How to Prevent Cylinder Gasket Wear of Diesel Engine

During the use of diesel generator set, the cylinder gasket of diesel engine is easy to be ablated, resulting in air and water leakage of diesel engine, which seriously affects the operation of diesel genset. Therefore, we should do a good job in preventive work to prevent damage. This article discusses how to prevent the damage of cylinder gasket when using diesel generator set.

A. Preventive measures

1. Correctly disassemble and assemble the cylinder block and cylinder head of diesel engine.

2. Correct assembly of cylinder liner. Before the cylinder liner is assembled into the cylinder, the dirt and rust on the surface, the upper and lower parts of the cylinder block seat hole to the shoulder should be thoroughly removed. The difference between the upper plane of the cylinder liner and the upper plane of the cylinder block, and the height difference between the cylinder liners under the same cylinder head must meet the specified requirements. During the press fitting of cylinder liner, special tools shall be used to press the cylinder liner with even force. It is strictly forbidden to hit the upper surface of cylinder liner to avoid local deformation of cylinder port.

3. Strengthen the inspection of sealing surface of cylinder head and cylinder block to see whether deformed or not. Use a ruler and a feeler gauge to check the sealing surface along the longitudinal and transverse directions. Generally, the unevenness of the sealing surface between the cylinder block and the cylinder head shall not be greater than 0.10 mm. The unevenness is not more than 0.03 mm in any 100 mm length. There should be no convex or concave parts on the sealing surface.

4. Remove the cylinder head bolts correctly. Tighten the cylinder head bolts according to the specified sequence, times and torque.

5. Correct selection of cylinder gasket. The selected cylinder head gasket must meet the requirements of the original accessories with reliable quality. The installation direction should be paid attention to when installing. The basic principle is that the curling edge should face the contact surface or hard plane which is easy to repair. The details are as follows:if the cylinder head gasket itself has an installation mark, install it according to the installation mark; if there is no mark, the cylinder head is cast iron, and the curl shall face the cylinder head. When the cylinder head is made of cast aluminum, the crimping should face the cylinder block. When the cylinder head and cylinder block are all made of cast aluminum, the crimping should face the convex edge of the wet cylinder liner.

6. Tighten the cylinder head bolts correctly. The tightening of cylinder head bolts is the most important part to ensure the sealing quality of cylinder head gasket. Whether this operation is standardized or not directly affects the sealing quality of cylinder head gasket, so it must be operated in strict accordance with the technical standards.

B. Proper use and maintenance

1. During the running in period (30-50h) and at intervals of about 200h, the cylinder head bolts of new or overhauled generating sets of diesel engines need to be inspected and tightened once according to the specified torque. At the same time, we must pay attention to some details: the sludge, carbon deposit, coolant, engine oil and other debris and liquid in the bolt hole shall be thoroughly cleaned. If necessary, the screw thread shall be cleaned with a tap, and the compressed air shall be used to blow clean;clean the cylinder head bolts thoroughly and check them carefully. If there are cracks, pitting and necking, they should be scrapped and cannot be used any more;before the installation of cylinder head bolts, a little oil should be applied on the thread part and flange support surface to reduce the dry friction of thread pair.

2. Check and adjust the injection timing in time. The injection pressure of the injector must meet the specified requirements, and the injection pressure error of each cylinder is not more than 2%. Try to avoid frequent flameout under heavy load, high temperature and high speed, and prohibit frequent rapid acceleration under no load.

3. Before replacing the new cylinder gasket, first check whether the surface of the cylinder gasket is concave, convex, damaged, etc., whether the quality is reliable, and whether the flatness of the cylinder head and cylinder block meets the requirements, then clean the cylinder gasket, cylinder head and cylinder block, and dry them with compressed air, so as to avoid the influence of dirt on the seal.

4. The selected cylinder head gasket must be the original accessories that meet the requirements (specification, model) and have reliable quality. Pay attention to the upper and lower orientation marks when installing, so as to prevent the installation from being reversed and causing human failure.