Opel cam-in-head engine


The Opel cam-in-head engine is a family of automobile engines built by former General Motors subsidiary Opel from 1965 until 1998, appearing extensively in Opel/Vauxhall badged cars during this period. Both four- and six-cylinder inline configurations were produced. The name derives from the location of the camshaft, which was neither cam-in-block nor a true overhead camshaft. In the CIH engine the camshaft is located in the cylinder head but sits alongside the valves rather than above them, so therefore effectively is still an overhead valve design. The valves are actuated through very short tappets and rocker arms. The engine first appeared in the Opel Rekord B in 1965, and was largely replaced in four-cylinder form by the GM Family II unit as Opel/Vauxhall's core mid-size engine in the 1980s, with the six-cylinder versions continuing until 1994 in the Omega A and Senator B. A large capacity 2.4L four-cylinder version continued until 1998.
A diesel version of the CIH was also developed. This engine debuted in the Opel Rekord D in 1972.

Design

The original design of the cam-in-head engine was done by General Motors in Detroit, Michigan.
Although the camshaft is in the cylinder head, the CIH is not a true overhead camshaft design. Rather it can be thought of as a cam-in-block engine with a greatly shortened valve drivetrain. The camshaft is driven by a roller chain. While the earliest engines use mechanical lifters, later versions use hydraulic tappets, which Opel pioneered for mass market production in the Family II unit which ultimately replaced the CIH. The cylinder head is a non-crossflow layout. This led to lowered fuel economy but was considerably cheaper to manufacture. The head and block are both made from cast iron. The CIH engine is oversquare, with the original three versions having a stroke of only. Later engines of over two litres received longer strokes; up to for the 2.2 and for the 2.4.
While an improvement over a cam-in-block engine, the advantages over an OHC design were limited. For one, the lower head allowed for a correspondingly lower bonnet line. The CIH engine was expected to require less maintenance than an OHC design and was also lighter, albeit negated somewhat by the use of a cast iron head.
Unlike its smaller stablemate - the Opel OHV, the CIH was never adapted for transverse mounting, and is always found in rear wheel drive Opel/Vauxhall cars.
Opel developed their own crossflow head for the CIH block, and tested it in the experimental GT-2 of 1975 with the intent of installing it in the production model. In four-cylinder form, this engine reached only limited production as the Kadett GT/E's 20EH engine. The crossflow head did see mass production in six-cylinder form as the 3.0 24V in the Opel Senator B.

Four-cylinder versions

1.5 litre I4

This is the smallest of the three original CIH engines introduced simultaneously. A bore and stroke gives a displacement. As with most of Opel's engines of the 1960s and 1970s, versions optimized for low and high octane fuel were offered, with the 15N for normal and the 15S for super. Power ranged from for the 15N while the rare 15S in the export-only Kadett B and Olympia A has DIN at 5000 rpm. SAE output was 76 hp at 5600 rpm.
This engine was imported by Daewoo's predecessor companies GM Korea and Saehan Motors and went on to be built in South Korea by Daewoo beginning around 1983. The automobile taxation system of South Korea greatly favours engines of less than 1.5 litres displacement. It was installed in the Saehan Camina, the Saehan Gemini series, and in the Saehan/Daewoo Royale. 1.9 and 2.0 litre versions were also built in Korea.
;Applications:
The version has a bore and the same stroke as most CIH fours. It was introduced in September 1970 with the all new Opel Manta A and then, seven weeks later, in the Opel Ascona A. As with the 1.5 litre, a 16N for lower octane fuel and a more powerful 16S for higher octane fuel were offered. Power outputs were at the time of introduction, but dropped to respectively in early 1975 when tighter pollution controls were introduced. From 1975 there was also a still-cleaner A16S version with 69 PS for some markets, this specific model also had a forged crank with 8 crankweights. It was replaced by a version of the Family II engine that appeared in the Opel Ascona C/Vauxhall Cavalier Mk II.
;Applications:
The CIH was another of the original three introduced. Bore is while stroke remains. The 1700 was only ever available in carburetted form, for either normal or super petrol with corresponding power outputs. Power output is for the original 17N, while the 17S version produces DIN at 5200 rpm. Claimed SAE output for the 17S was 84 hp at 5600 rpm. The output of the 17N went up to in 1969, and then back down to the original 60 after the compression was lowered in 1975.
The 17S received a new carburettor setup in 1972 when the Rekord D was introduced, and power rose to. In the larger Rekord, the 17S was popular in export markets like Italy and Greece where owners' costs were directly linked to engine displacement.
;Applications:
  • August 1965 - July 1966 Opel Rekord B
  • August 1966 - December 1971 Opel Rekord C
  • September 1967 – 1970 Opel Kadett B 1.7 S
  • August 1967 - July 1970 Opel Olympia A
  • January 1972 - August 1977 Opel Rekord D
  • August 1977 - 1980 Opel Rekord E
  • February 1970 - December 1971 Ranger A
  • January 1972 - August 1977 Ranger B
  • August 1972 - 1976 Chevrolet 1700

