Engine Noise? The Reason May Be These

- Jan 31, 2019 -

Speaking of the abnormal noise of the engine, many excavator masters may have headaches. Yes, the abnormal noise of the engine has always been the ill of the excavator. When the diesel engine is in normal operation, its sound has only uniform exhaust sound and slight noise, which has certain regularity. There are tolerances within the normal range between the various parts in the diesel engine. When the parts are excessively worn or improperly repaired, the tolerances exceed the normal range, and abnormal noises appear. The following small series lists several common causes of engine noise.

excavator engine noise, bulldozer engine noise

excavator engine noise, bulldozer engine noise


1. The piston knocks on the cylinder. Piston knocking cylinder is a common source of abnormal noise. Due to poor lubrication conditions, the piston and cylinder wall are excessively worn, resulting in a gap fit tolerance between the piston and the cylinder wall exceeding the normal range. When the engine is running, the piston skirt collides with the cylinder wall, resulting in “dang”. The crisp sound of dang is generally obvious when running at idle speed or low speed.


2, timing gear. After long-term use of the gears, coupled with improper adjustment of the gear clearance and poor lubrication conditions, excessive wear will occur. In severe cases, even the gear teeth will be worn out, the gears will be loose, and the machine will be "squeaky" when it is running. "hua" voice.


3. The piston pin is abnormally sounded. Due to excessive wear of the parts, the clearance between the piston pin and the connecting rod bushing is too large, the connecting rod bushing and the small-head bearing of the connecting rod are loosened, and the clearance between the piston pin and the pin hole of the piston is too large. The piston is oscillated during the movement and collides with the cylinder wall to generate an abnormal sound.


4, the bearing is abnormal. The bearings here include connecting rod bearings, crankshaft bearings and cam bearings. Due to excessive wear or improper maintenance, the bearing fit clearance is increased or the bearing bush is loose. When the mechanism is running, the parts are loosely impacted.


5, the valve is abnormal. Due to excessive wear of the tappet and the rocker arm or loosening of the related screws, the valve clearance increases, and the rocker arm and the tappet collide, causing abnormal noise. In addition, an increase in valve clearance may result in insufficient engine intake and exhaust, reduced output power, and increased fuel consumption.


6. In addition, abnormal combustion of fuel may also cause abnormal noise. More common is that due to improper adjustment or loose adjustment of the adjusting screw, the fuel injection fuel supply advance angle is abnormal, and the fuel injection time is too early or too late, causing abnormal fuel combustion and knocking sound in the cylinder.

excavator engine noise, bulldozer engine noise

excavator engine noise, bulldozer engine noise

Through the analysis of the above causes of abnormal noise, we can know that the abnormal noise of the engine is mostly caused by the excessive wear of the parts and the increase of the matching clearance. Therefore, the use of a suitable grade of lubricant and regular replacement, maintaining good operating habits can effectively reduce the wear of the parts. If the part is worn or loose, repair or replace it in time. For faults such as large valve clearance and improper oil supply, the relevant parts should be adjusted in time to avoid damage to important components and cause significant losses.


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