How to Adjust the Valve Clearance of Gasoline Engine

The adjustment method of valve clearance of gasoline engine is as follows: 1. When adjusting the valve clearance, the piston must be at the compression top dead center position, otherwise the valve will be supported by the rocker arm and the valve clearance cannot be adjusted; 2. Therefore, the crankshaft must be rotated first. You can turn the crankshaft with your foot on the starter. It is recommended to remove the spark plug and insert a small screwdriver from the spark plug hole of the cylinder head to press it on the top surface of the piston. When turning the crankshaft, it can be judged whether it reaches the top dead center by lifting the screwdriver. 3. But you must also know how to judge whether the piston is at the compression top dead center: at the compression top dead center, both valves are in the closed position, and there is a gap between the end face of the valve clearance adjustment screw on the rocker head and the top face of the valve stem, which is the valve clearance; 4. When the piston is at the exhaust top dead center, both valves are half open, and the valves are fixed by the adjusting screws on the rocker arm, so the valve clearance cannot be adjusted.