Low vibration polymeric composite engine

An internal combustion engine, comprising:

• high stress portions which are positioned in a direct load path of combustion forces produced during operation of said internal combustion engine and which are subjected to intense combustion pressure, said high stress portions being formed from metallic materials selected from the group consisting of cast iron, steel, metallic alloys, and metal matrix composite materials, said high stress portions comprising a plurality of cylinders and bearing members, said cylinders and bearing members being joined together at a plurality of metal to metal joints such that a suck up of said high stress portions results so as to provide a rigidity and durability necessary to withstand said intense combustion pressure;
• and
• low stress portions which are integrally joined to said high stress portions, but which are not positioned in said direct load path of said combustion forces produced during operation of said internal combustion engine and which are subjected to lower pressures than said high stress portions during combustion, said low stress portions comprising a crank case, at least one cylinder case, and bearing cap support members for holding said bearing members in a spaced alignment, at least one of said low stress portions being formed from a polymer material.