- 2/10/2025
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Valve train
When you look at the car engine after removing all its internal parts and components, you will discover that it contains many small and large parts that are placed inside it to contribute to its work, and among the most important internal engine components are the valves, without which the engine will not work at all.
The valves are thin arms that end with wide funnel-like bases that extend from the engine head to the beginning of the combustion chamber that is concave in the engine head, and the function of these valves is simply to introduce the air and gasoline mixture into the engine and expel the waste gases after combustion.
Over time, the valves are exposed to carbon buildup or micro-cracks on their bases that make them inefficient, or they can be damaged and broken due to an engine issue that causes them to stop working, and although it is rare for major valve issues to occur, if they do, they can be very damaging to the engine.
Since the valves are very important, Motorgy provides you with used cars for sale in Kuwait that are thoroughly checked by experts from the engine to the paint and electronics, so you can choose your dream car with the assurance that it is free of engine failures, especially valves, after viewing its comprehensive inspection report.
Read more: Engine valves common issues
Where are the valve train located?
The valve train or valves are located in the upper section of the engine on the part called the engine head, which is the upper part that also contains the valve train, camshaft and many other important parts.
The valves are at the top because they are connected to the main engine block that contains the cylinders, pistons, crankshaft, etc. Engines usually have 4 valves per cylinder, while older cars had only 2 valves per cylinder.
When you remove the plastic cover of the engine, you will immediately see a set of springs that meet each other, and these are the valve springs, which are the thin valve arms that extend from their center to the center of the engine head to the upper section of the combustion chamber.
Read more: Bad valves symptoms
The function of the valves in the engine
Engines have two types of valves, or valves that perform two functions:
Intake valves
The primary function of the intake valves is to allow the mixture of air and gasoline to enter the combustion chambers inside the engine, which occurs when the piston inside the cylinder moves down in the intake stroke, creating a vacuum inside the cylinder.
After the intake valves open at the right time controlled by the camshaft, the air and gasoline mixture enter the cylinders directly and quickly through the air inlets, and after the correct amount has entered through them, the piston ascends again in the compression stroke and then closes completely.
After the compression stroke is complete, in which the air and gasoline mixture is compressed, the explosion stroke begins, in which the spark plug releases the spark to burn the mixture, which pushes the piston forcefully down and into each cylinder individually until the engine moves on its own.
Exhaust pipes
After the explosion stroke is complete, the exhaust gases created by the explosion are generated inside the cylinders, immediately following the exhaust stroke, which opens the other valves, which are the exhaust valves that are connected to the exhaust outlets.
After the piston starts going up in this stroke, it expels the exhaust gases from the combustion chamber, because the valves are opened by the camshaft to allow them to exit, and after the gases leave the cylinders, they pass through the exhaust pipe to the outside of the car.
The bases of exhaust valves in engines are smaller than intake valves because the latter are designed to draw in a larger amount of the air-fuel mixture to ensure proper and accurate combustion, while exhaust valves are only intended to eject exhaust gases and do not need to be oversized.
