Mercedes-Benz W116

History

The W116's development began in 1966, which was only a year after the launch of the W108/09. This was the first Mercedes-Benz sedan to feature the brand-new corporate styling theme, which endured until 1993, when the 190 was discontinued. The design, finalized in December 1969, was a dramatic leap forward, with more masculine lines that combined to create an elegant and sporty character. The basic design concept continued the themes originally introduced on the R107 SL-Class roadster, especially the front and rear lights. As with the SL, the W116 received the ridged lamp covers which kept dirt accumulation at bay; this was to remain a Mercedes-Benz design theme into the 21st century. The W116 was Friedrich Geiger's last design for Mercedes-Benz; his career had started with the Mercedes-Benz 500K in 1933.

The W116 was presented in September 1972. The model range initially included two versions of the M110 engine (straight-six with 2746 cc displacement) — the 280 S (using a Solex carburetor) and the 280 SE (using Bosch D-Jetronic injection), plus the 350 SE, powered by the M116 engine (V8 with 3499 cc displacement). After the 1973 oil crisis, a long-wheelbase 280 SEL was added to the model range.

The larger 4.5-litre M117 V8 engines were developed in response to US emission regulations and initially fitted to the 350 SL and 350 SLC for the US market in 1972, which were renamed as the 450 SL and 450 SLC in 1973. Mercedes-Benz introduced the 450SE and 450SEL for both US and international markets in 1973. The 4.5-litre models were available with three-speed automatic gearboxes only, while the models with smaller 3.5-litre V8 engine could be ordered with a four-speed (and later five-speed) manual gearbox. The 450 SE and 450 SEL received a plusher interior, with velour or leather seats rather than the checkered cloth of the lesser models. The door cards had the velour or leather inserts.

The 4.5-litre M117 V8 engines had 225 PS in most European and international markets, 190 hp for the US market, and 200 PS for Swedish and Australian markets.

The W116 had independent suspension and disk brakes on all four wheels.

The most notable W116 model was the high-performance, limited-production 450 SEL 6.9, which was introduced in 1975. This model boasted the largest engine installed in a post-war Mercedes-Benz (and any non-American production automobile) up to that time, and it also featured self-leveling hydropneumatic suspension.

Exclusive to the North American and Japanese markets was the 300 SD TURBO DIESEL, the world's first passenger car with a turbocharged diesel engine, which was introduced in 1978. No 300 SD TURBO DIESEL model was offered in Europe (where diesel engines were well-received and had tax advantages) until 1991, when the W140 300 SD was finally introduced in Europe and international markets.

The 450 SE was named the European Car of the Year in 1974, even though the W116 range was first introduced at the Paris Motor Show in the fall of 1972. The W116 became the first production car to use an electronic four-wheel multi-channel anti-lock braking system (ABS) from Bosch as an option from 1978 on.

Production totaled 473,035 units. The W116 was succeeded by the W126 S-Class in 1979. The W116 was sold throughout Europe, the Americas, Asia, the Middle East, Africa, and Australia.

Fuel injection

In 1975, the W116 was upgraded with a new fuel injection system to comply with revised exhaust emission standards in European markets. A slight power reduction was a result of this update. In 1978, a series of engine upgrades restored original performance levels with new fuel injection systems. The D-Jetronic fuel injection system fitted to the early 280 SE (1973-1974) had computers and MAP sensor that are prone to failure after more than 20 years of use. From 1975 onward they used the K-Jetronic mechanical fuel injection system, a less complicated system that proved to be much more reliable in the long run with injectors costing significantly less than those used on the D-Jetronic system. The W116 equipped with the K-Jetronic system used a cast-iron fuel distributor which can be prone to rust over time if moisture or water is present in the fuel. This was changed to an alloy fuel distributor in the following model W126 and is not subject to corrosion.

Hydropneumatic suspension

W116 was first model from Mercedes-Benz to feature the hydropneumatic suspension system. While the principle is similar to Citroën’s, Mercedes-Benz made some changes. The hydraulic pump was driven by the timing chain instead of a rubber belt for more reliability (Citroën’s system would lead to loss of hydraulic power if the belt failed). Mercedes-Benz utilised the hard rubber dampers as temporary dampers in event of hydraulic failure. The height adjustment had a smaller range of height as compared to Citroën (5 cm versus 50 cm). Unlike Citroën, the car did not “sink” to the ground after shutting off the engine, and the driver did not have to wait for the hydraulic power to spool up and lift the car to the operating height.

