What is the valve clearance for intake and exhaust?
2 Answers
Intake valve clearance is generally within the range of 0.20mm to 0.25mm. Due to thermal expansion, the exhaust valve clearance is larger than that of the intake valve side, so it naturally requires a larger gap, typically between 0.29mm and 0.35mm. Below is relevant information about intake and exhaust valves: 1. Effects of excessive clearance: Excessive clearance can lead to incomplete valve closure, affecting engine performance, causing insufficient intake and incomplete exhaust, increased impact between the valve and valve seat, and valve noise. 2. Effects of insufficient clearance: Insufficient clearance can result in incomplete valve closure (no space), generating noise, increased wear, and phenomena like engine weakness.
The specific valve clearance really depends on the car model, and it's usually indicated in the manual. The intake valve clearance may range between 0.10 to 0.25 mm, while the exhaust valve clearance is slightly larger, around 0.20 to 0.40 mm. I've adjusted it myself a few times and found that excessive clearance causes the engine to make an annoying ticking sound, like knocking, which makes driving uncomfortable. If the clearance is too small, the valves won't seal properly, leading to increased fuel consumption and poor performance. I use a feeler gauge for measurement, ensuring the engine is cold, then open the hood, locate the valve cover, and slowly adjust the screws. Remember—don’t attempt it blindly. If unsure about the measurement, it's safest to seek help or consult the manual. Significant changes in clearance may affect ignition timing, so regular checks can prevent major repairs.
