Valve

Valves are the systems in internal combustion engines that enable the intake and exhaust processes. Intake valves allow the fuel-air mixture into the combustion chamber, while exhaust valves permit the expulsion of gases produced after combustion. Valves are vital for the proper operation of the engine and are typically mounted on the cylinder head.

What Is the Purpose of Valves?

Valves regulate the intake and exhaust processes by opening and closing the entry and exit pathways in the engine. Each cylinder has at least one intake valve and one exhaust valve. In Modern engines, this number is increased to enhance efficiency.

• Intake valve: Allows fuel and air to enter the combustion chamber.
• Exhaust valve: Expels exhaust gases produced after combustion.

Valves are operated by the camshaft and synchronized with the crankshaft via the timing belt.

Signs of Valve Failure

Valve faults directly impair engine performance. Symptoms include:

• Delayed engine startup
• Excessive smoke upon initial engine start
• Increased fuel consumption
• Engine misfires and irregular operation
• Unusual engine noises (valve tapping)
• Loss of performance

Valve Tapping Noise

Valve tapping is a metallic noise caused by excessive clearance in the valve mechanism, leading to hard contact between components. This noise may be intermittent when the engine is cold. However, if it persists when the engine is warm, it indicates incorrect adjustment or wear in piece components word.

What Is Valve Adjustment?

Valve adjustment is the process of setting the clearance between the valve and the rocker arm to the manufacturer’s specified values. This clearance changes due to thermal expansion during engine operation and must be checked and adjusted at regular intervals. It is generally recommended to inspect the clearance every 30,000 to 120,000 kilometers.

How Is Valve Adjustment Performed?

• A feeler gauge, wrench, and screwdriver are used.
• Adjustment must be done with the engine completely cold.
• The camshaft is rotated to position the piston at top dead center.
• The specified clearance is checked using a feeler gauge.
• If necessary, adjustments are made using a screwdriver and wrench.

Each vehicle has a different valve clearance specification; manufacturer data must be followed.

What Happens If Valve Adjustment Is Not Performed?

• Engine idle becomes irregular.
• Fuel consumption increases.
• Performance decreases.
• Mechanical damage occurs in the valve mechanism.
• If valves fail to close properly, exhaust gases and oil may leak.

Valve Breakage

Valve breakage typically occurs when the timing belt snaps. In this case, the pistons collide with the valves, causing them to bend or break. When a valve breaks, the engine stops completely and suffers severe damage. The engine will not start state and repair costs are high.

Which Vehicles Require Valve Adjustment?

Valves are present in all internal combustion engines. Therefore, valve adjustment is necessary for all gasoline, diesel, and LPG-powered vehicles. Only electric vehicles do not have valves. Valve adjustment is typically performed at authorized service centers using specialized equipment.

Valves are critical components that determine fuel efficiency, torque, and smooth engine operation. Regular valve inspections must be carried out, and valve adjustments at specified mileage intervals must not be neglected. If faults in the valve system are not detected early, they can lead to irreversible engine damage. When valve noises, smoke, or performance loss like are observed, prompt service attention technical is essential.