Mercedes-Benz M23 engine
{{Infobox automobile engine
|image = Autoseum_15_-_Mercedes-Benz.jpg
|name = Mercedes-Benz M23
|alt = 1936 Mercedes-Benz 130 engine block
|caption = 1936 Mercedes-Benz 130
|manufacturer = Mercedes-Benz
|production = 1933-1936
|configuration = Inline-4
|bore = {{convert|70-72|mm|in|1|lk=on|abbr=on}}
|stroke = {{convert|85-92|mm|in|1|lk=on|abbr=on}}
|displacement = {{convert|1.3-1.7|L|cuin|0|lk=on|abbr=on}}
|valvetrain = 16-valve, DOHC, two-valves per cylinder
|power = {{convert|25-55|hp|kW|0|lk=on|abbr=on}}
|torque = {{convert|74|lb.ft|N.m|0|lk=on|abbr=on}}
|fuelsystem = Carburetor
|fueltype = Gasoline
|compression = 6.0:1{{Cite web|url=https://sportlichleicht.com/info/engines/m23|title=Mercedes-Benz M23 Engine|website=Sportlich-Leicht}}
|oilsystem = Dry sump
|weight =
}}
The Mercedes-Benz M23 engine is a naturally-aspirated, 1.3-liter, inline-4 gasoline engine, designed, developed and produced by Mercedes-Benz; between 1933 and 1936.{{Cite book|url=https://books.google.com/books?id=fFg2EAAAQBAJ&dq=1936+mercedes-benz+m23+engine+specs&pg=PT189|title=Mercedes-Benz Saloon Coupe: The Complete Story|first=Nik|last=Greene|date=September 27, 2021|publisher=Crowood Press|isbn=9781785009341|via=Google Books}}{{Cite web|url=https://sportlichleicht.com/info/engines/m23/|title=Mercedes-Benz M23 Engine|website=Sportlich-Leicht}}{{Cite web|url=https://www.autoevolution.com/cars/mercedes-benz-typ-150-sport-roadster-w30-1934.html|title=MERCEDES BENZ Typ 150 Sport Roadster (W30) specs & photos - 1934, 1935, 1936|website=autoevolution}}{{Cite web|url=https://media.daimler.com/marsMediaSite/en/instance/ko/Mercedes-Benz-150-Sport-Roadster-W-30-series-1934---1936.xhtml?oid=9274461|title=Mercedes-Benz 150 Sport Roadster (W 30 series, 1934 - 1936)|website=marsMediaSite}}{{Cite web|url=https://media.daimler.com/marsMediaSite/en/instance/ko/Mercedes-Benz-150-Sport-Saloon-W-30-series-1934.xhtml?oid=9271852|title=Mercedes-Benz 150 Sport Saloon (W 30 series, 1934)|website=marsMediaSite}}{{Cite web|url=https://media.daimler.com/marsMediaSite/en/instance/ko/Mercedes-Benz-170-H-W-28-series-1936---1939.xhtml?oid=9271853|title=Mercedes-Benz 170 H (W 28 series, 1936 - 1939)|website=marsMediaSite}}{{Cite web|url=https://www.autoevolution.com/cars/mercedes-benz-typ-170-h-w28-1936.html|title=MERCEDES BENZ Typ 170 H (W28) specs & photos - 1936, 1937, 1938, 1939|website=autoevolution}}{{Cite web|url=https://dyler.com/posts/152/mercedes-170-h-the-beetle-before-the-beetle|title=Mercedes 170 H: The Beetle Before the Beetle|website=dyler.com}}
Development and prototype engines (W17/W25D)
At the beginning of the 1930s, there were attempts to move car engines from the forward compartment to the rear of the car. Such a move allows a reduction in the volume of the front compartment. At the same time, the voluminous rear provides a lot of space above and behind the rear axle. Moreover, when engines are rear-mounted, the drive shaft is eliminated.
In 1930, Daimler-Benz entrusted Hans Nibel with the development of a small rear-engined car, starting from the same principles. In 1931, working with Max Wagner, the type W17 or 120(H) was created, a two-door, equipped with a four-cylinder boxer engine in the rear with a displacement of 1200 cc and a power of 25 hp (18.4 kW). There were also attempts with transverse four-cylinder inline engines. In 1932/1933 Mercedes built a prototype with a front similar to the later VW Beetle, and a longer tail.{{Cite web|url=https://dkwautounionproject.blogspot.com/2017/07/dkws-1933-rear-engine-streamliner.html|title=DKW Auto-Union Project: DKW's 1933 Rear Engine Streamliner|date=April 1, 2017}}
Mercedes-Benz 130 (W23) engine
Created in 1931 by Nibel, it had the 1.3 liter sidevalveSetright, L. J. K. "Mercedes-Benz: The German Fountain-head", in Northey, Tom, ed. World of Automobiles (London: Orbis, 1974), Vol. 11, p.1311. four-cylinder engine mounted at the back, hence the "H", from German heck (rear),Lyons, Pete. "10 Best Ahead-of-Their-Time Machines", in Car and Driver, 1/88, p.73. With the fan between the rear coil springs,Setright, p.1311 photo. it drove a transmission with three forward speeds, plus a semi-automatic overdrive which did not require the use of a clutch.
Mercedes-Benz 150 (W30) engine
It was derived in 1935 from the 130, and a more powerful engine. Displacing 1498 cc and a power of 55 PS (40 kW). The engine powered the car to a top speed of 125 km/h.
Created in 1934 by Nibel and chassis engineer Max Wagner. the 150H was a two-seat sports roadster. It featured transverse leaf spring front and coil-sprung swing axle rear suspension. A water-cooled {{convert|1498|cc|cid|abbr=on|lk=on}} OHC four-cylinder engine, producing {{convert|55|hp|kW|abbr=on}}, was mounted in back, hence the "H", from German heck (rear). The radiator was behind that, above the transaxle, with a squirrel-cage blower (reminiscent of the VW Type 1) feeding both radiator and carburetor.
The gas tank, which in the case of the Mercedes-Benz 130 was installed over the engine, was transferred to the front compartment.
Mercedes-Benz 170 H (W28) engine
In 1936, in parallel to the classical front-engine Mercedes-Benz 170 V, Daimler-Benz AG introduced the Mercedes-Benz 170 H which had the same engine as the 170 V, with an architecture derived from that of the 130, its predecessor. The 170 H was powered by a four-cylinder 1697 cc engine with a power of 38 PS (28 kW). The "H" stood for "Heckmotor", or rear engine.{{cite journal|last=Osborne|first=Donald|title=1936 Mercedes-Benz 170H Saloon|journal=Sports Car Market |date=December 2013 |volume=25|issue=12|pages=56–57}}