Page 4 of Sportsman Racing Producs Catalog by JE Pistons

4 4032 2618 SRP pistons made from 2618 wrought aluminum alloy are designed for higher performance applications such as FlyWeight or domed highcompression pistons. These environments necessitate the higher tensile strength 2618 aluminum alloy. Physical Properties of 2618 Nominal Density 2.81 g/cc .100 lb/in 3 Mechanical Properties of 2618 Tensile Strength, Ultimate 440 MPa 64,000 psi Tensile Strength, Yield 370 MPa 54,000 psi Modulus of Elasticity 74 GPa 10,400 psi Fatigue Endurance Limit 125 MPa 18,000 psi SRP pistons that are made from 4032 wrought aluminum alloy are designed for street/strip applications utilizing compression ratios that are compatible with pump gas. These pistons also provide a quieter engine on cold start-up. Physical Properties of 4032 Nominal Density 2.68 g/cc .097 lb/in 3 Mechanical Properties of 4032 Tensile Strength, Ultimate 380 MPa 55,000 psi Tensile Strength, Yield 315 MPa 46,000 psi Modulus of Elasticity 79 GPa 11,400 psi Fatigue Endurance Limit 110 MPa 16,000 psi Coefficient of Thermal Expansion 2618 aluminum expands approximately 15% more than 4032 aluminum, thus the 2618�fs initial piston-to-wall clearance has to be 15% greater. This difference is most noticeable during a cold engine start. When cold, the 2618 piston can rock back and forth producing a slight noise (sometimes referred to as until the aluminum expands. Both types of aluminum have approximately the same clearances once the pistons have expanded and the engine is running at operating temperatures. Temperature Range Average Coefficient oC oF ��m/m K ��in/in oF 20 to 200 68 to 392 23.2 12.9 Coefficient of Thermal Expansion for 2618 Temperature Range Average Coefficient oC oF ��m/m K ��in/in oF 20 to 200 68 to 392 20.2 11.2 Coefficient of Thermal Expansion for 4032 PISTON FEATURES Fully CNC machined dome, dish, or flat top Symmetrical valve pockets fully radiused Machined oil drain back holes (not slotted) CNC diamond turned skirt Pressure fed pin oilers Forged side relief Honed pin bore Full floating wrist pin Double spiro locks SRP PISTON MATERIALS EXAMPLE: When measured at room temperature, a 4 inch diameter piston made from 4032 measures 4.000�h. If the same were measured at 375o, the piston would measure 4.0034�h. EXAMPLE: When measured at room temperature, a 4 inch diameter piston made from 2618 measures 4.000�h. If the same piston were measured at 375o, the piston would measure 4.004�h.

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