How to Adjust Engine Valves?
2 Answers
Engine valve adjustment method is as follows: 1. Rotate the crankshaft to align the pulley mark with the engraved line, which indicates the end of the compression stroke for cylinder one or four. If it is the end of the compression stroke for cylinder one, count from the front of the engine backward, and you can adjust the valve clearance for valves 1, 2, 4, and 6. 2. Insert a feeler gauge of the specified thickness between the valve stem and the rocker arm, and pull it back and forth. When you feel slight resistance, it is appropriate; otherwise, adjustment is needed. 3. During adjustment, loosen the lock nut, turn the adjusting screw, insert the feeler gauge into the gap and pull it back and forth. Slight resistance indicates the gap is appropriate. Fix the adjusting screw and check once more. If the gap changes, readjust. 4. After adjusting the above valves, rotate the crankshaft one more turn to align the flywheel mark with the engraved line on the flywheel housing window again. At this point, cylinder four is at the end of the compression stroke. Count forward from cylinder four, and you can adjust the clearance for valves 1, 2, 4, and 6.
I still remember my first experience adjusting engine valves. The key is to ensure the engine is completely cooled, otherwise thermal expansion and contraction will affect precision. The general steps are: open the hood, locate and unscrew the valve cover bolts to remove the cover plate. Then rotate the crankshaft to bring each cylinder to top dead center position, and use a micrometer to measure the valve clearance. The standard value is usually between 0.2 to 0.3 mm, but refer to the vehicle manual for specifics. If the clearance is too small, use a wrench to loosen the adjustment screw and turn it counterclockwise to increase; if too large, turn clockwise to decrease, then tighten the lock nut and repeat the check. Improper adjustment can cause excessive engine noise or power loss, so I always take my time to do it carefully. I recommend wearing gloves to prevent cuts since engine oil makes things slippery. For daily driving, check every 2 years or 30,000 km to extend engine life. Essential tools include a wrench, micrometer, and gloves. DIY can save money, but beginners should watch tutorial videos before attempting.
