When the engine is running in the vehicle, the piston striking the cylinder is abnormal. Piston knocking noise occurs in the upper part of the cylinder, which is similar with a small hammer cement ground rhythmic blah sound. When the engine is idling, the sound is clear and clear. Especially when the engine is running at low temperature, the sound is clear, the temperature rises, the sound is reduced and even disappeared.
Method for judging piston knocking cylinder:
(1) by cylinder off oil. Take off the oil cylinder by cylinder to determine the position of the knock off, if the oil to a cylinder, the sound was reduced or disappeared, and when the oil recovery when you can hear the obvious blah sound, the cylinder piston knocking.
(2) to further confirm the cylinder piston knocking cylinder, the cylinder of the injector can be unloaded, to CD booster cylinder with a small amount of oil (seal), and then installed injectors, engine knock, disappear or weaken, run for a knock again, it is the cylinder piston knocking undoubtedly.
The main reasons for the piston knocking cylinder are as follows:
(1) with the clearance between the piston cylinder is too big. Baotou beiben heavy truck accessories WD615 series engine piston skirt and cylinder standard clearance for the 0.143-0.182, the maximum wear limit is 0.35 – 0.40.
(2) the engine after a period of operation, the cylinder piston wear, and the lubrication is not good, clearance between piston and cylinder increases due to wear, and there is a serious step in the first air ring slightly lower, so that the piston cylinder knocking the abnormal noises.
(3) after a period of time, the piston skirt and the cylinder wear badly, resulting in serious failure of the cylinder.
(4) Baotou beiben heavy truck parts individual connecting rod deformation due to various reasons, caused by the eccentric wear of piston, big gap and knock. Piston knocking cylinder can lead to high engine fuel consumption, engine oil, oil consumption, poor economy. When the piston hit the cylinder, the piston will be broken, broken cylinder, so that the connecting rod broken, broken cylinder.
The piston knocking cylinder can be treated by the following methods:
(1) after the engine starts, when the low temperature operation hits the sound, after the temperature is normal, the sound disappears, may temporarily do not handle, continues to run.
(2) when the engine temperature is normal, there is a striking sound, should try to avoid high-speed operation, demolition and repair as soon as possible.
(3) remove the cylinder head, pull out the piston, the cylinder is found to be seriously damaged, or the piston and cylinder clearance is too large, should be replaced, replace the cylinder liner, piston and piston ring.
(4) if it is found that the Baotou beiben heavy truck parts connecting rod deformation, should be replaced.