The engine head is the most complex assembly of the mechanical part of the engine, given the function and loads to which it is exposed. The thermal and dynamic stresses are extremely high, with the least errors and damage.

This assembly can cause serious damage to the engine as a whole, and especially the piston mechanism. A defective or damaged engine head impairs performance and increases fuel consumption, and can cause hazardous mixing of coolant and oil. Therefore, the damaged cylinder head should be repaired (repaired) as soon as possible.

The engine head contains valves (suction and exhaust, 2 to 5 in total per cylinder), valve guides, valve cutters, valve springs, valve lifts (mechanical or hydraulic), camshaft (one or two), nozzles (petrol or diesel) and atria (for older diesel engines). The base part or base is made of aluminum alloy or cast iron. On the outside of the head there are camshaft pulleys; in the case of a chain-assisted engine, the chain is on the inside of the engine, the intake and exhaust manifold, the distributor (some gasoline engines), the sub-pump (diesel engine).

The most common engine head failures are valve and valve guides wear, damage to the head gasket, damage and local strain within the head itself, deformation of the cylinder head, combustion of one or more valves, damage to the cylinder head due to detonation combustion, and other unforeseen damage. The most devastating phenomenon, which regularly has consequences, is engine overheating. All the mechanical parts that are subject to critical temperature changes in structure, accelerate wear and cause the cylinder head to burst.

Valve burnout is most often the result of neglecting the valve adjustment procedure for motors that have mechanical valve lifts (both old and new types of motors have them). Adjusting the valves allows all valves to normally close the intake and exhaust ducts, so that the gas exchange in the cylinder takes place without loss. When the required clearance between the valve and the camshaft (due to wear of the valve) disappears, the valve no longer closes the seating position. Then the gases in the cylinder of temperature 600 to 800 ° C, which flows through the resulting opening, burn the edge of the valve. Thereafter, a fall and a complete loss of compression pressure occur, and that cylinder stops working.

Cessation of the cylinder with loss of power and uneven engine operation results in a very dangerous condition for the engine - flushing of the cylinder wall, oil film cracking, dry friction, extremely high temperatures (local), piston melting and extensive damage to the engine block, with costly consequences. The risk increases with driving time in this condition. This damage also causes irreparable damage to the catalytic converter, which intensively enters unburnt hydrocarbons (HxCy).

When this condition is recognized, the engine must be switched off immediately and the car serviced.

In addition to these extraordinary occurrences, regular wear and tear on the valves, valve guides, and valve heads are also occurring on the cylinder head. Changes in the negative sense occur on the suction and discharge ducts and the walls of the head. Micro-cracks between the intake and exhaust ducts, damage to the atoms (older diesel engines) are especially dangerous.

The most demanding and costly repairs are with multi-valve more powerful engines. So a thorough and quality repair of their engine heads can cost up to a thousand euros.

When any type of damage to the cylinder head assembly occurs, there is no alternative to doing the required cylinder head repair. The process of arranging the cylinder head has its logic and any deviation from it is improvisation, contrary to the rules of the profession, and for the vehicle owner is counterproductive. The process of overhauling the cylinder head is as follows:

• Dismantling the cylinder head
• Engine head revision
• Cleaning and washing of all engine head parts
• Condition recording, wear measurement
• Metallization- welding
• Replacement of worn and defective components on the cylinder head
• Machining of valve seams
• Machining-alignment of the cylinder head
• Grinding-polishing valves (if necessary)
• Testing the cylinder head with a hydro test

After the engine head has been so arranged and tested, it is necessary to carefully assemble the valve group, adjust the valves exactly (where necessary), or determine the distance between the top of the valve and the camshaft (valves with hydraulics). Most engines also require replacement of the cylinder head bolts. With the engine head edited as above, it gets multiple in quality:

• The engine no longer consumes oil via the valve guides
• Compression increases
• The amount of intake air in the cylinders increases
• The engine has more power and better performance
• Reduced fuel consumption
• The eco-test is improving

The mentioned works can last from two to five days, and before the beginning of the works, the total cost of the works can be calculated roughly. Prices range from around € 100, for smaller engines with two valves per cylinder, to more than € 1,000, for more powerful 4-valve and V-engines depending on the degree of damage. For more info visit Car parts marketing

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