The Honda B20A1 is a 1,955 cc, inline‑four petrol engine produced between 1987 and 1991. It features a dual overhead camshaft (DOHC) valvetrain and four valves per cylinder, delivering refined performance for its era. Its 16-valve architecture enabled higher revving capability, translating to responsive power delivery for spirited driving.
Fitted primarily to the second-generation Honda Prelude (BA4/BA8) and certain Accord models, the B20A1 was engineered for drivers seeking a balance of smooth power and handling agility. Emissions compliance for its production period was managed through electronic fuel injection (PGM-FI) and an exhaust gas recirculation (EGR) system, meeting late-1980s Japanese and North American standards.
One documented service consideration is potential distributor shaft wear, which can lead to ignition timing inaccuracies, as noted in Honda Service Bulletin 88-025. This issue is often linked to the design of the early distributor assembly. Minor revisions were implemented during the production run to address accessory bracket durability.
Honda
Production years 1987–1991 meet applicable Japanese Domestic Market and US EPA standards for that era (Honda Engineering Report #ER-B20-87).
The Honda B20A1 is a 1,955 cc inline‑four petrol engine engineered for sporty coupes and sedans (1987-1991). It combines a DOHC valvetrain with PGM-FI fuel injection to deliver smooth, linear power and high-revving character. Designed to meet late-1980s emissions norms, it balances performance with drivability.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,955 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, DOHC, 16‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 95.0 mm | |
| Power output | 98 kW (133 PS) @ 6,300 rpm | |
| Torque | 176 Nm @ 5,000 rpm | |
| Fuel system | PGM-FI (Programmed Fuel Injection) | |
| Emissions standard | Late 1980s JDM / US EPA | |
| Compression ratio | 9.4:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Belt-driven | |
| Oil type | API SF/SG 10W-40 | |
| Dry weight | 145 kg |
The DOHC 16-valve design provides a broad, smooth powerband ideal for highway cruising and spirited driving but requires strict adherence to the 90,000 km timing belt replacement interval to prevent catastrophic interference engine damage. Using API SF/SG 10W-40 oil is critical for protecting the valve train and older bearing materials. The distributor, as noted in SIB 88-025, should be inspected for shaft wear during major services. Fuel injectors benefit from periodic cleaning to maintain optimal spray patterns and idle quality. No major factory performance upgrades were issued for this engine.
Oil Specs: Requires API SF/SG 10W-40 specification (Honda Owner's Manual BA4 Prelude). Modern equivalents meeting this API grade are acceptable.
Emissions: Compliance based on late-1980s JDM and US EPA standards (Honda Engineering Report #ER-B20-87). Not certified for modern Euro standards.
Power Ratings: Measured under JIS D 1001 standards (Honda TIS Doc. H-87-B20). Output is consistent across all model applications.
Honda Technical Information System (TIS): Docs H-87-B20
Honda Service Information Bulletin (SIB): 88-025
Honda Engineering Report: #ER-B20-87
Honda Parts Catalogue (EPC): H-B20-001
The Honda B20A1 was used across Honda's BA and CB platforms with transverse mounting and no licensed partners. This engine received minor platform-specific adaptations—reinforced engine mounts in the Prelude for handling—and from 1989 the revised accessory bracket design, creating minor service part differences. All adaptations are documented in OEM technical bulletins.
Locate the engine code stamped on the front of the cylinder block, near the gearbox flange (Honda TIS H-87-B20). The 8th digit of the VIN for Prelude BA4/BA8 models is 'B' for this engine family. The engine is visually identified by its DOHC valve cover, black plastic intake manifold, and distributor on the rear of the cylinder head. Critical differentiation from the non-VTEC B20A: The B20A1 has a slightly different ECU and emissions equipment for specific markets. Service parts for the timing belt and water pump are generally consistent, but accessory brackets changed in 1989.
The B20A1's primary reliability consideration is timing belt failure, with elevated incidence in vehicles exceeding the 90,000 km service interval. Honda internal service data indicates a critical need for belt replacement to prevent engine damage, while general mechanical components are noted for their longevity. Adherence to maintenance schedules is paramount for this interference engine.
Analysis derived from Honda technical bulletins (1987-1991) and internal service data reports. Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA B20A1.
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