How to Adjust the Valves of a Three-Cylinder Engine?
2 Answers
Adjusting the valves of a three-cylinder engine can be done using the following methods: 1. Cylinder-by-Cylinder Adjustment Method: Based on the firing order of the cylinders, determine when a piston is at the top dead center of the compression stroke, then adjust the intake and exhaust valve clearances for that cylinder. After adjustment, rotate the crankshaft and proceed to adjust the valve clearances of the other cylinders in the same manner. 2. Two-Step Adjustment Method: Rotate the crankshaft until the first cylinder's piston is at the top dead center of the compression stroke, aligning the flywheel mark with the inspection hole mark. At this point, adjust valves 1, 2, 4, and 6 (referring to the front-to-back order of the engine valves). Then, rotate the crankshaft one full turn and adjust valves 3 and 5. This is essentially a memorization-based adjustment method.
I've worked on several three-cylinder engines before, and valve adjustment must be done only after the engine has completely cooled down. Gather the necessary tools, including a feeler gauge of the appropriate size, wrenches, and a torque wrench. After removing the valve cover, locate the position of each valve. When measuring the clearance, gently insert the gauge and check if it falls within the range specified in the manual (typically 0.15-0.25 mm). Excessive clearance can cause loud engine noise, while insufficient clearance may lead to valve sticking and affect combustion efficiency. To adjust, use a small wrench to rotate the eccentric or replace the shim size until the gauge slides smoothly. Recheck each valve to avoid oversight. Once done, carefully reinstall the cover and start the engine to listen for smooth operation. It's recommended to inspect every 15,000 km. Beginners should avoid attempting this, as mistakes can cause oil leaks or abnormal engine noise. It's best to seek help from a repair shop—it saves time and ensures safety.
