The invention concerns a method for casting a part made of metal alloy such as an aluminum alloy comprising the following steps: forming a core (N, PNC) having at least one shaft (PC) designed to form in the part a cylinder and at least one cavity (P) designed to form in the part a support and/or retaining zone for a working member, and at least a cooling unit (RE) proximate to the cavity; positioning the core in a metal mould cavity, and feeding the mould lined with its liquid alloy core by gravity. The invention is particularly useful for casting internal engine cylinder blocks with aluminum cylinders with improved geometrical and mechanical properties of the crankshaft bearing zones.