Replacing parts and elements of the engine gas distribution mechanism is a planned procedure. For example, it is recommended to change its tension roller and belt approximately once every 60,000 kilometers. If you ignore these recommendations, the belt may break, causing serious engine damage.
To carry out a replacement, many factors must be taken into account, so the process itself is a rather complex procedure. Despite this, many car enthusiasts prefer to service their car themselves. It is important not to make mistakes and not harm the engine in the process.
Signs and symptoms
There are six main signs that the timing belt has jumped.
- The car engine is unstable.
- The engine constantly stalls.
- Noticeable loss of engine power and thrust.
- The engine starts with problems or does not start at all.
- The power plant is stuck.
- The sound of the engine becomes louder - a metallic knock appears.
Most often, it happens that the product jumps one tooth, and because of this, the engine continues to operate, but increases fuel consumption, and there are also interruptions in operation and starting.
If you suspect that several teeth have jumped, you should not restart the engine. In the worst case, this can cause the valves to bend.
What's the result?
In relation to internal combustion engines with a timing belt drive, it should be taken into account that slippage of the belt even by one “tooth” can lead to malfunctions of the power unit or its breakdown. As mentioned above, if the belt breaks, there is a risk of bending the valves. As for diesel engines, a broken timing belt can render the camshaft unusable.
As a result, I would like to add that when replacing a timing belt, aligning it to the marks is the main task. In this case, if you are not convinced of your own abilities or have problems identifying the marks, then it is better to give up trying to set the belt on your own and turn to experienced specialists.
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Causes
The timing belt is an important element of the car, so it needs to be serviced promptly. The reasons that lead to its jump are as follows:
Contact of oil or cooling liquid on the belt surface
As soon as traces of technical fluid appear on the product, the belt should be changed immediately. Otherwise, this can lead to slipping through the teeth, sliding off the pulley, and even breaking.
It is a serious mistake when drivers simply clean the dirty surface and continue to use this product.
Practice shows that if liquid gets on the belt, it is completely absorbed into the rubber. It loses its properties and begins to stretch.
Late replacement
Most timing belt manufacturers recommend changing their products approximately every 60 thousand kilometers. However, this figure may vary up or down, depending on the quality of the product.
Improper use
It happens that a product may jump due to errors during its operation. A common example is a weakened roller or tensioner. When the belt tension weakens, there is a possibility of slipping from the pulley grooves. In the opposite situation, if when installing the belt, it is overtightened, this will lead to its breakage.
Slippage can also occur when one of the pulleys has strong play. Therefore, it is very important to monitor the tension level of all parts of the mechanism.
The labels are set incorrectly
Sometimes the jump is not visible outwardly, but the engine does not start well and immediately stalls. This can happen if the marks were knocked down or incorrectly set initially. A shift of even one tooth can cause problems with the motor. If the engine is diesel, it will not start even if there is an error of one tooth.
It is necessary to replace the timing belt in safe places using special tools.
This photo shows that the intake is offset by one tooth clockwise; this is one of the most common mistakes when replacing a belt. To prevent this from happening, you can use special pulley clamps when replacing the timing belt.
External damage
Over time, various cracks and depressions may appear on the surface of the consumable, and the threads of the product may begin to peel off. With heavy loads on the belt, even the smallest defects will develop quite quickly. Therefore, they cannot be eliminated on your own. All you can do is replace it as soon as possible.
Low quality spare parts
There are very cheap “non-original” belts on sale. But don't be fooled by their price. Often the resource of such a product is only enough for 20 thousand kilometers. This is followed by either stretching or breaking.
Difficult operating conditions
Unlike a chain, a belt is very sensitive to high and low temperatures, high humidity and other weather conditions. They affect premature wear of the product. Therefore, more frequent replacement may be required.
The main nuances of the functioning of the timing belt in cars
It is extremely important to understand that the rubber timing element is responsible for transmitting the timing gear in the motor shafts. The latter, in turn, are responsible for the maintenance of the air-fuel mixture in the cylinders of the power unit
How belts break
If the timing belt jumps or breaks, the entire timing belt system begins to function differently. All this is manifested by shifts and malfunctions of the most important component of the car - its engine. It was written in detail above that in these cases the power of the power plant necessarily decreases, fuel consumption increases and starting deteriorates.
In addition, slippage or rupture of the timing component can cause failure of the piston-valve group in the engine. When the belt breaks, the valves open towards the piston, which leads to internal engine problems.
Monitoring the condition of the timing belt is a guarantee of preventing severe consequences for the power plant
But it is important to be able to control not only the appearance of the belt, but also the degree of tension. On their own, which is quite natural, it will be extremely difficult for a person with non-professional skills to diagnose the correct installation of the belt
In order not to make a mistake, you need to pay attention to the service life of the belt and the condition of the parts accompanying the operation of the element. In particular, ensuring the degree of tension and uninterrupted operation
The period for replacing the most important timing part may vary. It depends on the specific car manufacturer. In addition, it is necessary to take into account such an indicator as the originality of the part. It is clear that “left” companies can easily produce defective belts or belts with a reduced service life.
It is also important to understand that on the modern market you quite often find parts of the universal type rather than the standard one. What does it mean? It's simple - universal parts, belts in this case, are not made for a specific car
They are not a priori characterized by good quality, and although they are cheaper than the original ones, they are not recommended for purchase.
Timing diagram
You can distinguish an original belt from a universal one (there are several effective ways). If the part is universal, then to determine the service life of the belt and its replacement, you will have to take this into account. In other words, if the manufacturer indicated that the belt can last 70 thousand kilometers on his car, this does not apply to the universal one. This one will definitely last less.
