Do not check the plunger stroke margin In the satirical test of the plunger-type fuel injection pump, many maintenance personnel did not pay attention to checking the plunger's travel allowance. The so-called plunger stroke margin refers to the amount of movement that the plunger can continue to ascend after it is top-dead-centered on the camshaft. After adjusting the start time of fuel supply, the reason why the travel allowance is also checked is because the stroke allowance of the plunger is related to the wear of the plunger and the sleeve. After the plunger and sleeve are worn out, the plunger must move upwards for a while to start oil supply, thereby delaying the start of oil supply. When the adjustment bolt is screwed out or replaced with a thicker adjustment pad or spacer, the lowermost position of the plunger moves upwards, so that the stroke margin of the plunger is reduced. Therefore, when repairing and debugging the fuel injection pump, it is firstly necessary to check the travel allowance to determine whether the injection pump also allows adjustment. During the inspection, the following different methods should be used according to the different structures of the fuel injection pump: a) Turn the camshaft, push the plunger to the top dead center, remove the oil valve and valve seat, and measure with a deep vernier. b) After the plunger is topped to the top dead center, use a screwdriver to pry the spring seat of the plunger spring to raise the plunger to the highest point. Then use a thick gauge inserted between the plunger lower plane and the tappet adjustment bolt to measure. The standard travel distance of the plunger is about 1.5mm, and the limit stroke residual after wear is not to be less than 0.5mm. Avoid the piston open flame heating Because the auger piston and the piston pin are interference fits, when installing the piston pin, the piston should be heated to expand. At this time, some maintenance personnel will directly heat the piston on an open flame. This is very wrong. Because the thick and uneven parts of the piston, the extent of thermal expansion and contraction will be different, the heat will make the piston heated uneven, easily lead to deformation; the piston surface will be attached to charcoal, reducing the life of the piston. If the piston cools naturally after reaching a certain temperature, its metallurgical structure will be damaged and wear resistance will be greatly reduced, and its service life will also be significantly shortened. When installing the piston pin, the piston can be heated evenly in hot oil to make it expand slowly, and it is not allowed to directly heat with an open flame. Avoid butter smearing (1) Apply grease to the drill cylinder pad. Butter is a commonly used grease in the repair of long spiral drills and can act as a lubricant and seal. Therefore, some repairmen apply a layer of butter to the cylinder pad when installing the cylinder pad, which is believed to increase the tightness of the diesel engine. As everyone knows, this will affect the performance of the diesel engine. The cylinder head gasket is the most important seal between the diesel engine cylinder block and the cylinder head. It not only seals the high temperature and high pressure gas generated in the cylinder, but also seals the cooling water and lubricant oil in the cylinder head and cylinder. When disassembling the cylinder head gasket, pay special attention to its sealing quality. If the cylinder pad is greased during installation, when the cylinder head bolts are tightened, some of the butter will be squeezed into the cylinder water channel and the oil channel. When the grease left between the cylinder pads is working in the cylinder, due to the influence of high temperature, part of the grease will flow. The human cylinder burns, and the other part remains on the joint surface between the cylinder block and the cylinder head, which creates a gap between the cylinder pad, the cylinder head and the plane of the machine body. The high temperature and high pressure gas can easily impact the cylinder pad from this and damage the cylinder pad, causing leakage. gas. In addition, the butter will produce carbon deposits at high temperatures for a long time, resulting in premature aging and deterioration of the cylinder mat. Therefore, do not apply butter when installing the cylinder head gasket. (2) Apply butter to tire nuts. In order to easily tighten the nut and prevent corrosion, many repairmen apply oil to the bolts and nuts of the tire. This is actually a wrong practice. Because the tire nut is tightened, there is a self-locking feature between the threads. This is because the thread helix angle is smaller than the equivalent friction angle between the threads. For a given bolt connection, the helix angle is a certain value, and the equivalent friction angle varies with the friction between the threads. Obviously, after the oil coating, the equivalent friction angle between the threads is reduced, and the self-locking performance of the bolt connection is deteriorated. Therefore, never apply grease or dripping lubricant to the bolts and nuts of the tire. Doing so will make the nut loose and even cause an accident. Avoid bolts tighten too tightly In the process of disassembly and assembly of long spiral pile drivers, bolts in many parts are required by the specified torque, such as transmission boxes, cylinder heads, hubs, connecting rods, and front axles. Tightening torques are specified in the manual. Must not change at will. However, many users mistakenly believe that tightening some of them will be more secure, but tightening them too tightly will cause the screws or bolts to break, and it may also cause malfunctions due to thread sliding. China Flat Gloss Powder Paint,Flat Powder Coat manufacturer, choose the high quality Flat Black Powder Coat Paint,Gloss Gold Powder Coat, etc. Flat Gloss Powder Paint,Flat Powder Coat,Flat Black Powder Coat Paint,Gloss Gold Powder Coat Longkou Guomei Decoration Material Co.,Ltd. , https://www.sdgmcoating.com