1, the valve chamber abnormal sound in the cylinder issued a rhythm of \"Jingle, jingle\" metal knocking sound, shutdown inspection can see the trace of the valve and piston top collision. The main reason is that the valve clearance is out of alignment, the valve seat ring is ablated or loosened, and the decompression mechanism is improperly adjusted. If the cylinder head makes a sound of \"crack, crack, crack\
2, gear room abnormal sound with a metal rod against the timing gear cover, when you hear the timing gear room issued a rhythmic \"clatter, clatter\" sound, low speed running louder, which is the timing gear shaft and shaft sleeve wear gap is too large caused; If the \"buzz\" whistling sound is emitted, the sound increases with the increase of the diesel engine speed, indicating that the clearance between the timing gear shaft and the shaft sleeve is too small; Diesel engine idle running, in the timing gear room and camshaft side of the rhythmless \"crunch, crunch\" sound, low speed sound is more prominent, high speed becomes chaotic and with broken sound, if the large load when the noise is enhanced, this is timing gear meshing gap is too large, tooth surface impact each other, or sleeve wear after the two gear meshing disorder and knock sound; The diesel engine produces severe vibration sound during operation, and it is difficult to operate, which is caused by the wrong installation of the timing gear, the wrong quality of the balance block, or the serious wear of the bearing of the balance shaft. When the flywheel is loose, it often makes a \"clanging, clanging\" or \"quack,\" sound, which is relatively large, especially when the diesel engine speed changes suddenly, the sound is larger, usually heard more clearly at the back of the diesel engine, and sometimes the sound is very small, so the sound does not have certain rules. If you do not supply oil after stopping, make the cylinder pressure reducing valve open, quickly shake the crankshaft, and then suddenly remove the decompression, at this time you can also hear the \"clanging, clanging\" sound. If the flywheel is seriously loose, there will be a feeling of loosening the gap when the flywheel is pulled by hand in the shutdown state. The main reasons for the loose flywheel are: the flywheel fastening nut loosens due to vibration during work, and the nut is not tightened when installing the flywheel. If the flywheel is found to be loose, the nut should be tightened in time, otherwise serious consequences will be caused.
3, crankcase abnormal noise When the diesel engine suddenly changes the load, in the vicinity of the crankcase (cylinder body middle to lower range) can clearly hear the short \"empty, empty, empty\" dull knocking sound, and with the increase of load or speed and rapid changes, the sound increases, no load is not obvious. This is caused by the excessive wear of the connecting rod shingle and the connecting rod journal. If a cylinder of the diesel engine is cut off, if the abnormal sound immediately disappears, it indicates that the connecting rod tile of the cylinder is ringing. When the lower part of the crankcase has a heavy and continuous knocking sound, the sound is clear at low speed, and the heavy load is more obvious, while the oil pressure is reduced, which is caused by the spindle tile clearance is too large; When the engine suddenly changes the speed at low speed, the \"thang, thang\" sound is issued in the upper part of the cylinder, which is caused by the excessive clearance between the piston pin and the connecting rod bushing or the piston pin seat.