The Honda R20A1 is a 1,997 cc, inline‑four naturally aspirated petrol engine produced between 2006 and 2012. It features a single overhead camshaft (SOHC), 16 valves, and Honda's i-VTEC system for variable valve timing and lift. In standard form it delivered 115 kW (156 PS) and 192 Nm of torque, with i-VTEC enabling a broad, flat torque curve for responsive everyday drivability.
Fitted to models such as the eighth-generation Civic (FA/FG) and the first-generation CR-V (RE), the R20A1 was engineered for drivers seeking a balance of fuel economy, refinement, and adequate power for highway cruising. Emissions compliance was met through precise fuel metering and a three-way catalytic converter, allowing compliance with Euro 4 standards.
One documented engineering update addressed potential for oil consumption in early production units, resolved in Honda Service Bulletin A07-022. The bulletin details a revised piston ring design to improve oil control, implemented in engines produced after September 2008.
Honda
Production from 2006–2012 meets Euro 4 emissions standards (EU Regulation (EC) No 715/2007, as amended).
The Honda R20A1 is a 1,997 cc inline‑four naturally aspirated petrol engine engineered for compact cars and SUVs (2006-2012). It combines SOHC architecture with i-VTEC variable valve timing to deliver smooth, linear power for efficient daily driving. Designed to meet Euro 4 standards, it prioritizes reliability and low running costs for mainstream applications.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,997 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 16‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 81.0 mm × 97.0 mm | |
| Power output | 115 kW (156 PS) | |
| Torque | 192 Nm @ 4,200 rpm | |
| Fuel system | PGM-FI (Programmed Fuel Injection) | |
| Emissions standard | Euro 4 | |
| Compression ratio | 10.5:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain-driven | |
| Oil type | Honda 5W-30 (spec. HTO-06) | |
| Dry weight | 127 kg |
The i-VTEC system provides smooth, linear power ideal for highway cruising but requires the specified 5W-30 HTO-06 oil for optimal VTEC solenoid and lifter operation. The timing chain is designed for life but relies on correct oil specification and level. Early production engines (pre-September 2008) may exhibit higher oil consumption; this was addressed by a piston ring revision per Honda SIB A07-022. Regular oil changes are critical for long-term reliability.
Oil Specs: Requires Honda 5W-30 (spec. HTO-06) for i-VTEC system compatibility and optimal lubrication (Honda Owner's Manual).
Emissions: Meets Euro 4 standards for all 2006-2012 production (EU Regulation (EC) No 715/2007, as amended).
Power Ratings: Measured under SAE J1349 standards. Output is consistent across model years (Honda TIS Doc. R20A1-A26015).
Honda Technical Information System (TIS): Docs R20A1-A24680, R20A1-A25142
EU Regulation (EC) No 715/2007 (Emissions)
Honda Service Information Bulletin (SIB A07-022)
SAE International: J1349 Engine Power Certification Standards
The Honda R20A1 was developed for Honda's Global Compact platform with transverse mounting. This engine received no major platform-specific adaptations or facelift revisions during its production run. All applications are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, below the exhaust manifold (Honda TIS R20A1-A24890). The 8th VIN digit for R20A1-equipped models is 'R'. Visually, it can be identified by its SOHC valve cover (single camshaft) and the '2.0 i-VTEC' badge on the vehicle. Critical differentiation from the K20 engine: The R20A1 has a timing chain cover on the front, while the K20 has a timing chain cover on the side. Service parts are specific to the R20A1 and model year.
The R20A1's primary reliability consideration is potential oil consumption in early builds, with Honda's internal data indicating a measurable improvement after the September 2008 update. UK DVSA MOT statistics show no significant pattern of engine-related failures for this model, suggesting overall robustness. Adherence to the correct oil specification and change intervals is critical for long-term health.
Analysis derived from Honda technical bulletins (2006-2012) and UK DVSA failure statistics (2013-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA R20A1.
Comprehensive technical documentation and regulatory references
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DVLA: Engine Changes & MoT
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Regulation (EC) No 715/2007
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Commission Regulation (EU) 2017/1151
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