Ford CVH engine

The CVH (Compound Valve angle Hemispherical combustion chamber) engine was introduced by Ford in 1980 in the third generation European Ford Escort and for the 1981 North American 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.

Ford CVH engine
1.6L Ford CVH engine in a 1988 Ford Escort XR3i
Overview
ManufacturerFord Motor Company
Production1980-2004
Layout
ConfigurationInline-4
Displacement
  • 1.1 L; 68.2 cu in (1,117 cc)
  • 1.3 L; 79.1 cu in (1,296 cc)
  • 1.4 L; 84.9 cu in (1,392 cc)
  • 1.6 L; 97.4 cu in (1,596 cc)
  • 1.8 L; 108.0 cu in (1,769 cc)
  • 1.9 L; 113.4 cu in (1,859 cc)
  • 2.0 L; 121.3 cu in (1,988 cc)
Cylinder bore
  • 77.2 mm (3.04 in)
  • 80 mm (3.15 in)
  • 82 mm (3.23 in)
  • 84.8 mm (3.34 in)
Piston stroke
  • 64.5 mm (2.54 in)
  • 74.3 mm (2.93 in)
  • 79.5 mm (3.13 in)
  • 88 mm (3.46 in)
Block materialCast iron
Head materialAluminum
ValvetrainSOHC ( 2 Valves per cylinder )
Compression ratio8.5-9.9:1 ( Naturally Aspirated version ) 8.3:1 ( Escort / Fiesta RS Turbo )
Combustion
TurbochargerOn some 1.6 L versions
Fuel system
Management
Fuel typeGasoline
Oil systemWet sump
Cooling systemWater-cooled
Output
Power output69–200 hp (51–149 kW)
Torque output86–133 lb⋅ft (117–180 N⋅m)
Dimensions
Dry weightCirca 100kg
Chronology
SuccessorFord Zeta engine
1.6 CVH cylinder head with valves, followers and rockers

The engine was originally conceived in 1974 and had a single overhead cam. Its valves were mounted at a compound angle in hemispherical combustion chambers, although some versions altered the combustion chamber shape to increase swirl. It also featured hydraulic valve lifters, a first for a European Ford engine. The engine was given different names throughout its production. From 1991 to 1996 in the Ford Escort, it was "1.9L SEFI"; and from 1997 to 2002, it was "Split Port Induction 2000". From 2000 to 2004 in the Ford Focus, it was "Split Port".[1]

Despite its considerable shortcomings in terms of Noise, vibration, and harshness (NVH) and its intolerance of poor or neglected servicing, the CVH was regarded as being a very easy engine to tune, 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 L version quickly became a stalwart of the tuning scene in the 1980s and 1990s with some significant increases in power output (over 200 bhp (149 kW)) being extracted from the turbocharged variants. The naturally aspirated 1.6 L was a popular choice for the kit car industry, where it could be relatively easily and cheaply tweaked to around 130 bhp (97 kW).

The CVH was produced in many different capacities from 1.1 to 2.0 L, the smaller versions being exclusively for the European market.

1.1
1.6 CVH cylinder head

The 1.1 L CVH was the shortest lived of the different variants, like the others it was first used in the 1980 European Escort. Displacing 1.1 L (1,117 cc), uniquely it was sold in parallel in the Escort with the "Valencia" version of the Ford Kent OHV unit with the same displacement. It offered a negligible improvement in terms of either performance or economy over the older Kent engine which was cheaper to manufacture, hence the 1.1L CVH was dropped in 1982.

1.3

The 1.3 L (1,296 cc) CVH was introduced in the 1980 European Escort and in the Orion and Fiesta from 1983 to 1986. Bore and stroke was 80 mm × 64.5 mm (3.15 in × 2.54 in). The 1.3 L was also planned for the North American version of the Escort, but engineering tests found it to be unacceptably underpowered, and plans to produce 1.3 L engines were scrapped just a few months before full-scale production.

For the facelifted "Mark 4", or "Erika-86" version of the European Escort in 1986, this engine was replaced by a 1.3 L version of the Valencia engine in low series trim models—the higher series models used the newer 1.4 L CVH described below.

