单项选择题
If the piston groove drain holes for the oil control rings become clogged, which of the following is likely to occur?（）
A.The oil control rings will seal improperly and wear rapidly B.The piston will overheat due to insufficient lubrication C.Excessive oil will remain on the cylinder wall D.Light brown smoke will emanate from the engine exhaust
单项选择题 Many cast iron pistons are designed with heat dams, which serve to （）
单项选择题 The adverse effects of burning high sulfur fuel can be compensated for by using a cylinder oil having sufficient（）
单项选择题 Scuffed cylinder liner surfaces in a diesel engine can result form（）
