Which valve is inlet and which is exhaust?

The main difference between the intake valve and the exhaust valve is the diameter of the plate: the intake valve has a larger one. Why? Because the absorption of air from the atmosphere into the cylinder under the influence of vacuum occurs at a lower speed than its expulsion from the cylinder by the piston.

It's simple: the amount of air (or air-fuel mixture) is the same, but the speed is different. Accordingly, where the speed is lower, the hole is wider, and the plate covering it is larger in diameter.

All this is true for those valve mechanisms where there are equal numbers of intake and exhaust valves - one or two each. However, there are engines with an odd number of valves: two intake + one exhaust or three intake + two exhaust. Here the opposite is true: the diameter of the exhaust valve plates will be larger than that of the intake valves, because the manufacturer compensated for the low suction speed by adding one “extra” hole, and not by increasing the diameter. You can read more about the relationship between valves and cylinders in the corresponding article.

The second important difference in valve design is their operating temperature. Intake valves operate at 350-500 degrees, but the exhaust valves are harder - hot exhaust gases heat them up to 700-900 degrees. Therefore, accordingly, exhaust valves are often made more heat resistant.

The heads (or discs) of the intake and exhaust valves can be either the same diameter or different. (on cars of outdated brands with small valve overlap) - my approx. Typically the intake valve head is made larger in diameter to improve cylinder filling. For example, the dimensions of the engine valves of the GAZ-53A car: the diameter of the intake valve head is 47 mm, and the exhaust valve is 36 mm. In the KamAZ-740 diesel engine, the diameter of the intake valve plate is 51 mm, and the exhaust valve is 46 mm. Inlet large outlet small.

Engine exhaust valve

The exhaust valve is a timing element, when opened, exhaust gases are removed (released) from the engine combustion chamber. Gases are released when the piston in an engine cylinder moves from bottom dead center (BDC) to top dead center (TDC). During engine operation, the exhaust valves are subject to significant thermal loads, as they are constantly in contact with hot exhaust gases. The valve head can heat up within 600-800 degrees during internal combustion engine operation.

After the end of the intake and compression stroke, the main requirement at the moment of ignition of the fuel in the combustion chamber is maximum tightness. The inlet and outlet valves are closed. When the piston has taken on the energy of the expanding gases after the fuel-air mixture has ignited, these exhaust gases must be removed from the combustion chamber. Sealing the chamber is no longer necessary at this stage. The exhaust poppet valve, which is located in the cylinder head (cylinder head), is responsible for removing exhaust gases in the design of the gas distribution mechanism.

During the intake stroke, a vacuum is created, and during the exhaust stroke, increased pressure is formed in the working combustion chamber of the engine. After combustion of the mixture of fuel and air, the exhaust gases leave the combustion chamber through the exhaust valve that opens at the right time. The pressure force allows gases to easily escape from the working chamber. This explains the smaller size of the exhaust valve disc compared to the intake valve disc. During the intake stroke, the vacuum is less powerful than the exhaust pressure. The exhaust gases are practically pushed out through the open exhaust valve.

Effective sealing of the combustion chamber has become possible thanks to the use of poppet valves in the timing structure of modern internal combustion engines. The valve design is simple; the element has a plate and a rod. The chamfer smoothly transitions into the rod, which makes the valve quite durable. The conical shape of the transition significantly reduces the resistance of the exhaust gases when exiting the chamber, and also further improves sealing.

The opening of the exhaust valve occurs due to the force received from the camshaft cam. The valve stem (stem) is located in the valve guide, which is pressed into the cylinder head. The camshaft cam presses directly against the valve stem or rocker, which transmits force to the stem. The valve seat is also located in the cylinder head. The valve seat is a recess that is shaped to match the top of the valve disc. The valve plate and valve seat are pressed against each other with filigree precision. This solution allows for maximum tightness when the inlet and outlet valves are closed. The main task is to eliminate gas breakthrough from the combustion chamber.

There is a special groove on the top of the valve stem. The indicated recess is where the “cracker” is installed. This “cracker” is a conical ring that is cut into two equal parts. A solution is needed to secure the valve spring retainer. If the valve is opened by a “push” from the camshaft cam, then the valve is closed by the force of the valve spring. This spring closes the valve, pressing the plate tightly against the seat. Additionally, there is a mechanism that rotates the valve. This is necessary for uniform wear of the valve and cleaning the valve from carbon deposits.

The exhaust valve operates under extremely difficult conditions. Exhaust gases cause severe corrosion of exhaust valves. If the fuel does not burn completely in the chamber, then this can lead to burnout of the valve. Adjusting the valve mechanism is an important procedure during the operation of an internal combustion engine. Closing the exhaust valve early can cause it to burn out quickly.

During operation of any internal combustion engine, the valve plate and seat become covered with carbon deposits. It is almost impossible to avoid carbon deposits on the valves. The presence of carbon deposits causes constant overheating of the exhaust valve. Sooner or later, the valve support surface begins to burn out, which leads to loss of tightness in the combustion chamber. The result is a progressive loss of engine power, difficult starting, etc.

The microcracks that appear on the valve plate due to overheating gradually increase in size, as hot gases under pressure begin to break out of the combustion chamber. The valve head under such conditions is deformed and further destroyed. Valve failure actually means the engine cylinder completely loses its functionality. After replacement, it is necessary to grind the valve to the seat for the most accurate fit. Ignoring the procedure or performing poor valve lapping will lead to rapid failure of the new valve.

It's pretty clear that overheating is a major problem with exhaust valves. For the manufacture of the exhaust valve, special chromium-nickel-molybdenum steel is used. The base is nickel, which increases the exhaust valve's resistance to mechanical damage. The steel used for making valves has high heat resistance.

The next step to reduce the thermal load of the exhaust valve is its design, which differs from the design of the intake valves.

The exhaust valve stem is hollow, the cavity is filled with sodium metal. The sodium melts and flows inside the valve stem, which improves heat transfer and distributes heat evenly.

The exhaust valve can also have additional protection, which can significantly extend the life of the element. The only drawback can be considered the final increase in the cost of production of the part.

Among the most common methods of protection are:

laser doping;
plasma-powder surfacing method;
surfacing with high frequency currents;

Plasma powder surfacing is considered one of the most economically and practically justified solutions. For such surfacing, various metal powders are used, based on cobalt or nickel. Coating technologies are different, but the main task of each of these methods is to fuse a thin layer of protection onto the surface of the valve to increase wear resistance, resistance to corrosion processes and mechanical destruction.