As mentioned above, the service life of the belt on front-wheel drive VAZs is approximately 60-70 thousand kilometers. If the car was purchased secondhand, you should not trust its owner who claims that the belt is new, there will be no problems with it.
When choosing a new timing belt for your car, it is recommended to pay great attention to the material. If there are no marks left on the rubber after several folds in and out, most likely, everything is fine with the material
But on the contrary, if even the slightest microcracks are noticed, it is better not to buy such a belt right away.
It is also recommended to check the belt model number with the number specified in the operating manual for a specific vehicle. The numbers are unlikely to match; it is a great success if such a belt can be found. But you can check belts in another way: by comparing the length, width and thickness of the old factory belt and the new analogue.
The belt must also be checked around its entire circumference. If protruding threads are noticeable on the ribs, the cord will be visible, it is better to immediately abandon this option.
Timing belt teeth
If you do not have the appropriate skills and ability to work with your own hands, it is better to entrust replacing the timing belt to professionals. Without a doubt, a seemingly simple operation at first glance can fray your nerves and take a lot of effort. And most importantly, an illiterate replacement can lead to even bigger problems.
Of course, in a big city it will be easier to find a quality car service among the many options. In rural areas, you have to rely on the honesty of service station workers or carry out this event yourself
The most important thing is that it doesn’t matter which method was chosen, what’s more important is to save time and money, getting the highest quality result
Consequences
The consequences of the timing belt jumping several teeth can be different - from replacing the timing belt itself to repairing the car’s gas distribution mechanism.
The amount of damage depends on whether the engine has recesses for valves in the pistons or not.
A jump can occur while the valves are being lowered to inject fuel or release gases. The pistons are still moving and can hit the valves hard. This will lead to bending of the latter. This situation is similar to a broken timing belt. You can read more about which engines this happens on in this article.
To avoid this situation, it is recommended to do a timely inspection and, if necessary, change the consumable.
Labeling
Before starting work, you need to understand that it is important that during the process of replacing the timing belt, the pre-set risks do not go astray. Otherwise, you will have to go deeper into the settings and spend more than one hour installing the part.
When installing the timing belt, it is important to align the pistons so that in the first cylinder the piston is at the highest point of the first cylinder. In this position, the piston is at its maximum distance from the crankshaft. This is the position the engine is in when the marks are correctly set. In this position it is necessary to change the timing belt.
The number of marks, as well as their location, may vary depending on your engine type.
The following marks can be distinguished:
- Mark on the flywheel.
- Mark on the pulley.
- Camshaft mark (two on a 16 valve engine).
Repair cost
The average price for replacing a belt and roller in car services ranges from one to three thousand rubles. The price range is due to the fact that replacing parts on foreign cars costs approximately 2–3 times more than on domestic cars.
If it turns out that you also need to change the engine water cooling pump and the crankshaft oil seal, then the price will increase by another 1 - 1.5 thousand rubles.
Although there is a huge selection of products on the market at different price levels, you should only choose brands recommended by the manufacturer or their high-quality analogues. Using cheap parts can lead to serious damage and expensive repairs.
For example, if the valves are bent as a result of a belt slipping, then almost the entire cylinder head will have to be replaced. Even if the repair is carried out by yourself, the cost of replacing valves, pump, belt, filling oil and antifreeze, and other parts will be at least 10,000 rubles.
Source
The timing belt has broken: what to do, reasons, signs
Car owners know about such a malfunction as a broken timing belt. For newbies behind the wheel, this topic is a kind of horror story. Quite often, after a broken belt, a car requires serious engine repairs. This article describes the main causes of breakdowns, describes what to do in such a situation, and also how to prevent breakdowns from occurring.
What happens to the engine when the belt breaks?
When the car is running, the engine pistons move in a certain direction. The piston moves down during the intake stroke and rises during the exhaust stroke. When the cylinder block is at the top point, each valve must be closed.
When the timing belt is torn, the valve stops rotating and stops. However, the crankshaft rotates and the pistons are directed towards the open valves. After their meeting, the parts bend and become unusable. Regardless of whether the car is idling or in gear, the likelihood that the pistons will knock on the valves and bend them is quite high.
But still, the higher the speed, the worse the likely consequences. In addition to the fact that the valves will be damaged, the pistons may be damaged and the guide bushings may burst.
If the timing belt breaks at high speeds, then all the valves will be damaged, and fragments of the bushings will pierce the pistons. Repairing the mechanism after such damage will be very difficult and expensive. In some engines it is easier to replace the entire head after this.
What to do if the timing belt breaks while the car is moving
If the timing belt breaks while driving, do not panic.
If a break occurs, the car's engine will stop working or start turning too easily. You need to pull over to the side of the road and put up a warning triangle.
First actions in case of timing belt breakage
- Open the hood and assess the situation.
- If you see a torn belt, immediately call the service station.
- To avoid part breakage, it is necessary to replace it in a timely manner. The car can be towed to a car service center or a tow truck can be called.
If it turns out that you don’t have a spare belt, you shouldn’t try to “fix” it; nothing good will come of it. On some engines, if you have experience, you can replace the belt on site, having a spare set on hand. But we recommend contacting the service.
The cost of replacing a belt depends on the car model and its production date. The approximate price range is from one thousand to ten thousand rubles. To avoid having to spend extra money and your time, carry out timely replacement and routine inspection of timing belts.
To avoid having to repair your car, you must follow a number of rules:
- Read the operating instructions and follow them.
- Periodically check the serviceability of the timing belt.
- Buy a spare part and always carry it with you.
- Write down the phone number of the service station.
On which engines do valves bend?
