Wiseco 6559M855 Pro Tru Sport Compact Forged Piston 85.5mm Dish w/ Rings & Pin

The Wiseco 6559M855 is a Sport Compact Pro Tru series forged replacement piston designed for high-performance Mitsubishi turbocharged engine builds. Featuring an 85.5mm (3.366 in.) bore, a dish-style piston head with -17cc dome volume, and a compression ratio of 8.3:1, this piston is purpose-built for forced induction applications requiring lower compression. Sold individually.

Key Specifications:

• Bore: 85.5mm (3.366 in.)
• Compression Height: 35mm (1.378 in.)
• Dome Volume: -17cc (Dish, no valve reliefs)
• Compression Ratio: 8.3:1
• Rod Length: 150mm
• Stroke: 88mm
• Gram Weight: 332g
• Pin Diameter: 0.827 in.
• Wrist Pin: .200" wall tool steel — included
• Ring Grooves: 1.0mm / 1.2mm / 2.8mm (1/16, 1/16, 3/16)
• Recommended Ring Set: 8550XX
• Rings & Pin: Included

Pro Tru Sport Compact Series Features:

• Forged from high-strength aluminum alloy and precision CNC-machined to final shape
• American-made by skilled craftsmen in Ohio using state-of-the-art forging presses
• Dedicated forgings specific to the final piston profile for superior strength-to-weight ratio
• Includes plasma moly pre-gapped ring package for excellent combustion seal, reduced friction, and extended service life
• Available in multiple dome volumes to allow precise compression ratio tuning

The Wiseco Pro Tru Sport Compact line delivers genuine forged piston performance at an exceptional value. Whether building a street turbo engine or a dedicated performance application, the 6559M855 provides the durability and precision that serious engine builders demand.