Mercedes-Benz M121 engine

The M 121 engine is a gasoline engine with four cylinders in line, designed and produced by Mercedes -Benz.

These engines were built in passenger cars, vans, small trucks and Unimog by Mercedes since the mid-1950s to 1968, more than a decade in large numbers.

The abbreviation " M" stands for "Motor" ( motor which is powered by gasoline / petrol ) and referred to today, the petrol engines from Mercedes -Benz.

History

The M 121 is derived from the published three years earlier six-cylinder engine of the Mercedes M 180 220. It was first used in 1955 model 190 series W 121 with 75 hp. The 190 was offered in parallel with the 180, which until 1957 still had the M 136 from the 1930s, before 121 ( 65 hp ) was equipped with a power-reduced version of the M.

The main difference to the engines of the 170 and 180 models is the Mercedes- overhead camshaft drive with a duplex roller chain with oil hydraulic tensioner rails and a valve actuation via rocker arms. The M 136 were still side -valve engine with its disadvantageous, very rugged combustion chambers.

Marking the publication of tailfins model W 110 in 1959 ( with the retained designation 190) the engine power increased by 5 hp to 80 hp. With the Type 200 from 1965, the motor M reached 121 two -liter displacement and delivered 95 hp. For the first time, where Daimler -Benz the same pressure -Stromberg carburettor, which spool is no longer actuated directly from the gas pedal, but indirectly via a vacuum - tracking. The carburetors that were used only in the four-cylinder engines from 1965 to 1968 were often initially criticized.

The first versions of the M 121 had only three crankshaft bearing: on the front pulley, a center bearing between cylinders 2 and 3 and the back of the flywheel. The engine is running very rough. Largest change in the M 121 was introduced in 1965 for the Mercedes 200 quintuple - bearing of the crankshaft. In order for the engine run was quiet.

Also, the same powerful engine M 115 with 95 hp of the tail fin successor Mercedes 200 is a barely modified M 121; However, Daimler- Benz sold for the new petrol engine type number ( parallel to the vehicle model W 115 ) new to M 115 fixed. With the optional now offered model 220/8 and the cubic capacity was expanded again, now at 2.2 liters. The concept of the engine type M 121 / M 115 should be expanded in 1974 with the model 230.4 to 2.3 liters; only with this engine capacity the possibilities of the four-cylinder engine block were exhausted. The M 115 came up in 1979 in the Mercedes models 200 and 230 (the latter also as a coupe ) of the 123 series for installation. The performance was at 220/8 at 77 kW (105 hp) and at 230.4 at 81 kW (110 hp).

From 1980 200 230 E and 123 series of the newly developed M 102 was used in the Mercedes.

Use

M 121

  • W 121 190 ( Ponton ) 75-80 hp 1955-1961
  • W 120 180 ( Ponton ) 65-68 hp 1957-1961
  • W 121 190 SL 65-68 hp 1955-1963
  • W 110 190 (small tail fin ) 80 HP 1961 to 1965,
  • W 110 200 ( small tail fin ) 95 HP 1965 to 1968,
  • Mercedes Unimog
  • Pick-Up Truck 319 L
  • O 319 minibus

M 115

  • W 115 200 ( line eight ) 70 kW ( 95 hp ) 1968-1976
  • W 115 220 ( line eight ) 77 kW (105 hp) from 1968 to 1973
  • W 115 230.4 ( line eight ) 81 kW ( 110 hp ) from 1973 to 1976
  • Series 123 200 69 kW ( 94 hp ) 1976-1980
  • Series 123 230 80 kW ( 109 hp ) from 1976 to 1980
  • Mercedes- Benz engine
Mercedes-Benz W123
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