The Honda B20A2 is a 1,958 cc, inline‑four naturally aspirated petrol engine produced between 1987 and 1991. It features a dual overhead camshaft (DOHC) 16‑valve design with Honda's PGM‑FI electronic fuel injection, delivering a balance of smooth power and efficiency for its era. The engine's high‑revving nature, enabled by its 81.0 mm × 95.0 mm bore and stroke, provides strong top‑end power for spirited driving.
Fitted primarily to the third‑generation Prelude (BA4/BA8) in Si and 2.0Si trims for the North American and Japanese markets, the B20A2 was engineered for drivers seeking refined performance and handling balance. Emissions compliance for its production period was achieved through precise fuel metering and exhaust gas recirculation (EGR), meeting applicable US Federal and Japanese standards.
One documented area for technician awareness is the potential for distributor shaft seal failure, leading to oil leaks into the distributor cap, as noted in Honda Service Bulletin 91-068. This issue, often linked to seal material degradation over time, can cause misfires and starting difficulties. No major generational updates were issued for this engine before its discontinuation.
Honda
Production years 1987–1991 meet applicable US Federal and Japanese emissions standards for their respective markets (Honda Emissions Doc. US-FED-87).
The Honda B20A2 is a 1,958 cc inline‑four naturally aspirated petrol engine engineered for sporty coupes (1987-1991). It combines DOHC valvetrain with PGM-FI fuel injection to deliver smooth, high-revving power. Designed to meet contemporary US Federal and Japanese emissions standards, it balances performance character with reliability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,958 cc | |
| Fuel type | Petrol (Gasoline) | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally Aspirated | |
| Bore × stroke | 81.0 mm × 95.0 mm | |
| Power output | 97 kW (132 PS) @ 5,800 rpm | |
| Torque | 169 Nm @ 4,500 rpm | |
| Fuel system | PGM-FI (Programmed Fuel Injection) | |
| Emissions standard | US Federal / Japanese 1987 Standards | |
| Compression ratio | 9.4:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven | |
| Oil type | Honda 10W-30 or 10W-40 | |
| Dry weight | Approx. 135 kg |
The DOHC design offers a smooth, rev-happy character but requires strict adherence to the 60,000-mile timing belt replacement interval to prevent catastrophic interference engine damage. The PGM-FI system demands a healthy battery and charging system for optimal operation. Using the specified 10W-30 or 10W-40 oil is recommended. The distributor-mounted ignition system is susceptible to oil leaks from the shaft seal, necessitating periodic inspection per Honda SIB 91-068.
Oil Specs: Requires Honda 10W-30 or 10W-40 motor oil (Honda Owner's Manual). API SF/CC or equivalent specification.
Emissions: Meets 1987-1991 US Federal and Japanese emissions standards (Honda Emissions Doc. US-FED-87).
Power Ratings: Measured under SAE J1349 standards for US market applications (Honda TIS Doc. H-B20-003).
Honda Technical Information System (TIS): Docs H-B20-001, H-B20-002, H-B20-003
Honda Service Bulletin 91-068
Honda Emissions Documentation: US-FED-87
SAE International: J1349 Engine Power Certification Standards
The Honda B20A2 was developed for Honda's Prelude (3rd Gen) platform with transverse mounting. This engine featured specific calibrations for the Prelude's chassis and was not shared with other contemporary Honda models. 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 H-B20-004). The 8th VIN digit for B20A2-equipped Preludes is typically 'E'. Visually, the engine features a black valve cover with "DOHC" and "PGM-FI" branding. Differentiation from the carbureted B20A1 is clear via the presence of fuel injectors and the ECU harness. The distributor is mounted at the rear of the cylinder head.
The B20A2's primary reliability risk is timing belt failure due to age or missed service intervals. Honda internal service data indicates a high correlation between neglected belt changes and engine seizure. The distributor shaft seal is another known wear item, with failure leading to ignition faults. Adherence to the maintenance schedule is paramount for longevity.
Analysis derived from Honda technical bulletins (1987-1991) and preliminary NHTSA owner complaint data (archived). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA B20A2.
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.
