The offset of piston may be occurred in the cylinder and cause local uneven wearing of piston:
Extremely bad parallelism of crankshaft connecting rod centerline and main shaft centerline .
Bending ,twisting of connection rod or unparallelism of connnection rod amll-head hole and big-head bearing hole centerline or not in the same plane.
Deformation of body makes the centerline of main shaft bearing hole not perpendicular to the centerline of each cylinder sleeve installing hole.
Extremely bad concentricity between the installing position cycle and inner hole or improper installation results in declination or deformation of cylinder sleeve.
After the deformation of crank,the unparallelism between the centerlines of main-bearing axlenecks or not in the same plane result in the declination of connection rod.
Overlarge axial interval of crank drives the connection rod to be declined to one side or over large conicity of axlenecks results in axial force on crank and connection the direction of axleneck conicity.