This research aims to analyze the voltage and the strain of tensile testing, while the impact test aims to find out the toughness of the material in absorbing energy from the application in the swingarm making process with the diesel piston remelting material variations on the variations addition of Magnesium (Mg) percentage of 1%, 2%, 3% and 5%. This research method uses a sand mold in the making-process of specimens on standardized test in accordance with ASTM-E8M and ASTM-E23. The tensile and impact test produce a positive result, where the maximum tensile strength is 71, 751 Mpa and the impact toughness at impact testing is 0,412 Joule/mm2, in the test shows the strength and load of remelting piston diesel with additions Magnesium (Mg) to be a new reference in component casting industry of automotive.