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How to Judge Fault by Abnormal Sound of Perkins Diesel Engine

Oct. 29, 2019

Today Starlight power company tells you how to judge fault by abnormal sound of Perkins diesel engine. Hope it is helpful to you.


When Perkins diesel generator is operating, the noise is mainly from mechanical friction sound of diesel engine. Experienced technicians can judge the hidden trouble of a part of diesel engine from the sound. We can judge fault from following sound:


1.When Perkins diesel engine is running at low speed (idle speed), the metal knocking sound of "bar da, bar da" can be heard beside the valve cover.


This sound is caused by the impact between the valve and the rocker arm. The main reason is that the valve clearance is too large. Valve clearance is one of the main technical indexes of diesel engine. If the valve clearance is too large or too small, the diesel engine will not work normally. Too large valve clearance causes the displacement between the rocker arm and the valve to be too large, and the impact force generated by the contact is also large, so we can hear the metal knocking sound of "bar da, bar da". This kind of sound often appears after the engine works for a long time, so the valve clearance should be readjusted every 300h or so.

 Perkins generator

2.When diesel generator set suddenly drops to low speed from high speed, the impact sound of "Dang, Dang" can be heard on the upper part of the diesel engine cylinder.


The reason is mainly oversize clearance between piston pin and connecting rod bush and suddenly changing speed of engine, which causes the piston pin to swing to the left and right while rotating in the connecting rod bush, and causes the piston pin to hit the connecting rod bush and make a sound.


To reduce the occurrence of larger faults and avoid unnecessary waste and economic loss, we should replace the piston pin and connecting rod bushing in time so as to make the diesel engine operation normally.


3.A heavy, dull knocking sound can be heard at the underpart of the diesel engine body.


This kind of noise is caused by the abnormal friction between main bearing shell of crankshaft or the contact between the main bearing of crankshaft and the main journal.


The main reason is that the clearance between main journal of the crankshaft and the main bearing shell or the crankshaft bearing is too large, which results in the uneven wear between the main journal and the crankshaft main bearing or the main bearing, and resulting in the abnormal sound.


If we hear this kind of sound, should shut down diesel generator set. Because if it continues to work in this case, and we do not inspect, it is likely to occur "holding tile" and "burning shaft" phenomenon. In order to reduce this fault, we should shut down the diesel genset, then check whether main bearing bolt is loosen. If not, we should remove the crankshaft and main shaft bearing or main bearing bush, calculate the clearance between them by relevant personnel measurement. And check the wear of the main shaft and the bush shaft at the same time, and repair or replace them if necessary.


4.When diesel engine is running, crystal knocking sound of piston striking cylinder block can be heard clearly at the upper part of the cylinder.


The root cause of this kind of fault is that the injection advance angle of diesel engine is too small.


As we know, the fuel supply advance angle of diesel engine is one of the main technical data of diesel engine. Whether the fuel supply advance angle is correct or not will directly affect the normal operation of diesel engine, and directly affects whether the engine can provide normal power and the working condition of the whole generator set.


In order to make mixture formation and combustion process normal, diesel engine needs fuel injection advance angle. When the injection advance angle is too small, the air injected into the cylinder will form combustible gas combustion, which will lead to combustion instability. In the upward phase of the piston, it will generate lateral deviation and collide with the cylinder wall to knock the cylinder block. So it generates crystal knocking sound.


5.At the front cover of diesel engine, a kind of "howl" sound can be heard clearly.


The reason is the meshing gear in the front cover, which is excessively worn, the clearance between the gears is too large, so that the gears can not enter the normal meshing state. The solution is that open the front cover, check the gear engagement with lead sheet or paint, and adjust it. If the gear clearance is too large, the gear shall be replaced in time.


After diesel generator has been used for a long time, it is inevitable that there will be abnormal sound. As long as we can find the abnormal sound in time and judge fault according to the abnormal sound, we will resolve it.


If you still have question or need to purchase Perkins diesel generator, contact us by sales@dieselgeneratortech.com.

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