ENGINE KNOCKING IN FRONT WHEEL VAZ CARS

In front-wheel drive VAZ cars, the engines may have different digital indices, since the engines are installed on different car models. But basically all power units have the same circuit diagram, but they may differ:

8-valve or 16-valve cylinder head;
Piston diameter;
Carburetor or injection fuel system;
Minor design features (different sensors, collector configuration, etc.).

In particular, the VAZ 2114 car is equipped with an 8-valve 4-cylinder engine with a volume of 1.5 liters of the VAZ 2111 model, with a fuel supply system of the “injector” type (distributed injection). Exactly the same internal combustion engine (ICE) is equipped with the VAZ 2115 and VAZ 2113.

Various knocking noises can occur in an internal combustion engine, and it is not necessarily the valves that are knocking. Knocks can occur:

In the piston group,
In the crank mechanism;
In the gas distribution system;
In attachments (water pump, generator, etc.).

Why does the engine knock, what could be causing the knocking:

insufficient amount of oil in the oil system crankcase;
wear of parts due to long-term use;
manufacturing defects;
engine overheating;
operation of the motor at constant maximum loads.

Knocking in the VAZ 2114 engine has a different character; determining the cause is sometimes difficult even for technicians who have some experience in repairs. But there are characteristic sounds that are identified quite easily:

a sharp “dry” metallic sound, clearly audible when you sharply press the gas pedal. This is how the crankpins (bearings) of the crankshaft knock. This is a serious knock, at a minimum, it requires crankshaft grinding;
the sound is medium in tone; when the speed increases, it seems that something is rolling around inside the internal combustion engine. This is how the pistons usually knock;
single clicking sound. As the speed increases, it seems to merge, and is similar to the sound of a working sewing machine. This is how parts of the gas distribution mechanism (camshaft, pusher) usually knock.

How do valves knock, how to determine it? The valve knock is usually quite sharp, clicking, and high-pitched. He can knock not just one, but several at once. To understand the cause of various noises in the gas distribution mechanism (GRM), you need to have at least a little idea of its structure. The VAZ 2114 timing belt consists of the following elements:

camshaft.
timing gear.
Timing belt.
Pushers.
Adjusting washers.
Inlet and exhaust valves.

Inlet and outlet valve - differences

It’s simple: the amount of air (or air-fuel mixture) is the same, but the speed is different. Accordingly, where the speed is lower, the hole is wider, and the plate covering it is larger in diameter.

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Valve mechanism design

As we have already understood, the internal combustion engine ensures that the valves in the internal combustion engine cylinders admit the combustible mixture, if it is gasoline fuel, or air, if it is diesel fuel, and also release them out. Therefore there are two valves, each of which can open or close at its own time under the pressure of the cams.

The pressure exerted on the rods when it touches the cam in an engine that has combustion of a combustible mixture or air mixed with diesel helps ensure that the rod holding the valve, made of high-quality material, has good movement.

The fact that the movement is smooth on the structure with valves indicates the correct material from which the structure is made.

The presence of the necessary gaps in the metal material of the rod part on which the entire structure rests facilitates the rapid opening and closing of the valves. It turns out that thanks to high-quality material, the engine performs better.

Modern engine parts have the right material, which promotes simplicity in design, they cost little, repairs are rarely required, and the reliability of the design is at the highest level. If a breakdown occurs, the parts should be repaired or completely replaced. We are talking about the camshaft, guide bushings, pusher and spring.

Upper shaft position

Depending on the design of the power unit, the shaft can be located either above the block or inside it. Let's consider the first case first.

Thanks to the upper position of the shaft, other parts are interconnected with cylinders or pushers.

The principle of operation is as follows: what pushes touches the part, which at this time transfers energy to the part, and it manages to rest on the valve leg; it is kept raised by a spring with a different force, that is, it is closed.

In the system described, the camshaft, located at the top of the engine, operates thanks to a drive having gears. It can also be seen that the cams and the pusher device located directly above the two gates are connected to each other.

The pusher pressure exerted on the cam causes the part that holds the valve to relax the spring. Next, when the shaft rotates, the spring moves and falls into place, then the valve closes.

It is this design that allows the engine to operate, which is equipped with an overhead valve mechanism.

Engine having one distributor shaft

There are internal combustion engines that do not have pushrods, so a single type camshaft is used to open and close the valves. This design is called a single camshaft engine. There the valve parts are placed in the head. The design has few moving parts, which is what contributes to its reliability, allowing it to operate even when the vehicle’s speed is at the limit. Moreover, the material from which spare parts are made is metal (special alloy).

For more efficient operation of the motor, there must be free space between the elements - a gap. If there are no clearances between the bolt foot, cam or rocker arm, then the system will wear out, causing serious damage.

It is also worth noting that excessive clearances will cause the valve to open prematurely and close later. Thus, the power of the internal combustion engine will be reduced, and under high valve pressure the operation will be noisier.

If the gap is small, then the pressure will become less, this will lead to the fact that the shutter stroke will become very difficult, thereby the car will lose power.

There are internal combustion engines that operate automatically, adjusting the valves themselves to the desired action. To do this, you need a plentiful amount of lubricating fluid, because it is under its pressure that the valve system will operate.

Rod and rocker

The first element is a metal tube with a diameter of 12 millimeters.

It serves to transmit the forces that come from the pusher to the rocker arm. The pipe has pressed-in spherical tips. The lower element rests against the pusher heel, the upper element rests against the adjusting screw. The tips also have holes for lubrication. They pass through the pipe cavities to the valve bearings. The rocker arm is designed to transfer forces from the rod to the valve. The element is made of steel. Above the bar, the rocker arm has a short arm. It is longer above the valve. The short one has a lock nut for setting the thermal gap (applies only to mechanical elements). The rod is located on an individual axis. Two bronze bushings are pressed into it.

