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Over the past five years, the US Automotive Materials Partnership (USAMP) has brought together representatives from DaimlerChrysler, General Motors, Ford Motor Company and over 40 other participant companies from the Mg casting industry to create and test a low-cost, Mg-alloy engine that would achieve a 15 - 20 % Mg component weight savings with no compromise in performance or durability. The block, oil pan, and front cover were redesigned to take advantage of the properties of both high-pressure die cast (HPDC) and sand cast Mg creep- resistant alloys. This paper describes the alloy selection process and the casting and testing of these new Mg-variant components. This paper will also examine the lessons learned and implications of this pre-competitive technology for future applications.

Powder metallurgy main bearing caps (MBC) are being used in General Motors 3100 and 3800 engines with over 1,500,000 bearing caps assembled to date. Powder metal was chosen to replace nodular iron because of its functional advantages and because its net shape capability eliminated major investments in bearing cap machining lines at General Motors. This paper explains the functional advantages of powder metal bearing caps. Grey cast iron, nodular cast iron and powder metal bearing caps are compared. Main bearing cap requirements of strength, fatigue life and consistency are discussed. The various experiments and durability tests used to develop powder metal caps are described.