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SKU: SC70458-4
CP Forged Piston and Ring Kit for Honda K20A/A2/A3 Engines – 87.5mm Bore, +1.5mm Oversize, 9.7:1 Compression Ratio
Honda K20A, K20A2, or K20A3 engine piston and ring kit, crafted specifically for high-revving K-series performance. This forged aluminum set stands out in boosted applications, whether turbocharged, supercharged, or running nitrous by handling extreme pressures while maintaining tight tolerances for efficient combustion and reduced blow-by. Compared to factory pistons, the SC70458-4 kit provides greater resistance to detonation and thermal expansion, allowing safer tuning for higher boost levels and delivering more consistent horsepower across the RPM range. For K20 enthusiasts chasing reliable daily-driven power or track-ready response, this kit integrates seamlessly into stroker or high-compression setups, making it the direct path to a stronger, more responsive engine without the guesswork of mismatched components.
Key Specifications
- Bore Diameter: 87.5mm (3.445 inches) +1.5mm oversize for precise cylinder wall clearance
- Compression Ratio: 9.7:1 Balanced for naturally aspirated or forced-induction use with stock or ported K20 heads
- Stroke Compatibility: 86mm
- Rod Length: 139mm
- Piston Style: Flat-top with four deep valve reliefs (accommodates +1mm oversized valves and high-lift cams)
- Piston Material: 2618-T6 high-strength forged aluminum with X-forging design for enhanced durability and lighter weight
- Compression Height: 1.181 inches
- Piston Head Volume: +3.30cc
- Wrist Pin Diameter: 22mm (0.866 inches) – Press-fit or floating style
- Piston Weight: 338 grams each (balanced to ±1 gram for smooth rotation)
- Ring Specifications:
- Top Ring: 1.0mm thickness, steel construction for low friction
- Second Ring: 1.2mm thickness, cast iron for reliable sealing
- Oil Ring: 2.8mm thickness, three-piece design with double pin oilers for superior lubrication
- Additional Features: Accumulator grooves to control ring flutter, custom skirt and barrel shaping for reduced friction, pick-lock grooves for simple circlip installation, and optional gas ports or coatings available upon request
This kit weighs approximately 1.35 kg total (pistons only), keeping your rotating assembly light for quicker revs and better throttle feel.
Vehicle Fitment
The SC70458-4 kit fits 2.0L K20-series engines in these models, ensuring bolt-on compatibility with stock or aftermarket rods and cranks:
- Acura RSX (DC5): 2002-2004 Base (K20A3), 2002-2006 Type-S (K20A2)
- Honda Civic Si (EP3): 2002-2005 (K20A3)
- Honda Civic Type R (EP3, JDM): 2001-2005 (K20A)
- Honda Civic Si (FA5/FG2): 2006-2011 (K20Z1)
- Honda Civic Mugen Si: 2008 (K20Z3)
Verify your engine code (K20A, K20A2, K20A3, K20Z1, or K20Z3) for exact match ideal for RSX Type-S swaps into Civics or refreshed JDM Type R motors.
What's Included in Your Purchase
Every SC70458-4 kit arrives complete and ready for installation, with no extras needed beyond basic tools:
- 4 x Forged Pistons: Pre-machined to 87.5mm bore, flat-top design with valve reliefs and anti-detonation grooves
- 4 x Complete Ring Sets: Premium file-to-fit rings (top: 1.0mm steel, second: 1.2mm cast iron, oil: 2.8mm) for each piston
- 4 x Chrome-Moly Wrist Pins: 22mm diameter, heat-treated for strength
- 8 x Wrist Pin Circlips: Heavy-duty locks (two per pin) for secure retention
- Part Number Engraving: SC70458-4 laser-etched on each piston for easy identification
No additional hardware required file rings to spec during assembly for optimal gap. Backed by CP's reputation for precision, this set ensures your K20 runs cooler, seals tighter, and pushes harder than ever.
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