When buying a car, not all motorists are interested in whether the power plant installed on the car is "plug-in" ie. whether the valve bends on it when the timing is broken. And this question is quite important and the answer to it depends on how laborious and how much it will cost to repair the engine in the event of such a breakdown.
What is a plug-in motor?
This concept characterizes the likelihood of collision of pistons with valves, as a result of which the latter are damaged - they bend.
This situation arises when the timing drive is broken, when the gas distribution mechanism stops, and the crank continues to operate by inertia.
"Plug-in" and "non-plug" power units are in the lineup of almost all car manufacturers, including VAZ. In this case, the second option of engines, of course, is a higher priority when choosing a car.
If we consider AvtoVAZ products, then this manufacturer has a fairly extensive line of power plants, and in some motors, when the timing drive is broken, the valve bends, while in others such a breakdown does not occur.
The problem when choosing a VAZ car for purchase is the fact that both "plug-in" and "non-plug" units can be installed on the same model, which can confuse the buyer.
What engines are on some VAZ models, see below.
It is worth noting that the likelihood of valve bending is influenced by the type of timing drive. For example, on the VAZ of the classic family (VAZ-2101-2107) as well as the "Niva", only "plug-in" engines were installed. But on the motors of these cars, a timing chain drive is used, which is highly reliable. Therefore, on classic VAZ and Niva, the problem of valve bending due to a collision with the piston is, in fact, not relevant due to the low probability of its occurrence.
Starting with the VAZ-2108 and ending with the latest models - "Priora", "Grant", "Kalina", etc., only the timing belt drive is used. Here it can break off and the damage that the motor will receive 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 a fuel-air mixture and the removal of 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 of the valve exit from the seat, and it is this that causes it to collide with the piston and subsequent bending.
Thanks to the drive of the gas distribution mechanism from the crankshaft, synchronous operation of the timing and KShM is ensured. During normal operation of the power unit, on the approach of the piston to the TDC, the valves are in the closed position, which excludes their contact.
If the drive of the gas distribution mechanism is cut off, the connection between the mechanisms is lost, and the timing immediately stops, and the KShM 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 turn so that they act on the valves and the latter turn out to be open.
In "non-stick" engines, it is structurally provided to maintain the distance between the valve plate and the piston crown, which is at TDC, therefore, 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 units and parts, and to restore the power unit's performance, it is enough to install a new belt and perform adjustment work (set 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 motors, a break in the timing drive is usually accompanied by a strong single knock. In this case, engine repair is laborious and expensive, since it is necessary to change damaged parts and restore the cylinder head.
On VAZ power units subject to valve bending in the event of a break in the drive, timely and periodic diagnostics of its condition, checking and adjusting the tension are especially relevant. Such measures are practically the only ones to prevent valve breakage.
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, on the classic VAZ (2101-2107) and VAZ "Niva" power units were installed, in which the valves bend. But since the timing drive on these motors is a chain drive, "sticking" can be disregarded.
Samara
On cars of the "Samara" family (VAZ 2108-21099) the following were installed:
- Units marked VAZ 21081, 2108 (carburetor and injection);
- Motors 21083, 21091;
- 8-valve VAZ-2111 (models of later years of production).
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 the models of the 10th family (VAZ-2110-2112), the line of power plants is even more extensive. Some units were installed on all cars of this family, and some were offered only for certain models.
Common to all models were motors with indices VAZ-2110, 2111 (8-valve), 2112, 21114, 21124. Of these, the VAZ-2112 and 21114 engines are "plug-in", and the rest of the valves are not bent.
In addition, the VAZ-2112 model car was equipped with a VAZ-21128 power unit, which is also "risky" and if the timing belt breaks, it bends the valves.
Samara-2
Cars of the Samara-2 family, to which the VAZ 2113-2115 models belong, are equipped with units of the VAZ-2111, 21114, 21124 and 21126 brands. Of these, only the VAZ-2111 and 21124 engines are “risk-free”.
Also, for the VAZ-2113 and 2115 versions, a motor with an index of 11183 was offered, in which a broken belt does not lead to bending of the valves.
