Which 16 valve engine does not bend the valve. Why the valve bends. How to check if the valve is bent yourself

Many car owners have heard about such an engine malfunction as a broken timing belt. This topic is a kind of horror story for novice car owners, and generates a lot of rumors around itself, sometimes not related to reality.

The engine's gas distribution mechanism is driven by the crankshaft gear. Initially, chains were used for this purpose, and timing belts, which began to be widely used about twenty years ago, caused distrust among car owners.

The undoubted advantages of a belt drive over a chain drive are its simple design, low weight and low noise. However, it is not devoid of shortcomings, the main of which is the relatively small resource of the timing belt.

The chain drive has a very long service life. If the motor is not raped, the chain may well last more than 200 thousand kilometers. As it wears out, it stretches and begins to rattle, thus signaling the need for replacement. A high-quality belt, meanwhile, works on average 60 thousand kilometers, after which it needs to be replaced, even if it looks whole. If this is not done in time, the belt may break.

What happens when there is a break

The consequences of a broken timing belt entirely depend on the design of the power unit. To imagine what will happen at this moment, you need to turn to the mechanics of the internal combustion engine.

In a running engine, the pistons move continuously from one dead center to another. During the intake stroke, the piston moves downward and the intake valve opens, during the exhaust stroke, the exhaust valve opens, while the piston moves up. At the moment when the piston is at top dead center, all valves must be closed.

If the timing belt breaks, the camshaft stops rotating and the valves stop in one position. At the same time, the crankshaft continues to rotate by inertia, and the pistons rush towards the open valves.

In some engines, for example, the 8-valve VAZ-2111, the pistons have special grooves to avoid contact with the valves in the event of a break. In this case, there will be no consequences, except that the car will not be able to get to the garage or workshop on its own.

Modern multi-valve motors are designed in such a way as to obtain maximum power with a small volume, therefore the pistons do not have such recesses, or they are not deep enough. For such engines, a broken timing belt means the inevitable meeting of the pistons with the valves, which makes the latter bend.

If the belt breaks off at idle, as a rule, only a few valves are bent, if the car was moving in gear, and the revs were high - most likely, the whole set will go for replacement.

Masters in car services, as a rule, rightly advise in any case to change the entire set of valves.

The higher the revolutions of the crankshaft at the moment of breakage, the more severe the consequences. In addition to bending the valves, their guide bushings can burst, which in turn threatens to repair or replace the cylinder head or the block itself. In addition, the pistons can collapse from the impact.

There are even known cases when the breakage occurred at high speed, and all valves were bent from the impact, the block head received damage "incompatible with life", guide bushings burst, and their fragments pierced the pistons through and through. These motors are extremely expensive to repair. According to statistics, two-shaft (DOHC) engines of Japanese manufacturers are more likely to receive such damage.

However, in comparison with diesel engines, the consequences of a timing belt break for gasoline engines are quite mild. Due to the design specifics, the valves have almost no free play when the piston is at TDC. As a result of the breakage, the destruction takes on the character of dominoes:

• valves bend;
• the camshaft and its bearings are destroyed;
• block head;
• the connecting rods and pushers are bent.

A break at high speeds can also destroy the pistons and damage the cylinder block.

Causes of a broken timing belt

The most common reasons for a break are related to the carelessness of the car owner. Chief among them is the untimely replacement of a worn out belt. As a rule, automakers set the intervals between its replacements at 60 thousand kilometers (the real resource of a high-quality belt exceeds the replacement interval by 5-10 thousand kilometers). If for the first time it is changed at scheduled maintenance, then in the future, car owners often forget about it.

By setting instead original spare part an inexpensive analogue of Chinese production, you should be prepared for the fact that it will break off long before its 60 thousand "departs". Such savings threaten with much greater costs, therefore it is advisable to purchase either regular spare parts or high-quality analogs, which sometimes cost more.

In addition, the belt becomes unusable due to the systematic ingress of dirt and oil, so you should monitor the condition of the protective casing and pay attention to the appearance of oil leaks from the engine. A foreign object caught between the belt and the gear can also lead to either breakage or shearing of its teeth.

In addition to these, the most common, there may be other reasons for a timing belt break, such as jamming or spontaneous release of the tension roller, pump wedge, as well as a jammed camshaft or crankshaft. A break can be caused by sudden loads on the belt, for example, if the car is often started "from the pusher".