If the timing belt breaks, the consequences can be different. Some will get away with an easy replacement of the necessary part, while others will require complex repairs.
When the timing belt breaks, the valves will suffer the main losses. After a break, the upper shaft stops working and the valves freeze in one position. At this moment, the crankshaft pushes the piston up, and it exerts a mechanical force on the parts. The valves are bent. This leads to very expensive repairs.
And also quite serious consequences after a belt break occur in diesel engines. This is due to the design of the mechanism; after one part breaks, a chain reaction is started, which causes irreparable damage to the remaining elements: the camshaft, bearings, pushers, etc.
Sometimes a broken belt leads to a broken camshaft or deformation of the top of the piston. After this, you will have to disassemble the engine, replace valves, etc. In some cases, such repairs will cost about thirty thousand rubles or more. And when the pistons need to be replaced, the amount increases even more.
Not all cars will need complex repairs. Some piston models have special recesses and when the belt breaks, the piston rises, but the valve remains motionless, the piston falls into the “hole”, the valve is not deformed. The driver just needs to install a new belt and the engine will start working.
Not all mechanisms are equipped with such recesses, as they reduce engine power. And manufacturers of famous brands are fighting for it as best they can.
The conclusion is simple: replace parts in a timely manner and no troubles will arise.
How to understand that the timing belt has broken
Inexperienced drivers will not always be able to independently determine what kind of breakdown has occurred in the car.
Signs of a broken timing belt:
- The car has stalled and the engine will not start. The compression is broken and the car will not start. Inexperienced drivers try to prevent the engine from starting and drain the battery. Such actions only worsen the situation. The piston causes mechanical stress to the bent valve, and when trying to start the engine, the damage becomes even greater.
- The engine turns very easily. This is due to the fact that there is no compression and nothing holds the pistons.
If you open the hood, in some car models you can see pieces of the timing belt. Let us note that it is important to timely replace the entire timing system, including belts, pumps, rollers, etc. By observing these requirements, the engine mechanism of your car will last a long time.
Why does the belt break?
The main reason why a belt breaks is due to the careless attitude of the car owner. It's all about untimely replacement of a worn part. The average belt replacement interval is sixty thousand kilometers. The first time drivers change a part at a service station, and then they simply forget about this event.
There are a number of main reasons why a belt may break:
Quality of spare parts
The quality of spare parts depends on the brand of timing belt manufacturer. You should not skimp on such details. For the middle price segment, belts from the following brands have become very popular: Balakovo, Bosch, Lemforder. More expensive - Gates, Contitech, Dayco. To avoid any troubles during operation of the part, carefully select parts. The roller jams or releases spontaneously.
Incorrect belt installation
Quite often, a break occurs after 1000-2000 km. after the previous replacement. The main reason is insufficient or excessive tightening. It is best to carry out such work from trusted professionals, and also check the condition of the car after the work. Listen to see if the sound the engine makes has changed. Check to see if the belt has slipped or cracked.
Broken tension rollers
Tension rollers are designed to tension the timing belt. They prevent parts from jumping off and slipping. A roller is a kind of bearing with a special coating. All parts have their own service life. A worn roller is noisy and if you do not replace it, it will ruin the timing belt in a short period of time.
Pump wedge
Most often, cars from Russian manufacturers are susceptible to such breakdowns. This is a rare occurrence in foreign cars. If the pump jams, the belt breaks and requires replacement.
Late replacement
Aging and wear of the part is one of the most common causes of rupture. According to average indicators, belt breakage occurs after sixty thousand kilometers. In foreign-made cars, this figure can reach one hundred and fifty thousand kilometers. But everything has its limit. During use, the part wears out and becomes unusable. Belt wear is the most common cause of component damage. In Russian cars, the service life of the belt may be even lower than described above, so when buying a used car, it is better to immediately replace the timing belt.
Foreign elements
Sometimes oil and dirt can get on the part and jam the distributor or crankshaft. Be sure to check the protective cover and fasteners. If necessary, replace.
Please note that if the car operates in difficult conditions (frequent short trips, cold seasons, insufficient engine warming up), then the timing of replacing the timing belt is reduced.
Consequences of timing belt breakage and likely costs
The consequences of a break depend on the type of engine, the presence of grooves on the pistons, the quality of the parts and the reasons for the timing belt break.
The most common consequences:
- Buying and replacing a belt
- Engine repair.
Read more about possible engine problems
- Overhaul of the entire engine.
- The need to repair the entire gas distribution mechanism. The most significant problem is bent engine valves that cannot be repaired. This problem most often affects cars in which the combustion chamber is reduced or the pistons do not have recesses. In order to accurately determine the level of damage, you need to take the car to specialists.
- Sections of the piston system are deformed. Such damage most often occurs in Japanese cars. When the blade breaks at high speed, the bushing breaks and the pistons are damaged by the fragments. The consequences are an expensive replacement of all parts.
Diesel engines suffer serious consequences after the fabric breaks.
Car owners will need to replace a number of main parts of the gas distribution mechanism:
- Camshaft.
- Cylinder head.
- Connecting rods.
- Valves.
Costs for eliminating the results of timing belt rupture
The average cost of a valve is about one thousand rubles (excluding replacement). To calculate the total cost, you need to take into account the number of valves that need to be replaced. If there are sixteen of them, the total cost will be high.
Additionally you need to buy small parts:
- Timing belt or complete timing gear kit with all bearings.
- Cylinder head gaskets and manifolds.
- Valve plugs.
- Fasteners.
