Der Zenit (Part One)

The 1991 W140 S-Class was a technological tour de force, and possibly the finest car Mercedes-Benz ever made. Its arrival was also painfully mistimed. We remember the Uber-Benz on the thirtieth anniversary of its launch.

Mighty. Image:

The arrival of a new Mercedes-Benz S-Class was always a seminal event for the automotive industry. It often heralded the introduction of new technology and safety features that would subsequently be adopted by other Mercedes-Benz models and, eventually, by its lesser competitors.

The 1959 W111 predecessor to the S-Class was the first car to feature a rigid passenger safety cell with front and rear crumple zones, to slow the deceleration that occurs in a high-speed impact and dissipate the kinetic energy released(1). In 1978, the W116 S-Class was the first car in the world to feature electronically controlled anti-lock brakes. The 1979 W126 S-Class introduced seat belt pre-tensioners, to restrain passengers in the event of an impact. This innovation was followed in 1981 by a driver’s side airbag, intended to work in concert with the seat belts(2) as part of the company’s Supplemental Restraint System (SRS).

The W140 S-Class was the replacement for the highly regarded and successful 1979 W126 model, which sold a total of 818,063 cars during its twelve-year production life. The design of the W126 had begun in the midst of the 1973 Middle East Oil Crisis and the anticipation of increasingly stringent US auto emissions standards, so fuel efficiency and low emissions were a priority from the beginning.

This resulted in a notably clean and elegant aerodynamic profile (with a Cd of 0.36) with limited and subtle decorative embellishment. The W126 was an understated car, even in long-wheelbase 560SEL form. That was exactly right for its intended customer base, who wished to travel in great comfort but relative anonymity. By any standards, the W126 would be a hard act to follow.

Image: carsbase

The driving force behind the W140 was Werner Niefer, who was chairman of the company’s board of management from 1989 to 1993, having sat on the board since 1987. It was Niefer who insisted that the company’s new flagship should look as impressive and imposing as possible, to be a visual metaphor for the peerless technology it contained and take its rightful place as the world’s best car.

Even in the critical North American market, where larger cars were the norm, the W140 must stand out as special, he insisted. To this end, all the development work took place on the standard LWB car, and the SWB version was a very late addition to the programme, sanctioned by Niefer with considerable reluctance.

The W140 was something of a shock when, after eight years in development, it was presented to the public at the Geneva Salon in March 1991. It was first revealed at a party in Geneva’s Noga Hilton Hotel ballroom, when a huge wooden container covering it was hoisted up into the ceiling. The journalists and industry watchers present clapped politely, but immediately began to discuss the social and environmental acceptability of such an apparent behemoth.

Mercedes-Benz’s marketing people explained somewhat unconvincingly that the car was finally catching up with the growth in size of its occupants over the preceding decades, but the doubts hardened. One German motoring magazine, Auto Motor und Sport, headlined its feature on the new S-Class “Sternegrog” or Star-Sized.

While still a commendably clean shape, it appeared to be a much bigger and bulkier car than its predecessor, which looked almost svelte by comparison. Appearances were deceptive, however: the SWB model was just 93mm (3¾”) longer, 66mm (2 ½”) wider and 49mm (2”) taller than its predecessor. The difference in length between the LWB models was even less(3), just 53mm (2”). One area where the two cars differed more markedly was their weight: the W140 SWB weighed from 1,880kg (4,145lbs), a hefty 360kg (792lbs) more than the W126.

Many might be surprised by the relatively minor differences in dimensions. The reason for the W140’s perceived greater bulk may be its overly deep side glass, which makes the cabin look much larger, and its smooth flanks, unadorned by any decoration other than the lower bodyside cladding. In any event, it makes the W126 appear to be a masterful design in the way it conceals its bulk.

Sacco’s vision: early concept drawings for the W140 (c) Mercedes-Benz

There is an interesting anecdote concerning the height of the W140 to be found in a 2004 book(4) titled ‘The Challenge: Accelerating the Mercedes-Benz Brand’: Wolfgang Peter, Mercedes-Benz chief engineer, and car line manager Rudolf Hornig were both 190cm (6’3”) tall. Bruno Sacco, head of design, had originally envisaged a low and sleek car, inspired in part by Jaguar’s XJ saloon, but in 1987 when his tall colleagues sat in the mocked-up interior, they found themselves with insufficient headroom.

The mock-up’s adjustable roof was raised until both men were comfortable and happy. Sacco and his colleague, Harald Leschke, to whom the W140’s design was credited, tried to disguise the additional height of the glasshouse, but it remained a feature of the production car. It is alleged that Sacco was dismayed by the corruption of his concept, but Niefer was not to be challenged: bigger, and taller, was what he wanted.

