How to adjust the valve of this engine?

There are several ways to adjust the valve of the engine. The valve clearance can be adjusted twice by rotating the crankshaft. For example, for a 4-cylinder engine with the working sequence of 1, 3, 4 and 2, open the cylinder head, rotate the crankshaft and observe the valve movement of 4 cylinders. When the intake valve and exhaust valve overlap, this is the exhaust top dead center of cylinder 4. At this time, 1 cylinder is at compression top dead center and can be adjusted. Then turn the crankshaft 360 degrees, find the compression top dead center of cylinder 4 according to this method, and adjust other valves. This is the simplest and most practical method. Generally, a multi-cylinder machine can adjust all valves twice.

In a four-cylinder engine (1-3-4-2 power sequence), the valve clearance can be adjusted according to 1 double, 2-in, 3-out and 4-out. When the compression top dead center of 1 cylinder is reached, the valve clearance can be adjusted.

At the end of the compression stroke (cylinder 1), the intake valve is closed and the exhaust valve is closed.

(2 cylinders) The power stroke ends, the exhaust stroke begins (exhaust is opened ahead of schedule), and the intake valve closes.

(3) When the intake stroke ends, the compression stroke starts (the intake is closed later) and the exhaust valve closes.

(Cylinder 4) The exhaust stroke ends and the intake stroke starts (intake starts early) (exhaust starts late), which is not acceptable!