- Pump (all belt manufacturers recommend changing the pump at the same time as the timing belt)
If the driver carries out car repairs himself, he will also need various tools
Preventive measures
To avoid problems with the operation of the timing belt, it is necessary to periodically replace it. It is best to buy original spare parts, not to wait until the blade is completely worn out.
Periodically (every 30 thousand km) check the condition of the belt to prevent breakage, monitor the belt tension level, the condition of the pump and tensioners.
Incorrectly installed timing belt symptoms
How can this be?! It took me 92,000 km, 3 (three!) years and as many as 3 (three!) timing belt replacements to find out that the reason for the constant jerking at idle is trivial! — timing marks
I'll start with some background. I bought a wad in 2013 with a defect - when working at XX, it shook and swayed cyclically. In a traffic jam you could feel your head swaying in time with the fawn...
Unfortunately, the video was not saved...
This confused me when I bought it, but it didn’t stop me.
So, the wad has been purchased, a normal discount has been requested for the uneven operation of the internal combustion engine, allowing you to immediately order the spare parts and solve the problem once and for all. We didn’t do anything with our fingers, we’ll fix everything now. Yeah. ))
Ordered spark plugs and ignition coil. I changed it - it didn't help.
Yeah, that means pillows. Ordered + replaced = did not help.
Apparently the injectors are clogged. My wynns'om three times did not help.
The diagnostician at work gives me an idea - maybe an air leak? OK, remove the intake manifold and find cracked o-rings on the intake ducts. Due to the lack of new ones, we smear the old ones with sealant, collect them - ZERO result.
Oh yes, I was undergoing diagnostics in a French repair garage (the diagnostician works for an official dealer in his free time from the garage). Verdict - “you need to remove the cylinder head, see what’s there...” (...what the hell is there - valves, pistons, what else). The idea was immediately dismissed as untenable.
By the way, usually when buying a used car, people change all the fluids and the timing belt. But the previous owner gave me a work order to replace the timing belt 15,000 km ago. Therefore, it was planned to get into the timing belt only after 45,000 km, at least.
I tried refueling with 95, 98 - to no avail.
The throttle body was washed, trained in Feng Shui, the pressure sensor in the intake manifold was washed...
A crack was found on the crankcase ventilation tube; it was successfully insulated to no avail.
In the end, I think maybe M E T K I G R M
? ! It’s okay if I change the belt and rollers earlier, but maybe I’ll fix the problem! So, I bought a timing belt kit, read up on how to change it, where the marks are and all that, and went to change it.
I read: “We fix the flywheel with wire. There is a small hole to the right of the oil filter on the block towards the gearbox. Remove the oil filter cover and look with a mirror. We insert a steel wire there, it should go in about 5 centimeters.” And there is even a photo:
Okay, I find a plastic plug behind the oil filter,
I pick it out (I couldn’t put it back, to do this you need to at least remove the oil filter housing...), lock the camshafts with bolts, stick it in the hole behind the oil filter (under the plug
) the letter “G” made of wire, she fit in there, bitch! I think - fire!
I look, and the mark on my HF looks at 7 o’clock, but it should look at 6!
Hmm... You need to unscrew the camshaft gear and look - maybe the key has been cut off. Fuck it! The KV bolt could not be unscrewed with a pneumatic impact wrench! Well, I think, okay, so I won’t touch the HF gear, otherwise you never know!
I put the belt as it was (the mark on the HF is at 7 o'clock, and the mark on the belt is at 6 :)))), I assemble it - naturally, the engine still rocks.
I have temporarily postponed the solution to this issue, I’m driving like this for now. The wad drives, in principle, normally, confidently. Consumption is around 9 l/100 km, which also suits me quite well. In general, there is no reason to worry. Besides the fact that he still sways, the bastard...
The main nuances of the functioning of the timing belt in cars
It is extremely important to understand that the rubber timing element is responsible for transmitting the timing gear in the motor shafts. The latter, in turn, are responsible for the maintenance of the air-fuel mixture in the cylinders of the power unit
If the timing belt jumps or breaks, the entire timing belt system begins to function differently. All this is manifested by shifts and malfunctions of the most important component of the car - its engine. It was written in detail above that in these cases the power of the power plant necessarily decreases, fuel consumption increases and starting deteriorates.
In addition, slippage or rupture of the timing component can cause failure of the piston-valve group in the engine. When the belt breaks, the valves open towards the piston, which leads to internal engine problems.
Monitoring the condition of the timing belt is a guarantee of preventing severe consequences for the power plant
But it is important to be able to control not only the appearance of the belt, but also the degree of tension. On their own, which is quite natural, it will be extremely difficult for a person with non-professional skills to diagnose the correct installation of the belt
In order not to make a mistake, you need to pay attention to the service life of the belt and the condition of the parts accompanying the operation of the element. In particular, ensuring the degree of tension and uninterrupted operation
The period for replacing the most important timing part may vary. It depends on the specific car manufacturer. In addition, it is necessary to take into account such an indicator as the originality of the part. It is clear that “left” companies can easily produce defective belts or belts with a reduced service life.
It is also important to understand that on the modern market you quite often find parts of the universal type rather than the standard one. What does it mean? It's simple - universal parts, belts in this case, are not made for a specific car
They are not a priori characterized by good quality, and although they are cheaper than the original ones, they are not recommended for purchase.
You can distinguish an original belt from a universal one (there are several effective ways). If the part is universal, then to determine the service life of the belt and its replacement, you will have to take this into account. In other words, if the manufacturer indicated that the belt can last 70 thousand kilometers on his car, this does not apply to the universal one. This one will definitely last less.
As mentioned above, the service life of the belt on front-wheel drive VAZs is approximately 60-70 thousand kilometers. If the car was purchased secondhand, you should not trust its owner who claims that the belt is new, there will be no problems with it.