"Granta", "Kalina", "Priora"
Lada "Granta" is equipped with a line of installations of the following brands: 11183, 11186, 21126 and 21128. The latter two of them are also equipped with the version of "Grant Sport". Of all the motors, only version 11183 is "non-stick", the rest are bent valves.
For Lada Kalina, engines of the brands VAZ 11183, 11186, 11194, 21126 and 21127 are offered. The latter 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 the valves when the timing belt breaks.
Lada "Priora" is equipped with installations with indexes 21114, 21116, 21126 and 21127. All these motors are "plug-in".
Note that only the main brands of power plants are indicated above, with which certain models are equipped. But AvtoVAZ almost always "sins" with experimental small-scale production, when units that are not typical for it are installed on some cars.
For example, an engine with an identical index was installed on the VAZ-2109, which differs from version 2108 in a lightweight design, and a small series of VAZ-2108 was completely equipped with a rotary installation marked VAZ-415.
READ BY TOPIC: Other characteristic and other models in the series.
Foreign cars
Let's touch on the topic of foreign cars a little. Below is shown on 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 bending the valve.
Determine which engine is risky
A large number of VAZ power units and the likelihood of hitting an experimental model makes it difficult to determine whether the engine on a particular car is "plug-in". Moreover, even studying those. the documentation does not always give a reliable answer.
To determine whether the valve bends on the engine, it is only possible to check it physically. This operation is not entirely simple, especially for 16-valve units, but it allows you to accurately establish their susceptibility to valve bending.
This method is suitable for checking cars from other manufacturers.
The verification work algorithm is very simple:
- Remove the timing belt from the engine;
- Install the piston of the first cylinder at TDC;
- We turn the camshaft (16-valve version - two) two turns;
- We set the TDC on the second cylinder and again make two turns.
If, during the check, the camshafts rotated without stopping, the engine does not bend the valves.
Although this method of verification is laborious - it is necessary to disassemble the timing drive, then reassemble, set according to the marks, but it gives an exact answer.
Ways to solve the problem
Since the collision of pistons with valves has rather serious negative consequences, many motorists are interested in whether this situation can be influenced.
There are several methods that make it possible to make a valve-bending motor into a "plug-free" one.
The simplest of these is the installation of grooved pistons. By the way, on some VAZ engines this is exactly 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 motors 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 "native" ones.
The second method is to make the grooves on the piston independently. This method is suitable for those who have not found "non-stick" replacement pistons. But this method has a significant drawback - it is very difficult to make the same indentations on all pistons. As a result, an imbalance of pistons by weight may form, which will affect the resource of the KShM. 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 block head. This method has a negative side - an increase in the volume of the combustion chamber, which entails a fall, and as a result - a decrease in power and an increase in fuel consumption.
Tuning and its impact on "sticking"
VAZ is an excellent option for, which many owners use. One of the main types is to increase its power, and this is done in the same way that designers use - ensuring better filling of the cylinders with an air-fuel mixture. To do this, it is enough just to install a tuning camshaft instead of a standard camshaft - with a higher cam height.
But the increase in power with the help of the tuning shaft also has a negative side - the valves leave the seats for a greater distance, which means that they are more likely to collide with the pistons when the timing drive is broken. Therefore, such tuning makes even a "risk-free" motor "plug-in".
In order not to make the engine "risky", during tuning it is better not to make adjustments to the timing design, but if it is decided to make an upgrade, then you should be ready to constantly monitor the state 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 such a breakdown as valve bending is very low and it may not occur throughout the entire period of vehicle operation.
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The valve mechanism works as follows: at the moment the piston reaches top dead center, both valves in the combustion chamber are closed - a certain pressure is created in it. Broken belt leads to the fact that valve do not have time to close in time before the arrival of the piston. Thus, their meeting occurs - a collision, which directly leads to the fact that the valve bends. Previously, in order to prevent such a problem, special grooves for valves were made on older engines. On engines of the new generation, similar recesses are also found, but they are intended only to avoid deformation of the valves during engine operation and, if a belt breaks, they absolutely do not save.