Signs of a broken timing belt

The main signs of a broken timing belt are as follows:

1. the motor suddenly stalled;
2. you cannot start it again;
3. when the starter is operating, a metallic knock is possible in the upper part of the engine (pistons hit the valves).

To establish exactly whether the belt has really broken off, you can only look under the hood. Most likely, there will be a torn belt itself and its damaged casing.

Valves are one of the important parts of the gas distribution mechanism and when the timing belt breaks, they most often undergo significant deformations. And as a result, it provides expensive repairs to the car owner.

This article describes the principles of operation of the gas distribution system, the reasons why the valve bends, the consequences of a broken timing belt for the engine, and also describes on which motors the valve bends or does not bend when the belt breaks.

The following main reasons can be distinguished:

• Timing belt condition (cracks, tooth wear, belt overtightened or loose)
• Failure to comply with the timing of belt replacement (high vehicle mileage).
• Foreign body ingress (check that the protective cover is installed correctly)

What happens in the engine when the belt breaks

Today, engines with 8 and 16 cl. Are most often used. They are responsible for the compression of the cylinders and for the release of exhaust gases. They move because of the camshaft, which unwinds and presses on the valve.
An engine's duty cycle is a periodically repeating series of sequential processes that take place in each cylinder of the engine.
The working cycle of the engine takes place in 4 strokes or 2 revolutions of the engine crankshaft. (such engines are called 4-stroke engines, there are also 2-stroke engines, but now they are not used in cars).
So you:

• Inlet
• Compression
• Expansion
• Release

The valves open and close at the right time. The drive is carried out by cams located on the camshaft. When the cams rotate, its protruding part presses the valve, as a result of which it opens. Cl. a spring closes it.

Fist- component camshaft (drivers call it camshaft). The camshaft has journal journals and cams. The torque from the crankshaft to the camshaft is transmitted by a chain or timing belt.

If with the engine running the drive belt breaksb, then the camshaft ceases to be associated with the crankshaft. And it can stop arbitrarily in such a position in which any of the valves will be fully open. In this case, the piston, when moving upward, may collide with the valve, which in this case bends. And as a result, the engine faces serious repairs. The motor is to be disassembled, it is necessary to replace the valves, and in some cases the "Head" of the block may also be damaged, and so that its complete replacement will be required.

On what machines the valve bends

On most cars, when the timing belt breaks, there is a problem of bending the valves. It doesn't even matter if the engine is idling or on the highway. They can still bend out. It is important exactly how much the gear cranked when the belt breaks. Bending can occur at 8, 16 and 20 cells. motors, diesel and gasoline engines, small cars and cars with a large displacement. therefore it is very important to timely replace the timing belt. But a timing break does not always lead to bending.

What machines does not bend the valve

Some engines have a little protection - grooves, which are small indentations. These grooves are set so that at high speeds the piston does not catch up with the closing valve. But when the timing belt breaks, they also help to reduce the negative consequences, and in some cases they do not bend the valve at all.

Sometimes car owners grind them out on their own, but this is not always correct. Because the presence of these recesses leads to a decrease in the engine, an increase in fuel consumption, and the content of nitrogen oxides in the exhaust gases... Many auto companies have now given up such protection.

The most reliable method of dealing with valve bending is timely belt replacement.

What to do to prevent the valve from bent when the timing belt breaks

In order for the valve not to bend it is necessary monitor the state timing belt. It is necessary to change it according to the terms indicated in the service book (approximately 60-70 thousand km.). But it is also necessary to periodically produce visual inspection belt, even if the replacement period has not come. Quite often, the belt breaks immediately after its installation after 1000–2000 km. This happens if the work on its replacement was performed poorly.

Remove the cover periodically and check the belt. Inspect it from the outside, check the ribs of the belt and the presence of microcracks. And also it should not be tightly clamped. Conduct such inspections from time to time. As soon as you see signs of wear on the belt, it is time to replace it.

How to understand that the valve is bent

If the belt breaks, there is little chance of engine damage. Before removing the cylinder head, it is necessary to measure the compression in the cylinders in case the crankshaft can be turned. If the valves are damaged, there will be a lack of compression. Always disconnect the battery when carrying out repairs to the engine. The spark plugs for the gasoline engine or the glow plugs for the diesel engine must be removed to facilitate crankshaft rotation.

The crankshaft can only be rotated in the normal position (usually clockwise).

The cost of repairing bent valves

Repair of this type usually costs the car owner quite expensive, at least 15 thousand rubles, and in case of head damage, the amount can significantly increase. In case of severe damage, even a new head may be required, and re-assembly does not make sense.

