The cylinder is cylinder and piston, piston ring subjected to mechanical damage, serious when the piston in the cylinder lock, and cause other damage. The phenomenon of multi cylinder surface in cylinder and the cylinder body on the plane perpendicular to the direction of the site is more serious, the inlet valve, the cylinder surface or in an axial direction of the piston pin. Every cylinder has a scratch track, in the piston ring working face and the piston group also often have scratch marks.

1. failure phenomenon

Crankcase gas abnormal increase, if there is a lot of smoke from the crankcase, cylinder crankshaft crank with abnormal sound, very difficult, even can not shake, to add lubricating oil in the cylinder, and shaking.

2. cause of failure

The following reasons can cause scuffing:

(1) the gap between the piston and the cylinder is too small.

(2) the cylinder diameter and the sleeve holes fit too tight or too loose: beiben V3 cylinder parts quality does not meet the requirements; the cylinder liner hardness is too low, causing the piston cylinder.

(3) the quality of piston itself is not up to the requirement, and the aging process is poor. The piston pin and piston pin hole assembly is too tight, causing the piston axial deformation, and the skirt diameter of piston skirt does not meet the requirements.

(4) the piston and cylinder are not well cleaned during assembly, which makes the piston and its ring groove grit, or the intake pipe is not cleaned. Due to the former cylinder, occurred in the circumferential direction of the cylinder, no rules. The latter part of the cylinder, usually occurs at the position opposite to the inlet valve.

(5) the air filter is invalid, or the air filter is not installed at the time of test.

(6) poor quality of lubricating oil, excessive impurity or non conformity of the variety.

(7) the piston ring is broken, bites to the piston, or the gap between the V3 parts of the North Run is too small.

(8) the wear of the piston pin hole and the spring groove, the piston pin spring is lost, distorted, broken, broken or leaked.

(9) the bending of the connecting rod, the deviation of the piston pin hole or the bushing of the connecting rod, the deviation between the center line of the cylinder and the central line of the crankshaft cause the front and rear deflection, forcing the piston and the piston ring to one side and compacting on the cylinder wall.

(10) when the temperature is low, the engine without preheating, cold start is often easy to cause the cylinder force.

(11) the failure of cooling liquid circulating cooling system or cooling system has large amount of air, which may cause the cylinder accident in the short term.

(12) the coolant leak into the lubricating oil, destroy the normal lubrication between cylinder and piston with side, the formation of dry friction caused by high temperature, causing cylinder.

(13) the engine cylinder outer scale is excessive, the heat transfer performance decreased when the load is too large to scuffing.

(14) the connecting rod bolts not tightened, when the engine is running, the occurrence of the impact load, plastic deformation, resulting in beiben V3 fitting the rod to be bending caused serious scuffing.

3. analysis and diagnosis

When we found this phenomenon, it may be concluded on, this is not allowed to start the engine, open the engine oil pan, rotate the crankshaft, from the lower part of each cylinder were observed.