Many car owners love their big four-wheeled toys to the extent that they seek to familiarize themselves with all the nodes and systems that make up the vehicle. After reaching the engine compartment, you can find there are many seemingly incomprehensible elements. For example, under the hood there is a cylinder head, what it is in the car, not many novice motorists know.
Content
- 1 Basic concepts
- 2 Design features
- 3 Node functionality
- 4 Gasket Features
- 5 System maintenance
- 6 Proper operation
- 7 How does a fault appear
- 8 How to clean the cylinder head
Basic concepts
On car courses and in transport schools, you can learn more about the cylinder head of the car, decoding the concept there is given and technical parameters. Under this abbreviation is commonly understood as the head of the cylinder block of the power plant. It is a cover that hermetically covers the motor from negative external influences.
The part in most cases has a rather complex cast form. In most cases, the main material for it are aluminum alloys. Also found products made on the basis of alloyed cast iron.
It is necessary to know that the cast head after the casting stage undergoes artificial aging of the material, thus relieving all the physical stresses established during the acquisition of the mold by the blank.
This operation is mandatory, since the workpiece passes through several stages of high-precision mechanical processing. If you skip the aging stage, then over time, the cylinder head of the engine due to residual stress deforms arbitrarily independently.
Design features
Understanding what a cylinder head is in a car, and what role it plays, it is necessary to take into account that this element is mated with a large number of additional nodes:
- intake / exhaust valve timing;
- nozzles;
- ignition system in gasoline cars;
- camshaft, etc.
You need to know that the head is located directly above the cylinder block.
In fact, it covers all cylinders at the same time, being their small continuation. On this basis, for classic in-line engines, automotive engineers cost one cylinder head, and for V-shaped structures, you need to put a couple of pieces.
The drive of the gas distribution mechanism, which is part of the head, includes valves. Structurally, they are located in one row opposite the cylinders. For proper operation of the system, they are installed in most cars at an angle of about 20.
Node functionality
The head of the engine block simultaneously protects all combustion chambers. An aluminum or cast-iron part is placed on the block, I place a special heat-resistant gasket between them. The latter provides maximum sealing system. In some cases, an additional layer of sealant is applied, which increases the performance of the gasket.
During maintenance or overhauls, the head gasket must be replaced. It is not suitable for reuse.
The aluminum part is subjected to high-temperature impacts, as it mates directly with the combustion chambers. The mixture of fuel and air during explosions also exerts a force on the inner surface.
The housing has threaded holes. Spark plugs (for gasoline power plants) or injectors (for diesel engines) are screwed into them. There are also holes through which the camshaft performs its operations. In his case, you have to install:
- bushings;
- springs;
- valves;
- thrust washers;
- rotation bearings, etc.
For each of these elements creates its own shape or hole in the cylinder head. All of them are parts of a complex gas distribution mechanism.
It is worth considering that the untimely or inappropriate maintenance of the site, or incorrect operation will lead to a rapid failure. What would entail costly repairs. At specialized stations it will cost a large sum. Even with self-repair, the operation will be time consuming and lengthy. One of the first difficulties is unscrewing fasteners.
The front of the head is used for mounting a chain drive. It also takes into account the need for chain tensioner.
The surface of the head, mating with the gasket and the cylinder block, is subjected to special machining. Provides a single horizontal plane without depressions and protrusions. Subsequently, due to temperature changes, it will be deformed, therefore, as a repair, it is subjected to additional polishing. Thus, the original geometric shape is restored. Otherwise, even the presence of the gasket will not save depressurization of the combustion chambers.
A special form is present in the parts of the head mated with the combustion chambers. Pistons provide compression of the fuel mixture at its highest point, and the shape of the chamber helps to ensure the best possible turbulence of the gases. This has a positive effect on the combustion process with maximum energy return.
The flange of a special form adjoins to the back. It is connected to several branch pipes, going further under the car. There are inlet and exhaust manifolds.
In the cavities circulating cooling fluid - antifreeze. Thanks to it, the temperature of the head and the block decreases.