From a physical point of view, from the moment the timing belt breaks, the camshafts instantly stop, under the action of the return springs that brake its cams. The crankshaft at this moment inertia continues to rotate (regardless of whether the gear was engaged or not, the speed was low or high, the flywheel continues to turn it). That is, the pistons continue to work, and as a result, they beat on the valves that are currently open. Quite rarely, but it happens when the piston itself is damaged.
Causes of a broken timing belt
- wear of the belt as such or its poor quality (shaft gears have sharp edges or oil ingress from the oil seals).
- crankshaft wedges.
- the pump wedges (the most common occurrence).
- wedge several or one camshaft (for example, due to the failure of one of them - however, the consequences here are slightly different).
- the tension roller is unscrewed or the rollers are wedged (the belt loosens or tightens).
Modern engines, since they are more powerful than their predecessors, have much lower survivability. If we consider the cause, relying on the valves, this problem arises due to the small distance between them and the piston. That is, if at the moment the piston arrives, the valve is slightly open, then it instantly bends. Since for greater compression and compression in the bottom of the piston there is no groove for the valve of the required depth.
On which engines does the valve bend?
On cars with an 8-valve engine, it bends less often, but 16 and 20 grade, be it gasoline or diesel, bend occurs in most cases. True, sometimes it can be one or more valves, and if the engine was idling, then the trouble will carry over. But such cases are few, mostly, the consequences are irreversible. A table with a list of engines on which the valve of all popular cars bends when the timing belt breaks.
| Engine | Oppression | Engine | Does not bend | |
| 1C | oppression | Camry V10 2.2GL | does not bend | |
| 2C | oppression | 3VZ | does not bend | |
| 2E | oppression | 1S | does not bend | |
| 3S-GE | oppression | 2S | does not bend | |
| 3S-GTE | oppression | 3S-FE | does not bend | |
| 3S-FSE | oppression | 4S-FE | does not bend | |
| 4A-GE | oppression (at idle does not bend) | 5S-FE | does not bend | |
| 1G-FE VVT-i | oppression | 4A-FHE | does not bend | |
| G-FE Beams | oppression | 1G-EU | does not bend | |
| 1JZ-FSE | oppression | 3A | does not bend | |
| 2JZ-FSE | oppression | 1JZ-GE | does not bend | |
| 1MZ-FE VVT-i | oppression | 2JZ-GE | does not bend | |
| 2MZ-FE VVT-i | oppression | 5A-FE | does not bend | |
| 3MZ-FE VVT-i | oppression | 4A-FE | does not bend | |
| 1VZ-FE | oppression | 4A-FE LB | ||
| 2VZ-FE | oppression | 7A-FE | ||
| 3VZ-FE | oppression | 7A-FE LB | does not bend (lean burn) | |
| 4VZ-FE | oppression | 4E-FE | does not bend | |
| 5VZ-FE | oppression | 4E-FTE | does not bend | |
| 1SZ-FE | oppression | 5E-FE | does not bend | |
| 2SZ-FE | oppression | 5E-FHE | does not bend | |
| 1G-FE | does not bend | |||
| 1G-GZE | does not bend | |||
| 1JZ-GE | ||||
| 1JZ-GTE | does not bend | |||
| 2JZ-GE | does not bend (in practice it is possible) | |||
| 2JZ-GTE | does not bend | |||
| 1MZ-FE type "95 | does not bend | |||
| 3VZ-E | does not bend |
| Engine | Oppression | Engine | Does not bend | |
| 2111 1.5 16cl. | oppression | 2111 1.5 8cl. | does not bend | |
| 2103 | oppression | 21083 1.5 | does not bend | |
| 2106 | oppression | 21093, 2111, 1.5 | does not bend | |
| 21091 1.1 | oppression | 21124, 1.6 | does not bend | |
| 20124 1.5 16v | oppression | 2113, 2005 1.5 engineer, 8 cl. | does not bend | |