Great Encyclopedia of Oil and Gas

Page 1

Spool valve timing diagrams. [1]

The intake and exhaust valves in internal combustion engines are controlled. [2]

The intake and exhaust valves are made of ESH-8 steel and heat treated. [3]

Inlet and outlet valves are checked for strength and tightness with a pressure exceeding 50% of the rated operating pressure for 5 minutes. Air leaks are not allowed. The assembled pneumatic system is tested for leaks and the functionality of all assembly units included in it is checked. When testing the pneumatic system, air leaks are not allowed. [4]

Intake and exhaust valves differ little in design. [5]

PD1M diesel cylinder cover valves. [6]

The intake and exhaust valves open at a certain moment depending on the position of the crankshaft of the diesel engine. The mechanism that opens the valves consists of a camshaft and a valve drive. [7]

The intake and exhaust valves are closed and opened by a valve mechanism consisting of pushrods and levers. The tappets receive reciprocating motion from the camshaft cams. Cast iron pusher guides are mounted in the block bores above the camshafts. Rollers are fixed in the eyes of the pushers on fingers with bronze floating bushings. The valve drive pusher has a ball surface inside to support the lower head of the rod. The rods are made of pipes, with heads pressed into them on both sides, the spherical surfaces of which are cemented and hardened. [9]

Gas distribution diagram of the ZMZ-53 engine. [10]

Intake and exhaust valves usually have different head sizes and are made from different steels. [eleven]

The inlet and outlet valves are usually located vertically in the service cover. This arrangement ensures the least wear on the spindle guide bushing. The valves open into the cylinder, thereby achieving a tight fit of the valve to the seat at high pressures. At low pressures and vacuum in the cylinder, the valve fit is ensured by a spring. [12]

The intake and exhaust valves of a diesel engine must open and close in a strictly defined sequence and at specified times. The sequence of opening and closing of the cylinder valves is ensured by the corresponding arrangement of the camshaft cams. [13]

The intake and exhaust valves are mostly driven by an eccentric; Release here is also forced. In order for the catching latch to sit smoothly on the valve lever, and sometimes in order to carry out large fillings, the inlet eccentrics are jammed, mostly with a delay, so that a slight excess lift is obtained; the highest position of the operating edge of the latch exceeds the valve lever, which is at rest and at the moment of closing, only so much that the latch definitely falls. Gripping occurs due to its own weight or spring pressure. Then the lift of the valves with direct eccentric drive for large fillings becomes disproportionately large, which prompts the use of fists. The advantages of disengagement valves include quick closing up to the seat and low adjustment force of the regulator. [14]

The intake and exhaust valve heads are not the same diameter. To better fill the cylinders with fresh fuel mixture, the diameter of the intake valve head is made larger than the diameter of the exhaust valve. Due to the fact that the valves heat up unevenly during engine operation (the exhaust valve, washed by hot exhaust gases, heats up more), they are made of different materials: intake valves are made of chromium steel, exhaust valves are made of silchrome heat-resistant steel. [15]

Pages: 1 2 3 4

Where are the valves located?

Human heart valves

Each of these “passers” appeared in its own time and place. And such wonderful harmony allows the cardiovascular system to work clearly and correctly. Moreover, each of them has already received its own name. The exit from the left atrium is equipped with the left atrioventricular valve. Another name for it is bicuspid or mitral. It is called mitral because it resembles the Greek headdress - miter. The exit from the left ventricle, the ancestor of the systemic circulation, is the location of the aortic valve.

It is also called crescentic in another way, because its three doors resemble crescents. The opening between the right atrium and the right ventricle is the location of the right atrioventricular valve. Its other name is tricuspid or tricuspid. The exit from the right ventricle into the pulmonary trunk is controlled by the pulmonary valve, also called the pulmonary valve. The pulmonary valve or pulmonary valve also has three leaflets, which also resemble crescents.

Work order

Now the sequence of actions:

We install the VAZ 2114 on a flat surface, the engine must cool completely so that there is no error in the measurements due to metal expansion;
Remove the valve cover, as well as the side cover under which the timing belt is located. The surface under the lid must be wiped of oil. You should also carefully inspect the timing shaft for burrs, holes, and signs of significant wear. If there are any, the shaft will have to be replaced;
We unscrew the spark plugs to make it much easier to turn the crankshaft in the future.
We combine the mark on the camshaft drive gear with the protrusion on the cylinder head, that is, we set the TDC on the first cylinder. This can be done using a wrench, which we use to rotate the crankshaft by the pulley bolt. But some car enthusiasts do things a little differently - jack up the front wheel on the left and engage 4th gear. Then they simply rotate the wheel, and since the gear is engaged, this rotation will be transmitted through the transmission to the engine;
After aligning the marks on the camshaft gear, strictly opposite the existing mark, we make another one with chalk. This will make future work somewhat easier.
We use a feeler gauge to measure the gaps on valves 1 and 3 (you need to count from the camshaft gear. The 1st is exhaust, and the 3rd is intake);
The gap on 1 valve should be 0.35 mm, but an error is allowed. That is, we take a feeler gauge 0.35 mm thick and insert it between the shaft cam and the adjusting washer. If the probe moves with little effort, then the gap is normal, but if the probe does not enter or is very loose, then adjustment is required. We do the same check on valve 3, but the gap on it should be 0.2 mm.
The adjustment of the valves is carried out as follows: we attach the device for pressing the valves to the studs securing the cover. This device has a curved lever that we place between the cam and the washer. Using the handle of the device, we press on this lever, as a result of which it will press on the pusher. This device comes with a special clamp, which we place between the camshaft and the pusher. After releasing the handle, the latch will hold the valve in a squeezed state, while the washer will not be pinched and can be removed with tweezers.
Let's look at an example of what kind of washer will need to be installed in order for the gap to be correct. For example, when checking the exhaust valve, it was found that it was not 0.35 mm, but 0.42 mm, that is, it was increased by 0.07 mm. Next, remove the washer that was installed. There should be a mark on it indicating its thickness (for example, 3.65 mm); if there is no such mark, then you will have to measure the thickness with a micrometer. Now we add to the thickness of the washer the value by which the gap is increased, in our case - 0.07 mm, as a result we get the value of the thickness of the washer for installation - 3.65 + 0.07 = 3.72 mm. But since a washer with such a thickness is not included in the kit, we install a new washer with a thickness as close as possible to the obtained value, that is, 3.7 mm. This is why an error of 0.05 mm is allowed.
We install the washer of the required thickness in place with the size mark down (towards the pusher). Next, use the lever of the device to press the valve again and pull out the latch. This completes the adjustment.
Next, the remaining valves are adjusted, but for this you need to know the order. After checking valves 1 and 3, turn the camshaft half a turn (for ease of installation, we made a mark on the gear in advance) and check valves 2 (intake) and 5 (exhaust). Then we turn it another half turn and adjust 6 (intake) and 8 (exhaust). To check the 4th (intake) and 7th (exhaust) valves, you still need to turn the camshaft half a turn once.

Which valve is larger, inlet or outlet ⋆ Proraboff.rf

If you are planning to increase engine power by replacing the intake and exhaust valves, then first of all you need to find out which one should be larger.

In this article we will tell you which valve is larger, the intake or exhaust, so that in the future you can know whether the necessary parts are in the engine.

Why are valves needed?