1.4
1.6 CVH cylinder head, combustion chambers

The 1.4 L CVH replaced the 1.3 L CVH in the Escort, Orion and Fiesta from early 1986. Bore and stroke was 77.2 mm × 74.3 mm (3.04 in × 2.93 in). In European trim, this engine produced 75 bhp (56 kW).

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 engines. The Ford variable venturi carburettor was replaced by a Weber carburettor 28/30 DFTM which benefited from a manifold vacuum-actuated secondary choke, instead of the more usual sequential linkage which opens the secondary butterfly at 3/4 to full throttle. The theory was to save fuel, especially with lead-footed drivers, but the result was mainly an engine which ran lean under load. This became worse on engines with worn cylinder heads owing to reduced engine vacuum. The 1.4 L version is less responsive to power modification than other CVH engines and some cylinder head parts are not interchangeable with the most common tuning parts; however replacing the carburettor with a Weber 32/34 DMTL and the appropriate inlet manifold makes them more tractable, albeit with a small increase in fuel consumption.

In South Africa, the 1.4 L CVH was fitted to the Ford Laser and Meteor, rebadged Mazda 323s. It replaced the 1.3 L Mazda E-series engine used in these cars and was itself replaced by the 1.3 L Mazda B-series engines.

1.6

The 1.6 L CVH was used in the 1980 European Escort and 1981 North American Escort. Bore and stroke was 80 mm × 79.5 mm (3.15 in × 3.13 in).

European Markets

Output was 69 hp (51 kW) and 86 lb⋅ft (117 N⋅m), while European versions produced 78 hp (58 kW) with the Ford variable venturi standard carburettor and 95 hp (71 kW) for the Fiesta XR2 and the Escort XR3 (twin venturi 32/34 DFT Weber carburetor), or fuel-injected 105 hp (78 kW) (Bosch K-Jetronic), 90 hp (67 kW) KE-Jetronic catalyst mechanical fuel injection, 108 hp (81 kW) (EFI Electronic fuel injection with Ford EEC-IV engine management) as found in the XR3i or Orion GLSI. A 115 hp (86 kW) version was offered only in the very rare Escort RS1600i – a car developed by Ford Motorsport Germany for FIA Group A Homologation. This version featured a reworked cylinder head, solid cam followers and bronze bearings for high-revving applications and a host of other motorsport features.

European versions of the carburettor CVH from 1986 model year were revised and, like the new 1.4 L, the 1.6 L engine benefited from cylinder heads with a heart-shaped lean-burn combustion chambers and a slightly raised piston crown, it utilised a twin venturi 28/32 TLDM Weber carburettor. Power output was improved to 89 hp (66 kW) with the benefit of improved torque and fuel economy. EFI versions used in the Escort XR3i, 1.6i and Fiesta XR2i retained hemispherical combustion chambers. From the 1989 model year all EFI Electronic fuel injection variants were fitted with the Ford EEC-IV engine management system.

North American Markets

Standard 1.6L output increased as years passed but was all made with the same formula of cast pistons and connecting rods, a low-flow version of the CVH head, flat hydraulic lifters, a .229" lift camshaft, 32/32 Weber Licensed carburetor, cast exhaust manifold, and low-dome pistons making 8.5-9.0:1 compression starting at 65hp in 1981 getting up to 74hp by 1985.

Optional 1.6L Higher Output motors became available in late 1982 through 1985 consisting of 4-2-1 headers, higher-lift (.240") camshafts, a 32/34 Weber carburetor, a dual-snorkel air-box, and high-dome pistons making 9.0-9.5:1 compression making 74hp in 1982 and 80hp in 1983-1985.

Optional 1.6L EFI motors became available in 1983 through 1985 with all the features of the HO (Higher Output) motor but with a totally different intake system to allow for multi-port injection EFI running on Ford's EEC-IV Engine Control Module. The 1.6 EFI still shared the same head as the carbureted 1.6s found in North America but without a mechanical fuel pump of course. The 1.6 EFI engine would be replaced with the 1.6 HO instead in all high-altitude regions helping to make the 1.6 EFI even more rare.

