Mercedes-Benz M 116 / M 117 V8 engine

Mercedes Benz
M 117
Manufacturer:	Mercedes Benz
Production period:	1969-1991
Style:	V, eight-cylinder
Engines:	3.5 liters-5.5 liters
Successor:	Mercedes-Benz M119

The M 116 and M 117 are eight-cylinder - V engines from Daimler-Benz . The 1969 built and 1991 gasoline engines found in various Mercedes-Benz - upper class -Pkw use.

They were derived from the technically very similar, larger and stronger V8 engine M 100 . There was no direct forerunner. Successor was the 1989 presented M 119 with four-valve technology .

The engines are water-cooled and have an overhead camshaft ( OHC ) per cylinder bank driven by a duplex roller chain . The valves (2 per cylinder) are operated by drag levers and are arranged in a row that is slightly inclined to the inlet side (inside the cylinder-V). This results in wedge-shaped combustion chambers . Until 1976, the D-Jetronic gasoline injection was used by Bosch, after which the K-Jetronic was used.

The engines have a steel forged five-way crankshaft in crossplane design and an angle of 90 ° between the cylinder banks. The firing order is 1-5-4-8-6-3-7-2, with the cylinders in the right bank numbered from 1 to 4 and in the left from 5 to 8. As a result, the mass forces and moments of first and second order are completely balanced.

The cylinder heads are made of aluminum alloy and the engine block was initially made of gray cast iron , with displacement of 3.5 (M 116) or 4.5  liters (M 117). In 1978, the 450 SLC 5.0 C 107 series was offered with a variant of the M 117 with aluminum engine block and 5 l displacement. From 1979 with the model change to the 126 series , all variants of the M 116 and M 117 were placed on the aluminum block and at the same time increased the displacement to 3.8 and 5.0 l respectively.

The aluminum engine block without cylinder liners was manufactured from a hypereutectic aluminum - silicon alloy. Larger Si crystals form in a matrix of fine Al and Si crystals. By electrolytic treatment of the cylinder surfaces, the matrix is ​​removed, and the 0.02 to 0.05 mm Si crystals stand out slightly and provide a wear-resistant tread for the piston and piston rings . The lubricating film adheres well to this slightly rough surface.

As part of the "Mercedes-Benz Energy Concept", the engines were extensively revised in 1981 to reduce gasoline consumption. Among other things, the diameter of the crank pins has been reduced from 52 mm to 48 mm in order to reduce the friction loss and increase the compression. The M 116 was designed long-stroke, with unchanged 3.8 l displacement. This results in smaller, more compact combustion chambers and improves efficiency because the hot gas loses less heat to the combustion chamber wall. The design has been changed in favor of more torque at low speed to support economical driving at high efficiency operating points . Added to this were other measures, such as exhaust gas recirculation to limit nitrogen oxide emission, regulationthe idling speed, which was also lowered, and much longer drive ratios .

In 1985, the catalyst technology for both engines was introduced, after previously had been offered a (but significantly reduced power) cat variant of the M 116. The KE-Jetronic was used, a further development of the K-Jetronic with electronic control interlocking for the lambda control . The capacity of the M 116 was simultaneously increased to 4.2 l, also was a version of the M 117 with 5547 cm ³ (sales name "560") added. Thus, there were three displacement levels of 4.2, 5.0 and 5.5 l.

The engines were available in RÜF- (catalytic converter retrofit) and KAT version. The 560 was also available for about a year in a 220 kW ECE variant, which was not factory retrofitted with Kat, but later could be converted with catalysts from third party (Wurm-Kat). Upgraded ECE engines are identifiable by split exhaust manifolds on each V-Bank, making the front exhaust system four-flow rather than double-flow as with other V8 engines. The limousines and coupes of the S-Class W126 equipped with this were the first vehicles to receive a maximum speed limit of 250 km / h. They should compete with the BMW 750i with V12 engine .

In 1987, the engines were revised again. They got a knock control and the compression was increased to 10: 1, which improved performance and efficiency.

Further development M117 to the M117 / 9 (AMG) and the M119 (DB) 

The then still independent, initially specialized in Mercedes vehicles tuning AMG mounted on the 5.6-liter versions at the end of the 1980s self-developed four-valve cylinder heads, which gave the M117 engines with high compression power of about 270 kW. The AMG engines, however, could not easily be installed in one of the cars produced at that time: Because of the space-demanding valve control at AMG on the vehicles of the W 126 series, the sheets of the front bulkheads were changed. These engines were given the designation M 117/9, an anticipation of the later produced by Daimler -Benz four-valve successor type M 119 for the models 500 E ( W 124 ), SE, SEL ( W, V 140 ), SEC (C 140 ) and SL ( R 129 ).