Before we find out the recommended valve ratio, we will tell you why they are needed at all. So, the intake and exhaust valve play an important role in the operation of the combustion system. The intake valve supplies fuel to the combustion chamber, and the exhaust valve allows the gases formed after fuel combustion to escape.

Which valve should be bigger?

Each of the valves is important and at first glance, differences in size do not matter at all, but this is a mistake, because even a few millimeters determine the engine power. According to professional researchers, the intake valve should be larger than the exhaust valve, and the ratio should be 1:0.75. This ratio is explained by the fact that it is much easier for the exhaust valve to release light gases, and therefore a larger size is not necessary. The ratio of 1:0.9 is suitable only for those cars that use nitrous oxide or turbocharging, and these, as a rule, can be counted on one hand.

Now you know which valve is larger, the intake or exhaust. Fuel economy also depends on the recommended intake/exhaust valve ratio. Even a small increase in the exhaust valve can lead to a decrease in power and an increase in fuel consumption, so you need to take this seriously. Good luck!

ICE with one shaft

There are ICE models that allow the cams to act directly on the levers; they are usually small and are also called fingers. In such an internal combustion engine, the valve material is carefully thought out. There are not many components that play a role in opening and closing the dampers. So, in particular, the movement of the car depends entirely on the cams, which directly act on the short parts that open or close the valves.

As you can see, such a system has few technical difficulties, and besides, such a design is light in weight. There are absolutely no rods in it, which act as a pusher and a rocker arm, which is provoked by the pushing device, exerting pressure on it.

The material of the chain, which contributes to the correct positioning of the shaft on the sprocket, affects the fact that it often hangs.

The core solution to this problem will be the need to add several small sprockets, as well as tension on the short chain. They also use straps that are non-stretchable; their material is rubber. Inside each oil belt there are sprockets that help rotate the camshaft and crankshaft.

How are they arranged?

There is a plunger in the body of the hydraulic pusher. The latter has two cameras. This is the discharge and supply chamber, which receives lubricant from the engine during operation. This oil then passes through the ball valve to the discharge part. To compensate for gaps with high precision, the volume of liquid is dosed into the plunger. It is pressed out of the pusher housing by a spring. Thus, the thermal gap is restored to normal values. When the intake or exhaust valve opens, oil is in the discharge chamber. The ball valve returns some of it back to the feed chamber. When the pusher body moves upward, a certain fluid pressure is created. The oil prevents the plunger from moving relative to the body. When the valve closes, lubricant leaks from the plunger side. However, with a new discovery, this disadvantage is compensated through the discharge chamber. When the engine starts, the elements of the gas distribution mechanism gain operating temperature. The metal expands, and the volume of oil in the discharge chamber decreases. Thanks to the coordinated operation of the mechanism, the gaps between the valves are compensated. The work also involves elements such as a rocker arm and a valve rod. Below we will look at what they are.

Which valve lifter should I choose?

As we noted earlier, there are mechanical, roller and hydraulic elements. When replacing these parts, the question arises of choosing the best type of pusher. So, let's take it in order. Mechanical elements are the simplest and cheapest pushers. Their main drawback is the inability to compensate for the gap. As a result, when the engine reaches operating temperature, they begin to make a characteristic noise. All gaps have to be set manually, through an adjusting bolt. As for hydraulic ones, they automatically set all the gaps.

These pushers are a small chamber where oil enters under pressure. Thus, the adjustment of the gaps is carried out by the lubrication system itself. They are inexpensive, and there is no need to configure them additionally. The only drawback is that the pushers “freeze” at high speeds. But in this case, roller elements based on them are used. Hydraulic roller tappets are designed for a long service life. Thanks to them, you can significantly increase the power of the unit. The dimensions of valve pushers of this type are identical to the standard ones, so you will not have any difficulties with replacement. Now this is the most suitable option among all that are on the market.

Valve springs

The spring operates under heavy loads. Its main task is to create a reliable and tight connection between the valve and the seat. When under load, the spring may break, often due to its resonance. In order to prevent this phenomenon, the spring coils are made with variable pitch.

You can also make a conical or double spring. Double springs have the added benefit of having two parts to increase the reliability of the mechanism and reduce the overall size of the springs.

In order to eliminate the possibility of resonance in the double spring, the direction of the turns of the inner and outer springs is made different. This also allows you to retain fragments of the part; in the event of a spring break, the fragments will be retained between the turns.

Valve springs are made of wire, the material of which is steel. After shaping, the product is hardened and tempered. To increase strength, blow with air with the addition of abrasive material.

To avoid corrosion, the springs are treated with zinc or cadmium oxide. The ends of the springs are ground and given a flat shape. This is done to more effectively fix the ends of the springs with special fixed plates in the cylinder block. The plates are made of low carbon steel; the top plate is fixed to the valve using a cracker.

Methods of protection against overheating

To resist erosion from overheating, the exhaust valves are made of heat-resistant steel (chrome-nickel-tungsten-molybdenum steel).

When replacing a damaged valve, grinding into the seat is absolutely mandatory. If the valve is not ground in, it will have to be changed again, and very soon

The base alloy from which exhaust valves are made is nickel. This metal increases the valve's resistance to mechanical wear. Because the exhaust valve is subject to greater thermal stress than the intake valve, it has a different structure. The exhaust valve stem is made hollow. The internal cavity is filled with sodium metal. This is necessary to improve heat transfer.

Modern technologies make it possible to further protect exhaust valves from aggressive influences.

The most universal method is plasma-powder surfacing. In addition, there are methods of laser alloying and surfacing with high frequency currents. These protection methods increase the cost of the part, but significantly extend its service life.

Classification by number of valves

The classic version of the four-stroke engine requires only two valves per cylinder to operate. But modern engines are increasingly subject to new demands in terms of power, fuel consumption and respect for the environment, so this is no longer enough for them. Because the more valves, the more efficient it will be to fill the cylinder with new charge. At different times, the following schemes were tested on engines:

three-valve (intake - 2, exhaust - 1);
four valves (intake - 2, exhaust - 2);
five-valve (intake - 3, exhaust - 2).

Better filling and cleaning of the cylinders is achieved by more valves per cylinder. But this complicates the engine design.

Today, the most popular engines are those with 4 valves per cylinder. The first of these engines appeared in 1912 in the Peugeot Gran Prix. At that time, this solution was not widespread, but since 1970, production cars with this number of valves began to be actively produced.

Why is it necessary to regulate?

There are only two reasons. This is their “squeezing”, when the thermal gap disappears between the camshaft cam and the pusher. And vice versa, increasing the gap. Both cases do not bring anything good. I will try to tell everything in more detail on my fingers

Why does the valve clamp?

