Mercedes-Benz M 121
| Daimler Benz | |
|---|---|
 M 121 installed in the Mercedes-Benz W 110 |
|
| M 121 | |
| Production period: | 1955-1968 |
| Manufacturer: | Daimler Benz |
| Working principle: | Otto |
| Motor design: | Four-cylinder in - line engine |
| Displacement: | 1897 – approx. 2000 cm 3 |
| Mixture preparation: | |
| Engine charging: | no |
| Power: | 48-77 kW |
| Previous model: | M 136 |
| Successor: | M 115 |
The M 121 engine is a four-cylinder in - line engine from Daimler-Benz . The gasoline engine was used in large numbers from 1955 to 1968 in Mercedes-Benz cars, minibuses and small trucks ; a Unimog prototype of the 411 series was also equipped with this engine in 1957.
The abbreviation "M" stands for "engine" (engine that runs on petrol / petrol) and is still used today to describe petrol engines from the Mercedes-Benz brand.
history
The M 121 is derived from the six-cylinder M 180 engine of the Mercedes 220 that appeared in 1952 and was first used in 1955 in the 190 model of the W 121 series with 75 hp. The 190 was offered parallel to the 180 , which until 1957 still had the M 136 from the 1930s before it was equipped with a reduced-power version of the M 121 (65 hp).
The main difference to the engines of the 170 and 180 Mercedes models is the overhead camshaft with drive via a duplex roller chain with oil-hydraulic tensioning rails and valve actuation via rocker arms . The M 136 was still a side valve with very rugged combustion chambers, which had an adverse effect on fuel consumption.
With the appearance of the tail fin model W 110 in 1961 (with the retained designation 190) the engine output increased by 5 hp to 80 hp. With the type 200 from 1965 onwards, the M 121 engine achieved a displacement of two liters and developed 95 hp. For the first time, Daimler-Benz used the constant pressure Stromberg carburetor , the slide piston of which is no longer actuated directly by the accelerator, but indirectly via a vacuum tracking system. The carburetors, which were only used in the four-cylinder engines from 1965 to 1968, were often criticized at first.
The first versions of the M 121 only had three crankshaft bearings : on the front pulley, between cylinders 2 and 3 and on the flywheel at the rear. The engine run is therefore quite rough. The most profound change to the M 121 was the crankshaft with five bearings introduced in the Mercedes 200 in 1965, which made the engine run smoother.
The equally powerful M 115 engine with 95 hp of the tailfin successor "Strich-Acht" ( W 115 ) is a hardly changed M 121; However, Daimler-Benz set the engine type number for the new gasoline engines to be M 115 in parallel with the vehicle model. In the model 220/8 now on offer, the displacement had also been increased to 2.2 liters, and in 1974 it was expanded again to 2.3 liters in the 230.4 model; only then were the possibilities of the old four-cylinder engine block exhausted.
use
M 121
- 190 SL ( W 121 B II ), 105 hp, 1955–1963
- Mercedes-Benz “Transporter” L 319 , 65 hp, from 1956
- Minibus O 319 , 65 hp, from 1956
- 190 ( W 121 , " small pontoon ") 75–80 hp, 1956–1961
- 180 ( W 120 , "small pontoon"), 65–68 hp, 1957–1961
- 190 ( W 110 , "small tail fin "), 80 hp, 1961–1965,
- W 110 200 ("small tail fin"), 95 hp 1965–1968,
M 115
- W 115 200 (Stroke-Eight), 70 kW (95 hp), 1968–1976
- W 115 220 (Stroke Eight), 77 kW (105 hp), 1968–1973
- W 115 230.4 (Stroke-Eight), 81 kW (110 hp), 1973–1976
- 123 200 series , 69 kW (94 hp), 1976–1980
- 123 230 series , 80 kW (109 hp), 1976–1980
- Series 601/602 (Bremer Transporter / T1) 208/308, 63 kW (85 PS), 1977–1982
Individual evidence
- ↑ Carl-Heinz Vogler: Unimog 411: Type history and technology . GeraMond-Verlag, Munich. 2014. ISBN 978-3-86245-605-5 . P. 42
