Mercedes-Benz W 109

Mercedes Benz
Mercedes-Benz 300 SEL 4.5 (US version)
W 109
Production period:	1965-1972
Class :	Upper class
Body versions :	limousine
Engines:	Gasoline engines : 2.8–6.3 liters (125–184 kW)
Length:	5000 mm
Width:	1810 mm
Height:	1440-1470 mm
Wheelbase :	2850 mm
Empty weight :	1655-1830 kg
Previous model	Mercedes-Benz W 112
successor	Mercedes-Benz W 116

The Mercedes-Benz W 109 was a luxury-class model from Mercedes-Benz and was in production from September 1965 to autumn 1972. The 300 SEL with air suspension received the designation W 109, while the models with conventional steel springs were designated as W 108 . The facelift in the spring of 1968 brought the transition from mechanical to electronic intake manifold injection .

Production of the successful series ended in November 1972. The successors were the “S-Class” models from the W 116 series .

Model history

General

Mercedes-Benz 300 SEL 6.3 in the Mercedes-Benz world

In August 1965, the 250 S, 250 SE and 300 SE, some of which had less power, appeared as the new generation of the Mercedes-Benz luxury class, but in September 1965 the successor to the 300 SE long (W 112) with air suspension was presented. He too received the body drawn by Paul Bracq , the lines of which were reminiscent of the coupé of the W 111 series .

Unlike the W 112, which was always equipped with air suspension and was available with a short and long wheelbase (+ 100 mm), the W 109, which was also always equipped with air suspension, was only available with a long wheelbase. The W 109 differs from the 300 model W 108, which is available with a short or long wheelbase, except for its air suspension in the details of the engines (suspension for the compressor), the interior, the basic equipment and the doors.

From January 1968 a revised version of the model series was offered. The changes affected, among other things, the range of engines, the interior and the design of the steering column.

In the automatic versions, the selector actuation on the center lever changed: the parking position P was initially at the rear, but in 1968 it came forward, as was common practice.

technology

The engine of the 300 SEL with an aluminum block and head developed 125 kW (170 hp) at 5400 rpm. A more powerful version of the 2.8-liter injection engine with 125 kW (170 hp) was not only installed in the two-seater 280 SL ( W 113 ) sports car , but also in the 300 SEL from January 1968. There he replaced the equally powerful, complex to manufacture and high-fuel consumption 3.0-liter light metal engine. This rare variant is also called the 300 SEL 2.8 without the additional displacement designation appearing on the trunk lid.

The top model of the W 109 model series was the 300 SEL 6.3 with the Mercedes-Benz M 100 V8 engine and the automatic transmission of the Mercedes-Benz W 100 (Mercedes 600) in March 1968 . It develops 184 kW (250 hp) at 4000 rpm. The maximum torque is 500 Nm at 2800 rpm. Its top speed is 220 km / h, the acceleration from 0 to 100 km / h takes 6.5 seconds (factory specification). His performance at the Geneva Motor Show was a sensation, especially since there had been no hints in advance. From the outside, the 6.3 could only be recognized by the wider tires, the H1 halogen double headlights and the additional long-range lights. The price of the new W-109 top model was initially 39,160 DM and at the end of the model series in January 1972 was 47,397 DM, which corresponds to 74,400 and 77,000 euros, respectively, based on current purchasing power and adjusted for inflation. Although in 1968 the model cost more than DM 13,000 more than the 300 SEL with 2.8 liter engine and was more than twice as expensive as the 280 SE (W 108), the "6.3" met with interest and was sold in quantities of 6,526 units produced.

Factory replica of the 300 SEL 6.8, the "Rote Sau"

The 6.3 quickly found its way into touring car racing and rallying . The car also became a popular tuning object, as the engine was designed with a low specific power of 29 kW / l and higher power could be extracted from it without any effort.

In the autumn of 1969, the 300 SEL with a 2.8-liter six-cylinder engine of the 300 SEL 3.5 was replaced. The newly designed Mercedes-Benz M 116 was a V8 engine with a displacement of 3.5 liters, 147 kW (200 hp). It was the first Mercedes engine with electronically controlled injection (Bosch D-Jetronic ).

US versions

Initially exclusively for the North American market, parallel to the 3.5-liter V8 engine, an enlarged version with 4.5 liters had been developed. a. was delivered in the export model 300 SEL 4.5. This was necessary in order to meet the American emissions regulations and, with a lower compression, the fuel in the USA, which at that time was still partially low-octane. The output of the 4.5-liter USA engines was 146 kW (198 hp), just about the level of the European engines with 3.5 liters.

There is one difference in the automatic transmissions of the 4.5-liter versions for the USA: they already correspond to the more modern type with a torque converter - but a three-speed automatic.

In contrast to the US versions, automatic cars for the European market have a four-speed transmission without a torque converter. The motor and gearbox are connected to a Föttinger or fluid coupling with a pump and turbine wheel without a stator.

All three V8 engines, the "smaller" types 3.5 and 4.5 liters as well as the large V8 engine were then also used in the successor model W 116 with a torque converter. The eight-cylinder got a three-speed, the six-cylinder a four-speed gearbox.

From mechanics to electronics

When construction began, the mechanical six-plunger injection pumps replaced the more simply constructed injection systems with two-plunger pumps and flow dividers, which were difficult to adjust and which were often noticeable with high consumption. In contrast to the simpler diesel injection pumps, these gasoline injection systems had a steel control cam ("space cam"). It was adjustable in two independent axes, namely it was moved lengthways according to the speed and rotated according to the load (accelerator pedal position). A fixed feeler roller determined the amount of fuel to be metered based on the radius at the moment. The complex, copy-milled space cam ("potato") depicts the engine's consumption map. There were also correction elements for warm-up and altitude.

