How to Deal with Abnormal Noise of Diesel Generator Gears?

When the diesel generator is running at idle speed, it makes a slight "rattle" sound. At medium speed, the sound is obvious, while at high speed, the sound is more chaotic. The sound at the timing gear cover is more obvious, and is not affected by cylinder breakage or engine temperature changes.

Judgment method

Before idling to medium speed, continuously change the speed of the diesel generator. When listening to the front of the engine and on the camshaft side, the sound is obvious, which may be a timing gear sound. Then, set the speed of the diesel generator to a position with a loud noise and use a metal rod or other tool to guide the sound on one side of the timing gear cover. If the sound response is strong, it can be concluded that the timing gear sound is making a sound. Abnormal noise from the timing gear must be eliminated in a timely manner, as the lower part of the cylinder head of the diesel generator is mostly flat. As the timing gear noise can change the valve timing phase, it may cause serious mechanical accidents due to valve piston collision.

Causes and handling methods

(1) The fuel injection nozzle at the front end of the cylinder block at the timing gear is blocked or the fuel injection port is too small, resulting in a shortage of oil in the timing gear and increased wear, resulting in abnormal noise. At this time, the machine should be stopped for inspection to eliminate impurities and oil stains in the fuel injection nozzle.

(2) The movement and sound of the timing gear shaft are often caused by the failure of the camshaft axial limit device or the detachment of the timing gear fixing screw. At this point, the camshaft axial limit device or timing gear fixing screw should be replaced.

(3) Individual teeth of the timing gear are damaged and make noise. When idling, a periodic double noise can be heard, and as the engine speed increases, the noise becomes more intense and the cycle shortens. At this point, the damaged timing gear should be replaced.

(4) After replacing the timing gear, the meshing of the gear is poor, and there will be some abnormal noise at this time. If this situation is worn in for a period of time, the noise will disappear on its own. Some are caused by excessive or small backlash, and if the noise persists for a long time, the timing gear should be inspected or replaced.

(5) The timing gears of the crankshaft and camshaft are uneven after replacement or installation, resulting in abnormal meshing. The timing gears should be adjusted, repaired or replaced.

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