SURFACE TREATMENT OF CYLINDER BLOCK, MASKING METHOD AND DEVICE USED FOR THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a surface treatment of a cylinder block which can be adopted even to the cylinder block or V-engine block having journal parts without the occurrence of defect, such as a difference in level of plating films and plating scorching, on the inside surfaces of cylinder bores. SOLUTION: A sealing member 52 is pressed to the inside surface 56 of a crank case part 4 to mask the crank case part so as to prevent the leakage of a surface treating liquid to the outside when the cylindrical bore surface 2 formed communication with the inside space of the crank case part 4 in a main body part of the cylinder block 1 integrally molded with the crank case part 4 in the lower part of a cylinder block body part is subjected to a surface treatment.