As the successor to the two-valve M 117 engines, Daimler-Benz's M 119 family of less-advanced four-valve engines, with their standard output of 200 to 235 kW, are considered by many to be the best V8 engines ever used by Daimler-Benz in passenger cars. In the successor models, Daimler-Benz moved away from four-valve technology for gasoline engines with more than four cylinders and offered three-valve cylinder heads with double ignition with the engine type M 113 as well as the successors for all V-engines. It was not until 2005 that the M 273 returned to four-valve technology.

Parallel to the European or normal versions of super-fuel engines, lower-compression versions for the United States have been manufactured for local standard fuel. Reasons: obligate catalysts (California environmental legislation) with the need to operate the engines with unleaded fuel, on the other hand, as at the time, lack of environmentally friendly TetraethylbleiSubstitutes in fuel for high compression. As a result, these US V8 engines deliver significantly less; An example is the 4.5-liter W 108 / W 109 engine (280 SE / SEL 4.5, 300 SEL 4.5), which only produced 143 kW compared to 147 kW of the smaller 3.5-liter engine. Motors of the Europe vehicles. The engine of the 560 SEL / SEC / SL in the US version is in contrast to the previous US versions of the M 116/117 not less compacted and makes with a compression of 9: 1 170 kW / 231 hp with Cat. The same Engine was also used in European vehicles, but he made here due to a modified exhaust system 178 kW / 242 hp with regulated catalyst (200 kW / 272 hp without Kat). In the ECE version of the Mercedes makes 560 220 kW / 300 hp.

In the fall of 1987, a knocking control system was set for all M 116/117The compression increased from 9: 1 to 10: 1, which also increased performance by about 10%. Only in the model R107 (420 SL, 500 SL, 560 SL) the less compacted unit continued to be used unchanged until the end of production of the 107 series in 1989. The US engines with lower compression, which were produced by 91 RON until 1985, due to the hardly available fuels in the US, can only be converted extremely expensive to the European standard: New cylinder heads with peripheral parts and new pistons are needed. These engines for the US consume approximately the same amount of fuel; Their speed level is also nearly equal, so they are not durable. Only difference remains the performance disadvantage.

The eight-cylinder engines of younger versions made due to poor choice of materials and suppliers often unpleasant attention, because camshafts, hydraulic tappetsand drag lever early tended to damage (" pitting "). Newer, better camshafts for replacement are marked - a feature that should be considered in vehicles with low mileage. Vehicles with more than 150,000 kilometers have often already mounted new shafts after damage. In addition, the ignition controllers of the versions from 1987 to 1991 are prone to drying thermal paste on the heat sinks of the power semiconductors, which leads to their failure and thus very expensive replacement need - a mistake that can be avoided by precautionary and cost-effective replacement of the paste.

After all, it is hardly possible to drive these engines under 12 liters of fuel consumption; strong versions, quickly moved, can also consume 20 liters. A consumption of 15 to 16 liters is considered normal. As a result, many vehicle owners incorporate LPG ( LPG ) systems into their cars . However, these conversions can be used in the technical examination for the issue of H license platesProblems with the decrease make, since this conversion under new legal situation must have been made "contemporary" - with technology, which was a maximum of ten years after Erstzulassung available. Vehicles that are already equipped with a Venturi LPG system and also have the H-mark, have grandfathering. Vehicles with a modern, sequential injection LPG system can not get H license plate according to German legislation.

Data and Vehicle Models

M 116

• 280 SE Coupe 3.5 ( W 111 )
• 280 SE, SEL 3.5 ( W 108 )
• 300 SEL 3.5 ( W 109 )
• 350 SE, SEL ( W 116 )
• 350 SL, SLC ( R 107 , C 107 )
• 380 SE, SEL, SEC ( W 126 )
• 380 SL, SLC (R 107, C 107)
• 420 SE, SEL, SEC (W 126)
• 420 SL (R107)

M 117 

• 280 SE, SEL 4.5 ( W 108 ) USA, 143 kW / 195 hp
• 300 SEL 4.5 ( W 109 ) USA, 143 kW / 195 hp
• 450 SE, SEL ( W 116 )
• 450 SL, SLC ( R / C 107 )
• 450 SLC 5.0 (C 107)
• 500 SE, SEL, SEC ( W / V / C 126 )
• 500 SL, SLC ( R / C 107 )
• 560 SE, SEL, SEC ( W / V / C 126 )
• 560 SL ( R 107 ) USA
• 500 GE ( Mercedes-Benz G-Class , W 463 Series)