Jump to content

Opel cam-in-head engine

From Alfawiki
Opel cam-in-head engine
IndustryAutomotive engineering
Founded1965
FounderGeneral Motors (Opel)
Defunct1998
FateReplaced by GM Family II engine (4-cylinder variants)
SuccessorGM Family II engine (4-cylinder variants)
Headquarters
Rüsselsheim
,
Germany
Area served
Worldwide (primarily Europe)
ProductsInline-4 and Inline-6 petrol and diesel engines
OwnerGeneral Motors (former)
ParentGeneral Motors

{{Infobox automobile engine | image = Opel Rekord E CIH engine.jpg | caption =A 4-cylinder 1,979cc (20E) fuel injected CIH engine in a 1984 Vauxhall Carlton (Opel Rekord E) | name = Opel cam-in-head engine | configuration = Inline-4, Inline-6 | production = 1965 - 1998 | predecessor = | successor = | bore = | stroke = | displacement = | block = Cast iron | head = Cast iron
Aluminium | valvetrain = | turbocharger = (Garrett) T25 Twin-turbos (Lotus Carlton) | fuelsystem = Carburettor
Multi-port fuel injection | fueltype = Petrol engine
Diesel engine |} The Opel cam-in-head engine (CIH) represents a series of inline four- and six-cylinder powerplants manufactured by the former General Motors subsidiary, Opel, spanning from 1965 through 1998. This engine family was widely implemented across Opel and Vauxhall models during these years. Its designation stems from the distinctive positioning of the camshaft beside the valves within the cylinder head, merging characteristics of overhead valve and overhead camshaft configurations. Valves are actuated through short tappets coupled with rocker arms.

Debuting in the Opel Rekord Series B in 1965, the CIH powered a variety of mid-sized automobiles. Four-cylinder variants were predominantly succeeded by the GM Family II engine throughout the 1980s, whereas six-cylinder versions remained in production until 1994, appearing in vehicles such as the Opel Omega A and Opel Senator B. Additionally, a large-displacement 2.4-liter four-cylinder CIH continued until 1998.

In 1972, a diesel iteration of the CIH was introduced with the Opel Rekord Series D, broadening Opel’s diesel engine lineup during that period.

Design

The cam-in-head (CIH) engine concept originated from General Motors’ design team based in Detroit, Michigan.

Although the camshaft resides within the cylinder head, this arrangement does not constitute a conventional overhead camshaft setup. Instead, it functions as a cam-in-block mechanism featuring a shortened valve train. The camshaft receives motion via a roller chain. Initial versions incorporated mechanical lifters; subsequently, hydraulic tappets were implemented—a technology Opel pioneered for mass production with their Family II engines that eventually replaced the CIH. The cylinder head employs a non-crossflow configuration, which lowered manufacturing expenses but adversely affected fuel efficiency. Both the block and head are constructed from cast iron. The CIH design is characterized by an oversquare geometry; early models had a stroke of , while larger displacement engines exceeding two liters utilized longer strokes—up to for the 2.2L variant and for the 2.4L (also found in the 3.6L inline-six).

In comparison to overhead camshaft engines, the CIH’s benefits were mainly confined to enabling a lower bonnet profile due to its reduced head height. It was anticipated to offer simpler maintenance requirements and reduced weight; however, these advantages were partially offset by its cast iron cylinder head.

Unlike the smaller Opel OHV, the CIH design was never adapted for transverse installation in front-wheel-drive vehicles and remained exclusive to rear-wheel-drive configurations within Opel and Vauxhall lineups.

Opel engineered a crossflow cylinder head compatible with the CIH block, which was trialed in the experimental GT-2 model of 1975 with intentions for future production use. This crossflow architecture saw limited application in four-cylinder form as the 20EH engine powering the Kadett GT/E. It achieved full-scale production solely in six-cylinder format as the 3.0-liter 24-valve unit featured in the Opel Senator B.