When choosing a new timing belt for your car, it is recommended to pay great attention to the material. If there are no marks left on the rubber after several folds in and out, most likely, everything is fine with the material
But on the contrary, if even the slightest microcracks are noticed, it is better not to buy such a belt right away.
It is also recommended to check the belt model number with the number specified in the operating manual for a specific vehicle. The numbers are unlikely to match; it is a great success if such a belt can be found. But you can check belts in another way: by comparing the length, width and thickness of the old factory belt and the new analogue.
The belt must also be checked around its entire circumference. If protruding threads are noticeable on the ribs, the cord will be visible, it is better to immediately abandon this option.
If you do not have the appropriate skills and ability to work with your own hands, it is better to entrust replacing the timing belt to professionals. Without a doubt, a seemingly simple operation at first glance can fray your nerves and take a lot of effort. And most importantly, an illiterate replacement can lead to even bigger problems.
Of course, in a big city it will be easier to find a quality car service among the many options. In rural areas, you have to rely on the honesty of service station workers or carry out this event yourself
The most important thing is that it doesn’t matter which method was chosen, what’s more important is to save time and money, getting the highest quality result
Causes of belt and timing chain jumping
The main reasons for timing belt skipping are:
- natural wear of the belt during operation;
- abrasion of teeth as a result of misalignment of the rollers;
- increased resistance to movement in the event of a malfunction in the gas distribution system;
- foreign objects getting into the belt drive;
- pulley wear;
- stretching of a low-quality belt;
- overheating of the power unit;
- Tensioner malfunction.
Old videos
As the vehicle is used, all elements of the gas distribution mechanism wear out. If the belt is worn out and loses its functionality, then the tension roller will deteriorate in quality even when it looks quite good on the outside.
It is not recommended to skimp on this important part, since excessive load on it when tensioning a new belt can lead to jamming and another break.
In addition, the new timing belt on the old pulley may slip. This phenomenon will inevitably lead to increased wear of all elements. In addition, the power unit will be noisier. So it’s better to change the entire set.
Causes
The timing belt is an important element of the car, so it needs to be serviced promptly. The reasons that lead to its jump are as follows:
Contact of oil or cooling liquid on the belt surface
As soon as traces of technical fluid appear on the product, the belt should be changed immediately. Otherwise, this can lead to slipping through the teeth, sliding off the pulley, and even breaking.
It is a serious mistake when drivers simply clean the dirty surface and continue to use this product.
Practice shows that if liquid gets on the belt, it is completely absorbed into the rubber. It loses its properties and begins to stretch.
Late replacement
Most timing belt manufacturers recommend changing their products approximately every 60 thousand kilometers. However, this figure may vary up or down, depending on the quality of the product.
Improper use
It happens that a product may jump due to errors during its operation. A common example is a weakened roller or tensioner. When the belt tension weakens, there is a possibility of slipping from the pulley grooves. In the opposite situation, if when installing the belt, it is overtightened, this will lead to its breakage.
Signs of a Dying Belt
Visual
It is believed that a visual inspection will help determine the life of the drive. Fraying, tears, cracks, etc. They can tell you whether the belt will still “run” or break after a few kilometers.
Let's figure it out right away. The belt can not only break. The teeth on it wear out. This is fraught with its “slip” on the camshaft. The valve timing will go wrong, the engine will not only lose its power, but will also have difficulty working. In some cases, pistons and valves may meet. The result of their “union” will be a major overhaul.
So, a visual inspection may not show wear or broken teeth. Some of them may be hidden far from your eyes. Others at this moment will be on the shaft sprockets. Everything looks good, but in reality they are already on the verge of a bummer.
Secondly, not all engines have timing belts within visual reach. Some are hidden by protective covers, which are under the front plate of the motor. Partial disassembly is required to get to them. On most BMW engines, it is necessary to “lower” the power unit in order to reach the timing belt. Having reached it, is there any point in inspecting it? – Since you are already there, it is better to replace it immediately, so as not to deal with nonsense for another 60-100 thousand km.
For example, the Opel Cadet engine belts can be easily seen by opening the hood of the car. But there are very few such models, so one can be skeptical about this sign of timing drive wear.
Best before date
Sorry, what is this, food? There is an opinion that there is an expiration date on the timing belt. Compliance with it guarantees reliable operation for this period only.
Each car manufacturer has regulations for replacing the gas distribution mechanism drive. Only strict adherence to it can give any guarantee, and even then it is not one hundred percent.
This also includes the myth about the inverse relationship between engine power and belt service life. V-shaped monsters with a volume of more than 4 liters can live with their “native” strap for hundreds of thousands of kilometers. And vice versa, low-volume engines, for example VAG engines, do not always live up to 100 thousand km.
Many people recommend changing the belt after 5-6 years of using the car. But if during this period the car has driven 200 thousand, then of course. If the mileage has barely exceeded 30,000, and the car is 7 years old, then why do a replacement operation that is not always cheap if it still “uses” enough time?
Many may argue that this is a rubber product, which dries out over time and loses its mechanical properties. Yes, but if external factors, aggressive liquids, dust, dirt, reagents do not have any negative impact on it, then why should it deteriorate? – This is another myth.
Unlike the cooling system hose, brake and fuel hoses, and suspension silent blocks, which face destructive factors, the timing belt does not experience this. Only in exceptional cases can it begin to “age” faster, but we’ll talk about this below.
Extraneous sounds
This is another sign of an imminent belt break. I am ready to agree with this. From my experience, I note that in 80% of cases, shuffling, cyclic sounds will be a direct sign indicating the need for replacement.
