Wiseco K566M81AP Forged 81 mm 5cc Dome Pistons for Honda B-Series

Vehicle Fitment

• Honda B16A (Civic / CRX, 1.6 L)
• Honda B17A (Integra, 1.7 L)
• Honda B18A1 / B18B1 / B18C (1.8 L) with compatible heads

Features

• Forged from 2618 aerospace-grade aluminum for high strength and durability
• ArmorPlating skirt coating for reduced friction and enhanced wear resistance
• +5 cc positive-dome design to boost compression
• CNC-machined crown with valve reliefs for B-series port clearance
• Strutted forging for added structural rigidity under load
• ArmorGlide® coating for smoother operation and seizure resistance
• Includes performance piston ring set (8100XX)
• 21 mm floating wrist pin for reliable pin support

Specifications

• Bore: 81.00 mm
• Compression Height: 30.10 mm
• Dome Volume: +5.0 cc
• Wrist Pin Diameter: 21 mm
• Material: Forged 2618 aluminum
• Piston Weight: ~275 g per piston
• Compression Ratio: ~10.5:1 (B16A), ~11.55:1 (B18C) depending on head

Included Components

• 4x forged pistons (81 mm, +5 cc)
• 4x 21 mm wrist pins
• 4x circlips / locks
• 4x piston ring sets (8100XX)

Product Description

The Wiseco K566M81AP piston kit is a high-performance, forged solution for Honda's B-series engines. The +5 cc dome raises compression, making it well-suited for naturally aspirated or slightly tuned performance builds. Forged from 2618 aluminum, these pistons offer excellent strength, fatigue resistance, and thermal characteristics for demanding applications.

With ArmorPlating on the skirts and ArmorGlide® coating, the pistons minimize friction and wear. The strutted design enhances rigidity, while the CNC-machined dome and valve reliefs ensure good clearance and optimal combustion. The set includes high-performance rings and 21 mm floating wrist pins for reliable sealing and durability.

Ideal for engine rebuilds, performance upgrades, or race applications, this kit requires careful installation: verify ring gaps, deck height, and bore clearance for best results. Depending on the head used, the compression ratio will vary (for example, ~10.5:1 with a B16A head and ~11.55:1 with a B18C head), so choose your head gasket accordingly.