Willys CJ2A: The "Go Devil" Engine Explained

The Willys CJ2A is a name synonymous with ruggedness, versatility, and the very beginnings of the civilian Jeep era. For many, the allure of these classic machines lies not just in their iconic design but also in the robust, no-nonsense engineering that powers them. At the core of the CJ2A's capabilities is its powerplant: the legendary "Go Devil" engine. While often referred to by this evocative nickname, understanding the specifics of this four-cylinder marvel is key to appreciating its enduring legacy.

This article delves deep into the engine that defined the early Willys Jeeps, exploring its design, performance, and the reasons behind its widespread adoption. We'll cover what makes it tick, common maintenance points, and why its reputation for reliability is still celebrated today.

The "Go Devil" Engine: A Closer Look

The engine found in the Willys CJ2A is the Willys L-134. This overhead-valve (OHV) four-cylinder engine was a workhorse, designed for durability and simplicity. Its displacement of 134.2 cubic inches (2.2 litres) provided ample torque for its intended use, whether that was on the farm, in industrial settings, or for general utility work. The "Go Devil" moniker, though often applied to this engine, was more famously associated with its predecessor in the military MB models, but the L-134 carried on this spirit of dependable performance.

Key Specifications of the Willys L-134 Engine:

Understanding the technical details helps paint a clearer picture of the L-134's capabilities:

The beauty of the L-134 lies in its straightforward design. This made it relatively easy to maintain and repair, a crucial factor for vehicles used in remote or demanding environments. The robust construction meant that with proper care, these engines could last for a very long time, a testament to Willys-Overland's engineering prowess.

Evolution and Variations

While the CJ2A primarily featured the L-134, it's worth noting that Willys-Overland produced a range of engines during this period. For instance, the later CJ3 models and other Willys vehicles saw the introduction of the F-head Hurricane engine, which offered a slight increase in power and torque. However, for the CJ2A, the L-134 was the standard and most common engine.

It's important to distinguish the CJ2A's engine from those found in other Willys models or later Jeeps. For example, the 1958 Willys Jeep Station Wagon mentioned in some classifieds, which had a V-8 engine, is a different proposition entirely. The CJ2A is firmly rooted in the L-134's capabilities.

Why the "Go Devil" (L-134) Was So Successful

The success of the L-134 engine in the CJ2A can be attributed to several key factors:

• Simplicity: Fewer moving parts and a less complex design meant fewer potential points of failure.
• Durability: Built with robust materials, it could withstand significant stress and wear.
• Torque: The engine delivered good low-end torque, essential for crawling over obstacles and pulling loads.
• Availability of Parts: As a mass-produced engine for a popular vehicle, parts were generally accessible, especially for common wear items.
• Repairability: Its straightforward nature made it a favourite among mechanics and owners who performed their own maintenance.

The experience of a complete body-off restoration, as mentioned in the provided text, often includes a thorough rebuild of the original engine. Companies like Jasper Engines & Transmissions specialise in breathing new life into classic powerplants, ensuring they meet or exceed their original specifications. A rebuilt L-134, painted and detailed, can be a beautiful and reliable centrepiece for a restored CJ2A.

Maintenance and Common Issues

While the L-134 is a tough engine, like any mechanical component, it requires regular maintenance to perform optimally. Key maintenance points include:

• Oil Changes: Regular oil and filter changes are crucial for lubrication and cooling.
• Cooling System: Ensuring the radiator, hoses, and water pump are in good condition prevents overheating.
• Ignition System: Points, condenser, and spark plugs need regular inspection and adjustment or replacement.
• Carburettor Tuning: The Carter W-1 carburettor may require periodic cleaning and adjustment for optimal fuel mixture.
• Valve Adjustment: Over time, valve lash can change, requiring periodic adjustment to maintain efficiency and prevent damage.

Common issues encountered with older L-134 engines can include oil leaks (especially from the rear main seal), worn piston rings leading to oil consumption, and cooling system problems due to age. However, these are generally addressable with proper mechanical knowledge or professional assistance.

The L-134 in Context: Comparing with Other Willys Engines

It's interesting to see how the L-134 compares to other engines Willys used. The F-head Hurricane, introduced later, featured an "F" head design where both the intake and exhaust valves were on one side of the cylinder head, but the spark plug was in the centre of the combustion chamber. This design offered improved combustion efficiency and a slight power boost. For example, a 1956 Willys CJ5 with an "F" head would likely have a bit more pep than a CJ2A.

The mention of a V-8 engine in a 1958 Willys Jeep Station Wagon highlights the diversification Willys-Overland undertook. While powerful, these V-8s were a departure from the utilitarian four-cylinder engines that characterized the early Jeeps.

Restoration and Modernisation

Many enthusiasts undertaking a body-off restoration of a CJ2A will opt for a full rebuild of the original L-134 engine. This ensures authenticity and preserves the vehicle's original character. As seen in the example of the restored CJ2A, the engine was completely rebuilt by Jasper Engines & Transmissions, a reputable firm known for its quality engine work. The subtle gold metallic paint and clear coat add a touch of custom flair while respecting the original mechanicals.

Some owners also choose to modernise their Jeeps during restoration. This can include converting the electrical system from 6-volt to 12-volt (as seen in some of the classified examples), which improves starting reliability and allows for the use of more modern accessories. Electronic ignition can also replace the original points and condenser for more consistent spark delivery.

FAQs about the Willys CJ2A Engine

Q1: What is the official name of the "Go Devil" engine in a CJ2A?

A1: The engine commonly referred to as the "Go Devil" in the context of early Jeeps, and specifically in the CJ2A, is the Willys L-134, a 134.2 cubic inch, four-cylinder, overhead-valve (OHV) engine.

Q2: How much horsepower does the Willys L-134 engine produce?

A2: The L-134 engine typically produced around 60-63 brake horsepower (bhp) at approximately 2400 RPM.

Q3: Is the L-134 engine a good engine for off-roading?

A3: Yes, the L-134 is renowned for its robust build and excellent low-end torque, which are crucial characteristics for effective off-roading and utility work. Its simplicity also makes it reliable in challenging conditions.

Q4: What is the difference between the L-134 and the F-head Hurricane engine?

A4: The L-134 is an L-head (or flathead) design in terms of valve placement relative to the cylinder bore, though it's an OHV design overall. The F-head Hurricane has both intake and exhaust valves on the same side of the cylinder head, with the spark plug centrally located in the combustion chamber, offering improved efficiency and a slight power increase.

Q5: Can I upgrade the engine in my CJ2A?

A5: While many owners prefer to keep the original L-134 for authenticity, engine swaps are possible. However, this is a significant modification that requires careful consideration of the vehicle's drivetrain and chassis. Common upgrades might involve swapping to a later Willys F-head engine or even more modern powertrains, but this deviates from the original CJ2A specifications.

Conclusion: An Engine for the Ages

The Willys L-134, the heart of the CJ2A, is far more than just a collection of metal parts; it's a piece of automotive history. Its design prioritized strength, simplicity, and unwavering dependability, making it the perfect companion for the versatile CJ2A. Whether you're admiring a meticulously restored example or hearing tales from those who have put these Jeeps through their paces, the "Go Devil" engine remains a symbol of enduring quality and the spirit of adventure that defines the Willys Jeep legacy. Understanding this engine is fundamental to appreciating the entire CJ2A experience.