Bent valves must not be bent back! Some unscrupulous car services say that they have spare parts for your car in stock, but in fact they bend them back, which is unacceptable. Be sure to ask to show deformed parts after repair.

In order not to bend the valves on the car, it is necessary to replace the timing belt on cars in a timely manner, and also remember that the cost of replacing the timing belt is 10% of the cost of repair work in case of its breakage.

Greetings to you friends on the do-it-yourself auto repair site. Experienced motorists know that a broken timing belt can lead to dire consequences. In particular, there is a great risk of "meeting" the valves that have already come out of the seats and the pistons rising by inertia.

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

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 perspective of the problem we are describing) were ideal, and the valves did not bend. Although on earlier models of the type eight, nines with a volume of 1.3 this problem was. The reason was that the piston constructively could not "meet" the valves.

Over time, a more modern model VAZ 2112, equipped with a one and a half liter engine, with a 16-valve engine, appeared in the “dozen” family. It was from this moment that the problems began. Many motorists and specialists could not understand why the valve was bending.

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 power of the car to 92 "horses", and on the other - broken timing belt invariably led to collision of pistons and valves, as well as deformation of the latter.

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

Updated car engine

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

Over the next few years, motorists 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 unpleasantly surprised - the valves also bent when the timing was broken.

At the same time, final repairs were 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 watch their "iron horse" were unlucky.

Unfortunately, even on the new 1.4-liter Kalina engines with 16 valves, repairs can not be avoided if the belt breaks in motion. So monitoring the status of this node is mandatory.

On which VAZ engines the valve bends, and on which not

Let's make intermediate conclusions, as well as highlight the most "dangerous" and "safe" models from the point of view of probable deformation of the valves in case of belt damage:

1. What kind of engine valve bend? This category includes motors of cars of the following lineup — 21127, 21116, 2112, 1194.

2. What kind of engine VAZ does not bend the valve? More reliable are the motors of such VAZ models as 1183, 21114, 21083, 21124, 21126 (bent until 2013, but not now), 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.

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. Cracking, hitting the surface engine oil, excessive stretching, peeling of the 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, 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.

But here, of course, one cannot do without consulting specialists. After that, you may need to reflash 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 that will be enough to keep the risks to a minimum.

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.

Before buying a car, many owners do not yet know about such a problem as a broken timing belt, and as a result, pistons collide with valves on some engines and bend them. This problem is not only for domestic cars, but also in modern foreign cars, and this threatens with rather expensive repairs. This trouble was still with the old models of Zhiguli, but now we are interested in modern engines and it is them that we will consider. And on the left in the picture, the consequences of this trouble are shown, so carefully read the information below to avoid a similar picture, because, as they say, no one is immune from this.

Bends valves on the following motors

1. 16-valve engine with a volume of 1.5 liters. Although it is no longer installed on cars, at one time there were quite a few of them on the tenth family. It was then that the owners of these cars felt what it was. On a personal example, 2112, my valve bent 2 times. And in both cases, even 10,000 km did not pass after replacing the timing belt.
2. Model 21126, which is currently installed on both Kalina and Priors and Grants. As you already know, the collision of valves and pistons is also inevitable when the belt breaks. Moreover, repairs can be very expensive, since, in addition to all this, it can break the entire piston, from the pistons themselves to scoring on the cylinders and bent connecting rods.
3. Modification 21116, which is now being put on both Grants and Kalina recently. Although this sia unit is 8-valve and has not changed much, it will bring a lot of trouble when the pistons and valves meet. This is due to the fact that the piston group in this engine is lightweight, so there is no room for the recesses in the pistons - accordingly, the valves are bent.
4. 1.4 16-cl. For the first time, the engine was installed on Kalina and it is also unsafe, although quite economical.
5. VAZ 21127, which will be installed on the Lada Kalina for the first time. It has a volume of 1.6 liters with a similar design to its predecessor from Priora, but slightly more power. It also belongs to this list of "dangerous" motors.

The valve does not bend on motors such as:

• 1.5 8-cl and 1.6 8-cl. The power unit with a smaller volume was installed on earlier versions of cars. And 1.6 for late ones, including Kalina too. Everything is fine here and no breaks in the timing belt are terrible, since the pistons have deep recesses for the valves, which are quite enough to avoid a collision.
• 1.6 16-valve modification 21124. This engine was installed on the VAZ 2112 at one time and was in quite popular demand, as it was both powerful and reliable in this regard.

