22/01/2018
Jowett's Engine Evolution: Powering a Legacy
The Jowett company, a name synonymous with British motoring innovation from the early 20th century, carved a unique niche for itself through its distinctive and often remarkably capable engines. Founded by brothers Benjamin and William Jowett in Bradford, the company's journey from a cycle works to a motor manufacturer was underpinned by a consistent focus on engineering excellence, particularly in the realm of engine design. The enduring slogan, 'The Little Engine with the Big Pull,' perfectly encapsulates the philosophy that guided Jowett's powertrain development for decades.
The Dawn of Jowett Power: Early Innovations
The Jowett brothers' foray into the automotive world began with a practical solution to a common problem. In 1901, they developed an engine conversion for early voiturettes, offering a 55-degree V-twin engine designed to replace less robust 6-hp De Dion and 6½-hp Aster units. These early engines proved their mettle, demonstrating remarkable durability. One such unit was still in service driving a wood mill as late as 1914, a testament to the brothers' early engineering prowess.
Building on this foundation, 1904 saw the introduction of a second power unit: a 950 cc straight-three engine. This air-cooled unit was notable for its overhead valves and a robust five-bearing crankshaft. It also featured an innovative ignition system that claimed to intensify the spark, and remarkably, could be run in either direction of rotation. This early experimentation laid the groundwork for their ambitious goal of creating 'the world's first light-car' with an operating cost of just a penny a mile.
The Iconic Flat-Twin: The Heart of the Jowett Legend
The car that truly defined Jowett's early success was powered by a water-cooled, horizontally opposed two-cylinder engine. This compact unit, initially of 816cc, was mounted in unit with a three-speed gearbox and employed a worm gear for final drive. The Jowett brothers were particularly proud of this engine's balance, claiming it rivalled any power unit with fewer than six cylinders. To demonstrate this, they would famously balance a pencil on the radiator cap, a feat that showcased the engine's exceptional smoothness.
This horizontally opposed twin-cylinder configuration became the hallmark of Jowett cars for many years. In the post-World War I era, to comply with the 1920 Road Traffic Act and its £1 per horsepower taxation, the bore was increased, bringing the engine's output to a tax rating of 7 hp. The swept volume was raised to 907 cc, and this revised unit continued to power models like the Long Four and the early saloons. Despite the engine's inherent virtues, the fixed cylinder heads did present challenges for routine maintenance, and the braking systems, while improved over time, were initially considered somewhat primitive compared to the rest of the industry.
Technical Specifications of Early Jowett Engines
| Engine Type | Capacity (cc) | Cylinders | Cooling | Key Features |
|---|---|---|---|---|
| Early Conversion | Not specified | 2 (V-twin) | Not specified | 55-degree V-angle, replacement for 6-hp units |
| Early Three-Cylinder | 950 | 3 (Inline) | Air-cooled | Overhead valves, five-bearing crankshaft, novel ignition |
| Original Light Car Engine | 816 | 2 (Horizontally opposed) | Water-cooled | Exceptional balance, unit with gearbox |
| Post-War 7 hp | 907 | 2 (Horizontally opposed) | Water-cooled | Increased capacity, 7 hp tax rating, fixed cylinder heads |
| Later 7 hp (1936) | 946 | 2 (Horizontally opposed) | Water-cooled | Bored out from 907cc, 8 hp tax rating |
Endurance and Development: The Jowett's Toughness
The robustness of the Jowett engine was famously demonstrated in the arduous 1926 'Wait and See' expedition across the heart of Africa. Two standard long-wheelbase 7 hp Jowetts, equipped with 'Safari' bodies, successfully completed the 3800-mile journey from Lagos to Massawa in just 60 days. This remarkable feat, undertaken with loaded trailers and through challenging desert terrain, highlighted the dependability of the Jowett's engineering, proving that 'The Little Engine with the Big Pull' could indeed tackle extreme conditions.