    1.9 litre I4

The CIH was the largest of the original three introduced. Bore is while the stroke remains. The 1900 was available in carburetted or fuel injected forms, for either normal or super petrol with a variety of power outputs. An N version was a later addition. Output is DIN at 5100 rpm for the original 19S; SAE power is 102 hp at 5400 rpm. There was also the 19HL, introduced in 1967 for the sporty Opel Rekord Sprint and Kadett Rallye Sprint models. This version has, compared to for the slightly more powerful 19SH only fitted to the Rekord. The 19SH lost some power in 1975, down to and the new 19N was introduced to replace the discontinued 17S; like the 17S it offered but used cheaper gasoline and more relaxed driving characteristics. The 1900 is the most common version in the CIH family, available in the most versions and with the longest production time.
The 19E was the first of the CIH four-cylinders to receive fuel injection. It first appeared in the Manta GT/E in March 1974, with. There is also a low-powered Austrian market version of the 19N with which was mostly fitted to the Opel Rekord E, and a special low emission version for the Swedish and Swiss markets called the S19S which develops. This specific model, along with the S16S, had a forged crank with 8 crankweights.
;Applications:
  • August 1965 - July 1966 Opel Rekord B
  • August 1966 - December 1971 Opel Rekord C
  • September 1967 - July 1973 Opel Kadett B Rallye
  • August 1967 - July 1970 Opel Olympia A coupé
  • October 1968 - middle 1973 Opel GT
  • September 1970 - August 1975 Opel Manta A
  • October 1970 - September 1975 Opel Ascona A
  • January 1972 - August 1977 Opel Rekord D
  • August 1975 - May 1981 Opel Manta B
  • September 1975 - August 1981 Opel Ascona B
  • September 1975 - July 1979 Opel Kadett C GT/E
  • August 1977 - August 1982 Opel Rekord E
  • February 1970 - December 1971 Ranger A
  • January 1972 - August 1977 Ranger B
  • May 1974 - February 1976 Holden Torana LH
  • February 1976 - November 1976 Holden Torana LX
  • November 1976 - March 1978 Holden Sunbird LX
  • March 1978 - 1978 Holden Sunbird UC
  • 1978 - 1985 Saehan/Daewoo Rekord/Royale
  • November 1975 - July 1981 Vauxhall Cavalier Mark I

    2.0 litre I4

The CIH was based on the 1.9 litre version, with the bore expanded to while the stroke remained. Unlike the earlier 1.9, the 2.0 received hydraulic tappets. Developed to counteract the diminishing outputs which resulted from stricter emissions rules, the 2.0 was available in carburetted or fuel injected forms, for either normal or super petrol with a variety of power outputs. Output of the original 20S, presented in September 1975, is at 5200 - 5400 rpm. This was soon followed by the fuel injected 20E version, with, and the slightly more powerful 20EH fitted to the Kadett 2.0 GT/E. This received the Bosch L-Jetronic system, until it was replaced by the updated LE-Jetronic towards the end of 1981. A 20N version appeared in August 1977. There are also two special low-emission versions for the Swedish and Swiss markets, called the S20S and S20E, with slightly less power than their dirtier counterparts.
;Applications:
  • September 1975 - August 1977 Opel Rekord D
  • September 1977 - August 1988 Opel Manta B
  • September 1977 - August 1981 Opel Ascona B
  • September 1977 - July 1979 Opel Kadett C GT/E, Rallye
  • August 1977 - June 1986 Opel Rekord E
  • 1984 - 1990 Chevrolet Rekord
  • 1978 - 1985 Saehan/Daewoo Royale
  • November 1975 - July 1981 Vauxhall Cavalier Mark I
  • late 1978 - June 1986 Vauxhall Carlton

    2.2 litre I4

The 2.2 CIH engine was fuel injected and was produced from 1984 through 1987. Its bore was 95mm but stroke was increased to 77.5mm. Also, the cylinder head was redesigned. It had bigger valves and intake ports were lifted. Also, hardened valve seats were added to accept unleaded fuel. Power output rose slightly:, with of torque.
It was used in the Opel Rekord E, Opel Monza A2 and Opel Senator A2.