1.5 litre I4

Among the original CIH engine lineup, the 1.5L model was the smallest, characterized by its bore and stroke dimensions that produced a displacement of . Opel provided two versions tailored to different fuel qualities: the 15N designed for regular octane and the 15S intended for premium fuel. Output ranged from for the 15N; meanwhile, the export-exclusive 15S found in the Kadett B and Olympia A delivered DIN at 5000 rpm (equivalent to 76 hp SAE at 5600 rpm).

This engine was initially imported by GM Korea and Saehan Motors before local manufacturing commenced under Daewoo around 1983. South Korea’s vehicle tax regulations favor engines below 1.5L, facilitating its use in models such as the Saehan Camina, Saehan Gemini lineup, and Daewoo Royale until 1987. Additionally, larger displacement engines of 1.9L and 2.0L were produced domestically in Korea.

Applications

1.6 litre I4

Introduced in September 1970 with the Opel Manta A and shortly thereafter in the Opel Ascona A, this CIH engine features a bore of and a stroke of . It was available as the lower-powered 16N for regular octane fuel and the higher-output 16S for premium fuel. Initial power figures were , which decreased to in early 1975 due to more stringent emissions regulations. From that year onward, the cleaner A16S version produced 69 PS and incorporated a forged crankshaft with eight counterweights. Eventually, this 1.6L CIH engine was superseded by a Family II engine in models like the Opel Ascona C and Vauxhall Cavalier Mk II.

Applications

1.7 litre I4

This CIH engine, featuring a bore of and stroke of , was offered exclusively with carburettors for use with either regular or super petrol fuels. The initial version, known as the 17N, produced , which increased to in 1969 before being reduced back to approximately 60 PS after compression adjustments in 1975. The sportier variant, the 17S, delivered , receiving an updated carburettor in 1972 for use in the Opel Rekord D. The combination of performance and cost-effectiveness associated with its displacement made the 17S especially popular in export markets such as Italy and Greece.

Applications

1.9 litre I4

The 1.9 litre inline-four CIH engine represents the largest displacement in the original four-cylinder CIH lineup, featuring a bore of 90 mm and a stroke of 78 mm. Offered in both carbureted and fuel-injected configurations, this engine powered a range of vehicles with outputs varying between 75 and 106 PS. The performance-oriented 19HL (Hochleistung) variant was introduced in 1967, debuting on the Opel Rekord Sprint and Kadett Rallye Sprint models with an output of 106 PS. Meanwhile, the 19SH, equipped with hydraulic lifters, initially delivered 90 PS before its power was reduced to 86 PS in 1975. The 19N succeeded the discontinued 17S engine, producing 75 PS and optimized for use with lower-octane fuels, catering to more relaxed driving styles.

The 19E version, launched in March 1974 on the Manta GT/E, marked the first fuel-injected four-cylinder CIH engine, providing 100 PS. Specific market adaptations included Austria’s lower-powered A19N variant (75 PS) and the low-emission S19S tailored for Sweden and Switzerland, generating 90 PS; these models incorporated forged crankshafts with eight counterweights.

As the most adaptable and longest-lasting CIH engine variant, the 1900 powered numerous Opel, Vauxhall, Holden, Daewoo, and Ranger vehicles across various international markets.

Applications

2.0 litre I4

Derived from the earlier 1.9 litre design, the CIH inline-four two-litre engine increased the bore to 92 mm while retaining the stroke length of 78 mm. Unlike its predecessor, this engine incorporated hydraulic tappets to compensate for power reductions mandated by stricter emission regulations. Available in both carbureted and fuel-injected forms, it operated on regular or premium petrol grades and offered a range of power levels. The initial 20S, released in September 1975, generated between at approximately 5200 to 5400 rpm. Subsequently, the fuel-injected 20E delivered , while the more powerful 20EH, fitted in the Kadett 2.0 GT/E model, utilized Bosch L-Jetronic fuel injection technology—later upgraded to LE-Jetronic systems by late 1981. Introduced in August 1977, the 20N variant produced . For markets such as Sweden and Switzerland requiring lower emissions, reduced-output versions S20S and S20E were also available.

