Mercedes-Benz OM 617

The OM 617 engine from Mercedes- Benz is a pre-chamber diesel engine with five cylinders in series. It was first in 1974 in the Model 240 D 3.0 W series 115 installed. It is derived from the four- cylinder OM 616 and differs from it only by the additional cylinder.

The abbreviation " OM " stands for " motor oil " (engine, which is operated with light oil / diesel). It represents the modular extension of the four-cylinder diesel OM 621 - OM 616 series and represents around a fifth cylinder and has the modular system with the OM 616 (240 D), the piston and connecting rod together - OM 615. The development was Ferdinand Piëch, grandson of Ferdinand Porsche and later CEO of Volkswagen AG, a major role. He practiced at that time an engineering office in Stuttgart and later built five-cylinder engines also at Audi.

Use in models

  • W 115 240 D 3.0
  • W 116 300 SD Turbodiesel (for U.S. export)
  • W 123 300 D
  • W 123 T 300 TD
  • C 123 300 CD diesel and turbo diesel (U.S. export)
  • W 123 300 D Turbo Diesel ( U.S. export )
  • W 123 300 TD Turbo Diesel ( also home market )
  • W 126 300 SD Turbodiesel (U.S. export)
  • Puch / Mercedes G 300 GD
  • Mercedes -Benz T 1 (209 D, 309 D, 409 D)

Data

  • Bore 91 mm, stroke 92.4 mm Displacement 3005 cc
  • Compression 21: 1
  • Power 59 kW (80 hp) at 4000 rpm
  • Torque 172 Nm at 2400 rpm
  • Maximum speed 5100/min

In August 1979, the performance using a modified cylinder head ( steeper camshaft, other atria ) was increased, and the bore slightly reduced:

  • Bore 90.9 mm, stroke 92.4 mm Displacement 2998 cc
  • Compression 21.5: 1
  • Power 65 kW (88 hp) at 4400 rpm
  • Torque 172 Nm at 2400 rpm unchanged

This was the five-cylinder naturally aspirated diesel in the 240 D 3.0 and 300 D comparable performance with the weakest four-cylinder petrol engine in the Mercedes 200 ( W 115, W 123).

Turbo variants

1978, attempts take place in the experimental vehicles C 111 with exhaust-gas turbochargers. These experimental versions of the OM 617 reached 190 horsepower initially, later 230 hp. Thus, several world record runs were carried out in the southern Italian Nardo.

In the 123- series turbo engine came in a throttled to 125 hp version for use.

Turbocharging, serially produced for the American market and the S 123 T- model "300 TD Turbo Diesel" in Europe was used from 1978 300 SD Turbo ( W 116 ), put it up to 250 Nm. Other brands such as BMW, Alfa Romeo, Audi, etc. had later comparably strong diesel on offer, such as BMW from 1983 to 2443 - cc six-cylinder engine with 85 kW, Audi from 1982 a 74 kW two-liter five-cylinder turbo with intercooler and from 1990 88 kW 2.5 -liter TDI.

OM 617 950 ( turbo ) in 1979:

  • Bore 90.9 mm, stroke 92.4 mm Displacement 2998 cc
  • Compression 21.5: 1
  • Power 85 kW ( 115 hp) at 4000 rpm
  • Torque 250 Nm at 2400 rpm
  • Maximum speed of 5200 rpm

OM 617 952 ( turbo ) in the year 1982:

  • Bore 90.9 mm, stroke 92.4 mm Displacement 2998 cc
  • Compression 21.5: 1
  • Power 92 kW ( 125 hp) at 4350/min
  • Torque 250 Nm at 2400 rpm
  • Maximum speed of 5200 rpm

This turbocharged engine was the first diesel engine, which has been found to collect in the bodies of the S-Class and the coupé ( the middle class ) for suitable - Daimler -Benz was about keeping within the U.S. government fleet fuel economy. So you let the models 300 SD ( S-Class diesel) and 300 CD (diesel coupe ) are produced, the first (S -Class W 116 Coupé C 123 ) ) and second body versions ( S-Class 126 series coupe C 124) were only sold in the United States. Only after the change came to the Successor engine S -Class cars with diesel engines in Europe in the sale.

In these turbo engines splash oil - cooled pistons were used and they were the first production engines in the world sliding bearing manufacturer Glyco, where on the steel backing layer, the bronze bearing layer and the galvanic coating in a vacuum nor a top -bearing layer by " sputtering " ( from gas deposit ) was applied.

This technique is due to their hardness and wear properties, since in many high-performance engines in series production. Tuning experiments with diesel engines failed often with engine failure at too low a piston cooling and low friction bearings on the crankshaft, which could not withstand the higher combustion pressures.

Development and problems

From the first series engines fell partly with problems with the quality of the cast now extended to the fifth cylinder engine housing. Likewise, there were initially problems with the turbos - the high pressures of the crankshaft bearing variously led to damage. Daimler- Benz sold in these engines then (see above) for the first time with a slide bearing a sputtered layer.

The first turbos were partially high continuous load at high outside temperatures no match when, after high-load driving such as on the highway at a rest stop the engine immediately, ie is switched off without a cool down and then stand in the glowing turbo residual oil can carbonize to the turbocharger shaft - an operator error, which still can provide turbocharger failures today.

Both the naturally aspirated large first-generation and especially the turbos away with their large displacement of three liters markedly from the old diesel reputation of economy. Below about 10 liters per 100 km can the 59 kW variant and the turbos (also as a result of the standard automatic transmission ) Experience has shown that hardly move. Only the 65 - kW version with manual transmission, especially with the five-speed gearbox available from 1982, brought the three-liter diesel with less than 9 liters per 100 km consumption values ​​that fall well below the small petrol engines this time.

Since the late 1990s, another advantage of this diesel generation is striking: The OM 617 is like its four-cylinder engines and sister and the subsequent generation of diesel engines well suited for operation with vegetable oil. With the original injectors ( Bosch DN0SD220 ) the cold start properties are relatively poor. It can, however, easily the Vorstrahldüsen ( DN0SD261/265/314 ) from the W 124 mount, which also improves the cold start. The regular emissions testing proves that it is possible that in this generation still quite high turbidity levels significantly reduced by vegetable oil.

Compared to more modern diesel engines is noticeable that the OM 617 series as his siblings still works quite rough. The five-cylinder can, especially in the series, in which he was employed prior to the six-cylinder three-liter ( U.S. models of the S-Class W126 ), not compete in comfort and consumption data with the following engine type OM 603. However advantage of the older type of motor is its comparatively insensitive to damage the cylinder head gasket, as the casting material of the motor housing and the cylinder head with the OM 617 is still the same, whereas the successor has an aluminum cylinder head with a consequently differing expansion behavior.

Mercedes-Benz W123 Engine displacement SDI (engine) Mercedes-Benz W124 Plain bearing
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