This happens very often among those who drive on gas (natural gas engine fuel). The widest part of the valve is called the plate (it has a chamfer along the edges), it is this that is located in the combustion chamber on one side, and on the other it is pressed against the “seat” in the head of the block (this is the part where the valve goes, thus sealing the combustion chamber).

From high mileage, the “saddle” begins to wear out, as well as the chamfer on the “plate”. Thus, the “rod” moves upward, pressing the “pusher” to the “cam” almost tightly. This is why “clamping” can occur.

THIS IS VERY BAD! Why? Yes, everything is simple - thermal expansion has not gone anywhere. This means that in the “clamped” case, when the rod heats up (elongation occurs), the plate will slightly come out of the seat:

Compression drops and power drops accordingly.
The contact with the block head (with the seat) is broken - there is no normal heat removal from the valve - to the head
When ignited, part of the burning mixture can pass past the valve directly into the exhaust manifold, melting or destroying the “plate” and its chamfer

Well, a secondary reason is that this mixture can negatively affect the catalyst.

It must be remembered that the “inlet elements” are cooled by the newly incoming fuel mixture!

But the heat removal of the “exhaust” depends on how tightly it is pressed against the “saddle”!

Increasing the gap

There is another situation. It is typical for gasoline engines. On the contrary, the “thermal gap” increases. Why does this happen and why is it bad?

Over time, the plane of the pusher, as well as the surface of the camshaft cams, wear out - which leads to an increase in the gap. If it is not adjusted in time, it increases even more from shock loads. The engine starts to run noisily, even when “hot”.

Engine power decreases due to irregular valve timing. To put it in simple terms, the intake valves open a little later, which does not allow the combustion chamber to be filled normally, and the exhaust valves also open later, which does not allow the exhaust gases to escape normally.

Now let's watch the video version of the article.

And here I end, I think my materials were useful to you. YOURSINCERELY AUTOBLOGGER

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Working principle of the intake valve

Timely opening and closing of the intake valve ensures the angular position of the camshaft is precisely synchronized with the same angular position of the crankshaft. That is, the angular position of one strictly corresponds to a certain angular position of the other.

Depending on the engine model, there may be several intake valves per cylinder.

To radically change valve timing, you must purchase a set of sports camshafts

Before the piston reaches its highest dead center, the intake valve begins to open - that is, during the intake stroke, by the time the piston begins to move downward, the valve is already slightly open. Different engine models have their own valve opening advance. The range of fluctuations is 5-30 degrees.

But the closing of the intake valve occurs with some delay, after the piston reaches bottom dead center and begins to move upward. Filling of the cylinder continues even after the start of movement. This occurs due to inertia in the intake manifold.

Shaft together with pushers inside the block

In this position of the valve structure, that is, when it is located inside the cylinder system, the pushing device can act on the part directly touching the valve, which opens it. This is considered a more advantageous position than the previous one, which was discussed above. After all, using a lot of moving particles, the speed of the car is reduced by an order of magnitude. As a result, the intake valve and exhaust valve have less pressure, which reduces the power of the internal combustion engine by an order of magnitude.

PERIODICITY OF ADJUSTING VAZ 2114 VALVES

Car owners have a question: how often is it necessary to adjust the valves on a VAZ 2114 if they do not knock, and is it necessary to make adjustments in this case? According to the factory settings, the valves should be adjusted every 20 thousand km during vehicle operation.

Why carry out adjustment work if the valves of the VAZ 2114 do not knock? The fact is that over time, seat saddles wear out over time. The valve becomes higher and the clearance decreases. And too small a gap threatens loss of power and burnout of the exhaust valves. Before the due date, the clearance in the valves should be checked if knocking occurs and if it is suspected that they are clamped.

A specific knocking sound indicates that the so-called thermal clearances between the valves and their pushers have been broken (that’s what it’s correctly called, not “valve adjustment”). Engine mechanics say this: “the valves are knocking” and “the valves need to be adjusted,” although in reality, of course, these same thermal clearances are adjusted. And the recommendations that I will give here are quite simple and will help you adjust the valves of a VAZ 2114 car with your own hands.

OTHER POSSIBLE TIMING KNOCKS

What should I do if the valves are knocking even after the adjustment has been carried out correctly? In this case, it is necessary to check the condition of the pushers and the camshaft. To do this, remove the camshaft and check:

The integrity of the camshaft cams and the condition of its supports;
The gap between the pusher and the seat in the cylinder head;
The condition of the camshaft bed in the block head. Many VAZ owners are concerned about valve knocking on a cold engine. But the valves knock the same way both on “cold” and “hot”. There are no rods in the timing belt of VAZ engines, as in some GAZ and UAZ engines, so the gap on 2114 practically does not change with heating.
Most likely, the knocking when cold is not due to the valves, but due to the increased gap between the pistons and the cylinder walls in the piston group.
Aluminum pistons expand as they warm up and the clearance decreases. Accordingly, the knocking disappears.

Products for cleaning carbon deposits on valves

Many car owners are interested in the question of how to wash off carbon deposits on valves? Currently, there are a number of chemical products designed directly to remove such deposits. Typically these are additives added to fuel. They are mixed with gasoline, and during the combustion process, together with the air-fuel mixture, they soften this composition, facilitating its combustion along with the fuel. Among these additives, the following are especially popular among car owners:

Valve cleaner from Liqui Moly Ventil Sauber . The additive is designed to be added to gasoline during the next refueling. Can be used with any type of gasoline. The function of the additive is to remove deposits formed on valves, injectors, carburetor and other elements of the intake tract. It also protects the listed elements from corrosion. Can be used with engines with catalytic converters and turbocharging. Sold in a 250 ml can, which is designed to be dissolved in 75 liters of fuel. The article number for this package is 1989. Its price as of winter 2018/2019 is about 470 rubles.
Valve and power system cleaner HI-GEAR FUEL SYSTEM & VALVES CLEANER . Another popular product among car enthusiasts. It cleans not only valves very well, but also other elements of the power system. Can be used with any gasoline engines, including those equipped with catalysts and turbochargers. The product is intended for engines up to 2.5 liters. It is recommended to use it as a preventive measure every 3,000 thousand kilometers. Sold in two different jars - 295 ml and 325 ml. The volume of the second can (325 ml) is enough to dilute 40 liters of gasoline. The article numbers for these packages are HG3235 and HG3236. The prices are respectively 440 rubles and 530 rubles.
Cleaning the engine without disassembling MITSUBISHI SHUMMA ENGINE CONDITIONER . This product was specially created by specialists from the famous Japanese automaker Mitsubishi for cars of this brand equipped with engines with direct fuel injection (GDI). It is recommended to use this product as a preventative every 100 thousand kilometers. However, given that these recommendations are given for Japanese conditions, for domestic roads and gasoline this interval must be significantly reduced. The product is a foam cleaner that is used to treat the internal working surfaces of fuel system elements. Detailed instructions are given on the packaging (in particular, you need to work with a cold engine!). Reviews about the product are very positive. Sold in a 250 ml can. The article number for this package is MZ100139EX. Its price for the above period is about 1300 rubles.

