What causes engine idle shaking when the valve clearance is too small?

[MacBrody]

The reason for engine idle shaking when the valve clearance is too small is: When the valve clearance is too small, it causes the valves to open prematurely or not close tightly. This affects the air pressure in the cylinders, preventing the fuel and air mixture from burning completely, resulting in abnormal engine shaking during idle. Engine idle shaking due to excessively small valve clearance is a common issue, which can be resolved by adjusting the valve clearance to the proper range. In addition to abnormal idle shaking, excessively small valve clearance can also cause difficulties in starting the car and engine overheating. Conversely, when the valve clearance is too large, it affects the engine's air intake, leading to increased fuel consumption, reduced power, and noise from the valve chamber.