Timing gear is a gear that plays the role of time scale positioning when completing relevant control functions in the mechanical device. The timing gear is introduced into the intake and exhaust system, clock and other local systems with sequential relationship of internal combustion engine to complete mechanical functions. The diagnosis and troubleshooting of timing gear noise is a compulsory course for mechanical equipment. Listen and analyze:
Diagnosis basis:
1. When the engine is stationary and the timing gear chamber makes a "suck, suck" sound, listen to the sound on the timing gear chamber cover. When the sound reaches medium speed, the sound will be more prominent. At this time, the vibration is more obvious when using the test bar or mechanical fault stethoscope, indicating that the timing gear produces noise due to excessive meshing clearance.
2. If the engine speed increases, the noise will also increase, and a rhythmic "choking, choking" sound will be issued regularly, indicating that the timing gear meshing is uneven.
3. When the engine runs at high speed, it will make a continuous and strong "click" sound, and there is vibration on the timing gear chamber cover, which indicates that the axial movement of camshaft is too large.
4. If the noise changes with engine speed and is similar to the sound of whistle, it indicates that the gear is not engaged correctly.
5. For the engine after overhaul or replacement of timing gear, it will make a continuous "ringing" sound during operation. The higher the speed, the greater the noise, indicating that the meshing clearance of timing gear is too small.