Wurth valve carbon cleaner . Like the previous one, this product is a foamy detergent composition that is used to wash the contaminated surfaces of the elements of the car’s fuel system. Allows cleaning without disassembling the engine. So, to do this you just need to disconnect a few hoses. Detailed instructions are indicated in the description of the drug. Please note that this product can only be used in combination with a spray wand. One cylinder is enough to treat a four-cylinder engine, and two cylinders are enough to treat six- and eight-cylinder engines.

Also, in addition to factory products, carbon deposits from valves can be removed using phosphoric acid. You can use not its pure composition, but a diluted one. It perfectly removes various deposits, so it will also cope well with carbon deposits. Tested by car enthusiasts in practice! Interestingly, the popular drink Coca-Cola also contains phosphoric acid in small quantities, so it can also be used to remove stains.

Gap adjustment

Adjustment is carried out only on a cold engine. The current thermal gap is determined by special metal flat probes of different thicknesses. To change the clearance on the rocker arms there is a special adjusting screw that is turned. In systems with pushers or shims, adjustment occurs by selecting parts of the required thickness.

Adjusting valves for a rocker mechanism

Let's look at the step-by-step process of adjusting valves for engines with pushers (cups) or washers:

Remove the engine valve cover.
Rotate the crankshaft so that the piston of the 1st cylinder is at TDC. If it is difficult to do this by following the marks, then you can unscrew the spark plug and insert a screwdriver into the well. Its maximum upward movement will show the dead center.
Using a set of feeler gauges, measure the valve clearance under the cams that do not push the tappets. The feeler gauge should move tightly, but not too freely. Write down the valve number and clearance.
Rotate the crankshaft one revolution (360°) so that the piston of the 4th cylinder is at TDC. Measure the gap under the remaining valves. Record the data.
Check which valves have gaps that are out of tolerance. If there are any, then select the pushers of the required thickness, remove the camshafts and install new cups. This completes the procedure.

It is recommended to check the gap every 50-80 thousand kilometers. Standard clearances can be found in your vehicle repair manual.

The allowable clearance for intake and exhaust valves can sometimes differ.

A properly configured and adjusted gas distribution mechanism will ensure smooth and smooth operation of the internal combustion engine. This will also have a positive effect on engine life and driver comfort.

Typical intake valve failures

Of course, the most common failure of valves is their bending as a result of a broken timing belt. The same thing can happen without a break if the belt was replaced by a non-professional who mistakenly placed marks on the crankshaft and camshaft (or camshafts) pulleys. Breaks are especially dangerous for modern complex engines equipped with variable valve timing and other high-tech systems.

Another common malfunction of the valve mechanism is the overgrowing of the intake and exhaust valves with carbon deposits. As a rule, the problem can be identified at a fairly early stage by a decrease in power and popping noises in the intake and exhaust pipes, a metallic knock in the cylinder head and a drop in engine power.

Carbon deposits on seats and valves prevent them from sealing tightly and reduce compression. As a result, engine power also decreases. Broken springs can cause the valve to not fit tightly against the seat and lead to deformation of the cylinder head, pitting, or sticking of the stem. A large thermal gap between the lever and the valve stem also leads to a sharp metallic knock and a drop in engine power.

Throughput and technical losses

Actually, the task of the timing belt, and in particular the valves, is one - to supply the air-fuel mixture as quickly as possible and also remove it from the cylinder block as quickly as possible. I think this is understandable and does not cause any difficulties.

Many engineers thought so too; on the first engines the valves were quite large, they closed large passages into the cylinder heads (which went to the intake and exhaust manifolds). It should be noted that four-stroke engines had exactly 8 valves; this is a kind of classic design.

But a large valve has greater inertia and at high speeds mechanical losses increased. After all, the camshaft cam needed to push this heavy mechanism.

Then they began to decrease. Yes, losses have decreased, but throughput has also decreased.

How to get out of this situation?

We began to increase the number, that is, to make them miniature, but larger. This is how options with 12 – 16 – 20 and even 24 valves appeared. BUT, again, only two survived, the main types are 8 and 16, that is, 2 and 4 valves per cylinder (if we take a 4-cylinder engine).

Why do you need a water check valve and how to install it correctly?

Check valves must be installed on any pipeline. Without them, many equipment and pipeline fittings will not be able to function normally and will most likely soon become unusable. Before purchasing pipeline fittings, you need to find out why you need a check valve for water and how to install it correctly. Let's try to look at the main issues in this article.

Purpose

The check valve is designed to protect the pipeline from reverse flow of the working medium and the effects of pressure. The pumping station or individual water supply system may suffer the most from a change in the direction of movement of the working environment. The check valve is installed next to equipment sensitive to changes in flow direction and solves several problems at once:

Protects the pipeline system and equipment from sudden pressure surges;
Prevents the working environment from changing the direction of flow. Many devices and types of pipeline fittings are unidirectional and when the flow changes, they almost instantly become unusable.
Stabilization of pressure in the system. This is especially important in apartment buildings where the pressure in the pipeline is not enough to supply water to the top floors.

A non-return valve installed on the sewer system plays a very important role. It prevents the movement of wastewater into the apartment even if the pipes are seriously clogged.

Design and principle of operation

The principle of operation of the valve is extremely simple. The device allows the working medium to flow freely in a given direction, and when it changes, it automatically closes the pipeline, preventing the flow from changing its direction. The valve is actuated by the force of the flow itself.

The device consists of three main elements:

Metal housing with two pipes for connection to the pipeline;
Locking mechanism with sealing gasket;

Volatile automatic valves operate reliably and reliably protect the pipeline from backflow of the working medium.

Kinds

There are several types of check valves designed for different piping systems and operating conditions. Depending on the type of locking mechanism, valves are divided into the following categories:

Lifting. The locking organ moves in a vertical plane. When liquid moves from bottom to top, the flow rests against the valve cover, holds it and flows freely. When changing the direction of movement, the water from above presses on the lid, closing it and blocking its path in the opposite direction.

