Engine repair is an extremely important repair skill in all industries, and the engine is the core component of all machines, so the repair and maintenance of the engine is very important. So today, let's discuss how to repair the diesel engine! Hope to help you solve all the problems of diesel engine failure!

Diesel engine repair tips are as follows:

1. "Three leaks". To repair the diesel engine, prevent and deal with the "three leaks" problem, the "five-character" principle can be adopted, that is, strict, clean, wiping, grinding, and tight. The "five-character" principle is described in detail as follows:

Strict: Strict requirements for the disassembly and installation of parts, abide by the operating rules, and prohibit random knocking. For example, when tightening the bolts, they should be tightened in sequence and several times, and do not twist in random order to prevent the parts from being deformed.

Clean: The parts must be cleaned before assembling, and beware of impurities. If the oil outlet valve and the valve seat contact annulus with very small debris, it will not only leak oil, but also directly affect the operation of the engine.

Wipe: Apply asbestos oil on asbestos pads, paper pads, various screw plugs and oil spills. When rubbing asbestos oil, it should be thin and even, not too thick, and do not rub the entire surface of the pad, but only the part where the oil leaks.

Grinding: Grinding or milling the joint surface of the parts, its function is to restore the surface finish and accuracy, so that the oil pipe joint or gasket can be kept sealed after grinding without oil leakage.

Tightness: The tightness of the sealing device should be suitable, not too tight or too loose. Such as various contact surfaces and sealing nuts of diesel engines, it is necessary to maintain a suitable tightness.

2. The cylinder pressure is closed. In order to ensure sufficient cylinder pressure, the matching gap between the piston and the cylinder liner, the end and edge gap of the piston ring must meet the requirements, the sealing performance of the valve and the valve seat, the sealing performance of the front end of the fuel injector should be better, and the cylinder gasket should be better, and Thickness meets requirements.

3. The volume of the incineration chamber is closed. After the diesel engine is repaired, the volume of the incineration chamber is often changed, and the original compression ratio is changed, which directly affects the normal operation of the diesel engine. The factors that change the volume of the incineration chamber are: the reverse position of the piston, the improper thickness of the cylinder head gasket, the mechanical wear or tortuousness of the crank connecting rod, the dislocation of the vortex chamber inserts, and the excessive valve sag. When repairing, pay attention to these conditions.

4. Time off. The timing switch includes the timing of oil supply and gas distribution. If the oil supply is not timely, the S195 and X195 diesel engines can be adjusted by the gasket between the fuel injection pump and the gear chamber cover. Equivalent to the flywheel arc length of 6.3mm. If the air distribution is insufficient, you should first check and correct the error on the timing gear device, and then adjust the valve clearance. Every time the valve clearance changes by 0.1mm, the crankshaft angle changes by 3°, which is equivalent to the flywheel arc length of 11.1mm. When adjusting, you should pay attention to the piston. When compressing to the top dead center, the gap between the intake and exhaust valves (cold condition) should not be less than 0.2mm, to prevent the parts from expanding due to heat, the valve is not tightly closed, or the valve head hits the piston.

5. "Three filters" off. The poor technical condition of the air filter will cause dust to enter the cylinder, accelerate the early wear of the piston ring, cylinder, valve and valve seat, resulting in difficult starting and reduced power. The poor technical condition of diesel oil and oil filter will cause impurities to enter between related parts, resulting in the early wear of the three major fine parts, accelerating the wear of the crankshaft and the bearing bush, and in severe cases, the diesel engine will be invalidated in the early stage.

6. Diesel atomization off. Poor technical conditions of the plunger pair, the oil outlet valve pair and the injector needle valve pair will result in poor fuel injection atomization, difficulty in starting the diesel engine, incomplete combustion, and increased carbon deposition, resulting in a decrease in engine power and an increase in fuel consumption. , Carefully check the fuel system, especially the fine parts.

7. The through hole and the small hole are closed.

(1) Through hole closing: Now take the S195 diesel engine as an example, the 5 through holes of the bearing and bushing should be aligned during installation.

① Main bearing. Each pair of main bearing oil grooves are drilled with oil holes, which are respectively connected with the oil holes on the cylinder block and main journal. During installation, as long as the flange notch of the main bearing is aligned with the locating pin, the main bearing can be prevented from rotating and the oil hole can be ensured. Align to make the lubricating oil path extending in all directions to avoid burnout.

② Rocker arm bushing. When the bushing is pressed into the rocker arm, if the holes are not aligned, the rocker arm shaft and bushing will be burnt due to the lack of smooth and dry friction, which will increase the valve clearance and produce a severe knocking sound.

③ Connecting rod bushing. The small end of the connecting rod is drilled with an oil collecting hole, which is connected with the oil hole of the connecting rod bushing. When the copper sleeve is inserted into the small end of the connecting rod, if the two oil holes are not aligned, the copper sleeve and the piston pin will be knocked "dangdang". Hit, and even bite to death.

④ Start the shaft bushing. When installing the starting shaft bushing, the oil holes of the two bushings should be connected with the corresponding oil collecting grooves on the body and the gear cover, otherwise the starting shaft and the bushing will wear faster, causing the oil supply angle and gas distribution phase to change. Causes the diesel engine power to drop.

(2) Small hole pass: There are mainly the following 4 small holes.

① Fuel tank cap vent hole. After the hole is blocked, the fuel tank is no longer connected to the atmosphere, and the upper part of the fuel tank will show negative pressure due to the drop of the oil level, resulting in the interruption of fuel supply. This hole cannot be blocked.

② Crankcase ventilation hole. After the ventilation holes are blocked, the exhaust gas in the crankcase will accumulate more and more, and the air pressure in the crankcase will increase, which will cause oil leakage, and the high temperature exhaust gas will be mixed into the oil, which will also accelerate the transformation of the oil and accelerate the wear of the parts. Therefore, it must be repaired. To clear this hole.

③ Drain hole of oil pump. The blockage of the oil drain hole on the oil transfer pump will cause a small amount of diesel leakage between the push rod and the conduit to enter the fuel injection pump, weaken the lubricating oil in the casing, and accelerate the wear of parts. Therefore, this hole cannot be blocked.

④ Water pump drain hole. If the hole is blocked, the leaking water cannot be discharged from the pump body and enters the bearing seat, which will accelerate the damage of the bearing. Therefore, this hole must be cleared during maintenance.

8, run-in off.

(1) Cold run-in. Remove the injector, use external force to drive the diesel engine to work, check the oil pressure and the temperature of each component together, pay attention to the sound of each component, after cold running in, release the oil when the temperature is high, and clean the oil filter and oil passage.

(2) Hot run-in. No-load thermal run-in, pay attention to the operating conditions of the diesel engine and the sound of various parts, and thermal run-in according to the specified load and time, often pay attention to the sound of various parts and the blow-by of the oil port, smoke exhaust, fuel return of the injector, etc., and the problem should be eliminated in time. .

The above are the repair skills of diesel engines. We can learn that there are eight repair skills in total, and each repair skill has corresponding solutions. It does not seem difficult. You can gradually master it and apply it to real life. I hope you can easily solve it when you encounter a diesel engine failure in the future!