Lower casing of engine crankcase

The casing has a cast-iron supporting part (17) formed with a semicircular supporting recess (15) on its top surface (16) for a crankshaft to be fitted in at a lower half of its journal (4). The part is built in aluminum cross unit body. A side unit, the surface, and the body are formed together through aluminum casting by using the part as an insert unit. A notch (23) is formed at a lower end of the part below the recess. An independent claim is also included for a mold for use in casting a lower casing.