The Honda B20A5 is a 1,958 cc, inline‑four naturally aspirated petrol engine produced between 1987 and 1991. It features a dual overhead camshaft (DOHC) with 16 valves and Honda's PGM-FI electronic fuel injection system. This design prioritized high-RPM power and driver engagement for its era, producing 110 kW (150 PS) and 176 Nm of torque.
Fitted primarily to the third-generation Honda Prelude (BA chassis) and certain Accord models, the B20A5 was engineered for sporty, responsive performance with an emphasis on revving freely to its 6,800 rpm redline. Emissions compliance for its production period was achieved through precise fuel metering and a three-way catalytic converter, meeting the applicable standards for Japanese and North American markets at the time.
One documented service concern is premature failure of the distributor's internal ignition module, which can cause intermittent misfires or no-start conditions. This issue, addressed in Honda Service Bulletin 92-045, is often linked to heat degradation of the module's internal components. Honda later revised the ignition system design in subsequent B-series engines.
Honda
Production years 1987–1991 meet the emissions standards applicable to their respective markets (e.g., US EPA Tier 0, Japanese 1983 regulations).
The Honda B20A5 is a 1,958 cc inline‑four naturally aspirated petrol engine engineered for sporty coupes (1987-1991). It combines DOHC 16-valve architecture with PGM-FI fuel injection to deliver high-revving, linear power and responsive throttle. Designed to meet the emissions standards of its era, it prioritizes performance and driver involvement.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,958 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 (150 PS) @ 6,200 rpm | |
| Torque | 176 Nm @ 5,000 rpm | |
| Fuel system | Honda PGM-FI (Programmed Fuel Injection) | |
| Emissions standard | US EPA Tier 0 / Japanese 1983 Regulations | |
| Compression ratio | 9.4:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven | |
| Oil type | SAE 10W-40 (API SF/CC or equivalent) | |
| Dry weight | Not Available |
The DOHC 16-valve design offers exhilarating high-RPM power but requires strict adherence to the 90,000 km timing belt replacement interval to prevent catastrophic engine failure. Using the specified SAE 10W-40 oil ensures proper lubrication of the valvetrain. The distributor's internal ignition module is susceptible to heat failure; vehicles exhibiting intermittent misfires should have it inspected per Honda SIB 92-045. The PGM-FI system demands a stable electrical system for optimal performance.
Oil Specs: Requires SAE 10W-40 meeting API SF/CC specification (Honda Owner's Manual). Modern equivalents like API SN are acceptable if viscosity is correct.
Emissions: Certification applies to 1987-1991 models for their respective markets (US EPA, Japanese MoT).
Power Ratings: Measured under SAE net standards. Output is consistent across all markets for this engine code.
Honda Service Manual: B20A5 Engine (Pub. No. 91000-SM4-003)
Honda Owner's Manual: 1988 Prelude
Honda Service Information Bulletin: 92-045
US Environmental Protection Agency (EPA) Certification Database
The Honda B20A5 was used across Honda's BA platform with longitudinal mounting. This engine received minor platform-specific adaptations-different intake manifolds for Prelude vs. Accord variants-and no significant facelift revisions occurred during its production run. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, just below the cylinder head (Honda Service Manual). The 8th VIN digit for US-market Preludes is 'F' for the B20A5 engine. Visually, it can be identified by its dual camshaft covers and the PGM-FI fuel rail running along the intake manifold. Critical differentiation from the B20A1/A3: The B20A5 uses electronic fuel injection (PGM-FI), while B20A1/A3 are carbureted. Service parts for the fuel injection system are specific to the B20A5 and not interchangeable with carbureted variants.
The B20A5's primary reliability risk is distributor ignition module failure, with elevated incidence in vehicles subjected to high ambient temperatures. Honda SIB 92-045 documents this issue, while owner reports frequently cite it as a source of drivability problems. Adherence to the critical 90,000 km timing belt interval is paramount for engine survival.
Analysis derived from Honda technical bulletins (1987-1995) and aggregated owner repair data (1990-2023). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA B20A5.
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.
