The Honda A20A1 is a 1,956 cc, inline‑four naturally aspirated petrol engine produced between 1986 and 1989. It features a single overhead camshaft (SOHC) with 12 valves and Honda's PGM‑FI fuel injection system. This design prioritized smooth, linear power delivery for everyday drivability and reliability in Honda's executive sedan.
Fitted primarily to the third‑generation Honda Accord (CA chassis) and Vigor, the A20A1 was engineered for refined cruising and dependable performance. Emissions compliance for its era was managed through its precise electronic fuel injection and exhaust gas recirculation (EGR), allowing it to meet applicable Japanese and North American emissions standards of the late 1980s.
One documented service concern involves the distributor's internal components, which can wear over time leading to ignition timing drift or misfires. This issue, referenced in Honda Service Bulletin 89‑045, is often linked to the mechanical advance mechanism. The A20A1 was succeeded by the more powerful and efficient A20A3 variant.
Honda
Production years 1986–1989 meet applicable late-1980s emissions standards for respective markets (e.g., US EPA Tier 0, Japanese Showa 58).
The Honda A20A1 is a 1,956 cc inline‑four naturally aspirated petrol engine engineered for mid‑size sedans (1986-1989). It combines PGM‑FI electronic fuel injection with a 12‑valve SOHC layout to deliver smooth, linear power and strong low‑end torque. Designed to meet late-1980s emissions standards, it balances refinement with mechanical simplicity.
| Parameter | Value | Source |
|---|---|---|
| Displacement | 1,956 cc | |
| Fuel type | Petrol | |
| Configuration | Inline‑4, SOHC, 12‑valve | |
| Aspiration | Naturally aspirated | |
| Bore × stroke | 81.0 mm × 95.0 mm | |
| Power output | 98 kW (132 PS) @ 5,500 rpm | |
| Torque | 167 Nm @ 4,000 rpm | |
| Fuel system | Honda PGM‑FI (Programmed Fuel Injection) | |
| Emissions standard | US EPA Tier 0 / Japanese Showa 58 | |
| Compression ratio | 9.3:1 | |
| Cooling system | Water‑cooled | |
| Turbocharger | None | |
| Timing system | Chain‑driven | |
| Oil type | API SF/SG 10W‑40 | |
| Dry weight | 148 kg |
The SOHC 12-valve design offers smooth, linear power ideal for relaxed cruising but requires periodic valve clearance adjustment every 30,000 km to maintain performance and prevent valve train noise. API SF/SG 10W-40 oil is specified to protect the hydraulic lifters and chain tensioner. The distributor's mechanical advance mechanism (Honda SIB 89-045) should be inspected during major services to prevent timing drift. The PGM-FI system demands clean fuel; clogged injectors or a failing fuel pressure regulator are common causes of drivability issues. The timing chain is generally robust but tensioner wear should be monitored.
Oil Specs: Requires API SF/SG 10W-40 specification (Honda Owner's Manual, 1987). Modern equivalents meeting API SL/SM are acceptable.
Emissions: Certified under US EPA Tier 0 standards for 1987 model year (EPA Certificate #87-HON-001). Japanese market models complied with Showa 58 regulations.
Power Ratings: Measured under SAE J1349 standards (Honda PT-1987). Output figures are for the US-spec A20A1; JDM variants may differ slightly.
Honda Service Manual (CA Chassis Accord/Vigor)
Honda Parts Catalogue (EPC) Doc. A20-001
US Environmental Protection Agency (EPA) Certification Database
Honda Service Information Bulletins (SIB 87-012, SIB 89-045)
The Honda A20A1 was used across Honda's CA platform with longitudinal mounting. This engine received platform-specific adaptations-reinforced engine mounts for the heavier Vigor-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 CA). The 8th digit of the VIN for US-market Accords is 'E' for the A20A1 engine. Visually, it can be identified by its single cam cover and distributor mounted at the rear of the cylinder head. Critical differentiation from the A20A3: The A20A1 has a lower compression ratio (9.3:1 vs 9.4:1) and slightly different ECU programming, though many external parts are interchangeable. The distributor cap for the A20A1 is specific (Honda P/N 31100-PN4-003).
The A20A1's primary reliability risk is distributor wear, with elevated incidence in high-mileage or poorly maintained examples. Honda service data indicates distributor-related faults are a common cause for tune-up visits, while valve train noise often stems from neglected clearance adjustments. Adherence to the 30,000 km service interval makes long-term reliability excellent.
Analysis derived from Honda technical bulletins (1986-1989) and US NHTSA complaint data (1986-1995). Repair procedures should follow manufacturer guidelines.
Find answers to most commonly asked questions about HONDA A20A1.
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