But tensioner rollers and sprockets can make noise. Incorrect operation of attachments, such as a pump, can be echoed. In this case, it is necessary to “open” the front plate or more detailed diagnostics in order to identify the source of the unpleasant noise.
Oil
This is a 100% sign that the timing belt needs to be changed. As mentioned above, the encounter of rubber products with aggressive media, such as oil, leads to a rapid loss of their mechanical properties.
Again, it is not always possible to visually diagnose this. Yes, if there are oil streaks on the front plate in the pulley area, not fogging, then the chance of an oiled belt increases. A leaking crankshaft oil seal will result in oil getting onto the belt.
In cases of Opel Cadet, where the belt is not covered with anything, it can suffer not only from oil deposits, but also from antifreeze, for example. Here we turn to the first sign - a visual examination does wonders for diagnosis.
Used car
This is not just a sign, but a primary necessity. After buying a used car, the first thing you need to do is go to a service center and change the timing belt. Troubleshoot the tensioner, shoes, sprockets, damper, if any, for wear. Often, previous owners did not bother preparing the car for sale. Why change something if you are going to “throw away” your old car.
Symptoms of malfunction
The main signs that the belt or chain has slipped:
- change in throttle response, power, engine torque;
- increase in the toxicity of exhaust gases, their shade;
- problems when starting the engine;
- a “check engine” error message appears on the dashboard;
- the occurrence of extraneous noise of a non-metallic (for belt drive) and mechanical nature (for both chain and belt drives).
If such signs appear, you should stop driving (start the engine), have the engine diagnosed, or contact a mechanic.
Why and when you need to change the timing belt
As is clear, the timing base is the camshaft, which is located in the cylinder head and pushes the intake/exhaust valves. The camshaft is driven from the crankshaft by a drive belt. Timely opening and closing of valves must be carried out in a strictly established order and in accordance with the engine operating cycles.
In other words, during the intake stroke the intake valve must open, so air or a fuel-air mixture (depending on the type of engine) enters the cylinders. Next, the consistency is compressed (the piston moves to TDC), at this moment all valves are closed. After the fuel charge is ignited and useful energy is released to the piston, the exhaust valve opens to remove exhaust gases from the engine cylinder. This is how the gas distribution process is carried out.
It becomes clear that any malfunction of the camshaft drive will lead to disruption of gas exchange in the cylinders, as a result of which the operation of the engine will be disrupted. As for the timing belt, this element is a rubber product that stretches, cracks, etc. over time. Belt slippage causes the valves to stop opening at the correct moment in relation to the engine operating cycles. Moreover, for many engines, a broken timing belt is especially dangerous. The fact is that if the belt breaks, then the gas distribution mechanism stops, the valves simply do not have time to close before the piston rises, an impact occurs, after which the valve usually bends, defects appear on the piston itself, etc. In such cases, the power unit needs to be repaired, and the repair itself will require significant financial expenses.
You should also take into account a number of reasons that can significantly reduce the service life of any belt. For example, engine oil getting on the timing belt as a result of leaks in the crankshaft front oil seal can quickly render the designated camshaft drive element unusable. Problems with the tension roller, jamming of the pump and other malfunctions are the reasons why the belt breaks or wears out quickly.
If signs of wear on the timing belt are noticeable or the time for its scheduled replacement is approaching, then it is not much to simply install a new element. When replacing, the belt should be set correctly. To replace and expose, you need to prepare tools; it is also better to service the car on a lift or in a garage with an inspection pit. The smallest set for this operation can be considered a jack, screwdrivers, spanners and socket wrenches, a socket wrench, preferably a wrench with a socket head, etc.
Read:
The car does not start after replacing the timing belt, timing chain or carrying out other work on the gas distribution mechanism drive. Main prerequisites, advice.
How to understand that the marks are knocked down, symptoms
After replacing the belt, a situation may arise that the marks were installed incorrectly. How to determine this is described below.
- Traction and throttle response disappear.
- The car begins to accelerate more slowly.
- The engine gets very hot.
At the end of the article, we would like to note that not every car owner can correctly set the timing marks. It is necessary to have information about the operation of the engine and its design features. If you don’t want to spend a single hour setting up the mechanisms, we recommend turning to specialists.
Do-it-yourself timing belt alignment
A timing belt is a relatively common solution for driving timing gear and other equipment compared to a timing chain. With all this, the designated belt serves less than the chain, in other words, it needs repeated replacement. Most drivers know that when replacing the timing belt, the drive pulleys are marked according to marks, which is necessary for precise synchronization of the operation of the engine and the gas distribution mechanism.
With all this, not many people fully understand how to correctly set the timing belt when replacing it themselves and why this is so important. Let us immediately note that if the timing belt is not aligned with the marks, then a failure of the valve timing occurs. As a result, the engine may not start after such a replacement, it will work unstably, or even the internal combustion engine may break down. In this article we will talk about what are the symptoms of an incorrectly aligned timing belt, as well as how to align the timing belt with or without marks.
Read in this article
Changes in engine performance after jumping
Typically, timing belt or chain jumping occurs as a result of the simultaneous action of several factors, for example, stretching, increased load during engine starting or driving. In this case, skipping can occur through the gears (pulleys) of both the crankshaft and the camshaft pulley. After this, the ignition shifts towards late.
The amount of this displacement in angular units depends on the number of timing belt teeth or chain links. A shift of the timing belt by one tooth corresponds to a change in the ignition angle by an amount equal to the ratio of 360 angular degrees/number of teeth. For example, if the number of teeth is 100, then the offset will be about 3.6 degrees.
