How to judge the abnormality of Cummins generator set by buzzing

How to judge the abnormality of Cummins Generator set by buzzing
     The maintenance technician uses the single-cylinder oil cut method to find that the cylinder is faulty when the sound is weakened or disappeared after the oil is broken. Then remove the cylinder injector, fill a small amount of lubricating oil into the cylinder, use a longer screwdriver to move the ring gear ring for 5~6 turns, then start the unit. If the knocking sound disappears or becomes smaller, after 1min The sound again appears, indicating that the matching clearance between the cylinder piston and the cylinder liner is too large, and should be replaced with the same type of piston and cylinder liner.
    During the inspection, the method of oil-cutting by cylinder is adopted. When a cylinder is cut off, the knocking sound is weakened or disappeared, and at the moment of recovery, a knocking sound of "嗒, 嗒" is issued, which indicates that the cylinder piston pin The fit clearance is too large. If you hear an abnormal knocking sound of the piston pin, you can also remove the inspection hole cover on the body and push the crankwheel flywheel ring to position the crank of the cylinder to the bottom dead center position, then hold it with your hand. In the middle of the cylinder connecting rod, swing the connecting rod back and forth, as shown in Figure 10-24. If the clearance is large, the cylinder head and piston rod assembly should be removed to further check the clearance between the piston pin and the connecting rod bushing. If the clearance exceeds the specified value, the connecting rod bushing should be replaced according to technical requirements.