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Spring maintenance knowledge

- Mar 31, 2018 -

Spring maintenance knowledge

First, the valve spring

Valve springs are subjected to high temperature and cyclic high-frequency alternating force. After a certain period of time, wear and plastic deformation will occur, weakening the elastic force, resulting in loose valve closing, reduced engine power, exhaust fumes, and start-up difficulties. malfunction. Therefore, check valve spring force periodically. A small piece of iron sheet can be placed between the old spring and the new spring, and the pressure is clamped on the bench vise to see if it is shortened. When the new spring is compressed to the original 2/3 length, if the old spring is 2mm shorter than the new spring, it should be replaced. If there is no spare part at a time, a flat washer of about 2mm can be put on the old spring to make up for its lack of elasticity. Under normal circumstances, valve springs should be replaced after 2500-3000 hours.

Second, the fuel pump plunger spring

The injection pump plunger spring is also subject to wear and deformation due to cyclic high-frequency alternating forces, thereby shortening its free length and weakening the elastic force. After the elastic force weakens, the plunger's return speed slows down. such. When the engine is running at a high speed, the reciprocating motion of the plunger cannot maintain a coordinated relationship with the high-speed rotary motion of the oil pump cam, so that the lift of the plunger is reduced, the amount of oil supply is reduced accordingly, and the engine power is reduced. Therefore, when the plunger spring is used 3600 ~ 4500h should be replaced.

Third, the oil valve spring

The elasticity of the outlet valve spring weakened. It will cause serious internal leakage of high-pressure oil. The remaining pressure in the high-pressure fuel pipe will be reduced, and the oil valve will not be seated quickly. As a result, the supply of oil will be reduced and unstable, and the engine will be unable to work. In addition, the injector will not be able to spray at all, the fuel will not be cut off, and the phenomenon of dripping will occur. As a result, the combustion will deteriorate, the engine will overheat, and the exhaust will emit black smoke. Therefore, the outlet valve spring should be replaced after 3600-4500h. If there is any bending deformation, it should be replaced in time.

Fourth, speed spring

The following points should be noted when using small diesel engine speed control springs:

1. After the diesel engine is parked and stalled, the speed control handle should be placed at the stop position so as to avoid the long-term tension state of the speed-adjusting spring, resulting in weakening of the elastic force.

2. Parts such as governor springs should be cleaned frequently to avoid blocking of dust and debris, resulting in jamming and affecting the normal operation of the governor.

3. It is forbidden to use the method of “damaging” the speed regulating spring to increase the engine speed; otherwise, serious consequences may be caused.

4. The spring of the speed-adjusting spring will become less than the required speed because the elastic force becomes smaller after long-term use. At this time, adjustment screws can be used to adjust. When adjusting the adjusting screw, the tachometer must be used to measure the engine speed.


Conical Stainless Steel Connecting Spring for auto use.jpg


Fifth, clutch spring

Most of the clutch spring is subjected to static pressure. When it is used for a long time, plastic deformation occurs, the free length is shortened, and the elastic force is weakened. After the spring force of the clutch spring is weakened, the torque transmitted by the clutch will be reduced, and the power of the engine cannot be fully exerted, resulting in the inability of the locomotive to work. When the spring force of the clutch spring is found to be weakened, it can be adjusted by adding an appropriate thickness of the gasket in the pit of the part that contacts the spring. When adding gaskets, it should be noted that the free length of each spring on the same clutch assembly (including gasket thickness) should be consistent. If the spring does not recover the original spring force after the spacer is added, a new set of springs should be replaced. Under normal circumstances, when the spring is used 2500 ~ 3000h, should be added 1 ~ 2mm thick gasket to adjust the pressure; use 5000h, all springs should be replaced at the same time.

Sixth, walking tractor steering spring

When installing the steering spring, first identify the left or right spring. The left side should be equipped with a right-handed spring, and the right side should be equipped with a left-handed spring. If the left and right springs are installed incorrectly, when the tractor turns, the steering spring will receive an anti-winding torque, which will deform the spring and even break the spring, or scrape the inner step of the steering gear. Once the spring is broken and the steering handle is relaxed, the steering gear loses thrust. The tooth cannot be returned and it is likely to cause a serious accident. The identification method of the left and right-handed springs: Hold the spring with your left hand and turn your thumb upwards. The other 4 fingers are exactly the same as the steel wire and they are left-handed springs: otherwise, they are right-handed springs.
In addition, insufficient spring force of the steering spring may cause the tractor to lose its stability. Therefore, the steering spring should be checked regularly. The inspection and adjustment method is the same as the valve spring, but the same thickness flat washer should be placed on both sides. It is usually checked and adjusted once a year or so.

Seven springs with adjustable elasticity

When the pressure regulator spring elasticity of the injector is weakened, the atomization of the fuel injection is poor, the combustion is deteriorated, the engine power is reduced, and the fuel consumption is increased; after the governor spring force of the governor speed is weakened, the engine speed is reduced, the power is decreased, and “travel” is also generated. “Car” phenomenon: after the elastic force of the pressure regulating spring and the hydraulic safety valve of the lubrication system is weakened, it will cause accelerated wear of the parts and the deterioration of the engine's technical status; after the elasticity of the shifting fork positioning spring is weakened, the gear position of the transmission can not be reliably positioned. Automatic skip and chaos phenomenon. Therefore, the above adjustable spring should adjust its pressure in time.

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