Wiseco K631M86 Forged Piston Kit for 2002-2006 Honda / Acura K20A / K20Z

Vehicle Fitment

• Honda / Acura K20A / K20Z engines (e.g. 2.0 L K-series, 2002-2006 RSX, Civic, etc.)

Features

• Forged 2618 aluminum construction for high strength and durability
• ArmorGlide® low-friction skirt coating reduces wear
• Flat-top crown for stable compression (approx. 9.6:1)
• Strutted-forge design enhances rigidity
• Precision-machined ring grooves for reliable sealing
• Anti-detonation groove helps resist knock under load
• Forced pin-oiling for optimized lubrication under high RPM
• Includes high-performance ring set (8600XX)

Specifications

• Bore: 86.00 mm
• Compression Height: 30.00 mm
• Compression Ratio: ~9.6:1
• Wrist Pin Diameter: 22 mm
• Piston Material: Forged 2618 aluminum
• Piston Set Quantity: 4
• Typical Piston Weight: ~302 g

Included Components

• 4x forged pistons
• 4x 22 mm wrist pins
• 1x ring set (8600XX)
• Circlips / pin retainers

Product Description

The Wiseco K631M86 is a high-performance forged piston kit engineered for Honda's K20A / K20Z engines (commonly in 2002-2006 models). These forged pistons are constructed from 2618 aluminum, offering excellent strength and reliability for high-RPM and tuned builds.

With a flat-top crown and approximately 9.6:1 compression ratio, this kit is well-suited for both naturally aspirated and mildly boosted setups. The strutted-forge design provides added structural rigidity, while the ArmorGlide® coating reduces friction and improves durability. Forced pin-oiling ensures consistent lubrication of the 22 mm wrist pins, even under aggressive driving conditions.

This set includes a premium 8600XX ring set for reliable sealing. For best results, proper installation - verifying ring gap, clearances, and torque - is critical to ensure long-term performance and longevity.