.

Over the next few years, car enthusiasts began to forget about bent valves and got used to the reliability of the new 16 valve motors. But the updated Priora model with a 1.6-liter power unit was an unpleasant surprise - the valves also bent when the timing belt broke.

At the same time, the final repairs were much more expensive. On the other hand, the developers made the belt as wide as possible to minimize the likelihood of the belt breaking. The only unlucky ones were those car enthusiasts who received a defective belt or those who did not take care of their “iron horse” at all.

Unfortunately, even on the new 1.4-liter Kalina engines with 16 valves, repairs cannot be avoided if the belt breaks while driving. So monitoring the state of this node is mandatory.

On which VAZ engines does the valve bend, and on which ones does not?

Let’s draw intermediate conclusions and also highlight the most “dangerous” and “safe” models from the perspective of probable valve deformation in the event of belt damage:

1. Which VAZ engines bend valves? This category includes the engines of the following cars: 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 (they bent until 2013, but not now), 21128.

The current problem has caused a lot of controversy among car enthusiasts. Many owners of “problem” VAZs are interested in what to do to prevent the valve from bending. In fact, there are several recommendations.

They are as follows:

1. First, try to periodically assess the condition of the timing belt and replace it at the first sign of damage. Appearance of cracks, contact with the surface motor oil, excessive stretching, peeling edges - all this is a reason to install new belt Timing belt and do 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 solution) installing a new camshaft.

But here, of course, you can’t do without consulting specialists. After this, flashing and removal of the catalyst may be necessary.

If you get a car with bent valves, then don’t despair ahead of time. The ideal solution there will be maximum attention to the engine and more frequent timing belt replacement. Even this will be enough to minimize risks.

As for replacing components and expensive repairs, these costs, as a rule, are not justified. Good luck on the roads and of course no breakdowns.

Often phrases flash in the conversations of car enthusiasts: “I got in for repairs, the belt broke, the valves were 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 general outline interaction of the connecting rod-piston group and the gas distribution mechanism.

This interaction is strictly coordinated, otherwise normal operation of the engine cannot be ensured.

Operating principle of the valve-piston system

Let's take the compression stroke as an example. When the piston, compressing the combustible mixture, approaches top dead center, it comes almost close to the combustion chamber (on diesel engines, to the surface of the head). If at this moment any of the valves are not closed, then loss of compression will be the lesser evil. Most likely, the valve, the rod of which is rigidly held by the rocker arm (or camshaft cam) from above, will take the impact of the piston.

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 what has been said, 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 pistons moving by inertia.

The coherence of the timing with the crank mechanism is ensured by the precise installation of gears or sprockets. To do this, installation marks are made on them and on certain points of the engine.

According to the type of torque transmission, the gas distribution mechanism drive can be:

Belt
Chained
Geared

Let's look at their common malfunctions, which can lead to bending of the valves.

Timing drive device

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 the sprockets or gears according to the markings - and the key is to start! Once the engine starts, you will immediately learn to recognize the symptoms of bent valves. Although, if you don’t “miss” too much, then everything can be corrected by assembling the timing drive according to the rules.
If just one valve is bent, the engine will run rough. Even if it is a V-shaped “six”, you will hear it.
If, after restoring the camshaft drive, the engine runs smoothly and develops the same power, then you are lucky and the manufacturer prudently supplied pistons with sufficient recesses in the bottoms. But, unfortunately, this is not always possible. First of all, when designing a motor, the designer strives to combine many seemingly contradictory qualities of his “brainchild”. For example, such as efficiency and power. This may, 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 of diesel engines, in which compression and the necessary swirl fuel mixture set power characteristics. Therefore, the combustion chamber is located at the bottom of the piston and often has a whimsical shape.

On diesel engines valves bend more often than on gasoline ones

However, behind this lies the precise calculation and modeling of vortex flows on a computer. Such chambers are called undivided and making recesses for the valves is impractical from the point of view of high-quality atomization and maximum efficient combustion of the fuel mixture. The piston is almost close to the head of the block. Therefore, it is not yet known for certain whether there are diesel engines on which “the valves do not bend.” Although, perhaps, human genius dealt with this disaster.

Repair

Bent car engine valves

Under no circumstances should you attempt to restore the software in any way. bent valves!
Replacement, and only replacement!