The head has a number of fixed elements, which include valve seats. They are necessary to create a tight system of gas distribution mechanism. By non-removable should include valve guide bushings.
They are mounted by pressing on special equipment. To conduct a similar operation at home is very problematic. Special tools and heat treatment equipment will be required.
Sometimes, the “craftsmen” offer to carry out such an operation in the garage, but such a process can lead to overheating of the part and its subsequent deformation. In this case, the product geometry will be irretrievably lost, and microcracks may also be formed. As a result, will have to buy a new node.
Gasket Features
Most of the problems arise from depressurization, which often occurs when a gasket fails. It must be properly selected to get rid of expensive repairs. As a result of a burnout, a knock of pistons will be heard, and also this will lead to a failure in the operation of the motor. Manufacturers offer two types of heads:
- based on paronite;
- from metal.
Cylinder head gasket
Metals perform better with their functions, but they do not suit certain types of motors. In particular, it is not accepted to put it on atmospheric power plants. There it is necessary to get along with paranitic, coping with most surface irregularities.
System maintenance
It should be borne in mind that in any case, all automotive systems and parts require service over time, including the cylinder head. An important factor in this situation is timely diagnosis. Special attention should be paid to the following factors:
- high-quality work of the laying providing tightness;
- valve testing;
- it is important to check the operability of valve seals;
- need to control the quality of the camshaft oil seals.
If there is trouble with the gasket, the oil from the lubrication system will penetrate the cooling system, and the antifreeze will get into the oil circulation cavities. With this mutual penetration of the motor will work with reduced efficiency.
When a part of the oil begins to circulate with antifreeze, the phenomenon of engine structure will appear. After a while, the engine will simply cease to start. At the same time, an increased temperature of the motor will appear on the dashboard according to the indicators.
The presence of antifreeze in the lubrication system will have a negative impact on the condition of candles. When unscrewing, they can be noticed by soot, which “floods” them.
Proper operation
After repair or diagnostics, it is important to correctly assemble the assembly of all elements of the head, since even an incorrectly fixed part on the cylinder block can deform during operation. In certain situations, dismantling the cylinder head will not manage:
- boring cylinder block;
- a problem with valves that will require replacement or repair;
- pressure testing of valve sleeves or saddles;
- loss of geometrical parameters of the interface;
- gasket broken (lost tightness);
- the need to eliminate microteschina.
It is important to know that it is necessary to use a torque wrench to tighten the head fasteners.
Surface geometry recovery
Due to the fact that the motorist can see the moment of achieving the necessary effort, sufficient tension is provided on the thread and the coils are not broken. It is categorically not allowed to use additional capacity keys when screwing. It is also important to observe the sequence when tightening the screws on the heels.
How does the fault appear
It is necessary to remove inoperability node in a timely manner. Otherwise, the breakdown will lead to increased gas mileage or even to a complete stop of the engine, which requires a major overhaul. To identify a problem in time, it is necessary to pay attention to indirect signs of the phenomenon:
- oil leaks appear under the gasket;
- the probe during diagnosis has a small amount of white foam;
- exhausts lose transparency, and there is a past haze from the pipe;
- oil stains and drips are noticeable in the radiator and expansion tank.
If you identify one of the signs, we recommend to contact the service station to diagnose the status of all nodes. You can also identify a punched gasket, in which integrity is violated. When installing it, there should be no foreign elements on one side between it and the cylinder head, as well as between the gasket and the block. Screwing studs, you need to protect the gasket from damage, as this will reduce its service life.
A non-standard sound in the form of an outside knock is evidence that damage is present. Complete breakdown of the gasket can stop the engine and damage the cylinder head. Most often, trouble occurs in the following cases:
- overheating of the power plant;
- incorrect installation of the gasket itself;
- increased compression values.
How to clean the cylinder head
To get rid of carbon on the metal part of the head, you can use various chemical means. It is quite resistant to most of the household mildly aggressive "chemistry." Seasoned motorists use such compositions:
- acetone;
- fuel;
- household cleaners;
- washing powders, etc.
The main thing is to use personal protective equipment against chemical preparations. It will also be necessary to rinse the metal well from residues of the cleaner.
