Yuexiang doesn't need to adjust the intake valve, just adjust the exhaust valve? But why is there an adjusting screw on the intake rocker arm?
First, the valve clearance knowledge
Yuexiang adopted SOHC? 16V？ JL475Q7 all-aluminum engine uses adjustable valves.
Valve clearance: When the engine is cold and the valve is closed, the clearance between the valve and the transmission part is called valve clearance. ?
Excessive clearance: After the intake valve and exhaust valve are opened late, the intake and exhaust time is shortened, and the valve opening height is reduced, which changes the normal valve timing and makes the engine power drop due to insufficient intake and unclean exhaust. In addition, the impact, noise and wear of valve train parts increase. ?
Too small clearance: after the engine works, the parts are heated and expanded, pushing open the valve, which makes the valve not close tightly, causing air leakage, reducing power, causing serious carbon deposition or burns on the sealing surface of the valve, and even the valve hits the piston. ?
2. Why does Yuexiang need to adjust the valve clearance?
Nowadays, many automobile engines adopt hydraulic injector technology, so there is no need to adjust the valve clearance. Yuexiang's engine adopts adjustable valve technology, and the valve clearance needs to be adjusted at an appropriate time.
Judging from most of Yuexiang's car conditions, in order to ensure the quality of the engine and the running-in of the new car under necessary working conditions, the manufacturer has left a lot of room for the valve clearance of the new car engine. When the engine runs in completely (about 5000- 10000 km), the engine valve clearance will enter a stable state. At this time, due to the influence of running-in, the engine valve clearance will be larger than when it was new, which directly shows that the engine valve noise is more obvious than when it was new. At this time, the working state of the engine can be improved by adjusting the valve clearance to make it meet the engine design standards.
If your Yuexiang meets the following conditions at the same time, you can adjust the valve clearance:
1, the mileage is at least over 8000 kilometers, and it is recommended that after 10000 kilometers.
2. When the engine is running at a low speed, there is an obvious "da da da" sound, especially when it is upshifting at a low speed. For example, 1 gear enters the second gear at a low speed, and the sound of stepping on the accelerator is extremely obvious.
3. Compared with the new car, the engine sound at idle speed is not thick enough, and the noise of "da da da" is obviously louder.
Third, adjust the valve technology
The standard data of valve clearance of JL475Q7 engine are as follows:
Intake valve: 0. 15
Exhaust valve: 0. 18
Adjustment method:
1. Remove the engine trim cover.
2. Remove the ignition coil
3. Remove the valve cover
4. Remove the four spark plugs.
5. Shift 1 to push the vehicle so that the piston of the first cylinder is at the lowest position. At this time, from the valve position, all valves of a cylinder should be in the open and closed state. If the valve of a cylinder is not completely closed, it means that the piston of a cylinder is at the bottom dead center. You should push the vehicle again and turn the crankshaft 360 degrees. Make a cylinder in the compression top dead center position.
(You can also turn the pulley manually, but you need to remove the pulley guard. )
6. Measure the valve clearance with feeler gauge and adjust it appropriately.
7. The feeler gauge whose adjustment specification (intake valve) is 0. 15 can go in and out freely, and the feeler gauge of 0. 18 cannot be inserted. The same is true for exhaust valve adjustment.
Four. Record of Sichuan Yuexiang Automobile Drivers Association adjusting valve clearance
Sichuan Yuexiang Driving Association took the lead in gathering 10 riders to participate in valve adjustment in Chengdu Qiangyi Changan Automobile 4S shop. According to the measurement of technicians, the valve clearance of most riders is between 0.28 and 0.3, which needs to be adjusted. Therefore, the valve clearances of eight vehicles that need to be adjusted are adjusted in turn.
It takes a long time to adjust the valve clearance, which tests the experience, technology and patience of the builder. Thanks to the maintenance consultant, stationmaster and service technician of Chengdu Qiangyi Changan Automobile 4S shop. Patiently adjust the whole process and answer various questions for the owner. It is worthy of being a demonstration 4S of Changan Automobile B network.
After adjustment, the idle noise of the vehicle obviously tends to be stable, and the sound of "da da da" is weakened to a small extent. Especially when the vehicle is driving, the pickup of "dadada" is obviously weakened when refueling at low speed. The noise of abortion basically returned to the new car level, and the adjustment of valve clearance achieved good results.
If your Yuexiang meets the following conditions at the same time, you can adjust the valve clearance:
1, the mileage is at least over 8000 kilometers, and it is recommended that after 10000 kilometers.
2. When the engine is running at low speed, there is obvious "da da da" noise, especially when shifting gears at low speed. For example, 1 gear moves into second gear at a low speed and presses the pedal.
As soon as the throttle is turned on, the sound of "da da da" is very obvious.
3. Compared with the new car, the engine sound at idle speed is not thick enough, and the noise of "da da da" is obviously louder.
Third, adjust the valve technology
The standard data of valve clearance of JL475Q7 engine are as follows (when the vehicle is cold):
Intake valve: 0. 15
Exhaust valve: 0. 18