What is the appropriate valve clearance?
1 Answers
Generally, when the engine is cold, the intake valve clearance is between 0.20mm and 0.30mm, and the exhaust valve clearance is between 0.25mm and 0.35mm. The valve clearance for different engine models is determined by the engine manufacturer through testing, and specific details can be found in the maintenance manual. Valve clearance refers to the gap between the end of the valve stem and the valve transmission components when the valve is fully closed. Effects of too small valve clearance: If the valve clearance is too small, the engine may experience leakage due to the valve not closing tightly when hot, leading to reduced power and even valve burning. If the valve clearance is too large, it can cause impact noise between transmission components and between the valve and valve seat, accelerating wear. Additionally, it reduces the duration of valve opening, worsening cylinder charging and exhaust conditions. Precautions: Valve clearance is determined by the manufacturer during design and testing, with each engine having its own standard. Adjust according to the standard. Ignition timing, whether advanced or delayed, affects engine power. Nowadays, ignition timing is often adjusted by feel, generally based on smooth acceleration, no smoke, and no knocking. After adjustment, it is best to conduct a road test.