BMW had wrong-footed its Stuttgart rival in 1986 with the launch of its E32 generation 7 Series, which introduced a 5.0 litre V12 engine to power the top range models. Mercedes-Benz could not countenance being trumped by the Bavarian upstart, so delayed the W140 programme for eighteen months to develop its own V12. Naturally, it had to be larger in capacity, so would be a 6.0 litre unit.

The increase in weight of the W140 was partly due to a stronger and heavier bodyshell, but also the much higher level of standard equipment fitted, including double-glazed windows, speed-sensitive power steering, electrically adjustable heated front seats (and rear seats on LWB models), dual zone climate control and self-closing doors and boot lid.

Image: Masbukti

Mercedes-Benz engineers had been developing an ultrasonic rear parking aid for the W140, but it was not yet reliable enough for the production car at launch. Instead, they installed motorised telescopic chrome-plated steel rods that rose automatically from the rear wing tips of the car whenever reverse was selected. This was an elegant, but complex and expensive solution to the problem.

The W140 was not launched with any specific new safety features, but a number were added during its production run. These included side-airbags, Electronic Stability Programme (ESP), Brake Assist System (BAS) Xenon HiD headlamps and rain-sensitive automatic wipers.

One extraordinary miscalculation in the W140’s otherwise meticulous development programme concerned its maximum total payload. Because of the weight of the car itself, the payload was just 402kg (885lbs) for the 300SE and 488kg (1,074lbs) for the 400SE. Potentially, that severely limited its luggage carrying capacity when travelling with five adults on board. That miscalculation would have serious implications for Wolfgang Peter, as we will see later.

In Part Two we will recall how the W140 was received by the motoring press and customers, and discover why Mercedes-Benz would never build another car like this.

Author’s note: How might the W140 have looked if Bruno Sacco’s original concept had not been compromised by Peter and Hornig’s intervention?  We investigate this question here.

(1) In the same year, Volvo began fitting three-point lap and diagonal seat belts to its cars, making 1959 the most significant year ever in the evolution of automotive safety.

(2) General Motors was actually the first company to offer optional airbags in some Buick, Cadillac and Oldsmobile models. Its 1974 ‘Air Cushion Restraint System’ (ACRS) was intended to replace, not supplement front seat belts, which were lap-only in ACRS equipped cars. The NHTSA waived the requirement for driver and front seat passenger to wear seat belts in cars so equipped. Despite this, take-up of the option was limited to 10,000 cars and ACRS was dropped in 1976.

(3) The reason for the difference is that the LWB version of the W126 had a 140mm (5 ½”) stretch in the wheelbase over the SWB version, whereas the W140 only had a 100mm (4”) stretch.

(4) ‘The Challenge – Accelerating the Mercedes-Benz Brand’ by Wolfgang Peters and Jürgen Zöllter, published by Delius Klasing. 

Author: Daniel O'Callaghan

Shut-line obsessive...Hates rudeness, loves biscuits.

17 thoughts on “Der Zenit (Part One)”

  1. Werner Niefer started his career in their large diesel department at Maybach Friedrichshafen/MTU. Later he became head of the bus division – maybe that’s an explanation for his love of large cars.
    The W140 suffered several hiccups during its development. Relatively late in the test programme it was decided that the brakes were under dimensioned and the car had to be redesigned for larger wheels to accommodate larger brakes. That necessitated a complicated and expensive change to inner wheelarches and contributed to the excessive weight and lack of payload.
    The V12 was added as an afterthought and because engineers were only told the engine should be bigger and more powerful than that of their Munich competitor nobody paid attention to other aspects of the engine which as a result was often criticised for its relatively noisy running and general lack of smoothness for a V12.
    The W140 marked a tipping point in Mercedes’ approach to design and engineer a car. For the original W140 Mercedes designed the headlamp reflectors and made Bosch/Hella produce them to this design. Post-facelift the headlights were bought in and were designed by the suppliers – with the result that they gabe fory percent more light and were thirty percent cheaper to make.
    Only after the W140’s presentation did they find out that it didn’t firt the cargo cars of Deutsche Bahn because of its excessive width. This was a major problem because the only way to get a car to the island of Sylt (a supposed holiday hotspot for wealthy W140 owners) is by train. The train cars had to be modified accordingly at enornmous cost…

    1. I would never have dreamed that I would come to the defence of the Mercedes-Benz brand:

      The story that the W140 wouldn’t have fit on the cargo train to Sylt is an urban legend. It was started by the political magazine “Der Spiegel” at the time.
      Deutsche Bahn had three different transport wagons in use at the time, and on one type, “DDm 915”, the guide rails were indeed too narrow for the track width of the W140. Vehicles with a track width similar to the W140, and these were some sports cars for example, were sent to another train on which they could be transported without any problems.

