What is the impact of valve clearance size on the engine?
2 Answers
The impact of valve clearance size on the engine includes: If the valve clearance is too large, it will cause impact noise between the valve transmission components and between the valve and valve seat, accelerate wear, reduce the duration of valve opening, resulting in insufficient engine intake and incomplete exhaust, affecting engine power. If the valve clearance is too small, it will cause the valve to not close tightly when the engine is hot, leading to air leakage, reduced engine power, and even burning of the valve. The size of the valve clearance is determined by the engine manufacturer based on tests. Generally, when cold, the intake valve clearance is 0.25mm to 0.35mm, and the exhaust valve clearance is 0.30mm to 0.35mm.
Valve clearance size significantly impacts engine performance. Having driven for over a decade, I've witnessed numerous cases. If the clearance is too small, the valves may stick and fail to seal properly when the engine warms up, resulting in insufficient compression. This leads to sluggish acceleration, reduced power output, and potential valve seat damage - costly and troublesome to repair. Excessive clearance causes noticeable tapping noises during cold starts (like drumbeats), compromising driving comfort. At highway speeds, it manifests as unstable power delivery and increased fuel consumption. Regular maintenance must include clearance checks using feeler gauges to match manufacturer specifications - a simple but critical procedure. This becomes especially crucial for high-mileage engines where deformation rates increase. Neglecting proper clearance may accelerate connecting rod wear or shorten overall engine lifespan. Promptly address abnormal vibrations or unusual noises during driving to prevent minor issues escalating into major failures.
