Wiseco K631M87 87mm Flat Top Piston Kit 11.0:1 for Honda/Acura K24 w/K20 Head

Vehicle Fitment

• Universal -- Honda/Acura K24 engine block with K20 cylinder head
• Common donor blocks: K24A1 (CR-V/Element), K24A2 (TSX), K24A4/K24A8 (Accord), K24Z1/K24Z3/K24Z7
• Common donor heads: K20A, K20A2, K20A3, K20Z1, K20Z3

Fitment Notes

• Designed specifically for K24 block + K20 cylinder head combination -- not a stock K20 or K24 replacement
• Verify compression height and bore size against your specific build before ordering
• 87mm bore -- requires cylinder boring from standard K24 bore (87.0mm overbore)
• Not CARB legal -- race and off-road use only
• Professional engine builder installation required

Features

• Wiseco Sport Compact series
• 2618 aluminum forged construction -- superior tensile strength over 4032
• ArmorGlide skirt coating -- seizure resistant, friction reducing, quieter operation
• Larger and deeper valve pockets -- fits aggressive camshafts
• Gas nitrided top ring -- excellent for turbocharged applications
• Napier 2nd ring -- superior oil control
• Anti-detonation groove
• Precision CNC-machined crown
• Engineered, forged, and machined in USA

Specifications

• Bore: 87.00mm (3.425")
• Compression height: 1.181" (30mm)
• Stroke: 3.897" (99mm -- K24)
• Rod length: 5.984" (152mm)
• Pin diameter: 22mm (0.866")
• Crown: Flat top, -3.4cc dish
• Compression ratio: 11.0:1
• Alloy: 2618 aluminum
• Quantity: Set of 4

Included Components

• 4x Forged 2618 aluminum pistons
• 4x 22mm 4130 chromoly wrist pins
• 4x Spirolox wrist pin retainers
• 4x Piston ring sets (gas nitrided top + Napier 2nd + oil ring)

Product Description

The Wiseco K631M87 is an 87mm flat top piston kit engineered for the popular Honda/Acura K24 block + K20 cylinder head engine combination -- one of the most common high-performance K-series builds used in both naturally aspirated and forced induction applications. The K24 block's longer 99mm stroke paired with the high-revving K20 cylinder head delivers significant displacement and power advantages over a stock K20 or K24 alone, and this piston set is designed specifically to accommodate the K20 head's valve placement and port geometry with larger, deeper valve pockets that clear aggressive aftermarket camshafts.

Forged in-house by Wiseco from 2618 aluminum -- the preferred alloy for high-stress and forced induction applications due to its superior tensile strength and thermal expansion properties -- each piston is CNC-machined to final dimension and coated with Wiseco's proprietary ArmorGlide skirt coating for reduced friction and seizure resistance. The included ring package features a gas nitrided top ring well-suited for turbocharged builds and a Napier 2nd ring for excellent oil control. Requires cylinder boring to 87.00mm. Professional engine builder installation required. Not CARB legal. Engineered, forged, and machined in the USA.