The CVH (Compound Valve angle Hemispherical combustion chamber) engine was introduced by Ford in 1980 in the third generation Ford Escort. It was later used in the Ford Sierra as well as the second generation Ford Fiesta and from 1983 it was used in the Ford Orion. Engines were built in the Dearborn Engine Plant for the North American market, and in Ford's then-new engine plant in Bridgend in Wales for the European market.
The engine was originally conceived in 1974 and is unique in terms of its valves mounted at a compound angle, which allows for a hemispherical combustion chamber shape without using a more expensive twin camshaft arrangement. It also featured hydraulic valve lifters, a first for a European Ford engine.
Throughout its 20-year production life, the CVH had a reputation for being almost painfully coarse and noisy at high revs (CVH, said some pundits, was an acronym for Considerable Vibration and Harshness). Jeremy Clarkson famously said of the CVH-powered Escort that "it was powered by engines so rough, even Moulinex wouldn't use them".
The CVH was also notorious for its lubricating oil to sludge prematurely if the service schedule was skipped. Timing belts frequently failed about 60,000 to 90,000 miles (100,000 to 150,000 kilometers).
Despite its considerable shortcomings in terms of NVH (Noise, Vibration and Harshness), and its aforementioned intolerance to poor or neglected servicing, the CVH was regarded as being a very easy engine to tune, and with many of its key components being considerably over-engineered. It wasn't long before the engine started receiving attention from the aftermarket tuning industry, and the 1.6 litre version quickly became a stalwart of the tuning scene in the 1980s and 1990s with some phenomenal power outputs (over 200 bhp) being extracted from the turbocharged variants. The naturally aspirated 1.6 was a popular choice for the kit car industry where it could be relatively easily and cheaply tweaked to around .
The CVH was produced in many different capacities from 1.1 to 2.0 litres, the smaller versions being exclusively for the European market.
The 1.3 L CVH was introduced in the 1980 European Escort and in the Orion and Fiesta from 1983 to 1986. Bore was 80.0 mm and stroke was 64.5 mm. The 1.3L was also planned for the North American version of the Escort, but engineering tests found it to be unacceptably underpowered, and plans to produce 1.3L engines were scrapped just a few months before full-scale production.
The 1.4 L CVH replaced the 1.3 L CVH in the Escort, Orion and Fiesta from early 1986. Bore was 77.2 mm and stroke was 74.3 mm. In European trim, this engine produced 75 bhp. It was widely known as the 'Lean Burn' engine as it was designed primarily for fuel economy and featured a different cylinder head which was aimed less at power output than other CVH powerplants. The carburetted versions feature an unusual Weber 28/30 carb with a manifold vacuum-actuated secondary choke (power valve), instead of the more usual sequential linkage which opens the secondary butterfly at 3/4 to full throttle. The idea was to save more fuel, especially with lead footed drivers, but the result was mainly a car which ran horribly lean under any kind of load, particularly after a the famous CVH top-end wear begins to reduce engine vacuum with some mileage on the clock. The 1.4 version is less tuneable than other CVH's, and some top-end parts are not interchangeable with the most common tuning parts; however replacing the carb with the common Weber 32/34 DMTL plus the appropriate inlet manifold makes them more driveable, albeit with a small increase in fuel consumption.
In South Africa the 1.4 CVH was fitted to the Ford Laser and Meteor, rebadged Mazda 323s. It replaced the 1.3 Mazda E-series engine used in these cars and was itself replaced by the 1.3 Mazda B-series engines.
The 1.6 L CVH was used in the 1980 European Escort and 1981 North American Escort. Bore was 80.0 mm (3.149 in) and stroke was 79.5 mm (3.130 in). Output was 69 hp (52 kW) and 86 ft·lbf (117 Nm), while European versions produced in standard carburettor trim, or , or in various fuel injected versions. The version was restricted to the very rare Escort RS1600i
An uprated, turbocharged version of the 1.6 which was developed by Ford Europe for the hugely popular RS Turbo version of the Ford Escort and also later the Ford Fiesta. It made at 6,000 rpm, and of torque at a very tractable 3,000 rpm. The boosted engine was substantially smoother than it's normally aspirated cousins, the forced nature helping to damp out unpleasant harmonics. The block was slightly modified to provide an oil return from the turbocharger. Crankshaft and connecting rods were identical to the lesser 1.6 models, but the Mahle pistons were unique to the RS Turbo. These are manufactured using a pressure cast method, which makes them considerably stronger and more expensive than the normal cast pistons. The pistons dropped the compression to 8.3:1, allowing the use of large amounts of boost pressure. The standard engine only needs 7 psi of boost to produce its quoted power output, and is considered to be detuned from the factory. Because of its strength and detuned nature, tuners continue to increase the standard figures by more than 100% for a relatively reasonable fee. Even today, some 20 years after its release, new ways are being developed to extract even more performance.
The CVH was bumped up to 1.9 L for the North American 1986 model year Escort. Bore was now 82 mm (3.230 in) and stroke was up as well to 88 mm (3.465 in). This stroke length would be used in the 2.0 L CVH engines, and continued into the Zeta engine which replaced it. This long stroke necessitated a raised engine block deck, a design also shared with later units. Output was 86 hp (64 kW) and 100 ft·lbf (136 Nm) with a carburetor; when electronic throttle-body fuel injection was added, the basic 1.9 added four horsepower, although torque was little changed.
Electronic fuel injection and hemispherical "hemi" combustion chambers were added for 1987's Escort GT, bumping output to 108 hp (81 kW) and 114 ft·lbf (155 Nm). This engine developed a good reputation for performance and surviving GTs of this generation are quite fun to drive.
The 90-horsepower 1.9 of the late 1980s, particularly when equipped with either the four- or five-speed manual transaxle, was notable for delivering outstanding fuel economy. Somewhat surprisingly, four-speed Escort Pony models achieved better mileage than five-speed cars, with upwards of 30 mpg in city driving and 40–45 mpg on the highway not uncommon.
The second generation of American Escort got sequential EFI for 1991-1996, but power and torque was little changed at 88 hp (66 kW) and 108 ft·lbf (146 Nm) respectively.
The second generation was one of the most durable, long lasting engines ever produced by ford. In racing applications the 2 valves per cylinder allowed for high revs.
The 2.0 was introduced in the 1997 Escort. It now used split port induction and produced 110 hp (82 kW) and 125 ft·lbf (170 Nm). The additional displacement was achieved by boring the 1.9 engine to 84.8 mm (3.339 in). It is the most refined CVH engine made, and continued to deliver excellent fuel economy, although due to the cars' increased weight, mileage is somewhat less than earlier models (usually mid-20s city, mid-30s highway). It is also the last CVH engine made and saw an end to production in the last of the 2004 Ford Focus LX/SE sedan and wagons.
Note that the 1.1 L version was only offered in Continental Europe, 1.1 L Escort Mk.3's for the United Kingdom used the 1117 cc Kent engine although some right hand drive examples were built with the CVH mechanicals in this capacity including the van variant.
The CVH-PTE is a revised version of the Ford CVH engine which was introduced on the European Ford Fiesta 1.4 Si in 1994 and the Ford Escort in 1994. It features multi-point fuel injection and a thicker crankcase to combat the harshness at high revs, although the 1990s saw it gradually being phased out in favour of the newer Zetec 16-valve unit.