Why is Valve Clearance Reserved?

[StEllie]

Reserving valve clearance is necessary for the following reasons: Since the valve is in contact with the cylinder block, which generates a significant amount of heat during operation, the heat is transferred to the valve, increasing its elongation. 1. Consequences of not reserving valve clearance: If valve clearance is not reserved in advance, when the engine is cold, the valve may tightly contact the cylinder block without any gap. As the cylinder block heats up and the valve elongates, the valve could damage the cylinder block or itself. Therefore, proper valve clearance must be maintained. 2. Hazards of excessive valve clearance: Excessive impact and faster wear between moving parts, along with reduced valve opening height and duration, degrade the quality of the gas exchange process. 3. Hazards of insufficient valve clearance: When heated, the valve may get stuck, leading to poor sealing, gas leakage, reduced power, increased fuel consumption, and phenomena like flames from the exhaust pipe.