Applications

2.2 litre I4

Manufactured between 1984 and 1987, the fuel-injected 2.2 CIH engine featured an increased stroke of 77.5mm while maintaining a bore of 95mm. The cylinder head was redesigned with larger valves, elevated intake ports, and reinforced valve seats to accommodate unleaded gasoline. This resulted in a slight boost in power output to , accompanied by torque of .

This engine was installed in the Opel Rekord E, Opel Monza A2, and Opel Senator A2 models.

2.4 litre I4

The ultimate four-cylinder CIH model had a displacement of , retaining the 95mm bore but extending the stroke to 85mm, delivering power of and torque of . Initially introduced in the German-market Omega A, it was replaced elsewhere as the premier four-cylinder option by the Family II 2.0 L engine. Its final application was in the Frontera SUV.

Applications:

400 I4 / Cosworth KAA

In the early 1970s, Opel embarked on developing a DOHC engine designed for Formula 2 competition, which debuted in 1975. Due to reliability challenges during Group 4 rallying, Opel collaborated with Cosworth, leading to substantial modifications in porting and camshaft configurations.

Using a 2.0E block with specific bore and stroke dimensions, displacement reached , featuring a compression ratio of 11.5:1. The engine produced at 7200 rpm and torque of at 5000 rpm, equipped with twin Weber carburettors and a dry sump lubrication system.

Cosworth manufactured the homologation batch of 400 units for the Opel Ascona 400 rally car and subsequently for the Manta 400. They also contributed expertise for the fuel injection system in road-going versions, where a detuned sixteen-valve variant generated at 5200 rpm and torque of at 3800 rpm.

Six-cylinder versions

From 1968 until 1993, Opel and Vauxhall equipped their largest vehicles with straight-six CIH engines, which were eventually replaced by the Opel-developed 54° V6 during the mid-1990s.

The majority of these engines utilized single cam-in-head designs driven by chains. Initially carbureted throughout the 1960s and early 1970s, Bosch fuel injection systems were introduced starting in 1969. Certain later six-cylinder models featured DOHC multivalve cylinder heads.

2.2 litre I6

This uncommon inline-six engine shared its bore and stroke measurements with the smaller 1.5-litre four-cylinder unit. Released in December 1966 with , it offered only slight improvements over the 1900S but added weight and cost penalties. Production ceased by late 1968 following the introduction of the six-cylinder Commodore.

Applications

2.5 litre I6

Opel's contemporary straight-six series began in 1968 with the 25S engine powering the Opel Commodore. With its bore and stroke dimensions, it generated power of and torque of , utilizing a single carburettor and a compression ratio of 9.2:1. The 25H version featured twin carburettors and a slightly higher compression ratio of 9.5:1, producing power output of and torque of .

The adoption of Bosch D-Jetronic fuel injection (later upgraded to L&LE-Jetronic) increased power to .

Applications

2.6 litre I6

Following the rollout of the 24-valve DOHC engine in Senator, Carlton, and Omega models, the previous 2.5-litre unit was expanded to 2.6 litres. This upgrade included a redesigned 12-valve cylinder head and RAM induction system, resulting in an output of . This powerplant was also incorporated into southeast Asian export variants of the Holden VP Commodore, Holden VR Commodore, and Holden VS Commodore produced between approximately 1992 and 1997, frequently marketed as the "Opel Calais."

2.8 litre I6

The 2.8-litre inline-six engine was utilized across Kapitän, Admiral, and Commodore models. Monza and Senator versions were equipped with carburetted variants, whereas later Commodores received fuel-injected versions.

