单项选择题
A.Lack of elastic tension, when the rings are pressed into the groove by means of a stick B.Blackish appearance C.Fractured rings and missing rings D.all off the above
If due to thick and hard deposits of carbon, the piston...
单项选择题If due to thick and hard deposits of carbon, the piston rings cannot move freely in their grooves, dark areas will often appear on the upper part of the cylinder wall (may not be the risible at port inspection)What condition of the piston rings can result in this phenomenon?（）
If over a period of time, the oi1 film partially disapp...
单项选择题If over a period of time, the oi1 film partially disappears, so that dry areas are formed on the cylinder wall, these areas and the piston surfaces will by frictional interaction, become finely scuffed and hardened, iegood mirror surface" will have deterioratedWhat condition of the piston rings can result in this phenomenon?（）
A.micro-seizure B.sticking C.scratched D.breakage/collapse
When good and steady service conditions have been achie...
单项选择题When good and steady service conditions have been achieved, the running surfaces of the piston rings and cylinder liner will be（）In addition, the rings will move freely in the grooves and also be well oiled intact, and not unduly worn.
A.hazy light B.hazy light brown C.hazy light blue D.hazy light grey
