How to adjust the valve clearance of automobile?

Cylinder-by-cylinder adjustment method: according to the ignition sequence of cylinders, the gap between the intake valve and the exhaust valve of a cylinder can be adjusted after determining the compression top dead center position of the piston; After adjustment, turn the crankshaft and gradually adjust the valve clearance of other cylinders according to this method. ? Two adjustment methods are adopted: shake the crankshaft so that the piston of the first cylinder is at the compression top dead center, and the flywheel mark is aligned with the inspection hole, so that the valves of 1, 2, 4, 5, 8 and 9 can be adjusted (refer to the sequence of engine valves from front to back); Then turn the crankshaft once, so that the six-cylinder piston is at the top dead center of the compression stroke, and then adjust 3, 6, 7, 10 "plus two valves (i.e. 1 1, 12), which is actually memory adjustment. When adjusting, while tightening the adjusting screw, insert the thickness gauge between the valve stem end and the rocker arm and pull it back and forth. If you feel slight resistance, check it again until it is suitable. ? The cylinder-by-cylinder method requires the crank to rotate the crankshaft more times, and the inspection and adjustment time is longer. However, for the seriously worn engine, the cylinder-by-cylinder method is more accurate to check and adjust the valve clearance. Adjusting the valve clearance twice saves time and effort, but it is difficult for maintenance personnel to remember the different adjustable valve serial numbers of different models, which is more complicated.