单项选择题
A.build up the piston crown by metal spraying
B.build up the cylinder head by metal spraying
C.insert shims between the crankpin bearing box and the connecting rod foot
D.install a thinner head gasket
单项选择题 A mixture of 45%cetane and 55% alpha-methyl-naphthalene is found to have the same ignition delay as a sample of diesel oil √The sample can be described as having a/an（）
单项选择题 Worn main bearing will cause the compression ratio of an auxiliary diesel engine to（）
单项选择题 With respect to diesel fuel, the ease with which a cold engine will start is dependent upon the（）