phenomenon:

1) engine idling operation without significant sound, and in the high-speed issue “giggle” sound (issued by the crankcase)

2) after the rapid release of oil throttle instantly more obvious sound.

3) No significant change after temperature rise. When the load increases, the sound increases.

4) sound than the crankshaft bearing sound slow, short.

the reason:

1) Baotou North Ben heavy truck accessories connecting rod bearing and journal wear excessive, radial clearance is too large.

2) connecting rod bearing cover fastening bolts loose.

3) rod bearing alloy ablation or fall off.

4) connecting rod journal rounded round.

5) Baotou North Ben heavy truck accessories connecting rod bearing and bearing relative rotation.

diagnosis:

1) Baotou North Ben heavy truck accessories engine speed from idle to moderate speed when the sound is clear, with the increase in speed, the sound is more prominent, for the connecting rod thinking ring.

2) on a cylinder for fire test, the sound weakened or disappeared, for the cylinder rod bearing ring.

3) regardless of speed and temperature are issued by the sound, and the engine vibration, do not change the sound test fire, then the rod bearing alloy ablation.