The engine cylinder head of a Kawasaki KLD85Z loader of a certain company was warped and deformed due to long-term operation under high temperature, high pressure, thermal load and alternating load. The cylinder gasket was damaged from the waterway outlet, causing the combustion chamber pressure to drop, the engine power to be insufficient, and water to leak out of the radiator water inlet. The following is the cause of the deformation of the loader engine cylinder head and the repair method.
The cylinder gasket was replaced twice in a row. After one month of use, the front end wheel loader engine cylinder head was deformed and even damaged.
After disassembling and inspecting the deformation of the loader engine cylinder head, it was found that both the cylinder block and the cylinder head were deformed. The flatness error of the cylinder block is 50um, which meets the technical requirements, but the flatness error of the cylinder head reaches 0.20mm. This deformation is the main reason for the damage of the cylinder gasket.
The deformation of the small wheel loader engine cylinder head is repaired. Since there is no combustion chamber concave on the engine cover, there is no need to consider the change of combustion volume (the change value of the combustion chamber volume should generally not be greater than 4% of the original volume). The repair method of the loader mainly uses plane milling to process the cylinder head plane. A copper pad (the thickness of the copper pad is 1.2 times the thickness of the concave platform of the waterway port) is installed at the waterway outlet of the joint surface between the cylinder head and the cylinder body to replace the rubber sealing ring on the cylinder gasket, and then the cylinder gasket is installed. At the same time, the cylinder head screw is tightened by cold tightening first and then hot tightening.
The engine repaired by this method has never had the failure of overshooting the cylinder gasket.