In a butterfly valve, the lid flips back and clears the passage, and when it moves back, the liquid locks it.

Ball valve, where a ball acts as a locking organ.

Double-disc consists of two leaves. In the absence of back pressure, they fold, and when the direction of flow changes, they open and block the gap in the pipe.

Lifting valves have gained the most popularity. Thanks to their simplicity and reliability, they have become an integral part of almost every household pipeline.

Selection and installation

When choosing a valve, only the diameter of the pipe and the expected pressure in the system matter. When purchasing, you should pay attention to the quality of the device (no defects).

Before installation, you must select the correct location for the valve:

In wells equipped with vacuum pumps, fittings are installed at the outlet to prevent water from draining under its own weight;
Surface pumps require the installation of valves in front of the accumulator;
In sewer networks, valves are installed before each additional source of wastewater.

A check valve is a fail-safe safety device that can help avoid pipeline accidents and breakdowns of expensive equipment.

How to clean a drain hose by disassembling the drainage system

Citric acid will again help get rid of scale on the electric heater. The amount of powder depends on the degree of soiling, but on average, a machine with a 5 kg load requires 250 g. Pour 200 g into the powder compartment, and 50 into the drum and run the wash at maximum temperature.
More aggressive acetic acid can also deal with scale. Just add 50 ml of vinegar to the conditioner container and turn on the machine. Be careful: vinegar can damage the rubber elements.

Materials for valve production

For the manufacture of intake valves, chromium steel is used, which is resistant to corrosion in gas environments at temperatures above 550 °C. This type of steel is quite fragile.

The intake and exhaust valves of automobile engines are poppet-shaped. The valve is opened by a valve mechanism controlled by an eccentric cam. The operation of the cam is synchronized with the position of the piston and the period of rotation of the crankshaft.

As a result, they are made from more durable materials than intake valves and are therefore more expensive.

The valve guide is located coaxially with the valve seat so that a sealed gas-tight contact is ensured between the operating face of the valve and the seat. The valve operating chamfer and seat are beveled at an angle of 30° or 45°. These are the nominal chamfer angle values. Actual values may differ by one or two degrees from nominal values. The valves and valve seats used in most engines have a nominal bevel angle of 45°. The valve is pressed against the seat under the action of a spring. The spring is held on the valve stem (some auto mechanics call it the valve stem) by a spring support plate, which, in turn, is locked on the valve stem by a lock (cottons). To dismantle the valve, it is necessary to compress the spring and remove the crackers. After this, you can remove the spring, cuff, and remove the valve from the head.

Extensive testing has shown that there are optimal relationships between the various valve geometries. For engines with cylinder bores ranging from 3 to 8 inches (80 to 200 mm) bore, the optimal intake valve head diameter is approximately 45% of the cylinder bore diameter. The optimal exhaust valve head diameter is approximately 38% of the cylinder internal diameter. The inlet valve must be larger in size than the outlet valve to allow the same mass of gas to pass through. The larger inlet valve controls the low-velocity flow of rarefied gas. At the same time, the exhaust valve controls the high-speed flow of compressed gas. A smaller valve can handle this flow. As a result, the diameter of the exhaust valve head is approximately 85% of the diameter of the intake valve head. To function properly, the valve head diameter should be approximately 115% of the valve port diameter. The valve must be large enough to cover the window. The valve lift above the seat is approximately 25% of the head diameter.

Valves with hollow stem and seat deformation

Some types of particularly powerful engines use exhaust valves with a hollow stem filled with sodium metal. When the valve is heated to operating temperature, sodium melts and turns into liquid. This melt splashes in the bore of the rod and transfers heat from the valve head into the rod. The heat is then transferred through the valve guide and absorbed by the cooling system. The monolithic design of the intake and exhaust valves, with the correct choice of materials, generally ensures good performance characteristics of automobile engines.

The valve is pressed against the seat with a working chamfer, hermetically closing the combustion chamber. The seat is usually formed as a structural element in the cast iron cylinder head - this type of seat is called an integral seat. The seats are usually induction hardened to allow the use of unleaded gasoline. This ensures slower wear of the seats during engine operation. As the seat wears out, the valve sits deeper and deeper into it - it is recessed. In applications where corrosion and wear resistance must be particularly high, plug-in seats are always used. In aluminum heads, valve seats and guides are push-in only. It should be noted that in aluminum heads the operating temperature of the exhaust valve seats is 180°F (100°C) lower than in cast iron. Insert seats are used as a rescue measure when rebuilding severely damaged inline valve seats.

Seat deformation is the main cause of premature valve failure. Deformation of the valve seat can be reversible - as a result of exposure to high temperature and pressure, or irreversible - as a result of internal mechanical stress. Mechanical stress is a force acting on a body that tends to change its shape.

Typical exhaust valve failures

Aggressive exhaust gases cause corrosion of exhaust valves. Products of incomplete combustion of fuel lead to burnout.

After a certain period of operation, the exhaust valve plate and the seat in the block head become covered with carbon deposits.

High temperatures heat up the soot. The supporting surface of the exhaust valve is burned out. This entails a loss of tightness. Disturbances in engine operation appear: power drops, engine starting becomes difficult. A stream of hot unexhausted gases rushes into the resulting cracks under pressure. This heats the valve head even more. The result is deformation of the head and destruction of the valve. When the valve breaks, the cylinder actually stops working.

Determining valve burnout without removing the cylinder head

The first step is to determine which cylinder is not working. The testing methods are in many ways similar to diagnosing faulty spark plugs. To check, you should start the engine, after which, with the engine running at idle speed, you will need to remove the caps from the spark plugs one by one.

After removing each spark plug cap, you need to carefully monitor the idle speed and the overall stability of the engine. If the engine starts to rev more strongly or stall, then the cylinder from which the cap was removed is working. If after removing the cap the engine operation does not change or the speed changes only slightly, then the problem cylinder has been detected.

Then you need to unscrew the spark plug on the inoperative cylinder and replace it with a known good one, and also check the high-voltage armored wire of this cylinder for functionality. It would also be a good idea to check the ignition coil, etc. Subsequent starting of the engine will show whether the problem lies in the elements of the vehicle’s ignition system or whether further diagnostics are necessary.

If the nature of the engine’s operation does not change after installing the working spark plug, replacing the high-voltage wire and checking other components of the ignition system (the engine continues to rev), then there is a high probability of more serious breakdowns:

valve burnout;
CPG malfunctions;

Burnout of the valves means that compression in the cylinder is reduced due to a violation of the tightness of the combustion chamber (leakage during the fit of the intake or exhaust valve, destruction of the disc and/or valve seat). Wear of the cylinder-piston group and piston breakage also lead to low compression in the problem cylinder. Also, the cylinder may not work due to stuck or broken piston rings.

