What are the effects of excessive or insufficient valve clearance?
2 Answers
The effects of excessive or insufficient valve clearance are: 1. Causing abnormal metal knocking sounds: Excessive valve clearance in the engine will cause abnormal metal knocking sounds, and may leave marks on components such as rocker arms and valve stems, resulting in persistent abnormal noises. It will also reduce intake and exhaust volume, affecting the engine's power and other performance; 2. Decrease in engine power: Insufficient valve clearance will cause the valves to not close tightly when the engine is hot, leading to air leakage and a decrease in engine power, or even burning out the valves. During cold assembly of the engine, a certain gap is left in the valve and its transmission mechanism to compensate for the thermal expansion of the valve. This gap is called valve clearance.
I often hear car enthusiasts complaining about strange engine noises, mostly related to valve clearance issues. When the clearance is too large, the camshaft knocking against the valve lifters creates a clattering sound, affecting the car's acceleration and increasing fuel consumption, making the drive feel sluggish. If the clearance is too small, the valves won't close properly, causing the engine to overheat, emit black smoke from the exhaust, and suffer from incomplete combustion leading to power loss. It may also burn out the valve seat pads. If not repaired promptly, the engine's lifespan will shorten, and repair costs will be high. It's best to regularly check and maintain, especially for older cars, and not wait until the problem becomes severe. Pay attention to engine sounds and temperature changes in daily use—developing good habits can save a lot of money and trouble.