However, as the automotive industry progressed, Jowett faced challenges. While the company was an early adopter of front-wheel brakes in 1929, the push for more advanced braking systems and the inherent simplicity of the twin-cylinder engine meant that Jowett cars gradually fell behind some competitors in performance and braking capabilities. Ben Jowett, ever the innovator, was actively involved in experimental workshops, focusing on improvements like four-wheel braking systems and, in the late 1920s, a high-compression version of their improved power unit for a sports model. This sports variant, however, gained a reputation as a 'gasket-blower' due to its demanding nature, though it still achieved notable success, including setting a 12-hour record at Brooklands despite multiple gasket failures.
The 1930s saw further refinements. The 7 hp model's flat-twin engine was bored out to 946 cc, increasing its tax rating to 8 hp. The company also experimented with a vertical four-cylinder engine for the rare La Roche model. More significantly, Jowett introduced a new horizontally opposed four-cylinder engine in 1936. This 1166 cc unit was rated at 10 hp and offered improved performance, with a top speed of 65 mph. While initial models like the Jupiter and Jason featured aggressive styling, a more conventional version of this flat-four engine was later fitted to updated chassis, demonstrating Jowett's ability to adapt and evolve its engine offerings.
Post-War Powerhouse: The Javelin and Jupiter Engines
The Jowett story took a significant turn after World War II with the development of the Javelin. Designed by Gerald Palmer, the Javelin was powered by a completely new, larger, horizontally opposed engine of 1486 cc. This sophisticated unit, featuring overhead valves and designed for smoothness and efficiency, was a departure from the long-serving flat-twin. The Javelin's engine proved its mettle, powering the car to victory in its class in the Monte Carlo Rally and the Spa 24-hour race, cementing its reputation for performance and reliability.
The sporty Jupiter model, a development of the Javelin, utilised a highly tuned version of the standard 1.5-litre four-cylinder horizontally opposed engine. Its success in endurance racing, including at Le Mans, further showcased the capabilities of Jowett's post-war powertrain design. Sadly, despite the advances in engine technology, Jowett's downfall came not from its engines, but from persistent issues with their self-designed gearboxes, leading to warranty claims and declining sales. The company ceased production in 1954, but the legacy of its engines, particularly the enduring flat-twin and the capable Javelin power unit, remains a significant chapter in British automotive history.
Frequently Asked Questions About Jowett Engines
- What was the most common Jowett engine?
The most iconic and long-serving engine was the horizontally opposed, two-cylinder flat-twin, famously known for its smooth operation and 'big pull'. This engine powered the majority of Jowett cars from their inception through to the post-war period, albeit with various capacity and minor design updates. - Which Jowett model used the 7hp engine?
The 7 hp engine, typically the 907cc or later 946cc flat-twin, was used across a wide range of Jowett models from the 1920s through to the early 1930s, including the popular Long Four, Saloon, and various two and four-seater variants. - Did Jowett ever make a four-cylinder engine?
Yes, Jowett developed and produced horizontally opposed four-cylinder engines. A notable example was the 1166cc, 10 hp unit introduced in 1936. The post-war Javelin and Jupiter models also featured sophisticated horizontally opposed four-cylinder engines of 1486cc. - What made the Jowett engine special?
Jowett engines were renowned for their exceptional balance, particularly the horizontally opposed twin-cylinder units, which allowed them to run with remarkable smoothness. They were also praised for their durability and economy, living up to the 'The Little Engine with the Big Pull' slogan. - When did Jowett stop using the flat-twin engine?
While the Javelin and Jupiter models introduced a new generation of horizontally opposed four-cylinder engines, the classic flat-twin design continued to be used in the Bradford van even as the company closed its doors in 1954, demonstrating its remarkable longevity.
The story of Jowett engines is one of consistent engineering focus, durability, and a unique approach to automotive power. From their humble beginnings to their successful post-war offerings, Jowett's commitment to quality and innovation left an indelible mark on the automotive landscape.
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