The full hydropneumatic suspension system was fitted to the 450 SEL 6.9 as standard. In 1977, the self-levelling rear suspension system was offered for 450 SEL as an extra cost option outside the North American market.

North American sales

North America was a key market for the W116. The model range for the U.S. market for 1973 was 450 SE and 450 SEL. Initially both models were unique to the US market, carrying on the tradition of the 4.5 litre W108/109 versions they replaced (and would become available in Europe only in early 1973). For 1975, the 280 S was launched as a response to the 1973 oil crisis. For 1977, the 280 S and 450 SE were dropped due to slow sales and replaced with the 280 SE. The 6.9 was added for 1978 with the MSRP of $38,230 and continued to be sold until 1980.

Due to the series of new federal safety and emission regulations in the 1970s, the W116 were described by journalists as if a "beautiful car was beaten with the malaise ugly stick." Furthermore, the performance was being continuously hampered by the increasingly stringent emission control and fuel economy legislation. Upon launch, the M117 engine for the US market developed a SAE net rating of 192 hp at 4750 RPM and 325 Nm at 3000 RPM for a car with curb weight of 1743 kg (450 SEL - 1755kg). In the final 1980 model year, the 450SEL was producing 162 hp at 4200 RPM and 312 Nm at 2500, weighing 1810 kg. For comparison, the European 450 SEL weighed 1765 kg, and its M117 made 225 hp at 5000 RPM through the entire production and 368 Nm at 3250 RPM at the end of production (performance would be adjusted twice - in November 1975 during the switch to K-Jetronic and its re-calibration in April 1978).

The 300 SD "TURBO DIESEL", the world’s first passenger car with a turbocharged diesel engine, was launched in the United States and Canada in 1978. It had a 3.0-litre turbocharged inline-five diesel engine developed from the C111 experimental vehicle. The 300 SD became a best seller and helped considerably raise Mercedes-Benz's Corporate Average Fuel Economy (CAFE). Mercedes-Benz would make S-Class models with the turbocharged diesel engines exclusively for the North American and Japanese markets until 1992.

{{anchor|6.9}}450 SEL 6.9

Main article: Mercedes-Benz 450SEL 6.9

The high-performance 450 SEL 6.9 version of the S-Class was built on its own assembly line by Daimler-Benz in Sindelfingen, Germany and based on the long-wheelbase version of the W116 chassis. The model was generally referred to in the company's literature as the "450 SEL 6.9" but simply "6.9" for the US market. Despite the model designation, the actual engine displacement is 6.8 litres.

The 450SEL 6.9 was first shown to the motoring press at the Geneva Auto Show in 1974 and produced between 1975 and 1980 in extremely limited numbers. It was billed as the flagship of the Mercedes-Benz car line and the successor to Mercedes-Benz's original high-performance sedan, the 300SEL 6.3.

Technical data

Features

The W116 S-Class incorporated a broad variety of Mercedes-Benz safety innovations.

• Four wheel anti-lock brakes were first featured as an option on the 1978 W116. This system prevents the wheels from locking while braking. The system improves steering control during hard braking situations, and to shorten brake distances.
• Strengthened body structure. The W116 featured a more stable security passenger cell with a stiffened roof frame structure. High strength roof and door pillars, along with other reinforced zones, provided enhanced vehicle occupant protection.
• Deformation zones (crumple zones) in the front and rear.
• A padded dashboard, deformable switches and controls, and a four-spoke steering wheel with impact absorber and broad impact cushion aimed to reduce occupant injury during collisions.
• The fuel tank was no longer fitted at the rear end, but was now placed above the rear axle for added protection.
• Wraparound turn signals made it easier to communicate with nearby drivers.

References

Bibliography

General

Workshop manuals

References

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2. (21 September 1972). "News". Autocar.
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4. Stjerna, Mikael. (June 2016). "Årets vinnare". Bonnier Tidskrifter AB.
5. [[#MS16. Stjerna]], p. 42
6. Stjerna]], p. 42
7. (2013-07-11). "In the lap of luxury: The Mercedes S-Class W116 | Classic Driver Magazine". Classicdriver.com.
8. [[#MS16. Stjerna]], p. 39
9. Ramey, Jay. (1 February 2016). "Mercedes W123 hits the big 4-0 The grandfather of the E-Class is still a daily driver all around the world". Autoweek.
10. (2012-03-12). "Exponat-Details: Mercedes-Benz 300SD". Daimler AG.
11. "MB Passenger Car Series 116, PDF p. 10".
12. "MB Passenger Car Types with Engine M117, PDF p. 13".
13. "MB AUS 1979, PDF p. 57".