A delay in the engine ignition angle by this amount often does not exceed the operating parameters of the engine.
When displaced by one tooth (link), the engine usually works. The following changes are observed:
- increased fuel consumption;
- difficulty starting the engine;
- increased toxicity of exhaust gases;
- reduction in engine response.
In the case when the belt has slipped by more than a tooth, the change in the ignition angle is more than 5 angular degrees. This is a critical value. In modern cars, the control unit usually turns off the engine to prevent serious mechanical damage, especially in engines where the pistons “meet” the valves in such a situation. Experienced drivers, when choosing or purchasing a car, are specifically interested in whether pistons and valves are found in a given model of engine installed in the car.
When a belt (chain) jumps over two or more teeth (links), the following are observed:
- misfires;
- uneven engine operation, the engine naturally “sausages”;
- engine start failure;
- extraneous sounds when the power unit is operating.
Operating a car in such a situation is extremely dangerous.
Aligning the belt according to the marks and how to set the timing belt without marks
Let's start with the fact that below we will focus on the general rules and instructions regarding how to set the timing belt. With all this, it should be taken into account that on cars with tuned sports camshafts, as well as on some models with 2 or only one camshaft, the order and features of the drive belt alignment may differ. To obtain clearer information, it is better to consult with specialists or separately study the operating instructions for a specific internal combustion engine model.
The timing belt jumped a tooth. Symptoms and consequences. VAZ 8 class.
In our case, the teeth on the belt are cut and the timing is off.
Before work, you should keep in mind that the main task will be to ensure that the previously set marks do not get lost during the replacement. This will help simplify the process because there will be no need for advanced configuration ahead.
- So, when installing a new timing belt, the most important step is to set the position of the pistons in the engine so that in the first cylinder the piston will be at top dead center (TDC). Then the marks are checked. Let us add that you can set the pistons to the required position using one of the available methods. The easiest way is to find a special notch on the pulley, as well as an arrow located on the timing belt casing. The indicated notch and arrow should be combined with each other. Alignment implies a position where the notch is in a vertical position and the arrow is pointing down.
- The second method, which complements the first, is to detect a special mark on the flywheel, after which the marked mark is aligned with the “tooth”. The mark is located in the control window, which is located in the upper part of the gearbox bell.
- The third and most unreliable method of aligning the pistons is to unscrew the spark plug in the first cylinder, after which a suitable screwdriver or a metal rod of suitable length is inserted into the spark plug hole. Then the rod rests against the piston, after which, as a result of turning the crankshaft, the point at which the piston is in the last upper position is determined. Please note that a similar method should only be used in this case if labeling is not feasible for some reason.
Timing device
To begin with, let us briefly recall how these mechanisms work. On most engine models, the gas distribution mechanism consists of the following components and parts.
So, the valves are controlled by the camshaft. Most often it is made of steel or cast iron. It is installed in the crankcase. This crankcase is covered by the timing cover. Also on modern engines, the camshaft can be found in the cylinder head. When the shaft rotates, it acts on the cams, which, in turn, act on their valve.
The design also includes pushers - they can be steel or cast iron. Their function is to transmit force from the camshaft and cams to the valves.
The mechanism has two valves - inlet and outlet. Their task is to supply the fuel mixture to the combustion chamber and then remove the exhaust gases. The valve is a rod with a flat head. The inlet and outlet elements are different from each other. The difference concerns the diameter of the head or plate. These timing elements are made of steel and heat-resistant steel (in the case of exhaust valves). The leg is a rod with a groove. It is needed to secure the springs. The valves can only move towards the bushings. To prevent oil from getting into the cylinders, sealing caps are used. An external as well as an internal spring is attached to each of the valves. Rods in the timing device are necessary to transmit force from the pushers to the rocker arm.
Reasons why valve bends
The following main reasons can be identified:
- Condition of the timing belt (cracks, worn teeth, the belt is overtightened or loose)
- Failure to comply with the timing of belt replacement (high mileage of the vehicle).
- Entry of a foreign body (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 compression of the cylinders and for the release of exhaust gases. They move because of the camshaft, which unwinds and presses on the valve. The engine operating cycle is a periodically repeating series of sequential processes occurring in each engine cylinder. The engine operating cycle occurs in 4 strokes or 2 revolutions of the engine crankshaft. (such engines are called 4-stroke; there are also 2-stroke engines, but they are not used in cars now). So you:
- Inlet
- Compression
- Extension
- Release
The valves open and close at the right time. The drive is carried out by cams located on the camshaft. When the cam rotates, its protruding part presses on the valve, causing it to open. Cl. the spring closes it.
The cam is an integral part of the gas distribution shaft (drivers call it the camshaft). The camshaft has bearing journals and cams. Torque from the crankshaft to the camshaft is transmitted by a chain or timing belt.
If the drive belt breaks while the engine is running, the camshaft is no longer connected to the crankshaft. And it can stop arbitrarily in a position in which one of the valves is completely open. In this case, when moving upward, the piston may collide with the valve, which in this case bends. And as a result, the engine faces serious repairs. The engine will need to be disassembled, the valves need to be replaced, and in some cases the “Head” of the block may also be damaged, so much so that it will need to be completely replaced.
On what cars do valves bend?
On most cars, when the timing belt breaks, the problem of valve bending occurs
It doesn’t even matter whether the engine is idling or driving along the highway. They can still bend. It is important exactly how much the gear is turned when the belt breaks.
The bend can occur at 8, 16 and 20 cells. engines, on diesel and gasoline engines, small cars and cars with large displacement. Therefore, it is very important to promptly replace the timing belt. But a timing belt break does not always lead to bending
It is important exactly how much the gear is turned when the belt breaks. Bend can occur at 8, 16 and 20 cells
engines, on diesel and gasoline engines, small cars and cars with large displacement. Therefore, it is very important to promptly replace the timing belt. But a timing belt break does not always lead to bending.