| 2112, 16 valves, 1.5 | oppression (with stock pistons) | 11183 1.6 l 8 cl. "Standard" (Lada Granta) | does not bend | |
| 21126, 1.6 | oppression | 2114 1.5, 1.6 8 cl. | does not bend | |
| 21128, 1.8 | oppression | 21124 1.6 16 cl. | does not bend | |
| Lada Kalina Sport 1.6 72kW | oppression | |||
| 21116 16 cl. "Norma" (Lada Granta) | oppression | |||
| 2114 1.3 8 cl. and 1.5 16 cl | oppression | |||
| Lada Largus K7M 710 1.6l. 8kl. and K4M 697 1.6 16 cl. | oppression | |||
| Niva 1.7l. | oppression |
Mitsubishi
VAG (Audi, VW, Skoda)
| Engine | Oppression | Engine | Does not bend | |
| ADP 1.6 | oppression | 1.8 RP | does not bend | |
| Polo 2005 1.4 | oppression | 1.8 AAM | does not bend | |
| Transporter T4 ABL 1.9 l | oppression | 1.8 PF | does not bend | |
| GOLF 4 1.4 / 16V AHW | oppression | 1.6 ЕZ | does not bend | |
| PASSAT 1.8 l. 20V | oppression | 2.0 2E | does not bend | |
| Passat B6 BVY 2,0FSI | bends + breaks valve guides | 1,8 PL | does not bend | |
| 1.4 BCA | oppression | 1.8 AGU | does not bend | |
| 1.4 BUD | oppression | 1.8 EV | does not bend | |
| 2.8 AAA | oppression | 1.8 ABS | does not bend | |
| 2.0 9A | oppression | 2.0 JS | does not bend | |
| 1.9 1Z | oppression | |||
| 1,8 KR | oppression | |||
| 1.4 BBZ | oppression | |||
| 1.4 ABD | oppression | |||
| 1.4 BCA | oppression | |||
| 1.3 MN | oppression | |||
| 1.3 HK | oppression | |||
| 1.4 AKQ | oppression | |||
| 1.6 ABU | oppression | |||
| 1,3 NZ | oppression | |||
| 1.6 BFQ | oppression | |||
| 1.6 CS | oppression | |||
| 1.6 AEE | oppression | |||
| 1.6 AKL | oppression | |||
| 1.6 AFT | oppression | |||
| 1.8 AWT | oppression | |||
| 2.0 BPY | oppression |
| Engine | Oppression | Engine | Does not bend | |
| X14NV | oppression | 13S | does not bend | |
| X14NZ | oppression | 13N / NB | does not bend | |
| C14NZ | oppression | 16SH | does not bend | |
| X14XE | oppression | C16NZ | does not bend | |
| X14SZ | oppression | 16SV | does not bend | |
| C14SE | oppression | X16SZ | does not bend | |
| X16NE | oppression | X16SZR | does not bend | |
| X16XE | oppression | 18E | does not bend | |
| X16XEL | oppression | C18NZ | does not bend | |
| C16SE | oppression | 18SEH | does not bend | |
| Z16XER | oppression | 20SEH | does not bend | |
| C18XE | oppression | C20NE | does not bend | |
| C18XEL | oppression | X20SE | does not bend | |
| C18XER | oppression | Cadet 1.3 1.6 1.8 2.0 L. 8kl. | does not bend | |
| C20XE | oppression | 1.6 if 8 cl. | does not bend | |
| C20LET | oppression | |||
| X20XEV | oppression | |||
| Z20LEL | oppression | |||
| Z20LER | oppression | |||
| Z20LEH | oppression | |||
| X22XE | oppression | |||
| C25XE | oppression | |||
| X25X | oppression | |||
| Y26SE | oppression | |||
| X30XE | oppression | |||
| Y32SE | oppression | |||
| Corsa 1.2 8v | oppression | |||
| Cadet 1.4 l | oppression | |||
| all 1.4, 1.6 16V | oppression |
How to find out if the valve bends?
Checking the engine is there a risk of bending the valves after a timing break
In this matter, neither visual inspection nor the numbers given in the "valve bending" tables will help you. Even if you have information from the manufacturer about damage in the event of a belt break, it is not known how reliable it is.
If you want to check for the likelihood of the valve piston bending when the timing belt breaks, it is necessary to remove the belt, set the first piston at TDC, turn the camshaft by 720 degrees.
If everything went well and he did not resist, you can continue checking - go to the second piston. When everything is fine there, then a possible belt break will not lead to negative consequences for your car's engine.
