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Forklift Cylinder Block Damage and Crack Analysis Search and Repair of Cylinder Head

Date: 2022-06-20 View:

 Forklift Cylinder Block Damage and Crack Analysis Search and Repair of Cylinder Head

The common causes of diesel forklift engine cylinder block damage and gas cover cracks are:

(1) Congenital cylinder depression. When the cylinder head is cast, the cylinder head is cracked due to the excessive wall thickness difference and the excessive interference of the valve seat ring.

(2) Overload. The overloading of diesel forklifts makes the diesel engine work under heavy load for a long time, and the temperature of the body rises, which causes the cylinder block and cylinder head to have excessive thermal load and causes cracks. The cracks are generally located at the bridge of the nose between the intake and exhaust valves and at the triangle where the injector is installed.

(3) Add cold water in winter. When the diesel engine is overheated in winter or on the way, do not rush to add cold water, because adding cold water at this time will cause the temperature of the diesel engine to drop suddenly, causing the cylinder block and cylinder head to deform sharply and cause cracks.

(4) Improper maintenance of the forklift, such as the cylinder head threads or nuts are tightened in the specified order, times and torque, the height of the cylinder liner above the upper plane of the cylinder block is too much or the height difference of each cylinder is too large, the cylinder is disassembled and assembled. body or cylinder head is hit, etc. In addition, the installed cylinder head gasket does not meet the requirements, or the cylinder head gasket loses its elasticity and blows air over time, which also causes cracks in the lintel between the two cylinders.

Judgment method

Cracks in the cylinder block and cylinder head of the forklift diesel engine will cause water leakage, tax leakage and air leakage. These phenomena can be used to determine where cracks occur. Cracks in the water jacket often cause the oil level to rise, but it is necessary to correctly distinguish whether it is the breakdown of the cylinder head gasket or the water leaking into the crankcase from the crack of the water jacket. Due to the different parts of the crack, the phenomenon is also different. The difference is: cracks near the oil passage are often accompanied by oil leakage and oil pressure drop; cracks near the water jacket are often accompanied by water leakage. If the cylinder liner is cracked, the diesel engine will not work smoothly, the cylinder pressure will drop, and water will be discharged from the exhaust pipe.

Repair method

For cracks in the parts with high temperature and high stress (such as near the combustion chamber and valve seat), the cracks in other parts can be repaired by welding, and the epoxy resin can be used to repair the cracks; When the crack length is less than 50mm, it can also be repaired by screw filling method; when the crack is long or there are many small cracks concentrated together, or there is a hole, it can be filled with a patch.