The Mercedes-Benz OM 352 is a 5.7 litre inline-6 cylinder 4-stroke Diesel engine, made by Daimler-Benz.
Development It is one of many models in the 300 series of engines, which were developed during and after World War II, while specifically the OM352 was revealed in 1964. The OM352's lineage can be traced back to the OM311, itself an inline-six engine. The OM352 has many applications, including marine, military, municipal, and agricultural vehicles, as well as stationary settings. The engine has differing trim and power levels, affording designations such as OM 352A a variant fitted with a turbocharger, or the OM352 LA, which is fitted with an intercooler and a turbocharger. (List of Mercedes-Benz engines.)
The engine is water-cooled, and is produced using cast-iron cylinder block, with cast-in cylinders. The engine utilizes diesel fuel delivered in a direct injection method from a Bosch PES style inline injection pump. The cylinder head is a single unit for all cylinders, and the cylinder head cover and air intake are shared by a single cast aluminum alloy. Exhaust ports 2&3 and 4&5 are siamesed together, presenting an exhaust manifold with only four outlets.
The crankshaft is a precision forged unit running in seven three-layer bearings, with counterweights bolted onto the crank webs, much like any other diesel motor of its vintage. The middle bearing is also the thrust bearing. The connecting rods are of a split design, with bronze bushings for the piston pin.
OM314 In 1965, a four-cylinder variant derived from the six-cylinder OM352 was introduced, the OM314. Typical output for trucks was , later .
Licensed production The OM352 was also one of many Mercedes engines licensed in 1979 for manufacture by Atlantis Diesel Engines (ADE) in South Africa. These were known as ADE 352 and are virtually identical to the Mercedes engines. Recently the OM352 was licensed by Tata Motors for use in their 713S Trucks. These are manufactured by Tata but however have slight differences like the weights no longer being bolted to but rather part of the crank and no holes for oil sprayers in the block. These modifications are likely to reduce complexity and cost of engine production.
Common output power can vary from depending on the fuel delivery and air charge options. Higher output can be achieved through special modifications, however engine longevity may be affected with such non-factory modifications.
Improved engines developed after the OM314 and OM352 include the OM364 (4 cylinders) and OM366 (6 cylinders), which look extremely similar in appearance and marked the final stage of development for the 300 series engines due to emissions requirements. Mercedes Benz 900 series engines are the successors of engines such as the OM300 series.
OM352 variants for the German market
+Variants for the German marketRated power (DIN 70020)48 kW50 kW59 kW62 kW66 kW74 kW81 kW92 kW93 kW96 kW110 kW115 kW124 kW127 kWType designationOM 352.919OM 352.902OM 353.902OM 353.902OM 352.xxxOM 352.xxxOM 353.901OM 352.xxxOM 352.xxxOM 353.961OM 352.xxxOM 352.xxxOM 352.xxxOM 352.xxxTurbochargernoyesYear19641966196919711965196919691970196319xx196x1966197919xxSource
Technical specifications
Model OM 352 OM 352 OM 352 A OM 353 OM 352 LAYear 1964 1966 1975 1975 1979Vehicle Unimog 406 (U 65) Mercedes-Benz L 322 (L 1113) Unimog 425 (U 1500) Unimog 435 (U 1300 L) Mercedes-Benz L 322 (LAF 1113)Type designation 352.919 353.961ConfigurationWater-cooled Straight-sixOperating principleDieselValve systemOHV, two valves per cylinderAspirationNaturalTurbochargedNaturalTurbocharged and intercooled Oil system Wet sump Fuel system Direct injection Bore × Stroke 97 mm × 128 mmDisplacement5.675 LRated power (DIN 70020) at 2550/min at 2800/min at 2550/min at 2800/min at 2800/minMax. torque (DIN 70020) 353 N·m at 1600/min 461 N·m at 1600/min 363 N·m at 1700/min Mean effective pressure 784.5 kPa 955 kPa Mean piston speed 11.95 m/s Injection pressure 19.6 MPa 19.6 MPa Compression ratio 17 : 1 16 : 1 17 : 1 Mass 410 kg 460 kg 460 kg Firing order 1–5–3–6–2–4 Sump capacity 7–9 L Cooling system capacity 24 L Alternator 12 V, 0.24 kWSource
References Bundesamt für Bevölkerungsschutz und Katastrophenhilfe: Typenblatt Rüstwagen RW1 Bundesamt für Bevölkerungsschutz und Katastrophenhilfe: Schlauchwagen SW 2000-Tr Verband der Automobilindustrie: Daimler-Benz AG. Typ L 1113 LK 1113 Gruppe 14, Dezember 1966. DK 629.113.5
Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 61. Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 71. Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 76. Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 80. Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 102. Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 104. Carl-Heinz Vogler: Unimog 406 – Typengeschichte und Technik. Geramond, München 2016, . p. 106. Daimler AG: Dieselmotoren in Mercedes-Benz-Nutzfahrzeugen. Retrieved 4 February 2018. Daimler AG: Geburt einer Legende: Die 1949 vorgestellte Motorenbaureihe 300 ist ein großer Wurf. 22 April 2009. Retrieved 4 February 2018. Oldtimer-Traktor. Volume 11–12/2012. A. G. Daimler-Benz (Hrsg.): Unimog 435 Workshop manual, Book 1 Section 1.2/1.