      (The transport wagons of the “DDm 915” series were then later converted to wider guide rails. But not because of the W140, but because there were fewer and fewer vehicles with a very narrow track width).

  2. The W140 was called ‘Sternegroß’ because of the alliteration to ‘gernegroß’ = wannabe show-off.
    Not a compliment and particularly bad coming from a magazine that otherwise was known for writing Mercedes propaganda.

  3. If you look at the small images and the little clay model you see the proposal has a much more raked rear screen. The eventual car became less dynamic – I notice the crease at the base of the C-pillar disappeared en route to production. This is the detail that makes the rear half of the car look so very heavy, visually. The baseline of the DLO also gained more curvature. There must have been a lot of conversations about the sculpting of the clay model. The end result is imposing and rather charmless. Being fair, there have not been so many very large cars as good as the W140´s predecessor – a hard act to appear after, I think.

    1. Good morning Richard. Have you taken a look at the Photoshop adjusted images on the accompanying Micropost? I’d be interested to read your thoughts.

  4. Despite all the tweaks to the images what a wonderful car it is. Goes like a train and solid as a rock. What ‘s not to like?

  5. They are wonderful cars. Ok, the styling was a bit slab sided, but they were built out of granite. I prefer the look of the coupe but I’m slightly biased as I owned one for several years. They were built for the autobahn and 4 of us had a great trip from the U.K. to Stuttgart and Essen. The car behaved beautifully and averaged 26 mpg over the 1600 mile road trip.

  6. What a machine.

    I take your point about the unbalanced design – it did cause something of a shock when revealed – but, of course, once on board those deep side windows convey certain advantages. An S class was always about the passengers, not to bring joy to onlookers.

    I’ve toyed with the idea of buying one of these. It would be a preposterous purchase, frankly, but I’m still tempted. I think a holiday in a W140 would be a lot of fun.

  7. I disliked the design of this car when it came out and I haven’t changed my mind. I’ve only sat in a V12 coupe, but it was stationary, so I have no idea how they drive. What I particularly dislike about the interior is the fact that the center air vents don’t align with the center console.

    1. That is very unfortunate to not been able to drive or be driven in a V12,your thoughts would instantly changed,trust me…

    2. It’s very unfortunate that you did not have a chance to drive or be driven in one of the V12 engined W140,your idea would instantly changed,trust me,l have one and it’s a privilege to own one.

    3. v140v12: Thanks for your comment. I don’t doubt that for a moment. Enjoy your 140.

  8. For what it’s worth, I quite like the W140 – it’s handsome, in its own, imposing way.

    That said, its predecessor, the W126, falls in to what I think of as the ‘Peugeot 205 category’. Realistically, it’s a lovely design which pretty much defines its segment and is hard to better (and went without any significant facelift).

  9. It is true that the Mercedes M120 V-12 engine was not as silent or as refined as the Jaguar V-12 (especially not the Series 2 carb fed 5.3-litre version in the XJ). Back to back comparison for certain bears that out. On the other hand, the Mercedes does have a considerable power advantage over the stock Jaguar V-12 (assuming we are comparing factory standard cars in factory standard state of tune). There were two standard states of tune for the Mercedes 6-litre version of the M120 V-12 engine. The earlier, more powerful 402bhp version provides strong acceleration and an impressively urgent throttle response, more satisfying than the later 390bhp tune. The S600 sedan which it powers is very much heavier than the Jaguar. Amazing that it can accelerate 2,100kg as hard as it does. I like the M120 and recommend it. It is reliable. Note that M120 works even better in a much lighter body than a W140. There is a place, just out of Bottrop, where there is a clever man who can tell you all about it…

    I understand that there was some strong criticism of the Mercedes M120 from certain quarters in the media- mostly unfair really. In my experience the Mercedes is not an unrefined engine, it is just not in the same league as the Jaguar. That wasn’t a problem and shouldn’t have been something that garnered the attention it did. It was just a matter of character. They were different engines in different cars with different capabilities, different styles, developed by different engineering teams with different priorities, appealing to different customer tastes.

    M120 is in some ways reminiscent of M100. Both engines make their presence felt. You are always aware that they are big and you are always aware that they are strong performers should you want to get generous with the pedal. That feeling is there. It is part of the character.

    The Jaguar is near silent. It is uncannily smooth. There is one car I’ve driven which approaches its refinement and lack of interior noise. That is Tesla Model S (which is spoiled by having more bump thump, squeaks, rattles and transmission whine). Above 160km/hr the Jaguar S-2 develops some wind noise around the A-pillar. In S-3 it isn’t as pronounced, but it is present. Sub-160 there isn’t anything much to pick on really.