If you straighten the valve “by eye,” you risk getting yourself into even more trouble. A valve restored by hand is unlikely to be aligned with the guide bushing and will press tightly against the seat. And if you want to “just a little” straighten the rod, it will work like a pump, pumping oil into the combustion chamber - no cap will hold it.
It would be prudent to troubleshoot other parts as thoroughly as possible. After all, an impact can damage guide bushings and valve seats. There are known cases when connecting rods were bent. Breakage of rocker arms is also not uncommon.

Models VAZ engines, the valves of which are not “afraid” of timing belt breakage:

VAZ 2111 1.5l; VAZ 21083 1.5l; VAZ 11183 1.6l (8 valve); VAZ 2114 1.5l and 1.6l (both 8 valve)

It is known that old 8-valve “Opel” engines (such as those on DAEWOO Nexia And Chevrolet Lanos), also calmly endure this trouble.

As a rule, if a person has bent at least one valve on his favorite car, even just once, such a person already begins to understand that even “hardware” does not have iron patience and will try to become a good owner of his “horse”.

In conclusion, it would be useful to add - keep an eye on your car, do not doubt whether there is a reason to “look under the hood”.

Continuous engine improvement internal combustion in order to increase and enhance fuel efficiency forced engineers to seriously rework the design of modern diesel and gasoline engines. Changes also affected the design of the piston group and combustion chamber. These modifications were made to maximize the efficient filling of the cylinders and their high-quality ventilation, that is, to obtain improved gas exchange.

If in the early stages of development the most common engine was with two valves per cylinder (1 intake and 1 exhaust valve), today an increase in the number of valves per cylinder is everywhere observed. Such changes are well illustrated by the most common version of the car with four cylinders. Previously, such engines were often 8-valve, with one. Today, such a unit is often a 16-valve version with two camshafts (for intake and exhaust valves), can be equipped with a variable valve timing system, etc.

Read in this article

Broken timing belt/chain: main reasons

If we compare modern engines with their predecessors, today's engines have more power and shorter service life. Regarding the problem of valve bending, it is precisely to achieve greater efficiency from the engine that the distance from to is minimal. Even a slightly open valve bends as the piston rises to TDC. It turns out that various technical innovations in engine building did not in any way affect the well-known problem, which is inherent in the vast majority of engines, regardless of the type of motor and manufacturer. We are talking about bending valves when they break drive belt or .

An important rule during vehicle operation is to monitor the condition of the timing belt and its timely replacement. The belt should not have any delaminations, cracks or other defects. Also, various technical liquids are not allowed to come into contact with its surface. The appearance of squeaking, squeaking and other extraneous sounds will require the owner to check the tension and condition, as well as the tension and other rollers.

To answer the question of when to change the timing belt, you need to study the operating instructions for a particular car. Often on new cars the belt is changed after 60 thousand kilometers traveled or after 2-3 years (whichever comes first). A planned replacement with an original belt involves the next replacement every 50 thousand km. It is advisable to select non-original belts with caution and change them every 40 thousand km.

Now a few words about the chain drive. The timing chain requires less attention, since replacing the chain on average is necessary once every 150-200 thousand km. and more. In this case, it is necessary to monitor the chain tension, the condition of the tensioner and chain guide. Increased noise during engine operation, the appearance of a metallic clang and other signs will indicate the need to immediately check these elements.

So, let's return to the belt, which is less reliable compared to the chain. The timing belt most often breaks for the following reasons:

belt wear as a result of long-term use or use of a low-quality product;
jamming (water pump);
wedging crankshaft, camshaft;
tension roller malfunction, timing rollers jamming;
destruction of the timing belt as a result of engine oil getting on its surface;
mechanical damage after contact with sharp edges, camshaft gears;

Why do valves bend when the timing belt or chain breaks?

Despite the improvements, the general traditional principle of operation of the timing belt and engine valve mechanism remains unchanged. As is known, raising the piston at TDC (top dead center) means that at the specified moment the valves are also closed. This is necessary to create pressure and seal the combustion chamber.

If the timing belt breaks, then the valves simply do not have time to close, which means they collide with the rising piston. When the timing belt breaks, the camshafts immediately stop. This immediate stop occurs for two reasons:

since the drive force from the belt or chain disappears;
the camshaft cams themselves are retarded by return springs;

As for the crankshaft, this element continues to rotate by inertia. The inertial rotation of the shaft does not depend on what gear and at what speed the car was moving, at what speed the engine was running, etc. still turns the crankshaft. In other words, if the timing belt breaks, then the timing mechanism immediately stops and the valves remain open, while the crankshaft continues to rotate and the moving pistons hit the valves that are open at this time.

