Wholesale ihi excavator parts manufacturer and supplier China

Regularly checking and replacing the fuel filter can prevent impurities from entering the fuel system, ensure fuel cleanliness and extend the life of the engine.

8 reasons for the engine speed drop of the excavator, 6 solutions are here!

As the name suggests, engine speed drop means the failure of the engine speed drop during the operation of the excavator. There are two manifestations of speed drop, one is a slight speed drop within 200 revolutions, and the other is a serious speed drop above 300 revolutions, which is likely to cause the excavator to suddenly shut down. There are 8 main reasons for the engine speed drop of the excavator.

1. The diesel oil circuit of the excavator is faulty. Generally speaking, when the diesel oil circuit is blocked, it may cause the speed drop phenomenon.

2. The hydraulic system of the excavator has a fault, so that the hydraulic pump cannot change the displacement normally, causing the system pressure to be too high, and the speed drop may also cause a machine failure.

3. The output power of the excavator engine itself is insufficient, the output power is lower than the rated power, and the speed is too low. There is also a problem with the main pump.

4. The engine uses fuel of poor quality or the water content of the fuel is too high, which will lead to insufficient engine power and speed drop.

5. When the air intake system leaks or is blocked, the engine will be short of air supply, resulting in incomplete combustion of fuel, and there will be speed drop and black smoke failure.

6. Due to the large gap of the solenoid valve, the fuel supply is insufficient, which causes the engine to drop.

7. The joint of the fuel supply circuit of the fuel system is loose or the pipeline is broken, causing fuel leakage or foreign matter blockage, resulting in insufficient fuel supply. In addition to speed drop, it may also cause flameout.

8. There are many reasons for speed drop, such as incorrect valve clearance, wrong injection timing, damaged turbocharger, faulty brakes, etc.

Having said so many reasons for the speed drop of the excavator engine, what should we do when the speed drop occurs?
The solutions are all here!

1. First, check whether the diesel used in the excavator is deteriorated, whether there are impurities in the oil, and whether the oil circuit is blocked.

2. Check the valve clearance of the excavator engine and the speed of the engine.

3. Check the intake pipeline, clean the air pre-filter and air filter element, and start the engine again.

4. Check whether the speed drop of the excavator occurs when the engine is under load?

5. Carefully check the engine to see if the engine failure causes the speed drop of the excavator engine.

6. In addition, the electronic control, hydraulic system, fuel system, etc. need to be checked.

Possible air in the hydraulic oil or internal component wear.

Solution: Bleed air from the system, replace worn components.

The pump housing will wear more in the oil inlet chamber. If the pump housing is symmetrical, it can be turned 180 degrees. Then use it. For the passive gear, the two ends cannot be replaced. Make a mark when removing it. Because the gear will wear on one side. The active gear is integrated with the rotating shaft and cannot be turned over; turning the passive gear over can change the contact point of the meshing line of the two gears. After the pump is assembled, add a little lubricating oil and rotate it slightly by hand. The feel should be smooth.

Reasons from the piston group
1. The piston ring gap is too small. If the opening gap, side gap or back gap of the piston ring is too small, the piston ring will be stuck due to heat expansion when the engine is working, and it will be pressed tightly against the cylinder wall, or the piston ring will be broken, which can easily pull out grooves on the cylinder wall.
2. The piston pin is out. Because the piston pin retaining ring is not installed or falls off or breaks, the piston pin will be out during movement, which can easily damage the inner wall of the cylinder and cause the cylinder to blow into the crankcase.
3. The piston cylinder gap is too small or too large. If the piston material is poor, the manufacturing size error is too large, or the piston is deformed after the piston pin is assembled, the matching gap between the piston and the cylinder is too small, and the piston is stuck after heat expansion, which will then damage the cylinder wall.
4. The piston ring is seriously carbonized. Excessive carbon deposits cause the piston ring to stick or bite in the ring groove. At the same time, carbon deposits are a hard abrasive that will grind into longitudinal grooves on the cylinder wall.
5. The piston is seriously off-cylinder. Due to the bending and twisting of the connecting rod, the parallelism and coaxiality deviations of the connecting rod journal, main journal, and piston pin seat are too large, causing the piston to be significantly off-cylinder, which will accelerate the wear of the piston ring, piston and cylinder wall and destroy the formation of the oil film.

Reasons for cylinder sleeves
1. The roundness and cylindricality tolerances of the cylinder sleeves exceed the allowable range, which greatly reduces the sealing of the piston and cylinder sleeves. The high-temperature gas in the cylinder flows down, destroying the oil film between the piston and the cylinder wall, and then causing cylinder pulling.
2. The cylinder sleeve is deformed during the assembly process. For example: the protrusion of the upper end surface of the cylinder sleeve is too large, and the cylinder sleeve is deformed after the cylinder head is installed; the cylinder sleeve water blocking ring is too thick, and the cylinder sleeve is deformed after being pressed into the body, which can easily cause cylinder pulling.

Reasons for use:
1. Whether the size of the cylinder sleeve used during assembly does not match the cylinder body and piston.
2. The air filter is not sealed, which makes the filtering effect worse. Dust, sand and other impurities in the air are sucked into the cylinder, forming abrasive wear. Tests show that if a few grams of dust are sucked in every day, the wear of the cylinder liner will increase by more than 10 times.