The Honda B20A3 is a 1,956 cc, inline‑four naturally aspirated petrol engine produced between 1987 and 1990. It features a dual overhead camshaft (DOHC) with 16 valves and Honda's PGM‑FI fuel injection system. This configuration prioritized higher specific output and a broader power band for spirited driving, delivering 110 kW (148 PS) and 176 Nm of torque.
Fitted primarily to the third‑generation Honda Prelude (BA chassis) and higher‑spec Accord variants, the B20A3 was engineered for responsive performance and refined high‑rpm operation. Emissions compliance for its era was managed through its precise electronic fuel injection and catalytic converter, allowing it to meet applicable Japanese and North American emissions standards of the late 1980s, including California's stricter requirements.
One documented service concern involves premature wear of the balance shaft bearings, which can lead to increased engine vibration and noise. This issue, referenced in Honda Service Bulletin 88‑032, is often linked to oil starvation or extended service intervals. The B20A3 was succeeded by the more powerful B21A1 variant.
Honda
Production years 1987–1990 meet applicable late-1980s emissions standards for respective markets (e.g., US EPA Tier 0, Japanese Showa 58, California ARB).
The Honda B20A3 is a 1,956 cc inline‑four naturally aspirated petrol engine engineered for sporty coupes and sedans (1987-1990). It combines PGM‑FI electronic fuel injection with a 16‑valve DOHC layout to deliver a broad, responsive power band and high specific output. Designed to meet late-1980s emissions standards, it balances performance with mechanical sophistication.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,956 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 95.0 mm | |
| Power output | 110 kW (148 PS) @ 6,200 rpm | |
| Torque | 176 Nm @ 5,000 rpm | |
| Fuel system | Honda PGM‑FI (Programmed Fuel Injection) | |
| Emissions standard | US EPA Tier 0 / California ARB / Japanese Showa 58 | |
| Compression ratio | 9.4:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt‑driven | |
| Oil type | API SF/SG 10W‑40 | |
| Dry weight | 154 kg |
The DOHC 16-valve design offers a broad, responsive power band ideal for spirited driving but requires precise valve clearance adjustment every 30,000 km to maintain performance and prevent valve train damage. API SF/SG 10W-40 oil is specified to protect the hydraulic lifters and timing belt tensioner. The balance shaft bearings (Honda SIB 88-032) are critical for smoothness and should be inspected if unusual vibration is present; failure is often linked to poor oil maintenance. The timing belt is a critical service item and must be replaced at 90,000 km intervals to prevent catastrophic engine failure. The PGM-FI system demands clean fuel; clogged injectors are a common cause of drivability issues.
Oil Specs: Requires API SF/SG 10W-40 specification (Honda Owner's Manual, 1988). Modern equivalents meeting API SL/SM are acceptable.
Emissions: Certified under US EPA Tier 0 and California ARB standards for 1988 model year (EPA Certificate #88-HON-002). Japanese market models complied with Showa 58 regulations.
Power Ratings: Measured under SAE J1349 standards (Honda PT-1988). Output figures are for the US-spec B20A3; JDM variants may differ slightly.
Honda Service Manual (BA Chassis Prelude/Accord)
Honda Parts Catalogue (EPC) Doc. B20-003
US Environmental Protection Agency (EPA) Certification Database
Honda Service Information Bulletins (SIB 88-015, SIB 88-032)
The Honda B20A3 was used across Honda's BA platform with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts for the Prelude-and no significant facelift revisions during its production run, ensuring broad parts interchangeability. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the engine block, just below the cylinder head and to the right of the water pump (Honda Service Manual BA). The 8th digit of the VIN for US-market Preludes is 'F' for the B20A3 engine. Visually, it can be identified by its twin cam covers and distributor mounted at the rear of the cylinder head. Critical differentiation from the B20A5: The B20A3 has a lower compression ratio (9.4:1 vs 10.5:1 for JDM B20A5) and different camshaft profiles, though many external parts are interchangeable. The intake manifold for the B20A3 is specific (Honda P/N 17100-PN4-003).
The B20A3's primary reliability risk is balance shaft bearing wear, with elevated incidence in high-mileage or poorly maintained examples. Honda service data indicates vibration complaints are a common cause for diagnostic visits, while timing belt neglect is the single greatest risk for catastrophic failure. Adherence to the 90,000 km timing belt interval makes long-term reliability excellent.
Analysis derived from Honda technical bulletins (1987-1990) and US NHTSA complaint data (1987-1995). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA B20A3.
Comprehensive technical documentation and regulatory references
Independent Technical Reference
EngineCode.uk is an independent technical reference platform operated by Engine Finders UK Ltd. We are not affiliated with HONDA or any other manufacturer. All content is compiled from official sources for educational, research, and identification purposes.
Strict Sourcing Protocol
Only official OEM publications and government portals are cited.
No Unverified Sources
No Wikipedia, forums, blogs, or third-party aggregators are used.
Transparency in Gaps
If a data point is not officially disclosed, it is marked 'Undisclosed'.
Regulatory Stability
EU regulations are referenced using CELEX identifiers for long-term stability.
HONDA Official Site
Owner literature, service manuals, technical releases, and plant documentation.
EUR-Lex
EU emissions and type-approval regulations (e.g., CELEX:32007R0715, CELEX:32017R1151).
GOV.UK: Vehicle Approval & V5C
UK vehicle approval processes, import rules, and MoT guidance.
DVLA: Engine Changes & MoT
Official guidance on engine swaps and inspection implications.
Vehicle Certification Agency (VCA)
UK type-approval authority for automotive products.
Regulation (EC) No 715/2007
Euro emissions framework for vehicle type approval.
Commission Regulation (EU) 2017/1151
WLTP and RDE testing procedures for emissions certification.
GOV.UK: Vehicle Approval
UK compliance and certification requirements for imported and modified vehicles.
VCA Certification Portal
Type-approval guidance and documentation.
Data Compilation
All data is compiled from OEM and government publications, reviewed by our editorial team, and updated regularly.
Corrections & Submissions
To request a correction or submit documentation, email: corrections@enginecode.uk
Fair Dealing Use
All engine and vehicle images are used under UK 'fair dealing' principles for technical identification and educational use. Rights remain with their respective owners.
Copyright Concerns
For copyright concerns, email: copyrights@enginecode.uk
GDPR Compliance
EngineCode.uk complies with UK GDPR. We do not collect personal data unless explicitly provided.
Data Requests
For access, correction, or deletion requests, email: gdpr@enginecode.uk
Trademark Notice
All trademarks, logos, and engine codes are the property of their respective owners. Use on this site is strictly for reference and identification.
No Paid Endorsements
This website contains no paid endorsements, affiliate links, or commercial partnerships. We do not sell parts or services.
Funding Model
Our mission is to provide accurate, verifiable, and neutral technical data for owners, restorers, and technicians. This site is self-funded.
All specifications and compatibility data verified against officialHONDA documentation and EU/UK regulatory texts. Where official data is unavailable, entries are marked “Undisclosed“ .
All external links open in new tabs. Please verify current availability of resources.
