单项选择题
Because of the close tolerances used in diesel engine fuel oil pumps, a worn plunger requires（）
A.grinding the spare plunger to the barrel B.replacing the plunger and the barrel C.highly polishing both the plunger and barrel D.replacing plunger only
单项选择题 Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?（）
单项选择题 Piston compression rings used in a diesel engine function to （）
单项选择题 An indicator card or pressure-volume diagram, shows graphically the （）
