JE Pistons Ultra Series GM Gen III/IV LS 4.01in Bore/4in Stroke Set of 8 Pistons

Ultra Series forged pistons from JE are the industry’s strongest, most fully featured pistons available off the shelf. Offered for LSX 12 and 15 Degree Engines. Ultra Series Pistons feature JE’s proprietary Aligned Grain Flow forging technology providing next-level tensile strength ideal for the extreme cylinder pressures of power adder engine builds. Equipped with the following custom level features

Additional Information

4.010 in. Bore - 1.115 CD - Dome - (12.70 cc) - 8 Cyl. Piston Kit

Part Type

Engine Piston Kit

• Accumulator Groove: A specialty groove between the top and second ring provides added volume for blow-by gases. This helps reduce pressure between the rings, improving top ring seal and minimizing ring flutter at high cylinder pressures.
• Designed specifically for LSX 12 and 15 Degree Engines. To provide optimized performance durability
• Double Pin Oilers: Deliver twice the amount of oil to the wrist pin as compared to the standard single pin oiler.
• Includes high-quality wrist pins, and locks
• JE’s proprietary Aligned Grain Flow forging technology providing next-level tensile strength ideal for the extreme cylinder pressures of power adder engine builds.
• Lateral Gas Ports: This process mills slots into the top of the top ring groove and provides a pathway for combustion pressure to get behind the top ring. Resulting in increased ring seal and is most common in circle track applications.
• Made 100% in the USA
• Pin Fit: The pin bore is precision honed to attain an exact pin clearance. Clearances typically range from .0003 to .0010 between the wrist pin and pin bore.
• Skirt Coat: Skirt Coat reduces friction and wear on piston skirts and cylinder walls while simultaneously reducing operating noise
• Thermal Crown: Applied to the piston crown, this thermal barrier coating reflects heat back into the combustion chamber to improve exhaust gas velocity and scavenging while reducing heat transfer to help extend piston life.

Note for Pistons, Rings, Rotors, Rods and engine internals

Unless otherwise specified, some brands supply brake rotors, pistons, strut mounts, rods and rings separately. In some cases, titles may indicate plural, or 'set' - eg the term “ring set” often refers to the rings for a single piston only. If you’re unsure about what’s included with this product, please contact our team for clarification.

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Reference Information