To avoid this problem (bending of the valves in case of breakage), it is necessary to constantly monitor the condition and tension of the timing belt. When the slightest unfamiliar noise appears during operation, you should immediately try to find out the cause of its occurrence, inspect the condition of the rollers and the pump.
When buying a used car, do it immediately regardless of what the seller told you. And then such an urgent question as Does the valve bend at a break You will not be disturbed.
Bent valve signs
When the belt broke, then simply changing the timing belt, hoping that everything went without consequences and you start the engine, is not worth it. Especially if the engine is on the list of those on which the valve bends. Yes, there are times when the bend was not large and several valves have ceased to fit snugly in the saddle, then you can turn with the starter, but often such actions will further aggravate the situation. Since with minor damage everything will work and spin, however, the engine will shake, and the consequences will only worsen.
Best of all, if you remove the "head" in order to check it visually or fill with kerosene, however, there are several ways to check if the valve is bent without disassembling the engine.
The main symptom if the valves are bent - small or completely no compression... Therefore it is necessary in the cylinders. But, such actions are relevant if the crankshaft can be cranked and nothing rests on anywhere. So the first thing to do is to install a new belt, manually, using the bolt on the HF, turn the entire gas distribution mechanism a few turns (you need to unscrew the candles).
How to check if the valve is bent
To determine if a valve stem is bent, literally five turns of manual cranking with a wrench for the crankshaft bolt will be enough. If the rods are intact, then the rotation will be free, bent - heavy. And there should also be clearly perceptible 4 points (at one revolution) of resistance to the movement of the pistons. If such resistances are imperceptible, then after screwing back the candles, unscrew them in turn and turn the crankshaft again.
Due to the force on manual torsion, with one of the candles missing, it is relatively easy to understand in which particular cylinder the valve (s) were bent. However, this method will not always be able to help you know exactly whether the valve is bent or not.
If the crankshaft turns freely, then you can check with a compressometer... No such tool? Means do a pneumotest, moreover, checking the tightness of the cylinders is the most correct way, which will give an answer as to how the valve discs fit in the seats, without additional consequences when cranking with the starter and without installing a new belt.
How to check if the valve is bent yourself?
For a pneumatic test, it is unnecessary to pull the car to the service station, you yourself can find out whether the cylinder is sealed or not. The easiest way is:
- select a piece of hose according to the diameter of the candle well;
- unscrew the candle;
- set the cylinder piston to top dead center (valves closed) one by one;
- insert the hose tightly into the well;
- try with all your might to blow into the combustion chamber (air passes - bent, does not pass - "carried").
The same test can be done using a compressor (even a car compressor). True, you will have to spend a little more time, as you need to prepare. Drill a central electrode in the old candle, and put a hose on the ceramic tip (fixing it well with a clamp). Then pump the pressure into the cylinder (provided that the piston in it is at TDC).
From the hiss and the pressure on the pressure gauge, it will be clear whether the valve hats are in the seats or not. Moreover, depending on where the air will go, determine the inlet bent or outlet. When the exhaust is bent, air goes to the exhaust manifold (muffler). If the intake valves are bent, then in the intake tract.
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 gives rise to many 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 without its drawbacks, 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 an average of 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 down 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 should 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 in order 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 is why 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 entire kit 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 the valves were bent from the impact, the block head received damage "incompatible with life", the 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 broken timing belt 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:
- the valves are bent;
- the camshaft and its bearings are destroyed;
- block head;
- 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.
When installing an inexpensive analogue of Chinese production instead of an original spare part, 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 analogues, which sometimes are more expensive.
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 jamming of the camshaft or crankshaft. Abrupt loads on the belt can lead to breakage, 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:
- the motor suddenly stalled;
- you cannot start it again;
- 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.
The gas distribution mechanism (GRM) is one of the most important elements in the design of diesel, gas and gasoline engines. There are not so many possible breakdowns for this node, but if they happen, then you should tune in to the most serious consequences. Most often, the timing belt breaks, which on most modern cars is made of high quality rubber. The danger of this malfunction is very high, because an interrupted drive often bends the valve. For more information about the essence of belt breakage, methods of eliminating its consequences and preventing breakage, read below.
