TOMEI Forged Piston Set 86mm for Mitsubishi 4G63

The TOMEI Forged Piston Set 86.00 mm (OEM +1.0) for the Mitsubishi 4G63 is designed for tuned engines where higher combustion pressure demands real strength and heat resistance from the rotating assembly. Built using a high-strength forging process instead of the cast construction common in mass-production pistons, it takes advantage of forging’s high-temperature durability to run thinner wall sections for weight reduction without sacrificing rigidity. TOMEI also minimizes excess material by using an exclusive forged material approach, reducing the need for heavy machining that can compromise strength. For stable movement and correct running clearance, the skirt uses an oval barrel profile with thermal expansion calculated into the shape. The piston includes a valve recess designed to support 1 mm oversized valves, and friction loss is reduced by thinning the piston rings to cut drag while maintaining sealing performance.

Features

• High-strength forging
• Oversized by +1.0mm over OEM
• Lightweight design without compromise
• Recess shaped for 1mm oversized valves
• Includes pins, clips and rings

Specifications

• Bore (mm): 86.00 (OEM +1.0)
• Pin Diameter (mm): 22.0
• Pin Length (mm): 60.0
• Circlip Inner Diameter (mm): 22.0
• Valve Recess: WITH
• Compression Height (mm): 34.70 (OEM -0.3)
• Piston Volume (cc): -14.6
• Piston Weight (g): 387.0
• Pin Weight (g): 121.5
• Total Weight (g): 508.5
• Top Ring (mm): 1.20 x 3.05
• Second Ring (mm): 1.20 x 3.70
• Oil Ring (mm): 2.50 x 2.85
• Piston Material: A4032

Applications

• Mitsubishi: 4G63

Notes

• Instruction manual can be found here

About TOMEI

TOMEI is a leading innovator in automotive performance parts, renowned for its expertise in developing high-quality exhaust systems, turbo kits, and engine components. With a commitment to excellence, TOMEI sources its own raw materials and maintains complete control over the manufacturing process, ensuring superior quality and affordability. Specializing in lightweight Titanium construction and advanced engineering, TOMEI delivers products that enhance performance, durability, and sound, making them a top choice for enthusiasts and professionals in the automotive racing industry. Their dedication to precision and innovation has solidified their reputation as a trusted name in automotive performance.