Wiseco K631M865 – Professional Series Flat-Top Piston Set (86.50 mm Bore) for Honda K20/K24

The Wiseco K631M865 is a top-tier, four-piece piston set crafted specifically for Honda K20A and K20Z (and select K24) engines. Boasting a precise 86.50 mm bore and flat-top design, this Professional Series kit is engineered to deliver enduring performance in both street and race applications.

The Wiseco 9.8:1 pistons are designed for a K20 cylinder head and engine block.

Features:

• Professional-Grade Forged Pistons: Constructed from robust 2618 aluminum alloy, these pistons provide superior tensile strength and resilience under extreme RPM and high-stress conditions, making them ideal for motorsport use.
• ArmorGlide® Skirt Coating: Each piston is treated with ArmorGlide® to reduce friction, resist seizures, and contribute to quieter operation.
• Precision Machining: Features include fully machined crown surfaces, finely-tuned ring grooves, an anti-detonation groove, and enhanced ring sealing technology—maximizing durability and efficiency.
• Optimized Fitment for K-Series Engines: Designed with 86.50 mm bore, 30.00 mm compression height, and -3.40 cc piston volume; equipped to perform optimally in Honda K20A/Z (and compatible K24) engine platforms.
• Complete Set Ready for Installation: Includes four pistons, premium ring sets, and wrist pins (0.866″ / 22 mm floating pins), providing everything necessary for a professional rebuild.

Includes:

• 4 pistons
• 4 wrist pins
• 4 wrist pin locks
• 4 rings.

The Wiseco K631M865 is a formidable piston set engineered for serious Honda K-series enthusiasts. With race-ready construction, advanced coatings, detailed machining, and all-inclusive kit components, it delivers exceptional performance and reliability when it matters most.

Specifications:

• Part Number: K631M865
• Engine Compatibility: Honda K20A / K20Z (and K24)
• Bore Size: 86.50 mm (3.405″)
• Compression Height: 30.00 mm (1.181″)
• Piston Type: Flat-top (with valve reliefs)
• Alloy Material: Forged 2618 aluminum
• Skirt Coating: ArmorGlide®
• Piston Volume: –3.40 cc
• Wrist Pin Diameter: 0.866″ (22 mm), floating
• Rings Included: Yes (complete ring set)