Measures to Prevent Burnout of Diesel Genset Cylinder Gasket

1. Improve the quality of engine maintenance and assembly

After investigation and inspection, it was found that the poor repair quality of the engine was the main factor causing the burning loss of the cylinder gasket. When repairing the engine for this reason, the following points should be done well:

(1) Fit the cylinder liner correctly

Before installing the cylinder sleeve into the cylinder, thoroughly remove the dirt and rust on the outer surface of the cylinder sleeve, from the top and bottom of the cylinder block seat hole to the bearing shoulder, and do a good job in the trial fitting of the cylinder sleeve and the cylinder block seat hole. During trial assembly (without water blocking ring), the cylinder liner should rotate flexibly in the cylinder block seat hole without jamming. There should be no obvious clearance feeling during radial shaking. The difference between the upper plane of the cylinder liner and the upper plane of the cylinder block, as well as the height between the cylinder liners under the same cylinder head, must meet the specified requirements.

During the press fitting process of the cylinder sleeve, special tools should be used for press fitting, and the force should be uniform. It is strictly prohibited to strike hard on the upper surface of the cylinder liner to prevent local deformation of the cylinder mouth.

(2) Strengthen the inspection of unevenness of air cover and cylinder block

The warpage and deformation of the cylinder head or the unevenness of the cylinder block do not meet the foresight requirements, which are the factors that cause the cylinder gasket to burn repeatedly. Therefore, during secondary and tertiary maintenance, overhaul, and replacement of burnt cylinder gaskets, they should be inspected. The general standard is: integral cylinder gasket. The unevenness is ≯0.10mm within the length range of 300mm; The separated cylinder head is ≯ 0.15mm in the entire length range, and the cylinder body length is less than 600mm. Its unevenness is ≯ 0.05mm, and if the length is greater than 600mm, its unevenness is ≯ 0.10mm. The cylinder head and cylinder block whose unevenness exceeds the specified requirements should be trimmed to meet the technical requirements. The protrusion of the trimmed cylinder head and upper surface of the cylinder sleeve above the cylinder block should meet the requirements. Otherwise, adjustments should be made.

(3) Correct disassembly and assembly of cylinder head

The correct disassembly and assembly of the cylinder head is an important guarantee for extending the service life of the defective cylinder gasket and preventing the deformation of the cylinder head. The following points should be noted for this purpose.

① Cylinder head removal. When disassembling the cylinder head, it should be carried out in a cold state. It is strictly prohibited to disassemble the cylinder head in a hot state to prevent warping and deformation. During disassembly, gradually loosen it from both sides to the middle symmetrically and several times. If it is difficult to firmly remove the cylinder head from the cylinder block, it is strictly prohibited to hit the cylinder head with metal objects or wedge into the seam with a sharp hard tool to pry it (an effective method can be used to drive the crankshaft to rotate by the starter, and the high-pressure gas generated in the cylinder will push it apart) to prevent scratching the joint surface between the cylinder block and the cylinder head or damaging the cylinder gasket.

② Cylinder head assembly. During cylinder head assembly, attention should be paid to removing oil stains and impurities from all joint surfaces and cylinder block bolt holes, and blowing them clean with high-pressure gas. To avoid insufficient compression force of bolts on the cylinder head. In order to prevent thread friction during cylinder head tightening from affecting the accuracy of bolt torque, a layer of lubricating oil should be evenly applied to the bolts, nuts, and the joint surface between the cylinder head and the cylinder block (it is strictly prohibited to apply lubricating grease or misuse sealant). When tightening the cylinder head bolts, they should be tightened symmetrically from the middle to the periphery in 3-4 times, and the final time should reach the specified torque, with an error of  ≯2% (After the engine hot test temperature reaches 80 ºC, the cast iron cylinder head should be tightened again according to the specified torque).

(4) Correct selection and assembly of cylinder liners

The quality of the cylinder gasket and the correct assembly method will directly affect its reliability and service life.

Therefore, the selected cylinder gasket must be of the same specification and thickness as the original cylinder, with a flat surface, firm binding, and free of scratches, dents, wrinkles, and rust.