Mercedes-Benz OM 636 diesel engine

Daimler Benz
OM 636
Production period:	1949-1990
Manufacturer:	Daimler Benz
How it works:	diesel
Engine Type:	line
Valve control:	Overhead valves
displacement:	1697-1767 cm 3
Fuel supply:	indirect injection
Engine charging:	none
Power:	18-32 kW
torque:	96-101 N · m
Previous model:	OM 138
Successor:	OM 621

The OM 636 is a four-stroke - antechamber - diesel engine with four cylinders in series , developed and produced by Daimler-Benz . He was introduced in 1949. Successor became the OM 621 .

These engines were installed in cars, vans and small trucks Mercedes-Benz since the late 1940s. Other manufacturers built this engine in their vehicles. The abbreviation "OM" stands for "oil engine", so an engine that runs on light oil / diesel, and refers to today's diesel engines from Daimler .

History 

During the Second World War, Daimler-Benz, headed by Fritz Nallinger, developed a successor for the OM 138 , which was to be used as an engine in the Mercedes-Benz 170 D passenger car of the W 136 series. By 1948 at the latest, the engine was ready for production, but was not yet installed in the car. Instead, the company Boehringer tested the engine with the model 636.912 for Daimler-Benz and built it into the then produced by Boehringer Unimog 70.200 series . This engine has a bore of 73.5 mm and, accordingly, only in 1697 cm ³ capacity, furthermore it has a split valve cover. The power is 25 hp (18.5 kW) at 2300 / min.

The series engines produced later by Daimler-Benz have a bore enlarged to 75 mm and a displacement of 1767 cm ³ .

After 1961, with the appearance of the tailfin successor model W 110 , the OM 636 was no longer used in passenger cars of Mercedes-Benz. He was replaced by the OM 621 .

In addition, however, the OM 636 was installed in a variety of other vehicles; Starting with the drive for the Unimog and in the first versions of the light-duty Mercedes-Benz L 319 and the minibus Mercedes-Benz O 319, the engine was also used in forklifts , as a built-in engine in ships, as well as to power generators , fire pumps and many others. In cars, engines of the type OM 636 were also installed: Seat in Spain equipped the derived from the Fiat 124 taxi models until the late 1980s optional with this Mercedes engine.

For example, since the engine was no longer installed in cars, the production took place only in Spain at the MEVOSA. As a built-in motor, z. For example, for forklift trucks, the engine type was in the price lists of Daimler -Benz until the 1990s..

The motor is water-cooled and has a thermostat with short-circuit cable. The engine block and cylinder head are made of cast iron , the OM 636.912 and OM 636.915 have two valve covers, all other models have only one through-going. The triple crankshaft and connecting rods are forged from steel. The pistons are cast forged depending on the model or and made of light metal. The engine has overhead valves (2 per cylinder) and a bottom camshaft driven by a pair of gears ( OHV). The in-line injection pump from Bosch is driven from the camshaft via a further pair of gears. The fuel is injected into prechambers . The inlet and the antechambers are left, outlet, camshaft and injection pump are arranged on the right. The model 636.914 has no injection timing and is throttled over the final speed, the model 636.930, however, has a injection timing. The cooling water pump is installed in the cylinder head as in the case of the OM 138 and is driven by a belt from the crankshaft.

The weak point of the engine is the thermal overload of the cylinder head, because the bridge between the valves is too narrow and the heat can not be dissipated. This can lead to hairline cracks and ultimately water ingress into the combustion chamber. 

Other use of the OM 636 

• Farm tractor driving D177 and D177S
• Bührer Special (UM4)
• Combine harvester Ködel & Böhm KÖLA Combi, Lanz MD 18 S, Fahr MDL, Claas Columbus
• Güldner A4M
• Hanomag Pickup Truck
• Built-in motors for
  • Electricity generators
  • fork-lift truck
  • marine propulsion
  • Thermoking cooling units