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Detection and repair of abnormal noise fault of automobile valve group
Release time:
2024-09-20
1. Valve noise fault detection and repair 1) Fault phenomenon Valve foot noise and valve seating noise are collectively referred to as valve noise.
1. Valve fault detection and repair
1) Fault phenomenon
Valve foot noise and valve seating noise are collectively referred to as valve noise. It is often manifested as a continuous and rhythmic "click" (at the valve foot) or "pop" (at the valve seat) metal knocking sound when the engine is idling; when the speed increases, the sound is also Increased; when the temperature changes and the single cylinder is out of fire, the sound does not decrease; if there are several valves, the sound appears messy.
2) Cause of failure
① Valve foot sound:
a. The valve foot clearance is too large;
B. The valve foot clearance adjusting screw is loose or the two contact surfaces at the clearance are uneven;
c. The shape of the valve cam is not processed accurately or worn too much, which causes the efficiency of the buffer section to decrease and aggravates the impact of the tappet on the valve foot;
d. Poor lubrication at the valve foot.
② Valve seating sound:
a. The matching clearance between the valve stem and its conduit is too large;
B. Poor contact between the valve head and its seat ring;
c. Loose valve seat ring;
D. valve foot clearance is too large.
2. Maintenance of valve train
(1) Requirements for matching of valve and valve seat
① The working cone angle of the valve and valve seat ring shall be consistent. In order to improve the running-in performance of the valve and the valve seat ring, when grinding the working cone of the valve, its cone angle is 0.50 ° ~ 1.0 ° smaller than the seat ring.
② The sealing band of the valve and seat ring is located on the inner side in the middle. Too close to the outside will reduce the strength of the valve; too close to the inside will cause poor contact with the seat ring.
The sealing belt width of the valve and seat ring should meet the original design requirements, generally 1.2~2.5mm. If the width of the sealing belt is too small, the valve will wear more; if the width is too large, the valve will be easily ablated. Generally speaking, the width of the exhaust valve sealing band should be greater than the intake valve; the width of the diesel engine sealing band is greater than the gasoline engine.
④ The coaxiality error between the valve working face and the rod shall not be greater than 0.05mm.
⑤ The matching clearance between the valve stem and the conduit should comply with the original factory regulations.
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CHONGQING YONGFENG ELITE AUTO PARTS CO., LTD.
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Tel: +86023-42815139
CHONGQING YONGFENG ELITE VALVE CO.，LTD.
Address: No.68 Ankang sub Rd.Airport Industrial parkYubei District Chongqing,401120,PRC
Tel: +86023-42815178
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