The result of a broken belt is that the piston meets the valves, after which the valves immediately bend. Often the valve stem is bent, although sometimes various deformations of the valve disc are also possible. Less common is damage to the piston itself, which is also a consequence of a broken belt and bent valves.

Engineers and car manufacturers are well aware of this problem. To prevent the consequences of a broken timing belt/chain, some old internal combustion engines had special grooves for the valves on the piston. These grooves actually provided the necessary free space, which allowed the open valves not to collide with the upward moving piston. In such motors, after the valve drive broke, the valves did not bend.

Modern engines also have characteristic recesses on the piston. It is worth noting that these grooves avoid the risk of damage to the valve while the engine is running. If the timing belt breaks on such engines, the indicated grooves do not prevent the valves from bending, that is, the valves still bend even if there are special grooves on the piston.

On which engines the valves bend: how to find out

Due to the seriousness of this problem and high cost subsequent repairs, many car enthusiasts are concerned about the question of how to find out whether the valve on the motor bends or does not bend when the timing belt breaks. To more accurately find out and determine whether the valves are bent on a particular engine, you can use the following recommendations:

Study in detail the technical documentation for the engine from the manufacturer. Let us add that holding visual inspection, as well as various data from the tables still do not give 100% confidence that the valves do not bend when the drive belt breaks. It is also not recommended to blindly trust statements on specialized auto forums or rely on information from other more or less authoritative sources. In other words, the reliability of any data must be questioned and double-checked.
Another way is the so-called “physical” test, which allows you to find out for yourself whether the valves are bent. This method allows you to determine the probability of valve bending, that is, confirm or refute the possibility of valve contact with the piston.

In order to find out whether the valve bends or does not bend, you will need to remove the timing belt. Next, the piston in the first cylinder is set to the TDC position, after which the camshaft of the gas distribution mechanism is rotated 720 degrees. If no stop is observed during the rotation of the camshaft, then it is necessary to carry out a similar check by alternately raising the pistons in all other cylinders of the internal combustion engine to TDC. If the camshaft does not rest anywhere, then there is a high probability that the this engine the valve does not bend when the belt breaks.

Regarding the various technical information, which is presented in tables, as well as referring to the experience of auto mechanics and ordinary drivers, the summary data allows us to note:

valves often do not bend on simple 8-valve engines;
valves are usually bent on 16-valve and 20-valve engines;
valves bend on almost all diesel engines;
valve bending occurs on most engines in the event of a timing chain break, that is, on engines with a timing chain drive;
valves usually bend on engines of small cars with a displacement of 1.1 to 1.4 liters;

Why are valves needed in an engine?

First you need to study the theory. Probably every car enthusiast knows the number of cylinders in the engine of his car, but not everyone can answer the question about the number of valves. Most modern internal combustion engines can have from 8 to 16 valves. There are power units where there can be 24 or more of them. The valve is an important part of the engine. It is responsible for supplying the fuel mixture to the combustion chamber and for releasing exhaust gases into the exhaust system. Each cylinder has two valves: one intake, the other exhaust. In 16-valve engines, there are four valves per cylinder if the engine is four-cylinder. There are also engines with more intake elements than exhaust elements. These are three- and five-cylinder engines.

The valve consists of two parts - a plate and a rod. When the timing belt breaks, it is the rod that gets hit. The valves are driven by the action of the camshaft. It, rotating around its axis in the cylinder head, can raise and lower the valves.

It is driven by the crankshaft - these two elements in any internal combustion engine are connected to each other by a belt, gear or chain drive. Through a gear drive, the camshaft rotates inside the cylinder block. This gear rotates the camshaft in the cylinder head. Today, internal combustion engines that use belts are more common.

The latter have a simple design, such a mechanism is cheaper to produce. However, their reliability is significantly lower than in the case of a chain drive. The latter is more complicated - there are also additional elements. These are chain guides and tension rollers.

Why do they bend?

A situation where the valves are bent can happen in any engine of any design. It does not matter how many cylinders there are in the engine and how many valves it has. The reason for the breakdown is simple, and there is only one. This is a broken belt in the drive or chain. The latter break much less often compared to belts. In the case of a chain, it stretches and the stars jump.

