After launching the OM616 in-line 4-cylinder diesel engine family in 1973, Mercedes-Benz decided to derive a further series of a slightly higher category, equipped with an extra cylinder.
In 1974, the Stuttgart company began production of the first ones OM617 5-cylinder engines, introduced on the 240D 3.0 and 300D versions of the W115 series sedans and coupes and used until 1991, when they gave way to the new OM602 family. The OM617 series is considered one of the most reliable ever produced, capable of accumulating mileage greater than million km without any kind of intervention except ordinary maintenance.
The aspirated versions
The first naturally aspirated version of the OM617 is the one offered with the W115 240D 3.0 which flanked the 4-cylinder 240D: it had a displacement of 3,005 cc (bore of 91 mm and stroke of 92.4 mm) and delivered a maximum power of 79 CV.
To improve combustion efficiency and meet new tax laws in Europe, Mercedes technicians built a update of the engine, equipping it with a new pre-combustion chamber and slightly reducing the bore to 90.9 mm for a displacement of 2,998 cc.
Exactly one year later the OM617 engines were made the subject of a further refinement through a new one camshaft which allowed a greater lift of the intake and exhaust valves. The power thus increased to 88 hp while the torque remained unchanged at 172 Nm.
In this version the engine fitted the W123, ancestor of the E-Class, the TN series vans and the W460 and 461 G-Class off-roaders, which were also the last to offer it until 1991.
The supercharged version
In 1976 an experimental turbocharged variant signed OM617A, which developed the beauty of 187 HP, went to equip the C111-IID prototype, setting numerous speed and duration records on the Nardò test circuit.
It was necessary to wait until 1978 for the arrival on the market of Mercedes’ turbocharged 5-cylinder: in that year on the North American market the flagship S-Class W116 was offered in the variant 300SD which made it the world’s first turbodiesel sedan. The power was downsized to 109 hp with 228 Nm of torque subsequently increased to 119 hp and 230 Nm and then again to 125 hp and 250 Nm and also used on several variants of the W123 medium.
OM617 naturally aspirated
|3.005 cc||1974-1978||79 CV||Mercedes-Benz 240D 3.0, 300D|
OM617 naturally aspirated
|2.998 cc||1978-1991||88 CV||Mercedes-Benz 300D, 300D North American, 300D Long, 300 TD, 300CD North American, 209D, 309D, 409D, Classe G W460/461|
|OM617 supercharged||2.998 cc||1978-1985||da 109 a 125 CV||Mercedes-Benz 300SD Turbo, 300TD Turbo, 300D Turbo North American,|
300CD Turbo North American