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| stroke = | displacement = | length = | diameter = | width = | height = | weight = | block = Cast iron | head = Cast iron | valvetrain = Cam-in-head | supercharger = | turbocharger = | fuelsystem = | fueltype = | oilsystem = | coolingsystem = Water-cooled | power = | specpower = | torque = | compression = | fuelcon = | specfuelcon = | oilcon = }} The Opel Cam-In-Head engine ("CIH" for short) is a series of inline engines which was built from 1965 until 1995 and was available in four- or six-cylinder configurations. Its name derives from the location of the camshaft, which was a compromise between an overhead valve and an overhead cam layout. The camshaft was mounted above the cylinder but aside the valves and actuated them through a very short tappet and a rocker arm, as it was not near enough to act directly upon the valves. The layout was an evolutionary dead-end and was not adapted for other engines. The 4-cylinder CIH was largely supplanted by the Family II unit as Opel/Vauxhall's core mid-size engine in the 1980s, with a large capacity 2.4L version of the CIH remaining in limited production until 1998 in the Omega A and latterly, the Frontera A models. The 6-cylinder versions of the CIH remained in volume production until 1995. There was also a diesel engine using this layout, first seen in the Opel Rekord D in 1972. ==Design== The CIH is not a true overhead camshaft design, although the camshaft is mounted in the cylinder head, driven by a roller chain - rather it can be thought of as a "hybrid" between an overhead valve (OHV) and an OHC configuration. Later versions used hydraulic tappets, a design which was pioneered by Opel for mass market production. The valves were in a reverse flow layout, both mounted on the right side of the engine (when longitudinally mounted). 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 was oversquare, with the original three versions having a very short stroke of only . Later engines of over 2000 cc received longer strokes, up to for the 2.2 and for the 2.4 (also used for the 3.6 litre inline-six version). While an improvement over an OHV engine, the advantages over an OHC design were limited. The biggest one may have been cosmetic, with the lower head allowing for a correspondingly lower bonnet line. The CIH engine was also lighter (although this was negated by the use of a cast iron head) and it should require less maintenance than the more common OHC design. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Opel Cam-in-head engine」の詳細全文を読む スポンサード リンク
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