Method for manufacturing siamese-type cylinder block and apparatus for casting blank for such cylinder block

摘要

A method for manufacturing a siamese-type cylinder block, which comprises the steps of pouring under pressure a molten metal of aluminum alloy into a siamese-type cylinder barrel molding cavity with an expansion force applied to the sleeve placed in such cavity, and then removing the expansion force after the completion of solidification of the molten metal to cast a cylinder block blank, and subjecting the resulting blank to a working operation for forming the peripheral inner surface of the sleeve into a true circle.