Ford Kent engine
The Ford Kent engine is a family of pushrod-operated, inline-four internal combustion engines developed by Ford of Britain, introduced in 1959 as a replacement for earlier sidevalve designs and renowned for its durability, tunability, and extensive application in compact vehicles and racing.[1][2] Named after the Kent county in England—home to a key Ford engineer—the engine debuted in the Ford Anglia with a 997 cc displacement, producing 39 horsepower at 5,000 rpm from its cast-iron block and cylinder head.[3][1] Over its production run until 2002, it evolved through pre-Crossflow and Crossflow variants, powering a wide array of Ford models while becoming a cornerstone of affordable motorsport.[2][3] The engine's early pre-Crossflow iterations, produced from 1959 to 1967, featured a non-crossflow cylinder head where intake and exhaust ports were on the same side, limiting efficiency but offering simplicity for models like the Anglia and Prefect.[1] Displacements ranged from 997 cc to 1.5 liters, with bore and stroke dimensions such as 80.96 mm × 48.41 mm for the base 1.0-liter version, and power outputs typically between 39 and 65 horsepower depending on the application.[2] In 1967, Ford introduced the Crossflow head design, which separated intake and exhaust ports to opposite sides for better airflow and cooling, marking a significant upgrade that extended the engine's lifespan and performance potential.[3][1] This version added variants like the 1.1-liter (1,098 cc), 1.3-liter (1,298 cc with Heron combustion chambers), and popular 1.6-liter (1,598 cc with five main bearings in later "uprated" forms), achieving up to 135 horsepower in tuned configurations such as the Caterham Seven Supersprint.[2][3] Widely adopted in Ford's European lineup, the Kent engine propelled vehicles including the Cortina, Escort, Capri, Transit van, and later the Fiesta via the related Valencia adaptation (introduced in 1976 for transverse mounting).[1][3] Its robustness made it a favorite for aftermarket modifications and specialist cars from manufacturers like Lotus (in the Seven and Elan), TVR, and Morgan.[2] In the 1990s, fuel-injected Endura-E derivatives powered the Ford Ka until 2002, while production continued in Brazil and racing restomod versions were reintroduced in the U.S. in 2010.[3][2] The Kent engine's motorsport legacy is particularly notable, serving as the standardized powerplant for Formula Ford from 1967 to 2010, where its 1.6-liter Crossflow variant enabled emerging talents like Ayrton Senna, Michael Schumacher, and Mika Häkkinen to hone their skills on equal machinery.[1] It influenced high-performance derivatives, such as the Lotus-Ford Twin Cam and Cosworth BDA/BDT engines, which pushed outputs to over 800 horsepower in rally and circuit applications like the Ford RS200 and Formula 2/3 series.[2][1] Today, the engine remains a staple in historic racing, kit cars like the Caterham 7 and Birkin, and enthusiast restorations due to its parts availability and modifiable nature.[3][2]Overview
Naming and Origins
The Ford Kent engine family is named for the county of Kent in southeastern England, home to lead engineer Alan Worters; the engines were primarily assembled at Ford's Dagenham plant in neighboring Essex, across the River Thames.[4][1] Developed by Ford of Britain in the late 1950s, the Kent engine was specifically engineered as a replacement for outdated inline-four designs, debuting in 1959 to power the compact Ford Anglia (model 105E).[2][1] Production commenced that same year at the Dagenham facility, marking the start of a long-lived engine lineage that spanned over four decades in automotive applications until 2002, while continuing in specialized uses such as racing into the 2010s.[2][5] At its core, the Kent series consists of overhead-valve (OHV) inline-four-cylinder gasoline engines featuring a cast-iron block and cylinder head, providing a robust and cost-effective foundation for various displacements and configurations.[4] This foundational architecture later evolved into variants like the Crossflow and Valencia models, adapting to different vehicle layouts and performance needs.[1]Design Principles
The Ford Kent engine family embodies fundamental engineering principles centered on simplicity, durability, and cost-effective production for mass-market vehicles. At its core, it features an overhead valve (OHV) inline-four cylinder layout with a cast-iron block and cylinder head, employing pushrod actuation via a single chain-driven camshaft mounted in the block. This configuration, with rockers operating the valves, prioritizes mechanical reliability and ease of maintenance over high-revving performance, making it suitable for everyday automotive use.[6][4] Bore dimensions across the family generally span 74 mm to 80.96 mm, while stroke lengths vary from 48.41 mm to 77.62 mm, enabling a range of displacements from under 1.0 L to 1.6 L without major redesigns. These engines operate on gasoline, with fuel delivery primarily handled by carburetors such as Solex or Weber units in most variants, though electronic fuel injection appeared in later adaptations like the Endura-E. Compression ratios typically range from 8.0:1 to 9.5:1, supporting power outputs from 39 hp (29 kW) in the smallest units to up to 111 hp (83 kW) in higher-performance configurations, balancing efficiency and drivability.[6][1] Shared components underscore the family's modular design, including a nodular iron crankshaft supported by three or five main bearings (progressing to five in later models for enhanced stability) and a robust valvetrain capable of withstanding prolonged operation. Emphasis on durability is evident in features like thicker cylinder walls in upgraded blocks and reinforced bearing caps, ensuring longevity in demanding applications while keeping manufacturing straightforward for high-volume production. Adaptations, such as the crossflow cylinder head in later variants, refined airflow without altering the foundational pushrod architecture.[6][7]Pre-Crossflow Engines
Development and Features
