Why is valve clearance necessary in the valve train?

[EvelynAnn]

Here are the reasons why valve clearance is necessary in the valve train: 1. Prevent gas leakage: If there is no clearance when the valve train components expand due to heat, it may push the valve open when it should be closed, causing combustion chamber leakage. 2. Affect power output: Excessive valve clearance will result in insufficient valve opening, affecting air intake; insufficient clearance will prevent the valve from closing tightly, causing leakage and affecting engine power. 3. Adjustment method: Adjust the adjusting screw at the rear of the valve rocker arm, measuring the clearance between the rocker arm head and the valve stem head. During adjustment, the tappet should be positioned at the base circle of the camshaft lobe, which is when the valve is in the closed position.