Eaton Char-Lynn Motor – Motor Valve Clearance Adjustment
When the motor is working, because the valve is working at high temperature, the valve and other parts are elongated due to thermal expansion. Therefore, a certain valve clearance must be reserved when the valve is cold, so as to ensure that when the valve is thermally expanded and extended, The valve can be closely matched with the valve seat. Due to the long working hours of the valve, the original valve clearance was changed. Therefore, when you hear the abnormal sound of the valve, you should check and adjust the valve clearance.
When adjusting the valve clearance, it must be adjusted according to the manufacturer’s specified value, and the valve is fully closed. Adjust the position of the valve clearance: the side-mounted motor is on the tappet and the overhead motor is on the rocker arm. Common valve adjustment methods are: cylinder-by-cylinder adjustment method, secondary adjustment method, expression method, and so on. However, due to the wide variety of motors, the order of the intake and exhaust valves is different. Using the above method to adjust the valve clearance, there is a sense of inconvenient memory and cumbersome. And if you don’t know the firing order of the motor (or the fuel injection sequence), it will be more troublesome to adjust. The methods and techniques for adjusting the valve clearance for two different situations are now presented.
Valve clearance adjustment for known ignition sequences
1. A convenient way to determine the top dead center of 1 cylinder compression
If you know the ignition sequence (or injection sequence) of the motor, when adjusting the valve clearance, you should first find the position of the 1st or 6-cylinder compression top dead center accurately. The method of determining the top dead center of 1 or 6 cylinders is complicated, and it is very troublesome to operate (ie, the first cylinder spark plug is removed, the first cylinder spark plug hole is blocked with a thumb or cotton yarn, and then the handle is shaken by hand. Turn the crankshaft. When the thumb feels pressure or the cotton yarn bobs out, it is the position where the first cylinder compresses the top dead center. According to the author’s maintenance experience, a simple and practical method is introduced: the pistons of 1, 6 cylinders (4 cylinders) are used on the same plane. When the compression of one cylinder is finished, the rule of 6 or 4 cylinder valves is determined. That is, when the 1 cylinder is compressed to the top dead center, the 6-cylinder (4-cylinder) exhaust valve is close to close, the intake valve is just above the top, and the exhaust valve is not well grasped. The top of the intake valve is easy to observe, as long as the intake valve top The rod is slightly up, and the 1 cylinder is at the compression top dead center position. Similarly, when the 1-cylinder intake valve push rod is slightly moved, the 6-cylinder (4-cylinder) is in the compression top dead center position.
2. Determine the skill of the adjustable valve
In the following, a six-cylinder motor with a work order of 1-5-3-6-2-4 is taken as an example to illustrate its simple adjustment method and mouth. When it is determined that the motor 1 cylinder is at the compression top dead center, the 1 cylinder 2 valve is fully adjusted, the 5 and 3 cylinders are at the start of compression and the intake process, and the 2 exhaust valves are adjustable. The 6 cylinders are not adjustable in the state of air intake overlap. 2, 4 cylinders in the exhaust and work end, 2 intake valves are adjustable. After the adjustment is completed, after turning the crankshaft 360°, all the remaining valves can be adjusted in turn.
Can be summarized into a mouthful: full adjustment, not adjusted. It can also be summarized as follows: take the first cylinder, go to the middle, the front adjustment, the rear adjustment, the three hundred and six, the remaining cylinder, and then come. That is, the cylinders in front of the 6 cylinders are adjusted to the intake valves, and the cylinders after the 6 cylinders are adjusted to the intake valves. If the 6 cylinders are at the compression top dead center (6-2-4-1-5-3), the reasoning method is the same, starting from the 6 cylinders, it is also full adjustment and no adjustment. That is, the cylinder in front of one cylinder adjusts the intake valve, and the cylinder after one cylinder adjusts the intake valve.
This method can also be applied to 4-cylinder and multi-cylinder motors. The 4-cylinder motor with the order of work 1-3-4-2 is introduced as an example: the mouth is still fully adjusted and not adjusted. That is, the cylinders in front of the 4 cylinders are adjusted to the intake valves, and the cylinders after the 4 cylinders are adjusted to the intake valves. The 4 cylinder inlet and exhaust valves are not adjusted.
The above reasoning shows that as long as we remember the “mouth”, knowing the order of the motor’s work can easily determine the adjustable valve.
Valve clearance adjustment for unknown ignition sequence
When we repair some cars, we sometimes don’t know the firing order (or the fuel injection sequence). How to check and adjust the valve clearance? The following Eaton Char-lynn Motor introduces two methods and techniques for adjusting the valve.
Method 1: In-line 4-stroke cylinder, divide the number of cylinders into two, with the middle of the symmetry axis, so that the number of cylinders on both sides is equal. The two cooperated and one person turned the crankshaft. When checking the adjustment of the cylinder clearance on the right side of the symmetry axis, just pay attention to the intake valve of the corresponding cylinder on the left side of the symmetry axis. When the valve is slightly moved, the valve clearance of the right cylinder can be checked. 6-cylinder in-line motor, if you want to check and adjust the 5th cylinder intake and exhaust valve clearance, when the second cylinder intake valve is slightly moved, the 5th cylinder is at the end of compression end, and then check and adjust. 2 valves of the cylinder. For the V-type motor, it can be regarded as two in-line in-line analysis, and the inspection and adjustment are respectively carried out, and the specific method is the same.
This method is correct from the analysis of the pin journal arrangement of the motor crankshaft. Because the left and right link journals of the symmetry axis are symmetrical. When the fifth cylinder is at the compression top dead center, the second cylinder is just at the exhaust top dead center. Since the intake and exhaust have overlapping angles, the intake valve of the cylinder has just opened.
Method 2: When one valve in a cylinder is in the maximum opening position (the side-mounted valve mechanism can be viewed from the valve chamber cover, that is, the tip end portion of the cam faces the plunger; the overhead valve mechanism can observe the valve rocker arm When the end of the valve is opened to the lowest position of the valve, the other valve clearance of the cylinder can be checked. According to this, one by one, one by one, the entire valve clearance of the cylinder motor can be adjusted. The feasibility of this method can be verified from the structure of the camshaft, because the angle of the different name cam of the same cylinder is 90°, that is, when one valve of the same cylinder is in the maximum open state, the other valve must be It is in the closed state, and the base circle of the cam is toward the tappet, and the condition for adjusting the valve clearance is provided.