Abstract: A heat resistant slide member for an internal combustion engine is a plastically worked member formed from a quenched and solidified aluminum alloy, with a metal flow line in a sliding portion thereof set in a sliding direction. The aluminum alloy contains at least one selected from the group consisting of Cr, Fe, Zr and Ti in an amount of 5% or more and 30% by weight or less and has an average diameter of precipitates and crystallizates therein of 50 .mu.m or less and a tensile strength at 300.degree. C. of 18 kg/mm.sup.2 or more.

Abstract: A cylinder block as a main part of an engine block includes a cylinder barrel assembly block, a skeleton-like frame surrounding the outer periphery of the cylinder barrel assembly block and a plate-like rigid film member, within a fluid passage in the skeleton-like frame. The skeleton-like frame is integrally joined to the outer surfaces of left and right side walls of the assembly block along the crankshaft axis and includes crossbeam bone members, longitudinal beam bone members and post bone members which are rigid and unitarily assembled into a three-dimensional latticework structure. A cylinder head is integrally coupled to the deck surface of the cylinder block and a lower case is integrally coupled to the lower surface of the cylinder block, lateral outer surfaces of the block and lower case along the crankshaft axis being formed flush with each other in parallel with the cylinder bore axis.