CVH XR3 engine (Europe)

1.6 Turbo

European 1.6T

An uprated, turbocharged version of the 1.6 L which was developed by Ford Europe for the hugely popular RS Turbo version of the Escort and also later the Ford Fiesta RS Turbo. It made 132 hp (98 kW) at 6,000 rpm, and 133 lb⋅ft (180 N⋅m) of torque at a very tractable 3,000 rpm. The boosted engine was substantially smoother than its normally aspirated cousins, the forced induction 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 L 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 ratio to 8.3:1, allowing the use of large amounts of boost pressure. The standard engine only needs 7 psi (0.48 bar) 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.

North American 1.6T

The North American 1.6 turbocharged CVH was developed by Ford's Special Vehicle Operations (SVO) with help from Jack Roush for 1984 and 1985 in the Ford EXP Turbo, Ford Escort GT Turbo, and Mercury Lynx RS Turbo. Making 120 hp (89 kW) (50% more than the carbureted High Output 1.6 for North America) it is the most powerful production CVH of North America proving to make EXPs, Escort, and Lynxes faster than their competitors' compacts while retaining impressive fuel efficiency numbers all without reducing the engine's lifespan. The 1.6 turbocharged Fords also came standard with TRX packages to further improve performance with upgraded suspension and specialty Michelin tires. The modified turbocharged engine featured not just a turbocharger but a specially designed cam profile (.240" comparable to the 1.6 HO and EFI camshafts), Ford Performance/SVO modified head (comparable to European 1.6s), the EFI intake manifold, unique cast exhaust manifold, low-dome pistons, and Ford's top-of-the-line EFI and ECU system. With this being the only North American CVH with forged pistons and connecting rods among its other unique features, these engines are rare among smaller North American Ford vehicles and are heavily sought after for their power output, durability, and fuel efficiency. These engines only appeared in the 1984-1985 Ford Escort GT Turbo and 1984-1985 Ford EXP Turbo of which only about 10,000 were made in total.

1.8

The 1.8 L (1,769 cc) CVH was a very rare engine: it was used only in the European Ford Sierra. There are not many differences from the 1.6 engine. Bore was still 80 mm (3.15 in), but a different crankshaft with a stroke of 88 mm (3.46 in) gave the engine its higher capacity. The cylinder head was equipped with hydraulic roller camshaft followers to reduce noise and help the engine to run more smoothly.

1.9
The 1.9-liter "High Output" EFI engine in a 1990 Ford Escort GT

The CVH was enlarged to 1.9 L for the North American 1986 model year Escort. Bore and stroke were now 82 mm × 88 mm (3.23 in × 3.46 in). This stroke length was later 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. The camshaft and water pump are driven by the timing belt. This engine is of a non-interference design: the valves don't contact the pistons if the timing belt breaks. Output was 86 hp (64 kW) and 100 lb⋅ft (136 N⋅m) with a carburetor; when electronic throttle-body fuel injection (CFI, or Central Fuel Injection) was added, the basic 1.9 L added 4 hp (3.0 kW), although torque was little changed.

All 1.9s from 1989 forward would be equipped with a roller camshaft & roller lifters.

Multi-port fuel injection and hemispherical "hemi" combustion chambers were added for the 1986 Escort GT's EFI HO engine, increasing output to 108 hp (81 kW) and 114 lb⋅ft (155 N⋅m). This engine developed a good reputation for performance and surviving GTs of this generation are quite fun to drive.

The 90 hp (67 kW) 1.9 L CFI engine of the late 1980s, particularly when equipped with either the four- or five-speed manual transaxle, was notable for delivering outstanding fuel economy. These engines all came equipped with roller camshafts & lifters. Somewhat surprisingly, four-speed Escort Pony models achieved better mileage than five-speed cars, with upwards of 30 mpg‑US (7.8 L/100 km; 36 mpg‑imp) in city driving and 40–45 mpg‑US (5.9–5.2 L/100 km; 48–54 mpg‑imp) on the highway not uncommon.

The second generation of American Escort utilized sequential electronic fuel injection (SEFI) for 1991–1996 (sharing the same head as the 1.9 CFI), but power and torque were little changed at 88 hp (66 kW) and 108 lb⋅ft (146 N⋅m) respectively.