The camshaft stops abruptly after a timing belt breaks. The cranked one will continue its movement. Thus, valves that are recessed in the cylinders will collide with the pistons when they reach the position top dead points. And since the pistons have high impact energy, they can easily bend or break open valves.

Eliminating the consequences of this breakdown is very expensive. It is necessary to remove all damaged valves from the engine. The entire cylinder head also necessarily suffers. It is not always possible to restore the cylinder head, and then only replacement with a new one or a contract one will help.

Causes of timing belt breakage

The most common reasons that lead to drive belt breaks are the owners' failure to comply with the manufacturer's replacement instructions. When the car is new and under warranty, the owners very rarely look under the hood - all maintenance work will be performed by the official dealer. When the warranty ends, many people try to save money by replacing the belt.

Often the pump can fail. In many car models it is driven by the timing belt. If the pump fails, the system will jam and the belt will wear out in a few hours. Also one of the most popular reasons is poor quality belts. Therefore, it is better to purchase high-quality and original consumables.

The camshafts may also fail, and the latter may fall off or become jammed - the belt either flies off the gears or breaks. This is why the valves on the VAZ were bent.

Not only a break can happen to the belt. Often the teeth are cut off, and they are not so easy to detect. The teeth may slip if the tension roller spring is broken. On some engines, the camshaft gear has a special one. Only a tightened bolt serves as insurance against turning the gear. If you do not reach it, then there is a risk that the gear will turn, and as a result, the valves will bend. Replacement is the only way out of the situation.

How to avoid trouble?

There is only one way. It is necessary to strictly follow the manufacturer's replacement instructions. Supplies. Not only the timing belt must be replaced, but also the tension rollers, as well as other elements that are engaged with the belt and are specified by the manufacturer in the regulations.

All components should be purchased only from trusted automotive stores.

Is it possible to turn it on with a starter?

The starter bends the valves, and easily. This happens if you incorrectly install the stars or gears of the gas distribution mechanism according to the corresponding marks. Then just crank the starter. If the engine starts, the driver will immediately learn how to recognize that the valves are bent. But if you miss the marks slightly, then damage can be avoided. In order to solve the problem completely, all that remains is to assemble the drive according to the rules.

How to identify bent valves?

It is impossible to determine by eye what bent the valves. This will require simple, simple steps. First you need to install the timing belt according to the marks, and then rotate the crankshaft manually. It usually takes two to five turns to determine that the valves are actually bent. If the crankshaft rotates easily and calmly, then the timing elements are intact. When rotation is difficult, the valves are damaged.

It also happens that when the crankshaft rotates freely and easily, the valves are still bent. In this case, the problem can be identified by measuring the compression. If the compression is zero, then the timing elements are damaged. Many people do not know how to check whether the valves are bent. It will be heard. The engine will run rough. It feels good even on large engines, where there are six or more cylinders.

On what engines do the valves not bend?

Such motors exist. Some engines were even produced by AvtoVAZ. The whole secret is in pistons with special recesses on the working part of the piston. These recesses are made specifically for the valves. If the timing belt breaks, the element will simply go into these holes, and the structure will remain intact. It will only be necessary to align the gears to the marks and install a new belt.

How do you know if the engine is bending its valves?

But this cannot be done. There are no tricks or signs here. It is not possible to visually determine whether the motor is safe.

There are also no inscriptions or any references. Information can be obtained from the operating instructions or from official dealer.

Conclusion

To avoid having to replace valves, it is recommended to change the timing belt on time. If this is an AvtoVAZ car, then you can install special protected pistons. But they eat up some of the power and increase fuel consumption. It is imperative to remember that if the timing belt breaks, not only the valves fail - the entire head may break. And this makes repairs even more expensive. You shouldn't skimp on the timing belt.

When buying a car, not all car enthusiasts are interested in whether the power plant installed on the car is “plug-in”, i.e. Do the valves on it bend when the timing belt breaks? And this question is quite important and the answer to it determines how labor-intensive and how much it will cost to repair the engine in the event of such a breakdown.

What is a “plug-in engine”?

This concept characterizes the likelihood of a collision between pistons and valves, as a result of which the latter are damaged - they bend.

This situation occurs when the timing drive breaks, when the gas distribution mechanism stops, but the crank continues to work by inertia.

“Plug-in” and “non-plug-in” power units are available in the lineup of almost all automakers, including VAZ. At the same time, the second engine option, naturally, is a higher priority when choosing a car.