Now it is necessary to localize the malfunction, that is, to accurately determine the burnout of the valve or identify problems with the CPG. The most common way to determine burnt valves is to measure the compression in the cylinders.

Low compression clearly indicates a malfunction, but one caveat should be taken into account. It will not be possible to establish a burnt-out valve and rule out problems with the CPG only based on the compression indicator. The fact is that compression in the engine can decrease both as a result of a burnt-out valve, and due to broken piston rings, as well as a number of other defects. For this reason, in parallel with the compression measurement, additional engine diagnostics should be carried out.

The easiest way to determine valve burnout after you have measured the compression in the cylinders is to pour several “cubes” of engine oil through the spark plug well. Then the compression must be measured again. An increase in compression in the cylinder after adding oil will indicate that an oil film has formed, acting as a “seal”. This phenomenon is typical in the case of piston wear. If the compression indicator has not changed, it means that the valve has burned out, since the oil in the cylinder in this case will not affect the compression in any way.
Also, to determine whether the valves are burned out, you should inspect the spark plug on the problem cylinder. A clear sign of valve burnout is that the spark plug is completely dry, that is, it does not have a characteristic oil deposit. There may also be smoke or air coming out of the engine breather. The intensity of smoke production directly depends on the degree of wear of the CPG.

As for breakdowns that are associated with the piston, in this case the spark plug is covered with oil, and the appearance of bluish smoke can be observed from the breather. Note that oil on a candle is an indirect sign. Even if the spark plug is dry or covered with a slight soot, but smoke comes from the breather, then this symptom indicates problems with the piston or piston rings. On new engines with low mileage, there is a high probability that.

Let us add that the appearance of engine oil that comes out through the breather also indicates a malfunction of the partitions between the piston rings. Taking into account the above, you can accurately determine why the compression in the engine has decreased, identify problems with the cylinder-piston group, or determine burnout of the timing valves.

Causes of burnout

Valves burn out for various reasons, including:

factory defects or low-quality spare parts;
incorrect valve adjustment or malfunction of hydraulic compensators;
valve wear (valve stem or guide bushing);
early or late ignition;
lean mixture.

No one is immune from purchasing defective and low-quality spare parts, so buy spare parts from trusted sellers who value their reputation. If the valves are adjusted incorrectly (they are tightly clamped), the engine operation will be noticeable by the characteristic “tractor” sound. In this case, due to non-compliance with the thermal clearance, the valve overheats, which will invariably lead to its burnout.

If the ignition is set incorrectly, combustion of the combustible mixture occurs when the valve is open and leads to its malfunction. A lean mixture is dangerous because the combustion temperature of the combustible mixture increases, which leads to overheating and burnout.

Since this DTC indicates a problem with the circuit, you will use

Connector and Harness Inspection - Make sure the VVT solenoid valve connector is in good working order with no bent or loose pins, corrosion, or water ingress. Make sure the connector is securely installed. Check the wiring harness for damage, fraying, exposed or broken wires. Repair as needed.
Voltage Check - With the engine running, you should have a minimum of 13.4 volts at the battery. Check the VVT solenoid valve check probe, usually located in the cylinder head or valve cover, and check the battery voltage.
If the voltage is incorrect, suspect an open circuit between the ECM and the valve. Disconnect the connector and recheck the battery voltage. If not, suspect an open circuit between the ECM and the valve. Inspect the wiring harness and repair if necessary.
If the voltage is correct, suspect a grounding problem. With the key turned off and the engine off, disconnect the VVT solenoid valve connector and the ECM connector. From the VVT solenoid valve connector, check both pins for short to each other and short to ground. You should measure the infinite resistance to ground and across the pins. If incorrect, suspect a short circuit. Repair as needed.
VVT Solenoid Valve Check
Check the resistance between the solenoid valve contacts. You should measure between 5 Ω and 15 Ω, depending on the manufacturer and temperature. Check your manual for the correct specification. If incorrect, replace the valve.
Check resistance between contacts and ground. You must measure the infinite resistance to ground. If incorrect, replace the valve.

The combustion process of the mixture in a working engine

Fuel system check valve: 4 main faults and how to fix them

To better understand the causes of valve burnout, you need to know the basics of gas exchange processes in the engine and their sequence.

Intake stroke. The intake valves are open, the piston moves down, creating a vacuum zone. At this moment, a mixture of fuel and air is sucked from the intake tract (gasoline engines with distributor injection into the intake or with a monoinjector) or a pure air charge (internal combustion engines of the Diesel cycle and gasoline engines with direct injection).
Compression stroke. The piston begins to move upward, the intake and exhaust valves close. The mixture compresses, the temperature in the combustion chamber rises.
Working stroke. A few degrees before the highest dead center (TDC) of the cylinder, the mixture is ignited by a spark (gasoline internal combustion engines) or self-ignites from contact with heated air (diesel engines). Under the influence of the force of expanding gases, the piston rushes down. The reciprocating movement of the piston through the connecting rod and crank mechanism is transmitted to the rotational movement of the crankshaft.
Release stroke. The exhaust valves open. The piston moving towards TDC pushes the exhaust gases into the exhaust tract.

The phases of valve overlap and inertial filling are omitted intentionally, since they do not significantly affect the consideration of the issue of valve burnout.

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Equipment used for commercial and industrial purposes must meet increased requirements for quality and functionality. Such units are resistant to intense loads and continuous operation in difficult conditions. Such operating characteristics, of course, negatively affect the degree of wear of components, and it is extremely important to promptly diagnose and repair systems and components of machines, be it a truck, a piece of special equipment, a bus or other equipment.

The key aspect of effective repairs is experienced craftsmen and high-quality spare parts. If you want to ensure long-lasting and trouble-free operation of your equipment, please contact. Our team will not only help you find and order any spare parts for the Cummins engine or other components for equipment, but will also promptly repair damage and engine malfunctions.

Professionalism and rich work experience,

Use and sale of original spare parts with a guarantee of up to 12 months,

Individual approach to every customer,

Favorable prices and special terms of cooperation for wholesalers.

Contact our manager at the phone numbers listed on the website (the call is free throughout Russia) or write to us on the website. We accept orders from customers from any region of Russia and provide prompt delivery using trusted transport companies. The transparency of our work and the excellent quality of products will pleasantly surprise you - contact us and take care of the work of your technology park!