The Ford Kent engine debuted in 1959 as an inline-four overhead valve (OHV) unit with a non-crossflow cylinder head design inspired by earlier side-valve architectures, featuring parallel intake and exhaust ports positioned on the same side of the head for a reverse-flow configuration.[8] This layout utilized a cast-iron block and head with three main bearings, prioritizing simplicity and cost-effective manufacturing for small economy cars.[9] The engine family offered displacements ranging from 1.0 L (997 cc) to 1.5 L (1,498 cc), including variants at 1.2 L (1,198 cc) and 1.3 L (1,340 cc), achieved primarily through stroke adjustments while maintaining a consistent 80.96 mm bore.[10] Power outputs varied by displacement and application, with the base 1.0 L version producing 39 hp (29 kW) at 5,000 rpm, while larger units reached up to 65 hp (48 kW) in the 1.5 L configuration, reflecting modest tuning via carburetion and compression ratios around 8.9:1.[8] In 1962, Ford updated the design for broader use, introducing a stronger cast-iron block with thicker walls, a reinforced cylinder head, and a five-main-bearing crankshaft to enhance durability under higher loads, particularly in mid-size models.[9] These revisions improved reliability without altering the fundamental non-crossflow architecture, allowing the engine to support increasing production demands. Manufactured at Ford's Dagenham plant, the pre-crossflow Kent engines remained in production through the 1960s and were gradually phased out in the 1970s as more efficient designs emerged.[11] This evolution paved the way for the 1967 crossflow redesign, which improved breathing and thermal efficiency.[3]Applications and Production
The pre-crossflow Kent engines found primary application in Ford's compact and mid-size models during the early 1960s. The 1.0 L (997 cc) variant powered the Ford Anglia 105E from its introduction in 1959 until 1967, serving as the standard engine in this popular small saloon and estate car, with a 1.2 L (1,198 cc) option from 1962.[12] The 1.3 L (1,340 cc) was fitted to the Ford Consul Classic saloon initially (1961–1962), with the 1.5 L (1,498 cc) replacing it from 1962 to 1963; the early Ford Corsair (1964–1965) used the 1.5 L (1,498 cc).[13][14] In mid-size cars, the 1.5 L (1,498 cc) version equipped the early Ford Cortina Mk1 (1962–1966), contributing to its success as a bestseller with options for standard, deluxe, and GT trims. The 1.5 L engine also appeared in the short-lived Consul Capri coupé (1961–1964), a sportier two-door derivative of the Classic lineup. These engines were three-bearing designs optimized for everyday driving, delivering power outputs around 39–60 bhp depending on displacement and tuning.[15][13] Production of pre-crossflow Kent engines ramped up significantly in the early 1960s, with over 1 million units manufactured by the mid-decade to support high-volume models like the Anglia, which alone exceeded 1 million vehicles by 1967, and the Cortina Mk1, which reached more than 1 million units during its run. The Consul Classic totaled 111,225 units, while the Corsair's initial inline-four phase contributed to its overall 310,000 production through 1970. These figures reflect Ford's Dagenham plant output, where the engines were built alongside vehicle assembly.[12][15][13][14] By the late 1960s, pre-crossflow production in Europe was phased out as the improved crossflow Kent variant, introduced in 1967, superseded it in new models like the later Cortina Mk2 and Escort. Engines continued in limited export markets, including Australia, where they powered local variants of the Anglia and Cortina until the early 1970s. Minor applications extended to non-Ford vehicles, such as the Marcos 1500 GT sports car (1960s) and the Turkish Otosan Anadol (1.2 L version, 1966–1975).[8]Crossflow Engines
Introduction and Improvements
The Ford Kent Crossflow engine was introduced in 1967 as a significant redesign of the original Kent engine family, featuring a crossflow cylinder head that positioned the intake and exhaust ports on opposite sides of the head to enhance airflow, breathing, and overall efficiency compared to the pre-Crossflow versions.[16] This overhead-valve (OHV) inline-four architecture, shared with earlier Kent designs, allowed for better thermal management and reduced backpressure, contributing to improved power delivery across the range.[17] In 1970, Ford further refined the engine with updated cylinder blocks for the 1.3 L and 1.6 L variants, incorporating thicker walls, stronger square main bearing caps, larger diameter cam followers, wider cam lobes, and modified crankshaft seals to boost durability and reliability under higher loads.[16] These changes, marked by the A711 block for 1.3 L and A711M for 1.6 L castings, addressed weaknesses in earlier blocks while maintaining the compact, lightweight design principles of the Kent series.[18] The Crossflow lineup included displacements of 1.1 L (1,098 cc), 1.3 L (1,298 cc), and 1.6 L (1,599 cc), with the 1.6 L version delivering typically 68–86 hp in standard form depending on the model.[19] This represented a notable power increase over pre-Crossflow equivalents, and the engine's simple construction lent itself to tuning, often exceeding 100 hp with modifications like porting and cam upgrades.[20] Production of the Crossflow Kent continued in various configurations through the early 1980s, powering a range of Ford models before evolving into derivative forms. The Crossflow design influenced later derivatives like the Valencia engine.[19]Specifications and Applications
The Crossflow Kent engine was offered in several displacements, primarily 1.1 L, 1.3 L, and 1.6 L, with power outputs varying by application and tune. The 1.1 L version typically produced 53 hp, while the 1.3 L delivered around 60 hp, and the 1.6 L ranged from 68 to 86 hp depending on the configuration. These engines featured a standard compression ratio of approximately 9.0:1, contributing to their reliable performance in everyday driving.[21][22][23]| Displacement | Power Output | Typical Application Example |
|---|---|---|
| 1.1 L | 53 hp | Ford Escort base models |
| 1.3 L | 60 hp | Ford Cortina and Escort |
| 1.6 L | 68–86 hp | Ford Capri and Escort (including Mexico) |