|Mercedes-Benz OM617 engine|
|Cylinder block alloy||Cast iron|
|Cylinder head alloy||Cast iron|
|Valvetrain||SOHC 10 valve|
|Turbocharger||No (OM 617.91x 617.931)
Yes (OM 617.95x)
|Fuel system||Indirect injection|
|Management||Bosch M pump
Bosch MW pump
|Fuel type||Diesel fuel|
|Oil system||Wet sump|
The OM617 engine family is a straight-5 diesel automobile engine from Mercedes-Benz used in the 1970s and 1980s. It is a direct development from the straight-4 OM616. It was first fitted to the W115 series in 1974. The OM617 is considered to be one of the most reliable engines ever produced with engines often reaching over 1,000,000 km without being rebuilt and is one of the key reasons for Mercedes' popularity in North America in the 1980s, as it was powerful and reliable compared to other automotive diesels of the 1980s. It is also a very popular choice for the use of alternative fuels, mainly straight or waste vegetable oil and biodiesel, although the use of these "alternative" fuels may cause engine damage over time if not processed properly before use.
The very first OM617, a 3.0 L (3005 cc) engine, debuted in 1974 with the W115 chassis. Power output was 80 hp (59 kW) @ 4000 rpm and torque was 17.5 mkg @ 2400 rpm.
- 1974-1976 240D 3.0 / 300D
This was introduced with the W123 series. It was originally 80 PS (79 hp/59 kW.) This engine had a few improvements over the .910, mainly in the air, fuel, and oil system, to adapt to the 123 chassis. In August 1979 the precombustion chamber was updated for more swirl and more efficient combustion. The new camshaft pushed the valves deeper so the air and exhaust gases had less resistance. By changing the bore to 90.9 mm, the engine capacity was lowered to 2998 cc to satisfy engine displacement tax laws in Europe, but power output rose to 88 PS (87 hp/65 kW). Torque remained at 172 Nm @ 2400 rpm.
- 1982–1988 209 D / 309 D / 409 D
- 1979-1991 W460/W461
The revised .950 displaced 3005 cc. It was heavily upgraded to withstand the extra stresses of the turbocharger. Modifications included oil squirters to cool the underneath of the pistons; sodium filled valve stems and a stronger crankshaft. Also an uprated chain driven oil pump was fitted as the turbocharger lubrication required higher flow. In 1978, the OM617.950 was mated with the Mercedes-Benz W116 to produce the North American market-only 300SD, the world's first production turbodiesel sedan. Power originally was 111 hp / 82 kW @ 4200 rpm, torque 228 nm @ 2400 rpm. From October 1979 - 121 hp / 89 kW @ 4350 rpm, torque 230 nm @ 2400 rpm.
- 1978-1980 300SD Turbo
The .951 was introduced in 1979 and displaced 2998 cc, using a 90.9 mm bore and 92.4 mm stroke. It was an upgraded .950. Power originally was 121 hp / 89 kW @ 4350 rpm, torque 230 nm @ 2400 rpm. From October 1982 - 125 hp / 92 kW @ 4350 rpm, torque 250 nm @ 2400 rpm.
The .952 is identical to the .951 apart from minor changes to fit the North American only 123 chassis. It was also fitted to the European market W123 wagon, the 300TD. This was the only turbocharged OM617 fitted to a European W123. Power originally was 121 hp / 89 kW @ 4350 rpm, torque 230 nm @ 2400 rpm. From October 1982 - 125 hp / 92 kW @ 4350 rpm, torque 250 nm @ 2400 rpm.
- "Mercedes-Benz W115 240D 3.0 Wiki". http://wiki.mercedes-benz-classic.com/index.php/W114-W115-240D3.0-Motor/en.
- "Mercedes-Benz W123 300D Wiki". http://wiki.mercedes-benz-classic.com/index.php/W123-300D-Motor/en.
- "Mercedes-Benz W460 300GD Wiki". http://wiki.mercedes-benz-classic.com/index.php/W460-300GDK-Motor/en.
- "Mercedes-Benz W116 300SD Wiki". http://wiki.mercedes-benz-classic.com/index.php/W116-300SD-Motor/en.
- "Mercedes-Benz W126 300SD Wiki". http://wiki.mercedes-benz-classic.com/index.php/W126-300SD-Motor/en.
- "Mercedes-Benz W123 300D Turbo Wiki". http://wiki.mercedes-benz-classic.com/index.php/W123-300TD-Motor/en.