Smaller Opel OHV 4-cylinder engines 1.2-litre (1973–1979) The Kadett C was launched in Germany with the 1.2-litre engine that had become an option for the Kadett B in 1971. As before in high compression (9.2:1 later, in 1975, reduced to 9.0:1)) "1.2S" form the unit returned a maximum output of at 5,400 rpm. However, the 1,196 cc engine was now also available as a "1.2N" with a lower 7.8: 1 compression ratio and in this form it produced a maximum of power at 5,600 rpm. The power output of the low compression ratio unit was improved in August 76 to at 5,400rpm, at the cost of a small reduction in maximum torque. The 1.2-litre unit powered 1,389,940 of the European Kadett Cs, equivalent to almost 82% of the Kadett Cs produced by Opel in West Germany and at their daughter plant in Belgium. Nevertheless, following the
1973 Oil price shock car buyers in western Europe had become far more economy minded. In the Kadett B, the 1.0 engines had been reserved for Mediterranean countries with punitive, displacement-based tax levels, but with the Kadett C the manufacturer begun to make the smaller unit available to West German domestic buyers as well. 254,723 Kadett Cs using the 1.0 engine were produced whereas only 10,691 of the Kadett Bs produced had incorporated this anemic motor., although it would appear again as the entry level engine in the
Opel Corsa A in 1982.
Larger Opel OHV "CIH" 4-cylinder engines 1.6-litre (1977–1979) May 1977 saw the addition of a smaller version of Opel's
Camshaft in Head (CIH) engine to the Kadett range, this time in high compression form as the "1.6S" unit. The 1584 cc engine shared the stroke of the larger CIH units, but the bore was reduced to . Maximum power of was quoted, providing for a listed top speed of in saloon bodied cars.
1.9-litre (1975–1977) For its first two years the Kadett C was offered with a choice between only the 1.0-litre and 1.2-litre motors, but September 1975 saw a return of the larger CIH power units to the Kadett range in the form of the Kadett GT/E, inheritor of the Kadett Rallye's mantle. The GT/E's 1897 cc engine had till 1973 featured in the earlier Kadett B range of power units, but now it incorporated
"Bosch L-Jetronic" fuel-injection. Maximum output of at 5400 rpm was virtually identical to that achieved by the Kadett B with its limited edition "Hochleistung" (high power) version of the same engine, but the earlier car had achieved its power level using old fashioned twin carburetors, a fuel feed approach now losing out to fuel injection in the face of increasingly stringent emission regulations.
2.0-litre (1977–1979) In September 1977, the 1.9-litre engine was replaced, in the "Rallye" Kadett, with a new enlarged 1979 cc unit. Fitted in the "Kadett Rallye 2.0E" this engine produced of power at 5400 rpm, which propelled the car to a top speed of , comfortably faster than any previous "Rallye" branded performance Kadett. The car's fuel consumption, listed at , was also a clear improvement. ==Running gear==