    The Mercedes is of a different nature. It always conveys that there is a big and powerful engine up ahead of the driver, up out there in front. It remains smooth, but it is audible. It certainly has much, much more power than the Jaguar in stock form. Like the Jaguar its delivery is surprisingly cammy (just be careful turning off the traction control when you want to experience this characteristic of the Merc and the road is a little slick- you’ll need to be quick with your reactions).

    What is responsible for the difference in refinement? The Jaguar has a heavy crankshaft with massive journal diameters with plenty of cross-sectional overlap between big ends and mains. I’ve hefted quite a few of these forgings around and they are not svelte, that’s for sure. They are a nice piece though, with generous counterweighting (albeit not quite perfect from the point of view of journal forces but good enough so that nearly no unbalanced forces or moments escape the engine in the operating range from low idle to +6,500 rpm). There is a large harmonic damper on the crankshaft nose. That helps. The crank is well supported in a Y-shaped cylinder block with four bolts per main cap. This all yields great rigidity, far more than needed for a road car cylinder block and crank assembly (generous enough to allow that cylinder block to be used successfully as a stressed member of the chassis of a ground effect race car). The rod/stroke ratio is conservative. All in all, single minded purity and wonderful overkill.

    In the XJ, the engine is supported on engine mounts which provide rubber isolation from the front sub-frame which in turn is cleverly isolated from the chassis of the car. The transmission housing is a one-piece casting, again much stiffer than usual, avoiding bending resonances between the bell-housing and the gear casing (they can’t move relative to each other since they are all of a piece). When GM supplied its TH400 to Jaguar, they provided it with a special casing, just for Jaguar (a pity they deployed the wrong second gear ratio though). The tail of the transmission is supported on a spring mount which is rubber damped and the drive shaft is a three-piece affair, all carefully isolated from the car body. Jaguar were skilled at deploying rubber as an isolation medium and were especially aware of harmonic damping. They probably were THE masters at the time their V-12 was first mounted in an XJ4. It is likely they retained their lead for more than a decade, perhaps for even longer.

    The Jaguar V-12 combustion chamber has low values of turbulence and swirl, with no squish at all, resulting in a relatively modest rate of pressure rise after ignition. This assisted in making the Jaguar extraordinarily refined. Don’t forget that absolute refinement and smoothness were key priorities for the Jaguar engineering team. They went after these attributes to the exclusion of all else (well OK, almost everything else).

    Jaguar altered the combustion chamber is later cars. It went over to the high compression, high squish May “Fireball” cylinder head. Sure enough, this engine is not as sweet as the old “flat-head” version of the engine. Later still, Jaguar put the V-12 into the last of the XJ40 type cars. The engineers (for reasons with which I disagreed) cut corners and fitted the car with stiffer, much less effective engine mounts. Induction systems were altered also. Suddenly the Jaguar engine went from being silent to having an audible presence during acceleration and, sadly, at idle. It was still smooth and refined, just not as refined as it had been. Power was improved though.

    Details do matter. Small alterations can make a significant change to the perception and experience of those in the passenger cabin. Returning back to the Mercedes after driving the last of the XJ sedans (post Series 3) fitted with the V-12 and criticisms of the Mercedes for lack of refinement are less convincing.

    In brief, the main differences between the Jaguar and the Mercedes engines (in relation to refinement) are in the crankshaft, the block, the mounting scheme, the combustion, the induction. The Mercedes crankshaft is more conventional in proportion. It has a longer throw. There is less overlap and it is less rigid. The mounting of the Mercedes engine in the car is not as soft as is the Jaguar, nor was it intended to be. The Mercedes has a classic pent-roof combustion chamber with good squish, hence a much faster rate of pressure rise after ignition than the disc chamber of the Jaguar (or even the May “Fireball” head of later Jaguar V-12s). This all matters and it is noticeable.

    An aside. BMW’s V-12 was considered to be well refined at launch in the 7-series sedan. Interestingly enough it was reported to be rough, coarse even, when mounted in the 5-series sedan by Alpina. It was certainly very racey in character in Harmann’s 3-series (although that was deliberate). The mounting scheme was the key difference in the 5, especially since the BMW engine is very light (for its size and type). Details matter.

    Anyway, there is nothing uncouth or under-developed about the Mercedes engine. It was aimed at different targets than was the Jaguar. They were criticised for it and were sensitive enough to the complaints to make some alterations (mainly to engine mounts and later to timing and finally to the EFI strategy). All goes to show just how refined the Jaguar was. Also goes to show how this was really just a matter of taste. That’s about all there is to it.

  10. It is somewhat amazing at the depth and long-lasting influence of a cheap little saloon designed and conceived in ’60s Coventry.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.

%d bloggers like this: