How to Adjust the Valve of Wei Chai Engine?

I'm a maintenance worker, too. It's a hard job. I have sorted out a little bit myself, hoping to help you: First, the cylinder-by-cylinder adjustment method, which is a textbook adjustment method, is relatively simple and basically suitable for novices to understand and master, but it is more complicated when adjusting multi-cylinder engines; Therefore, ordinary maintenance personnel do not use this method.

Second, the two-step adjustment method, which is the most widely used valve adjustment method, is also recognized by most people. Some experienced maintenance engineers can directly find the valve to be adjusted according to their own experience. For those who have just come into contact, the method of "double row but no entry" is recommended. "Double exhaust does not enter" method is a general and simple method to adjust valve clearance. According to the working order of the engine, it divides the conditions of whether the valves of each cylinder can be adjusted into four types: "double" means that the intake and exhaust valves of the cylinder can be adjusted;

"Row" means that only the exhaust valve of the cylinder can be adjusted;

"No" means that the intake valve and exhaust valve of the cylinder are not adjustable;

"Intake" means that only the intake valve of the cylinder can be adjusted. Here are some examples to illustrate.

A three-cylinder engine, look at its working order, for example, its working order is 1-2-3. When the piston of 1 cylinder is compressed to the top dead center, the intake and exhaust valves of 1 cylinder are adjustable, the exhaust valves of cylinder 2 are adjustable, and the intake valves of cylinder 3 are adjustable; When 1 cylinder is located at the exhaust top dead center, the intake valve of cylinder 2 and the exhaust valve of cylinder 3 are adjustable.

Second, for a four-cylinder machine, it can be done according to its working order. If its working sequence is 1-3-4-2, when the first cylinder is at compression top dead center and the intake valve and exhaust valve overlap (when the intake valve is just closed and the exhaust valve is just about to open), it can be done according to the "double exhaust method", that is, the intake valve and exhaust valve of 1 cylinder can be adjusted, and the exhaust valve of cylinder 3 can be exhausted.

There is a clear chart about six-cylinder engine. Because I can't draw my chart, I will briefly talk about the arrangement of adjustable valves in a six-cylinder engine, and the working sequence is 1-5-3-6-2-4, the first time (top dead center of one cylinder).

Adjust 1 cylinder dual valves, exhaust valves of cylinders 5 and 3, dual valves of cylinder 6 are not adjusted, and intake valves of cylinders 2 and 4. I don't need to say the rest. The last thing to note is:

1. For engines with different structures, the arrangement of intake valve and exhaust valve is not necessarily the same, and the valves should be clearly identified before valve adjustment.

2. There is no mistake whether the cylinder is at compression top dead center or exhaust top dead center.

Generally, there are timing marks on engines. When the timing marks are aligned, it may be that one cylinder is at compression top dead center or one cylinder is at exhaust top dead center. At this time, turn the crankshaft counterclockwise for an angle, and the exhaust valve of the first cylinder will open; Turn an angle clockwise, the intake valve of a cylinder will open, and then a cylinder will be at the exhaust top dead center. If both valves of a cylinder are not open, it means that the cylinder is at compression top dead center.

3. For engines with the same number of cylinders, if the working sequence is different, the order of valve adjustment is also different.

4. Different engine valve clearances are different; The valve clearance of the same type of engine is different in cold state and hot state; The gap between the intake valve and the exhaust valve of the same engine is also different. When adjusting, it must be adjusted according to the maintenance manual and standards.