Ford Kent engine
|Ford Kent engine|
|Manufacturer||Ford Motor Company|
|Also called||Ford pre-crossflow
|Configuration||Pushrod straight 4|
|Cylinder block alloy||Iron|
|Cylinder head alloy||Iron|
|Fuel system||carburettor (later (92-on) versions were fuel injected)|
|Power output||39–111 bhp|
|Predecessor||Ford Sidevalve engine|
|Successor||Ford Zetec engine|
The Ford Kent is an internal combustion engine from British Ford. Originally developed in 1959 for the Ford Anglia, it is an in-line four-cylinder overhead-valve–type pushrod engine with a cast-iron cylinder head and block.
The Kent family can be divided into three basic sub-families; the original pre-Crossflow Kent, the Crossflow (the most prolific of all versions of the Kent), and the transverse mounted Valencia variants.
The arrival of the Duratec-E engine in the fifth generation Fiesta range in 2002 has finally signalled the end of the engine's use in production vehicles after a 44 year career, although it is still in limited production in Brazil, and produced as an industrial use engine by Ford's Power Products division, where it is known as the VSG-411 and VSG-413.
This series of engines became known as the Kent engine because Alan Worters, the company's Executive Engineer (Power Units), lived across the river from Ford's Dagenham plant in the English county of Kent.
Originally within Ford, it is said that the Kent name was actually born with the A711 and A711M blocks (commonly called the 711M block) with square main bearing caps for the Crossflow series, which represented a vast improvement in the durability of the engines. However, the name caught on to be used outside of the company to include pre-711M engines as well.
The original OHV three main bearing Kent engine appeared in the 1959 Anglia with a capacity of 996.70 cc developing 39 bhp (29 kW) at 5,000 rpm - unusually high for the time. With a 3-3/16 in (80.9625 mm) bore and 48.40 mm (1.906 in) stroke, combined with independent (non-siamesed) four intake and four exhaust ports, it was a departure from traditional undersquare English engine design.
The same engine, with its bore unchanged, but with longer 65.00 mm and 72.75 mm stroke and thus larger capacities were subsequently used in the Ford Consul Classic (1339 cc) and Consul Capri (1339 cc and 1498 cc), the Mk1 and early Mk2 Cortinas (58.20 mm stroke 1198 cc, 63.00 mm stroke five main bearing 1297 cc and the 1498 cc), and the early Corsairs.
In addition to its 'over-square' cylinder dimensions, a further unusual feature of the Kent engine at its introduction was an externally mounted combined oil filter/pump unit designed to facilitate efficient low-cost production and easy maintenance.
The engine is now referred to as the pre-crossflow Kent, in reverse-flow cylinder head configuration with both the inlet and exhaust being on the same side of the head.
- Ford Anglia
- Ford Cortina
- Ford Consul Classic and Consul Capri.
- Ford Corsair
- 107E Ford Prefect
- Otosan Anadol 1.2L – 1.3L (1966–1984)
A 1967 redesign gave it a cross-flow type cylinder head, hence the Kent's alternative name Ford Crossflow. It would go on to power the smaller-engined versions of the Ford Cortina and Ford Capri, the first and second editions of the European Escort as well as the North American Ford Pinto (1971, 1972 and 1973 only). In South Africa it also powered the 1.6 L Mk II, Mk III, Mk IV, & Mk V Ford Cortina and 1.6 L Ford Sierra.
The Crossflow featured a change in combustion chamber design, using a Heron type combustion chamber in the top of the piston rather than in the head. The head itself was flat with each engine capacity (1098 and 1297cc) featuring different pistons with different sized bowls in 681F and 701M blocks.
In 1970, the new A711 block for 1297cc and A711M block for 1599cc were introduced with thicker block wall, square main bearing caps, large diameter cam followers and wider cam lobes, with the latter block having a 7/16" taller deck height. These changes represented a significant improvement in the reliability of the engines, and the blocks are commonly referred to as '711M' blocks.
The Ford Crossflow engine (1298 cc and 1,599 cc) also powered the Reliant Anadol (1968–1984). Other makes such as Morgan used the Crossflow on Morgan 4/4, Caterham on Caterham 7, and TVR used the engine in the Grantura, Vixen, and 1600M. It has been fitted in countless other applications as well, being a favourite of kit-car builders not only in Great Britain.