Risk of malfunction
For more or less experienced motorists, it has long been no secret that monitoring the health of some units significantly extends the service life of others. This rule is more than ever applicable to the timing belt under consideration today. In many ways, this state of affairs is due to the fact that the drive of the gas distribution mechanism performs the most important function, connecting its elements into a perfectly working system. The latter, by the way, ensures the synchronous operation of the valves and pistons of the motor, and in such a way that they do not interact with each other at all and serve their full operational life.
Timing operation is truly debugged, however, a failure can occur in such a device. The most dangerous of these, primarily for the condition of the engine, is a belt break. This malfunction provokes the asynchronous operation of the valves and pistons of the motor, which results in the following sequence of phenomena:
- First, the valves get stuck in the open position;
- Then the pistons start hitting them. The blows continue until the motor that has lost its compression stalls;
- As a result, either the valves, or the pistons, or other elements of the engine (cylinder head, valve tracks, timing) fail and require expensive repairs.
In rare cases, of course, it is possible to "get off with a little blood", that is - exclusively by breaking the timing belt, but this happens infrequently, so it is worth preparing for the most serious consequences.
Belt break diagnostics
Many inexperienced motorists often ask the question - "How to diagnose a broken timing belt?" In fact, it is very simple. The specificity of this breakdown is such that if it is present, the motor will simply refuse to work. Immediately at the moment the belt breaks, a short but loud bang occurs in the engine compartment, after which the engine stalls. At the moments following the break of the belt, starting the motor becomes impossible, and the starter turns quite easily and with a characteristic metallic knock (the piston hits the valves). Naturally, all this is accompanied by the loss of compression engine.
For a better and more correct diagnosis of a timing failure, an analysis of what happened is not enough. At a minimum, you need to "get" under the hood and check the condition:
- valves (up to a third of all available can be affected);
- parts of the pistons visible through the cylinder head;
- the belt itself.
On most modern cars, the procedure for such a check looks like this:
- The timing is located (it is either in the public domain, or is under the protection of the motor);
- An assessment of his condition is carried out;
- The cylinder head or its protection is removed and the condition of the internal elements of the motor is assessed.
Due to the fact that the process of replacing the timing belt is very simple, it is quite possible to carry out such repairs in the place where the breakdown occurred, therefore, as an ambulance, it is better to have a spare drive with you specifically for the operating model of the motor.
Reasons for the break
Most often, the valve is oppressed due to a break in the timing belt, but few know why it breaks. Naturally, operational wear is at the top of the causes of this malfunction. It is important to understand that a rubber belt, even of high-quality production, is not capable of traveling more than 70,000 kilometers, so it needs to be changed every 60-65,000. You can determine if the drive should be replaced ahead of schedule by examining it in detail. The surface of the belt, at a minimum, should not contain any cracks, torn teeth or oil stains, and in the best case, no wear and tear.
In addition to wear and tear, the timing belt can break for the following reasons:
- the wedge of the gas distribution mechanism due to its internal breakdowns (rollers and tensioner often suffer);
- installation of the drive with a weak or excessively strong tension;
- frequent use of the machine under heavy load conditions;
- violation of the tightness of the engine protection;
- oil on the belt due to leakage of gaskets or wear of oil seals.
The complete elimination of the factors noted above, the timely replacement of the belt and the use of only high-quality parts are exactly what will help reduce the risks of its breaking to a minimum. Otherwise, it is worth preparing for the consequences that take place when the timing belt breaks.
Replacement procedure
The process of replacing a broken belt is conventionally divided into the organization of three main activities:
- Purchase of necessary spare parts;
- Tool preparation;
- Directly repair.
For a better understanding of the entire procedure, it will not be superfluous to consider each stage separately. Let's start, of course, with the purchase of the necessary spare parts. In addition to the belt itself, it is also required to purchase bypass rollers and tensioners. All auto experts agree that they need to be changed together with the timing belt and not save on this. When purchasing certain spare parts, it is important to make sure that they are identical to the parts installed earlier. Achieving the goal is not so difficult if you turn to the technical documentation of the engine being repaired or remove the old timing elements and use them as an example.