On what cars does the valve not bend?
Some engines have small protection - grooves, which are small notches. These grooves are installed so that at high speeds the piston does not catch up with the closing valve. But when the timing belt breaks, they also help reduce the negative consequences, and in some cases they do not bend the valve at all.
Sometimes car owners grind them themselves, but this is not always correct. Since 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 abandoned such protection.
The most reliable method of combating valve bending is timely replacement of the belt.
Measures to prevent serious consequences of a malfunction
If possible symptoms of belt or chain jumping occur, computer diagnostics should be performed. The malfunction can be determined by the ignition angle being too large. In static mode, diagnostics may not show an engine error, since the electronic components remain operational.
It is necessary to measure parameters in dynamic mode. At the same time, it is dangerous, especially if more than one tooth has slipped through. When an engine is running in which the timing belt has slipped, mechanical damage to individual components is likely.
You can determine the malfunction visually. This requires access to the marks and belt drive. Older gasoline cars use a strobe light as a control device.
Timing belt repair and maintenance
The main problem with this mechanism is worn journals, cams and increased clearance in the bearings. To reduce the gap, grinding of the camshaft journals is necessary. At the same time, the grooves for oil supply are also deepened. The necks are ground to repair size. Next, after repair, check the height of the cams.
There should not be even minimal damage on the supporting parts under the necks. There should be no cracks in the bearing housings. After cleaning and washing the camshaft, be sure to check the gap between the journals and the hole in the cylinder head support.
The chain should not be stretched or have mechanical damage. As long as it is not worn out, it can be adjusted. Unscrew the locking bolt half a turn. Then turn the crankshaft 2 turns and then tighten the locking bolt.
Source
Instructions for replacing the timing belt step-by-step
1. The first step, before removing the power steering, alternator and air conditioning belts, I would advise loosening the 4 bolts, under the 10 head, securing the pump pulley.
2. Remove the power steering belt. We loosen the power steering mounts - this is a long bolt on the lower mount under the head at 12
3. Remove the power steering belt;
4. Remove the power steering pump housing from the engine and fix it by tightening the bolts;
5. Loosen the upper mount of the generator (bolt on the side of the tension bar) and the belt tension bolt
6. Remove the right plastic casing at the bottom of the car
7. Loosen the lower generator mounting bolt
8. Remove the alternator belt
9. Remove the water pump pulleys (the bolts of which we loosened at the very beginning)
10. Loosen the air conditioner belt tensioner roller
11. Loosen the air conditioner belt tension adjustment bolt
12. Remove the air conditioner belt
13. Remove the tension roller of the air conditioner belt and replace it with a new one
14. We proceed directly to removing the timing belt. The first step is to lock the brakes so that when you try to unscrew the crankshaft pulley, the engine will not turn over.
15. We turn on 5th gear on cars with manual transmission
16. Using a 22 wrench, loosen the crankshaft pulley mounting bolt
17. Remove the crankshaft pulley
18. Remove the stopper from the brake pedal
19. Remove the timing belt cover. It consists of two parts, upper and lower
20. Raise the front right wheel on a jack.
21. Rotate the wheel to align the marks on the camshaft and crankshaft gears
22. Check the marks again. On the crankshaft it is now a mark on the sprocket and on the oil pump housing, for the camshaft it is a round hole on the pulley and a red mark on the bearing housing located just behind the camshaft pulley.
23
Using a 12mm socket, unscrew the 2 bolts securing the timing tension roller, remove it carefully, holding the tension spring, and remember how it was positioned. 24
Unscrew the adjustment bolt and the tension roller mounting bolt, remove the roller with the spring
24. Unscrew the adjustment bolt and the tension roller mounting bolt, remove the roller with the spring
25. Remove the timing belt
26. As a rule, the timing belt is changed along with the rollers; we change them. Using a 14mm socket, unscrew the upper bypass roller. We fasten the new one, tightening it with a torque of 43-55 Nm.
27. Install the tension roller with the spring. Initially, tighten the bolt by hand, then pry it up with a screwdriver and tuck it behind the stop.
28. For further convenience, before installing the timing belt, move the tension roller as far as possible and fix it by tightening the right fastening bolt.
29. Install a new belt
If there are arrows on the belt indicating the direction, then pay attention to them. The movement of the gas distribution mechanism is directed clockwise; to put it simply, we direct the arrows on the belt towards the radiators
When installing the belt, it is important that the right shoulder is in a tense state with the camshaft and crankshaft marks installed, the left shoulder will be tensioned by the tensioning mechanism. The belt installation procedure is shown in the diagram below. 1 – crankshaft toothed pulley; 2 – deflection roller; 3 – camshaft toothed pulley; 4 – tension roller
1 – crankshaft toothed pulley; 2 – deflection roller; 3 – camshaft toothed pulley; 4 – tension roller
30. We release both bolts of the tension roller, as a result of which the roller itself will be pressed against the belt by a spring with the necessary force
31. Turn the crankshaft two turns while rotating the hanging wheel. We check the coincidence of both timing marks. If both marks coincide, then tighten the tension roller to a torque of 20-27 Nm. If the marks are “gone”, repeat.
32. Check the timing belt tension. When you squeeze the tension roller with your hand and onto the tensioned branch of the timing belt with a force of 5 kg, the timing belt should bend to the center of the head of the tension roller mounting bolt
33. Lower the car from the jack and install everything in the reverse order.