If we consider AvtoVAZ products, then this manufacturer has a line power plants is quite extensive, and in some engines, when the timing drive breaks, the valve bends, while in others such a breakdown does not occur.

The problem when choosing to purchase a VAZ car is the fact that the same model can be equipped with both “plug-in” and “non-plug-in” units, which can confuse the buyer.

See below for which engines are installed on some VAZ models.

It is worth noting that the type of timing drive affects the likelihood of valve bending. For example, on the VAZ of the classic family (VAZ-2101-2107) and also the Niva, only plug-in engines were installed. But the engines of these cars use a timing chain drive, which is highly reliable. Therefore on classic VAZ and Niva, the problem with valve bending due to a collision with the piston is, in fact, not relevant due to the low probability of its occurrence.

Starting from the VAZ-2108 and ending with the latest models - Priora, Granta, Kalina, etc., only a timing belt drive is used. So it can break off and the damage that the motor receives depends on whether it is “plug-in” or not.

Why do engines bend valves?

One of the ways is to ensure the most efficient filling of the combustion chambers with the fuel-air mixture and removal exhaust gases. And this is done in two ways - by increasing the number of valves per cylinder and increasing the throughput of the intake and exhaust ports.

The second method is implemented by increasing the distance where the valve exits the seat, and this is what causes it to collide with the piston with subsequent bending.

Thanks to the drive of the gas distribution mechanism from the crankshaft, synchronous operation of the timing belt and crankshaft is ensured. During normal operation of the power unit, as the piston approaches TDC, the valves are in the closed position, which prevents their contact.

If the drive of the gas distribution mechanism is broken, the connection between the mechanisms is lost, and the timing belt immediately stops, and the crankshaft continues to function (due to the inertia of the flywheel). In this case, the return valve springs set the camshaft in a position in which most of the cams of the shaft do not press on the valves (they are closed), but some of them still rotate so that they act on the valves and the latter are open.

In “non-plug-in” engines, it is structurally designed to maintain the distance between the valve plate and the piston bottom located at TDC, so even with the valves open, contact does not occur.

On these power plants, a break in the gas distribution mechanism drive does not lead to any internal damage to components and parts, and to restore the operation of the power unit it is enough to install a new belt and perform adjustment work (align everything according to the marks).

But if the power plant is “plug-in”, strongly protruding valves collide with the piston, which leads to their bending. On such engines, timing drive failure is usually accompanied by a strong single knock. Engine repair in this case is labor-intensive and expensive, since damaged parts have to be replaced and the cylinder head restored.

On VAZ power units that are susceptible to valve bending when the drive breaks, timely and periodic diagnostics of its condition, checking and adjusting the tension are especially important. Such measures are practically the only way to prevent valve failure.

VAZ engines – “non-stick” and “risky”

Since several power plants are installed on each of the VAZ models, it is important to know which of them are “plug-in”.

As already noted, the classic VAZ (2101-2107) and VAZ Niva were equipped with power units in which the valves bend. But since the timing drive on these engines is a chain drive, “stick-in” can not be taken into account.

"Samara"

The following were installed on cars of the Samara family (VAZ 2108-21099):

Units marked VAZ 21081, 2108 (carburetor and injection);
Motors 21083, 21091;
8-valve VAZ-2111 (late model years).

Of these, units 21083 and 2111 did not bend the valves when the timing belt broke, but versions 21081 and 2108 were “risky”.

VAZ 2110-2112

On models of the 10th family (VAZ-2110-2112), the range of power plants is even more extensive. Some units were installed on all cars of this family, while some were offered only for certain models.

Common to all models were engines with the indexes VAZ-2110, 2111 (8-valve), 2112, 21114, 21124. Of these, the VAZ-2112 and 21114 engines are “plug-in”, and the remaining valves do not bend.

Additionally, the VAZ-2112 model car was equipped with a VAZ-21128 power unit, which is also “risky” and bends the valves when the timing belt breaks.

"Samara-2"

Cars of the Samara-2 family, which includes the VAZ 2113-2115 models, are equipped with units of the VAZ-2111, 21114, 21124 and 21126 brands. Of these, only VAZ-2111 and 21124 engines are “risk-free”.

Also for the VAZ-2113 and 2115 versions, a motor with index 11183 was offered, in which a broken belt does not lead to bending of the valves.

"Granta", "Kalina", "Priora"

The Lada Granta is equipped with a line of units of the following brands: 11183, 11186, 21126 and 21128. The last two of them are also equipped with the Granta Sport version. Of all the engines, only version 11183 is “non-plug-in”, the rest have bent valves.

