wikipedia says,
On its debut,the C-Class was the only Mercedes model with a complete lineup of multi-valve engines. The new family of four cylinder petrol units,called M111,debuted in the C 180 (1.8 L,122 PS (120 hp/90 kW)),C 200 (2.0 L,136 PS (134 hp/100 kW) and C 220 (2.2 L,150 PS (148 hp/110 kW),the only four cylinder of the range sold in the U.S.). In 1996 the C 220 was replaced by the C 230,enlarged to 2.3 L displacement but with the same output,although with torque increased to 220 N·m (162 lb·ft). The C 280 was the high end model of the class,with a four-valve-per-cylinder straight-6 engine,capable of reaching 193 PS (190 hp/142 kW).
so,there it is,a c-180 has 1.8L,c200 has 2.0L,c-220 has 2.2L..similarly,the s-600 v12 has a 6.0 litre engine..
cheers.
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