2.0

The 2.0 L was introduced in the 1997 Escort (North American) sedan and wagon as SPI2000 (Split Port Induction). It now used split port induction and produced 110 hp (82 kW) and 125 lb⋅ft (169 N⋅m). The additional displacement was achieved by boring the 1.9 L engine to 84.8 mm (3.34 in). It is the smoothest and quietest CVH engine made, and continued to deliver excellent fuel economy, although due to the car's increased weight, mileage is somewhat less than earlier models (usually mid-20s city, mid-30s highway). As with the 1.9, the water pump is driven by the timing belt. This engine is also a non-interference design. It is the last CVH engine made and saw an end to production in the last of the 2004 Ford Focus LX/SE sedan and wagons. These engines have "Split Port Induction" in raised letters on the top of the valve cover.

Applications

Note that the 1.1 L version 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.

CVH-PTE

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.

Common problems

Throughout its 20-year production life, the CVH had a reputation for being almost painfully coarse and noisy at high RPM (CVH, said some pundits, was an initialism for "considerable vibration and harshness," other epithets include "clattery, vapid, and harsh"). Jeremy Clarkson famously said of the CVH-powered Escort that "it was powered by engines so rough, even Moulinex wouldn't use them".

The harshness the CVH is known for is mostly due to the cylinder head and valvetrain design, the valve springs used in the CVH are considerably stiffer than usual compared to other engines, with 220 lb (100 kg) at full lift, the stiff springs are needed to prevent valve float, and they do until engine speeds of around 6700 rpm, and also maintain under control the also unusually heavy rocker and hydraulic self adjusting tappet used in CVH engines, due to the angle at which the engine's valves are positioned due to the hemispherical combustion chamber.

The stiff valve springs add more friction and pressure to the already high friction design of "flat tappet" design, the camshaft is oiled by small holes in the cylinder head casting next to the lifter bores that are prone to blocking up with sludge if the engine is not serviced regularly, starving the camshaft of oil, due to this, camshaft and tappet wear problems are common, especially in higher mileage engines or engines that have not had regular oil changes, a worn camshaft can cause heavy clattering and ticking from the engine's top end, specially at high engine speeds, another possible source of noise from a ticking or clattery CVH engine are the washers that are found under each rocker that might be worn. [2]

Changing the hydraulic tappets and the previously described shims is a relatively simple operation and can quieten a noisy CVH, however if the camshaft is heavily worn, it will have to be replaced together with the hydraulic tappets, this can be done without removing the cylinder head, having removed the distributor or coil pack.

The CVH was notorious for turning its lubricating oil to sludge prematurely if the service schedule was skipped or if poor quality oil was used. This tended to cause top-end oil starvation and the tortured mechanical noises these engines were known for. The culprit was the design of the crankcase ventilation circuit, which Ford altered several times over the engine's lifetime but never properly cured. Timing belts frequently failed about 60,000–90,000 mi (97,000–145,000 km) if not changed, because of this Ford recommended that timing belts be replaced every 30,000–36,000 mi (48,000–58,000 km)

Valve seat failure

The most common problem with the later CVHs is the tendency to drop a valve seat,[3] which most often happens in vin number P engines, due to the steel PM valve seat inserts in the aluminum head. (the 2000-2004 Ford Focus with the 2.0L CVH/SPI SOHC engine and also seen in 1991-2002 Ford Escorts). These engines usually drop a valve seat with no warning, even if the engine has been well maintained. In most cases, a seat drops on the number 4 cylinder, with the next most common being the number 2 cylinder (this peculiarity may have something to do with the engine's secondary harmonics) . With the factory valve seats, the typical life of the 2.0L SPI in a Focus is about 100,000 to 120,000 mi (160,000 to 190,000 km),[4] but it can happen as early as 70,000 mi (110,000 km). When the valve seat drops out of the cylinder head, it falls into the cylinder and damages the piston and cylinder head. In some cases, the valve seat is drawn from its cylinder through the intake manifold into another cylinder until it is obliterated. A valve seat dropping into the cylinder can scar the cylinder wall and bend the piston connecting rods.

See also

References
  1. Kronik, Anatoly Y.; Ives, David C.; Wiemero, Timo A.; Stockhausen, William F. (1 May 1996). "Development and Application of the Ford Split Port Induction Concept" – via www.sae.org.
  2. "cvh history". www.gomog.com.
  3. "2.0L SPI valve seat problems". Archived from the original on 2011-04-10. Retrieved 2011-05-29.
  4. "Valve seat life". Retrieved 2011-05-29.


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