For the Lada Kalina, engines of the VAZ brands 11183, 11186, 11194, 21126 and 21127 are offered. The last two units are also installed on the Kalina Sport model, and the Cross version is equipped with engines 21127 and 11186. Of the entire line, only the VAZ-11183 engine does not bend valves when the timing belt breaks.

Lada Priora is equipped with units with indexes 21114, 21116, 21126 and 21127. All these engines are plug-in.

Please note that only the main brands of power plants that are equipped with certain models are listed above. But AvtoVAZ almost always “sins” with experimental small-scale production, when units that are uncharacteristic for it are installed on some cars.

For example, the VAZ-2109 was equipped with an engine with an identical index, which differed from the 2108 version in a lightweight design, and the small VAZ-2108 series was even equipped with a rotary unit labeled VAZ-415.

READ ON THE TOPIC: Other characteristic and other models of the series.

Foreign cars

Let's touch on the topic of foreign cars a little. Below is shown which engines from Toyota, Suzuki, Daewoo, Chevrolet, Citroen, Hyundai, Renault, Volvo, Kia, Fiat, Mercedes, Peugeot, Honda, Ford, Geely, Mitsubishi, Nissan, Audi, Volkswagen, Skoda, Opel, Lifan, Chery, Mazda, Subaru valve bends.

Determining which engine is risky

A large number of power units VAZ and the likelihood of hitting an experimental model makes it difficult to determine whether the engine in a particular car is “plug-in”. At the same time, even studying those. documentation does not always provide a reliable answer.

Determining whether a valve on an engine is bent can only be done by physically checking it. This operation is not entirely simple, especially for 16-valve units, but it allows you to accurately determine their susceptibility to valve bending.

This method is suitable for checking cars from other manufacturers.

The verification algorithm is very simple:

Remove the timing belt from the engine;
Set the piston of the first cylinder to TDC;
We turn the camshaft (16-valve version - two) two turns;
We set TDC on the second cylinder and again make two revolutions.

If during testing the camshafts rotate without locking, the engine does not bend the valves.

Although this testing method is labor-intensive - you have to disassemble the timing drive, then reassemble it, set it to the marks, but it gives an accurate answer.

Ways to solve the problem

Since the collision of pistons with valves has quite serious negative consequences, many car enthusiasts are interested in whether it is possible to influence this situation.

There are several methods that allow you to convert a valve-bending motor into a “plug-inless” one.

The simplest of them is installing pistons with grooves. By the way, on some VAZ engines this is how the problem with “sticking” is solved.

On the bottom of such pistons there are special recesses for valve plates. Due to this, the latter in the open position do not come into contact with the pistons installed at TDC.

But not all engines can be modernized in this way, for the reason that it is not always possible to find pistons with factory-made grooves to replace the “original” ones.

Second method - self-production grooves on the piston. This method is suitable for those who have not found replacement “non-stick” pistons. But this method has a significant drawback - it is very difficult to make identical recesses on all pistons. As a result, an imbalance in the weight of the pistons may occur, which will affect the service life of the crankshaft. Also, grooves of different sizes can cause, and this problem cannot be eliminated.

The third method is to increase the height of the combustion chamber. This is done by installing 2-3 gaskets under the head of the block. This method has a negative side - an increase in the volume of the combustion chamber, which entails a drop, and as a consequence - a decrease in power and an increase in fuel consumption.

Tuning and its influence on “sticking”

VAZ – great option for, which is what many owners use. One of the main types is to increase its power, and this is done in the same way that designers use - by ensuring better filling of the cylinders with the air-fuel mixture. To do this, you just need to install a tuning camshaft instead of the standard one - with a higher cam height.

But increasing power using a tuning shaft also has negative side– the valves extend from their seats to a greater distance, which means that the likelihood of them colliding with the pistons increases when the timing drive breaks. Therefore, such tuning makes even a “risk-free” engine “plug-in”.

In order not to make the engine “risky”, when tuning it is better not to make adjustments to the timing belt design, but if you decide to upgrade, you should be prepared to constantly monitor the condition of the drive.

Finally, we note that if the engine is “plug-in”, this does not mean that it is very problematic. With timely maintenance of the timing drive, the likelihood of a breakdown such as valve bending is very low and it may not occur throughout the entire period of operation of the vehicle.

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