The precision mechanical requirements of these Bosch systems led to the most complex maintenance and repair work to date on automobiles in the 1960s. One of the most expensive spare parts in automotive history is the mechanical eight-piston injection pump for the 6.3-liter V8 engine, which in the 1980s cost up to 40,000 DM as a new Bosch spare part in small series. With their manufacturing costs, peculiarities and defects, these systems were the reason for the development of simpler injection systems during the transition into the 1970s.

The smaller eight-cylinders were the first series vehicles from Daimler-Benz to have an electronic injection system, the Bosch D-Jetronic.

The front wheels are individually suspended on double wishbones with coil springs, telescopic shock absorbers and a stabilizer . The axle and the motor are mounted on a subframe , which is connected to the body at the rear by rubber bearings and at the front by leaf springs (which absorb the longitudinal forces). A single-joint swing axle is installed at the rear .

The W 109 series had disc brakes on all four wheels from the start. A vacuum servo was part of the brake. The parking brake acts on the duo-servo drum brakes on the rear axle via cables . The steering gear works with a ball screw drive (recirculating ball steering).

Model variants

• 300 SEL (2.8)
• 300 SEL
• 300 SEL 3.5
• 300 SEL 4.5 (US version)
• 300 SEL 6.3.

Motors and drive

1. 300 SEL (2.8) and 300 SEL have six-cylinder in - line engines with mechanical six-piston injection pumps from Bosch and in both cases an output of 125 kW (170 hp).
2. The V8 engines ( M 116 / M 117 ) with a displacement of 3.5 and 4.5 liters (US version) have electronic injection (Bosch D-Jetronic ) and engine outputs of 147 and 146 kW (200 and 198 hp).
3. The 6.3-liter V8 engine ( M 100 ) has a mechanical Bosch eight-piston injection pump and an output of 184 kW (250 hp). The engine comes from the Mercedes 600 .

Vehicles with a six-cylinder engine were supplied with a four-speed manual transmission as standard. A four-speed automatic transmission and, from 1969, a five-speed manual transmission, a very rarely ordered option , were available as special equipment . The eight-cylinder models had a four-speed automatic transmission with hydraulic clutch (i.e. no torque converter) installed as standard, or, on request and at a reduced price, the four-speed manual transmission, which was rarely ordered. Only the 4.5 series models, which were delivered exclusively to the USA from 1971, had a three-speed automatic transmission with torque converter, which was also used in the successor model, the W116.

A limited slip differential was optional . The 300 SEL 6.3 had it as standard.

Model overview and technical data

model	construction time	Model	Engine type	Art	Displacement	power	number of pieces	0-100 [s]	V max	consumption
					[cm³]	[PS] / [kW]		aut / man	aut / man	[l / 100 km]
300 SEL	9 / 65-12 / 67	109.015	M 189.988	R6	2996	170/125	2,369	12	195/200	18th
300 SEL (2.8)	12 / 67-1 / 70	109.016	M 130.981	R6	2778	170/125	2,519	10.5	200	12
300 SEL 3.5	8 / 69-9 / 72	109.056	M 116.981	V8	3499	200/147	9,583	10	200	13
300 SEL 4.5	5 / 71-10 / 72	109.057	M 117.981	V8	4520	198/146	2,553	9.5	205	14.5
300 SEL 6.3	12 / 67-9 / 72	109,018	M 100.981	V8	6332	250/184	6,526	6.5	220	15.5

Variants and special equipment

Mercedes-Benz 300 SEL Landaulet

There were only four-door sedans with a long wheelbase as standard. Occasionally they are said to have been converted into convertibles or landaulets . A landaulet for Pope Paul VI is known. that was later partially armored for Pope John Paul II . Daimler-Benz also fulfilled unusual customer requests for a corresponding surcharge.

Export models

US export vehicles are standardly “more environmentally friendly” than the other vehicles. The strict Californian approval regulations were achieved with lower compression and corresponding reduced power, exhaust gas afterburning and closed tank ventilation.

In the USA, the sedans were offered with two circular headlights ( sealed beam ) one above the other, in accordance with American law . One-piece, round headlights behind oval lenses in two variants were the rule for European vehicles.

From 1969, similar double headlights were also offered for the European market and were standard in the top model 300 SEL 6.3 . Since many older cars were converted to the more modern double headlights, the single headlights are rarer and more popular today.

literature

• Heribert Hofner: The S-Class from Mercedes-Benz. From the culture of driving. Bleicher, Gerlingen 1993, ISBN 3-88350-164-6 .
• Alexander Franc Storz: Mercedes-Benz W 108/109. Motorbuch Verlag, Stuttgart 2016, ISBN 978-3-613-03906-3 .

Web links

Commons : Mercedes-Benz W 109  - Collection of pictures, videos and audio files

• Mercedes-Benz W 108/109 . In: Mercedes-Benz-PublicArchive.com
• Mercedes-Benz W 108/109 . In: MercedesClubs.de
• Mercedes-Benz W 108/109 . In: Media.Daimler.com

Individual evidence

1. ↑ This figure was based on the template: Inflation determined, rounded to 100 EUR and applies to the previous January
2. ↑ Oldtimer Markt, issue 7/1998 (July 1998), VF Verlagsgesellschaft mbH, Mainz, p. 8 ff .: Der Kraft-Wagen
3. ↑ http://sterntwiete.mparschau.de/html/einspritzung_2.html