Considerations About Diesel Engine Repair

Engine repair is a systematic work, each link affects the maintenance quality and operational safety, need to follow the standardized process to avoid secondary failure.

Adequate preparation is required before maintenance. Cut off the power supply, close the fuel valve and release the fuel system pressure by loosening the high-pressure fuel injector hose according to the regulations to prevent fuel injection from causing danger. Clean the engine surface of oil and debris, especially the cylinder head, oil sump gap, to avoid impurities into the interior. Prepare special tools, check the model of replacement parts, and strictly prohibit the use of non-compliant substitutes for precision parts.

Disassembly should emphasize the order and marking. Disassemble according to the order of outside and inside, from top to bottom, first disassemble the external accessories, then disassemble the internal core components. Mark confusing parts such as valve sets and bearing caps to ensure accurate installation reset. Disassemble the bolts according to the principle of “symmetrical loosening and step-by-step disassembly”, and the cylinder head and main bearing cover bolts should be loosened step by step in a specific order to avoid deformation of the parts.

Parts cleaning and inspection is the core. General metal parts with diesel fuel or special cleaning agent cleaning, precision parts such as injectors need to use diesel fuel light flushing, soft brush cleaning, prohibit force brush. When checking, measure the piston and cylinder liner clearance, crankshaft journal precision, check the gear tooth surface, valve sealing surface condition, to ensure that the parts meet the assembly requirements.

Assembly requires control of fit clearance and bolt torque. The fit clearance of the moving parts should be in accordance with the regulations and adjusted by measuring with a plug gauge. Tighten the bolts with a calibrated torque wrench, and tighten them in 2-3 times according to the specified torque and sequence. For example, install the cylinder head bolts from the center to the ends of the symmetrical tightening, gradually reach the standard torque, if necessary, add anti-loosening device.

Comprehensive inspection should be carried out after repair. Turn the crankshaft manually before starting to check whether the operation is smooth. After starting, observe the instrument indication, listen to the running sound, and check whether there is any leakage in the sealing part. After idling to normal temperature, run at medium and high speed for 10-15 minutes and continue to observe. After cooling down, check the tightness of key bolts to make sure there is no loosening.

Engine repair requires a rigorous attitude and standardized operation, follow these precautions can reduce the risk, to protect the engine long-term stable operation.