In order to somehow reduce the likelihood of getting into an expensive repair, be careful about the choice of components and spare parts. Change the belt in time and before buying it carefully inspect it for the presence of a seam and if there is one, then it is better to refuse it. And don't forget about videos, which must also be of high quality.

As I wrote about the engines "PRIORA", I was asked - "", read it very informative. In this article, I promised to talk about the very principle of why this happens on some engines, but not on others. In general, about the breakdown process itself, today I will try to sort everything out on the shelves, just for you "beginners". I will not delay, let's go ...

So the valve is part razorasp ra separate mcar mechanism (timing). It should be noted that the part is quite important, without them there would be no release of exhaust gases, and compression in the cylinders would not be created during fuel injection and ignition. In modern engines, their number varies from 8 to 32. But most of them use variants with, they are the most common of all.

Principle of operation

"Makes" them work to open and close camshaft, which is located on top, in the block head.

It spins up and, thanks to special ovals, presses on the valve - it opens, or releases it - it closes. In turn, the camshaft runs on a belt or chain drive from the crankshaft.

The distribution and the crankshaft are necessarily synchronized so that the opening of the valves and the movement of the piston coincide in a certain sequence - when the piston goes down, the valves open ("sink" into the chamber), when the piston rises up, they close (go up), thus creating pressure in the combustion chamber, then the candles ignite the mixture and the piston goes down under pressure. This cycle is repeated many times. Here is a short video clip of work for understanding.

This is a perfectly working circuit, with due maintenance (timely replacement) everything will go many thousands of kilometers.

The reason why the valve bends

I would like to note that this can be both on 8 and 16 valve engines. The reason is simple - it is a broken timing belt or chain. In fairness, it is worth noting that the "chain" very rarely breaks, it basically stretches out and the "hook" stars begin to jump, which may also be the reason.

When a break occurs, the camshaft stops abruptly, but the crankshaft continues to push the pistons. Thus, the valves are lowered and "drowned" into the combustion chamber, the piston also goes up - which should not be the case during normal operation. They meet at the "high point" and the piston, having high energy, simply bends or breaks the valve. As you can see, everything is quite commonplace.

Such a breakdown is very expensive - you need to "half" the motor and pull out the bent elements, sometimes even the block head itself suffers (but rarely), so it will also need to be changed. You can also find damage to the pistons (the valve breaks it), but here it is even more serious, it will be necessary to remove the camshaft and pistons with "connecting rods".

Why does the belt tear and how to protect yourself from it

1) The most common reason is simply not following the manufacturer's instructions for replacing the belt. As a rule, if your car is under warranty, then the replacement will be under warranty, but if you service it yourself, then many people forget or save on replacement. It "comes out" sideways.

2) Low-quality belt, now there are just a lot of fakes, especially for our VAZ. In fact, they don't even walk 5,000 kilometers (they were in a company car several times), so take the best proven options. Or change to a service station with a guarantee.

3) The pump fails. In some car models, it is also in the engagement of the belt and if it fails, then it will simply wedge, it will wipe the belt in a matter of hours.

4) The camshaft itself wears out. It is made of metal and it is clear that after some time it will wear out (it can jam), although a very long time must pass (high mileage).

5) Tension rollers of the timing system fail. They can fall off, they can get jammed - in any case, the belt will either break or it will fly off - there is one end, the valve will bend.

The guys are only protected here. Change the belt in time, as well as the tension rollers and other elements of this system that are assigned to you according to the regulations. Take "consumables" at official or verified stores, because fakes are sold much less than originals, here you risk every thousand kilometers, in general, a belt is not a spare part that is worth saving on.

Are there options that don't bend?

Of course there is, but now they are very rare. Once again I advise you - there are models of motors that were not "bent" before. However, unfortunately now there are practically no such people. Therefore, many are doing - such tuning of power units.

The essence here is also banal, simple - they put instead of ordinary pistons. Then even if a break occurs, the valves will simply fall into these pits and nothing terrible will happen. You will need to install a new belt and synchronize the camshafts and crankshafts.

“Great,” you say. But why, then, such pistons are not put on all models? After all, this is 100% protection.

Again, everything is simple - such pistons consume part of the engine's power, and decently. There are still debates about “how much”. Some say that by about 5 - 7%, and this is excuse me - GREAT! The thing is that such a piston is heavier, and the compression is not as effective. That is why many have rejected this decision. Many - but not all!