As for the toolkit, its minimum list includes:
- set of screwdrivers;
- mount;
- jack;
- wrenches and heads;
- pliers.
Having prepared and purchased the necessary parts, you can begin repair work. The replacement process itself looks like this:
- Disconnect the battery (just disconnect the negative terminal);
- We get access to the belt;
- We combine the timing marks;
- We dismantle the replaceable rollers and tensioner;
- We unscrew the faulty drive;
- We clean the seats;
- Installing new elements;
- We are replacing other consumables of the removed motor units (gaskets, for example);
- We assemble the car in the reverse order;
- We use the machine, henceforth not forgetting to monitor the condition of the entire timing belt and the belt in particular.
Note! If, in addition to the torn belt, any other breakdowns were identified, be sure to eliminate them as well. Otherwise, the repair will have a short-term effect and, in fact, become useless.
If you have any questions - leave them in the comments below the article. We or our visitors will be happy to answer them.
Every time before buying a car, we think about its engine size, how many "horses" under the hood, what fuel consumption, we compare the car by color, interior trim, as well as various elements of the exterior. Of course, these questions 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 this option that you are going to purchase, the popular Renault Logan people's car. The designers of the Renault concern equipped the 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 speaks of 1.4 and 1.6 liter 8V engines (valves), respectively. A car of the "LUX" class has a 1.6-liter engine with a 16-valve "head" with the K4M index. In each of them, a belt protrudes in the form of a timing mechanism drive. And about which engine to choose in the material:
Now we will consider each engine separately and figure out in which of them, when the timing belt breaks, the valves will bend.
K7J - 1.4-liter 8-valve engine (valve bends)
The most popular engine among the domestic consumer of the valve is oppression
The four-stroke four-cylinder gasoline engine K7J evolved in our time straight from the 80s of the XX century. Due to the fact that the engine is a continuation of the line of engines of the previous generation, it has a distinct feature in the form of an outdated design with increased fuel consumption. However, this does not prevent it from remaining one of the most maintainable engines in the lineup.
This engine does not have 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 valves out of 4
Some "loganovodov" this engine prefer its more powerful version K7M.
K7M - 1.6-liter 8-valve engine (valve bends)
Less popular 1.6-liter 8-valve engine - K7M
The K7M engine from Renault is structurally no different from its predecessor K7J. , the same liquid cooling and combined lubrication system. The same problem with oil leakage and lack of hydraulic lifters remained - we adjust the valves.
Bent valve
However, if you look at the technical characteristics, then this engine has a 10.5 mm increased piston stroke (due to the fact that the block height is changed), as well as the largest engine displacement and flywheel.
Nevertheless, all of the above advantages did not help in any way to save the engine valves, if the timing belt breaks, they are oppressed.
K4M - 1.6-liter 16-valve engine (valve bends)
The valve on the K4M engine is bent
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 in comparison with the K7M has increased by 20 hp, while the economy and stability in operation have increased. On the K4M motor, there is no problem with adjusting the valves after a certain mileage interval, since the aforementioned hydraulic lifters are already present there.
The timing is still driven by 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 are bent. And below we will describe the reasons why cliffs occur at all and how to avoid this.
- Timing belt wear (low quality or technical wear), oil ingress, etc.
- Various foreign bodies get under the belt
- Pump jams
- The tension roller (s) jammed or released
- Seizes the crankshaft or camshaft
In order not to worry about the condition of the timing belt, you must constantly monitor its external condition, the degree of tension, replace it according to the regulations or change immediately if it has any damage. Make sure that oil and other liquids do not get on the belt (this is the beginning of premature wear).
It was once a piston and part of an engine
If, when the timing belt breaks, only the valves are bent, we can say that this is great luck. In some situations, with such a breakdown, the pistons themselves and the surfaces of the cylinders may suffer.
Symptoms and behavior of the car in which it is necessary to replace the timing belt
As a result of increased loads or wear of the connecting rod-piston group, the timing belt can jump one turn, as a result of which,. This phenomenon is a symptom to check the condition of the belt and the correctness of its installation.
Repair cost
Specifically in each situation, depending on the state of the engine, after stopping it due to a break in the 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 cost of repair (with materials) will be approximately 10-15 thousand rubles.