Destined for the American market, beginning with the 1977 model year, the Valencia plant began manufacturing a 1.6L, 63BHP, 5 main bearing version that included a low emission bowl-in-pistons combustion chamber design based on the Crossflow head, and was equipped with a Dura-Spark electronic ignition. This version was used in the short-lived 1977-80 USA Mk1 Fiesta. This engine would be later used in the XR2 version of the Mk.1 Fiesta, using the US 1600 bottom end and GT spec head and cam. 1.3L versions of the Mk I Fiesta also used the Crossflow, as opposed to the Valencia (see below).
A redesigned version of the Kent engine was conceived to suit transverse installation in 1976, coinciding with the launch of the Ford Fiesta. This derivative would go through two major revamps in 1988 and 1995 and would be a mainstay of Ford's entry level compact range for nearly 25 years.
Original Valencia (1976-1988)
For adapting the Kent Crossflow for front wheel drive the ancillaries were repositioned, the cylinder block shortened slightly with a new transmission flange to suit the BC4/5 transaxle and the cylinder head redesigned using flat-top pistons and the traditional combustion chamber in the head. Although internally named within Ford as "L-Series" it became better known as the Valencia to the wider world, after the new Spanish factory built for its manufacture, but eventually the name was officially adopted by Ford as well - although in sales literature it was always called simply OHV. It was available in 957cc and 1117cc versions, the 1.3 Fiesta having a modified Kent block (Very few minor components were shared between the Valencia and Kent engines.
It would later see service in the third and fourth generation Ford Escort. The cylinder heads and pistons were modified in 1986 for unleaded fuel and the cams changed to meet the new European emissions standards along with the addition of electronic ignition.
In 1988 the second generation of the Valencia unit was launched to meet with tightening European emissions legislation. The redesign included an all-new cylinder head with reshaped combustion chambers and inlet ports, and a fully electronic distributorless ignition system. The engine was renamed the Ford HCS (standing for High Compression Swirl), although some internal Ford service publications call it the Valencia-HCS in reference to its heritage.
It first appeared in 1118cc and 1297cc guises on the Ford Escort and Orion for the 1989 model year, and on the then new Ford Fiesta Mark III the same year, which also offered a smaller 999cc version to replace the older 957cc Valencia.
The HCS is distinguishable from the original Valencia by its grey rocker cover, the "mirrored" arrangement of the spark plugs (they appear to "point inward" towards each other), and the absence of a distributor drive on the rear face of the cylinder block.
The final redesign came in 1995, with the launch of the fourth-generation Ford Fiesta. This edition was effectively another redesign of the Valencia/HCS derivative, known as the Endura-E, and featured many revisions to combat noise and harshness, including a thickened cylinder block. This engine would also feature in the Ford Ka and the 1.3 Ford Escort.
This type of engine still has tappet noise even after adjustment. This noise is said to come from the cams due to incorrect valve setup (when setting valve clearance each cylinder must be set to TDC) or from age and use of incorrect oil grade. The correct oil grade is 5W-30 semi synthetic oil. Another reason is the large tappet clearance on the exhaust valve. This could of course be reduced to lower the noise level but the engine would then suffer from a rough idle and usually stalled.
Despite Ford's engines being well regarded for their ease of service, the Endura-E has a very awkward placing for its oil filter, which is quite high up, at the back of the engine and facing from left to right rather than pointing downwards or out – meaning it is very difficult to access from underneath the car (without a mechanic's ramp), and despite being very short, the can-type oil filter still manages to protrude past the tip of the adjacent starter motor, meaning it is very difficult to remove using chain-type grips.
In 2000, Ford of Brazil developed a cheaper version of the Zetec-SE engine, to compete with the classic Volkswagen EA827 engine series also known as AP (from "Alta Performance", or "High Performance", in English) engine in Brazil. It is 8v SOHC instead of 16v DOHC and its block is made of iron instead of aluminum. Also, its camshaft is driven by a chain instead of a belt. As a result this engine exhibits rougher behaviour, producing more vibration and noise.
On the other hand, it has a superb torque output thanks to the addition of the RoCam (Rollifinger Camshaft) feature. It's also a much smaller engine than the SE version, which allowed it to be installed on the Ford Ka, replacing the Endura-E engine which by that time was considered underpowered and outdated.
The engine also featured a new patented process for the aluminum head production, which resulted in a better alloy than those produced in Spain and UK, and at a lower production cost.
