... 00-00A Main Features :(a)Composite piston With Steel Crown and Aluminum skirt,shake cooling,piston skirt adopt convexity ... structure ,optimized bolt layout .(c)Good wearability , Piston crown ring groove adopts effective strengthen treatment .(d)Good versatility , ... diesel engine , DF4B,DF4C,DF4D,DF5,DF7C,DF7D locomotives .(e)Convenient assembly , disassembly and overhauling . 240/275 Composite Piston ...