Single Carburettor (28S): Dual Carburettors (28H): Fuel Injection (28EC):

3.0 litre I6

Introduced in 1977, the engine came in two forms: the carburetted 30S delivering , and the fuel-injected 30E offering and outputs in the Opel Monza GSE, Opel Senator 3.0E, along with their Vauxhall equivalents. The bore was enlarged to , while the stroke remained unchanged.

In 1986, the Opel Omega 3000 / Vauxhall Carlton GSi adopted an enhanced 3.0-litre engine producing and , featuring larger valves and Bosch Motronic engine management technology. This iteration was subsequently fitted in Senator and Omega 3.0i models.

By 1989, a DOHC variant with a 24-valve head and a variable length intake manifold raised power figures to and .

3.6 litre C36GET I6

Lotus unveiled a high-performance version in 1990 for the Lotus Carlton/Omega, increasing displacement to by lengthening the stroke to , while maintaining the original bore size. After evaluating various forced induction options, Lotus selected twin Garrett T25 turbochargers paired with a Behr air-to-water intercooler arranged in parallel—each turbocharger serving three cylinders. The fuel injection system was specially calibrated, and compression ratio reduced to 8.2:1. This configuration generated at 5,200 rpm and torque of at 4,200 rpm.

Third-party tuner versions

Multiple German tuning companies such as Irmscher, Mantzel, Risse, and Steinmetz Opel Tuning developed crossflow and multi-valve cylinder heads compatible with the CIH engine block.

Swedentop

The Swedish company ENEM from Nacka extensively modified four-cylinder cylinder heads by incorporating larger valves, improved ports, and revised camshaft profiles tailored for rally racing; these advancements subsequently influenced official Opel designs.

3.0i I6

The Omega Evo was equipped with an Irmscher-enhanced 24-valve engine featuring strengthened internal components that produced .

3.6i I6

Irmscher engineered a 3.6i twelve-valve engine (designated code 36E) installed in Monza E/GSE models as well as select UK-market Vauxhall Senator Bs. From late 1987 onwards, updated Irmscher-tuned variants (codes 36NE, C36NE, C36NEI) powered Omega A/Mk3 Carlton and Senator B vehicles, delivering around , slightly below earlier Monza engines rated at . Moreover, Irmscher developed several 24-valve versions of the 3.6-litre unit.

4.0i I6

Irmscher and Mantzel both produced 4.0 litre CIH six-cylinder engines featuring a 24-valve DOHC configuration.

Mantzel’s M4024V engine converted standard Opel blocks such as the 30NE/C30NE/C30LE/C30SE to achieve a displacement of 4.0 litres; these were utilized in the Bitter SC manufactured between 1980 and 1986.

In contrast, Irmscher’s C40SE engine employed a uniquely cast block engineered specifically for this capacity increase, with bore and stroke measuring and , respectively, resulting in a total displacement of . It generated , powering models including the Opel Omega A, Senator B, and offered as an option on the Opel Omega Evolution 500.

Overhead Camshaft Diesel Variants

The CIH diesel engines were introduced in September 1972 and maintained popularity for over twenty years. Engineered with an emphasis on fuel economy and longevity, these compression-ignition units incorporated a strengthened block, extended stroke, and a single overhead camshaft design—making them taller than the petrol CIH counterparts. All models were inline four-cylinder engines available in three different displacements.

2.0-Litre Diesel

By the late 1970s, the 2.0-litre diesel gained wider adoption, initially appearing in markets such as Italy from late 1974. This engine was created by decreasing the bore of the prior 2.1-litre diesel to , while maintaining the stroke at , resulting in its specific displacement. Offered exclusively as a naturally aspirated 20D model with a 22:1 compression ratio and Bosch fuel injection system, it generated at 4400 rpm and of torque between 2000 and 2200 rpm. This engine was fitted in:

2.1-Litre Diesel

The 2.1-litre diesel debuted in 1972 alongside the Opel Rekord D, marking Opel’s initial foray into diesel engine manufacturing. Featuring a bore and stroke of , it displaced , offered solely as the naturally aspirated 21D variant. Matching the later 20D's 22:1 compression ratio and Bosch injection technology, it produced at 4400 rpm and delivered torque at 2500 rpm. This engine powered:

2.3-Litre Diesel

Launched in 1979, the CIH 2.3-litre diesel became a cornerstone engine for Opel’s premium diesel lineup during the 1980s. It evolved from the earlier 2.1-litre model by increasing bore size from 88 mm to 92 mm, elevating displacement to 2260 cc while preserving the original stroke of 85 mm. Unlike other CIH diesels, this engine was available in multiple versions including turbocharged and the uncommon Comprex pressure wave supercharger variants. The forced induction models featured sintered metal dry cylinder liners, oil squirters for piston cooling, and high-capacity oil pumps.

23D

The initial naturally aspirated version of the 2.3-litre diesel maintained a 22:1 compression ratio paired with Bosch fuel injection, resembling characteristics of the preceding 2.1-litre engine. It produced a power output of 65 PS at 4200 rpm and torque of 127 Nm at 2500 rpm; subsequent updates raised these figures to 71 PS at 4400 rpm and torque to 135 Nm at 2400 rpm. This engine was installed in:

23DK

Manufactured from 1984 to 1986, this supercharged variant employed a Comprex pressure wave supercharger instead of a traditional turbocharger. Featuring a compression ratio of 23:1 and Bosch injection system, it delivered a maximum output of 95 PS at 4200 rpm with peak torque reaching 195 Nm at 2200 rpm. It was utilized in:

  • Opel Senator A 2.3 Comprex D (1984–1986)

23DT

Also introduced in 1984, the turbocharged version known as the 23DT represented Opel’s first turbodiesel offering, equipped with a KKK K24 turbocharger. Retaining the same compression ratio of 23:1 and Bosch fuel injection setup, it generated power of 86 PS at 4200 rpm and torque measuring between 192 Nm within the range of 2200 to 2400 rpm. This engine was fitted in:

23YD

Launched in September 1986 alongside the Opel Omega A, this naturally aspirated engine increased its compression ratio to 23:1 while continuing to use Bosch fuel injection. It delivered a power output of 73 PS at 4400 rpm and generated 138 Nm of torque at 2400 rpm. Starting from 1989, a catalytic converter was incorporated.

23YDT

This 2.3-litre turbodiesel represented an evolution of the 23DT, providing higher horsepower at 4200 rpm and a maximum torque slightly lower than the previous 23DT at 2200 rpm.

23DTR

The last diesel variant of Opel’s CIH Four engine debuted in August 1988 as an enhancement over the 23YDT. It featured a turbocharger swap from the KKK K24 to the K14 model and included an air-to-air intercooler. Power output was achieved at 4200 rpm, with applications in:

Torque peaked between 2000 and 2200 rpm in the Omega, while in the Frontera it reached just under at 2200 rpm.

Motorsports

The CIH engine made a notable impact in motorsport competitions, available in both four- and six-cylinder configurations. It clinched the 1966 European Rally Championship with driver Lillebror Nasenius behind the wheel of an Opel Rekord B.

In 1969, Virgilio Conrero was appointed as Opel’s official rally team manager, responsible for vehicle preparation and driver selection until 1986. Under Conrero’s guidance, vehicles initially competed in hill climb events; notably, an Opel GT secured victory in the GT2.0 category at the 1971 Targa Florio.

In June 1972, shortly before introducing their diesel engine, Opel established two world records and eighteen international records at Dudenhofen using a diesel Rekordwagen—a one-seat Opel GT powered by a turbocharged 2.1 L OHC diesel engine producing .

Further reading

  • Lotus Carlton, Car and Driver, April 1991
  • Opel Straight 6-cylinder cars, Carfolio.com, March 5, 2006
Retrieved from "https://www.alfawiki.org/index.php?title=Opel_cam-in-head_engine&oldid=35217"