Honda Gasoline Engine Series Part XI: Inline-Four A-Series Engines

Honda Gasoline Engine Series Part XI: Inline-Four A-Series Engines
Original | Honda Enthusiasts Journal | Updated: 2024-11-15, 11:00:00

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The Honda A-Series: The First Categorized Inline-Four Engine Family

In our previous article, we dedicated an entire section to the ZC engine, a pivotal development in Honda’s engine lineup during the 1980s. The ZC engine marked the beginning of a systematic approach to Honda's engine classifications based on displacement and valvetrain architecture. The first engine series to embody this philosophy was the A-Series inline-four engines.

Introduction of the A-Series

The A-Series made its debut in 1985, equipping the third-generation Honda Accord (CA1) with the A18A engine. Its design evolved from Honda’s Ex-series engines, retaining key features such as:

👉 Two intake and one exhaust valve per cylinder.
👉 Side-mounted spark plug position adjacent to the exhaust valves.
👉 Cast iron cylinder block, marking Honda’s last use of this material before transitioning to all-aluminum engine construction.

The A-Series family included three displacement variants: A16A, A18A, and A20A. These engines featured a combination of cast iron blocks and aluminum cylinder heads with SOHC valvetrains and 12 valves.

🚗 Applications of the A-Series

The A-Series powered models like the third-generation Accord and the second-generation Prelude.

Key Specifications of the A18A (1985)

📌 Displacement: 1,829cc
📌 Valvetrain: SOHC, two intake valves, one exhaust valve per cylinder
📌 Fuel Delivery: Carbureted
📌 Power Output: 110 hp @ 5,800 rpm
📌 Torque: 15.2 kgm @ 3,500 rpm

Despite its respectable performance for the era, the A18A's design featured limitations, such as spark plug placement adjacent to the exhaust manifold—a configuration prone to overheating.

The Evolution: A20A

In 1986, Honda introduced the A20A, primarily for export markets, powering third-generation Accord models like the CA5.

A20A Variants

👉 Carbureted Models: A20A1 and A20A2

• Power Output: 105 hp @ 5,500 rpm
• Torque: 15.5 kgm @ 3,500 rpm§§

👉 Fuel Injected Models: A20A3 and A20A4

• Features: Equipped with PGM-Fi and OBD-0 engine management.
• Power Output: 120 hp @ 5,800 rpm
• Torque: 16.9 kgm @ 4,000 rpm

Engineering Highlights of the A-Series

✔️ Legacy Technology: The rocker arm design laid the foundation for Honda's iconic VTEC system.
✔️ Durability: The A-Series was robust, even inspiring performance builds such as carbureted quad-throttle setups.§§§

The Short Life of the A-Series

The A-Series engines had a brief production run, from 1985 to 1990, as they were overshadowed by the B-Series engines (like the B20A) and eventually replaced by the more advanced F-Series.

Why the A-Series Was Short-Lived:

⚙️ The B-Series offered DOHC configurations and higher performance.
⚙️ The F-Series brought a leap forward in efficiency and engineering sophistication.

🌟 Key Takeaways:

🔹 The A-Series engines served as Honda’s first categorized inline-four engine family, bridging the gap between the Ex-series and modern engine lineups.
🔹 Though short-lived, they left a legacy of innovation and served as a precursor to Honda’s future advancements.

What’s next? Stay tuned as we explore the Honda F-Series engines in our upcoming article!