In 2003 the Zetec RoCam engine was introduced in Europe, but labeled as Duratec 8v, for the SportKa, StreetKa and Fiesta. Later a 1.3 litre version was also released as an option for the standard model, but the European versions of the engine are produced in the South Africa plant.
In October/2004 a newer bi-fuel version was introduced labeled "1.6L Flex", capable of running on both petrol and ethanol, even mixed at any proportion. This version also featured a high compression ratio (11.8:1) and "Compound High Turbulence" chambers, as used on the CHT engine.
Currently, this engine powers nearly all Brazilian Ford models – except those with 2.0 litre engines – in many different variants:
- 68/72 hp 1.3L Flex (Ford Ka)
- 101/106 hp 1.6L Flex (Ford Ka)
- 65/68 hp 1.0L Flex (Ford Fiesta)
- 105/111 hp 1.6L Flex (Ford Fiesta/ Fiesta Sedan), (Ford Focus), Ford EcoSport)
1.3 L Endura(1299 cc/79 cu in) applications:
1.6 L (1596 or 1597 cc/97 cu in) applications:
- –present Latin America Ford SportsKa 1.6, 95 PS (94 hp/69 kW) and 100 lb·ft (136 N·m)
- –present Latin America Ford StreetKa 1.6, 95 PS (94 hp/69 kW) and 100 lb·ft (136 N·m)
Ford Kent engines had a profound influence on motorsport, possibly more so than any other mass-produced engines did in the history of motorsport. Satta/Hruska designed Alfa Romeo 750/101 1290cc DOHC unit, and Alex von Falkenhausen designed SOHC 1773cc BMW M118 engine may have had similar influence on the motorsport scenes in Italy and Germany respectively, but not even comparable internationally.
Lotus used Ford Kent engines on Lotus Mk.VII to establish its corporate foundation, and subsequently used most of the Cosworth early racing engines for the legendary success in motorsport. Lotus also built the successful Lotus TwinCam engine for Lotus Elan on the Kent block, crank and conrods.
Furthermore, the Kent Crossflow engine was used as the regulation engine in Formula Ford, although it was originally proposed to be the pre-crossflow 1498cc Cortina GT unit in 1967 (before the establishment of the series). In Europe, Formula Ford switched to the Zetec, but American Formula Ford continued to be Kent-powered until 2010; the SCCA having approved the use of the Honda L15A i-VTEC for Formula F.
As it was nearly impossible to succeed in motorsport without some activities in Formula 2, 3 or Formula Ford, most of the well-known racing drivers in the 1960s, 70's and 80's owe their careers to Ford Kent to some extent, and the current historic motor racing depends heavily on the Kent based engines.
On 16 October 2009, Ford announced that it would be putting the Kent block back into production in order to supply the historic racing community with spares. According to a Ford press-release, engineering work began at Ford Racing's Performance Parts division in the USA, with sales scheduled to start in 2010. Link to Kent block in Ford Motorsports Parts online catalog
Harry Mundy designed the Lotus TwinCam engine for Colin Chapman who needed the replacement for the Coventry Climax FWE engine used in Lotus Elite. As Keith Duckworth and Mike Costin, the co-founders of Cosworth, used to be Lotus Development Ltd employees, the initial racing adaptation of Lotus TwinCam was carried out by Cosworth, and the Kent block Cosworth SCA was designed using the basic SOHC reverse-flow cylinder head configuration of the FWE. Due to Harry Mundy being also the co-designer of the FWE, the Kent block Lotus TwinCam initially used the cam profile of the FWE, and shared the same valve clearance adjustment shims with Coventry Climax FWA, FWB and FWE in production.
The Ford diesel engines "Endura-DE and Endura DI" bear no similarities to the petrol namesake. However Ford did produce a diesel HCS engine. These engines are notoriously underpowered.
- "Time Machines: Little belter: Ford Anglia 1959–1967". Drive (Magazine of the British Automobile Association) 116: pages 18–19. March 1985.
- See the talk page on this article under the heading "Ford Kent engines"
- Abuelsamid, Sam (2009-11-05). "Ford Kent engine being replaced by Honda Fit based engine by SCCA". Autoblog.com. Retrieved 2010-11-05.
- "Ford Introduces 1.6L Duratec Race Engine, Restarts Kent Production". Jalopnik.com. 2009-10-16. Retrieved 2010-11-05.
- Wilkins, Miles (1988). Lotus Twin-Cam Engine. Osprey. p. 15. ISBN 1855209683.