What Is The Cause Of The Abnormal Noise Fault in The Piston Pin

Some engines may experience abnormal piston pin noises during use. If the abnormal noise of the piston pin is severe, it will damage the piston pin liner, and the wear of the connecting rod bearing and crankshaft connecting rod journal will cause the piston pin or the top of the connecting rod to be pulled apart, damaging the cylinder block. Do not take it lightly.
The phenomenon of piston pin abnormal noise fault is:
(1) The abnormal noise is located in the upper part of the cylinder, and the sound is like a "special" sound made by two steel balls colliding.
(2) After the engine temperature rises, the sound generally does not change much, and some may become more pronounced, which is a major difference from the abnormal sound of the piston knocking on the cylinder.
After experiencing abnormal noise from the sales of household plugs, the following methods can be used to determine:
(1) Conduct a cylinder by cylinder oil cut-off test. After the oil cut-off, the sound will significantly weaken or disappear, and after the oil supply is restored, it will become more pronounced. When the fault is severe to a certain extent, there will be continuous and continuous double sounds. After cutting off the oil, the sound will not only not weaken or disappear, but also intensify.
(2) Conduct an engine shake throttle test. When shaking the accelerator rapidly, the abnormal sound is quite obvious, and the cycle of the sound varies with the change of engine speed.
The main reasons for the abnormal noise in the sales of household plugs are as follows:
(1) The piston pin and connecting rod bushing are severely worn and the fit is severely loose. The main reason is due to poor lubrication. There are no oil holes on the connecting rod of WD615 series engines. The lubrication of the piston pin and liner is achieved by spraying oil upwards through the oil collection groove at the small end of the connecting rod through the lubricating oil nozzle. If the oil pressure is too low and the injection situation is not good, it will cause poor lubrication of the piston pin and connecting rod liner. Moreover, due to poor injection, poor piston cooling will also exacerbate the wear of the piston pin and connecting rod liner. If the engine oil deteriorates or becomes thinner, it can also cause increased wear and tear. So, it is important to pay attention to the quality of the engine oil. It is best to change the oil and replace the oil filter on a regular basis, and always check the oil level and quality before driving every day.
(2) During the repair of the connecting rod bushing, inaccurate dimensional positioning and poor fit between the bushing and the connecting rod can also result in abnormal piston pin noise. During maintenance, it is necessary to install according to the standard so that the connecting rod bushing can be pressed in under a certain pressure.
After the occurrence of abnormal piston pin noise, different treatment measures can be taken depending on the severity:
(1) If there is a slight abnormal noise from the piston pin, continue driving; But if there are repair conditions, it is best to replace them.
(2) If the piston pin has a serious abnormal noise (when operating at high speed and normal temperature, the sound is very obvious), it should be repaired and replaced immediately.
(3) The replacement of piston pins and connecting rod bushings should be strictly carried out according to standards, and the clearance fit should be correct.