Author Topic: 300 SEL 6.8 AMG W109  (Read 36140 times)

Offline fasteddy

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300 SEL 6.8 AMG W109
« on: November 04, 2006, 09:18:01 PM »
  Translation of an article from German "Auto Motor und Sport" issue 17/1973 written by Helmut Luckner
Famous racing touring cars of the last years
Mercedes 300 SEL 6.8
The Mercedes-star ensured for world-wide attraction, a spectacular debut in Spa for respect: The Mercedes 300 SEL 6.8 from the tuning firm AMG left more lasting impressions in one year than other cars in the course of a long career.
Graphics: Robert Rettenmayr/Auto Motor und Sport 17/1973   

The high repute of Mercedes-racers has survived the time of their winnings until the middle of the 1950's. In 1955 competition manager Alfred Neubauer sent the Silver Arrows into a Grand Prix for the last time - on them Juan Manuel Fangio and Piero Taruffi made the first and second place at the Italian Grand Prix. After another double-win which was gained by the 300 SLR-racers at the Targa Florio in the same year (Moss/Collins followed by Kling/Fangio) the Mercedes-star finally disappeared from the race courses. But it didn't fade. The myth of the undefeatedly retired Mercedes-racers did pass unfailing to this three 6.8-litre sedans which were entered in 1970 by Mercedes for the 24-hour race at Spa - the first official engagement after 15 years.
To show it to the others after such a long time of abstinence from racing and afterwards newly to withdraw into splendid isolation - this wish the play instinct of the Daimler engineers awoke during the preparation for the series of the 300 SEL 6.3.
The serial 250 hp became 280, at last the 1700kg-car, after the enlargement of the bore was equipped with modifications on camshafts, intake manifolds, lubrication and others, had 370 hp. 
On intense tests in Hockenheim, Zeltweg, Jarama, Monza, Salzburg and on Nuerburgring test pilots Hans Herrmann, Dieter Glemser and test engineer ((Erich)) Waxenberger did not only search for overcoming of the race-unsuitable comfort of the air suspension, but also for tyre constructions, which proved suitable for the heavy weight. The normal way to durable tyres in form of more width wasn't workable: Together with also bigger rims they would have to be put into larger wheel arches. But before the FIA homologates such fender flares it demands precisely defined numbers of the corresponding serial bodies. To go this way the Untertuerkheimers were not ready.
Involuntarily walking on smaller feet the 300 SEL-fleet nevertheless went to the 24-hours of Spa-Francorchamps - but it didn't lead to the sensational premiere. The fresh chippings on one part of the course exposed the tyres to such strong mechanical stress that the tread-strips on the Mercedes-tyres came off. After two hours of consultation following the training the eleven-council of the Mercedes-heads called off the project out of reasons of security. 

When one year later the world's only Mercedes-tuner, the small company AMG (Aufrecht, Melcher, Grossassbach) ((AMS errs here, the name of the little village some 30 km north-east of Stuttgart is Grossaspach, the village where AMG was founded)) from the Swabian Burgstetten newly brought a 6.8-litre 300 SEL to Spa, everyone suspected, Mercedes wanted to try again under a foreign flag. But more than all Daimler-denials the genesis of the AMG-Mercedes exonerated the suspected Untertuerkheimers. The red 6.8-litre loner which was given the red carpet treatment and presented itself with a fighting weight of 1635 kg and 398 hp (at a compression ratio of 10:1 and 5600 revs/min) was built under circumstances which stood in strong contrast to the Mercedes-perfection. The engine experts Hans Werner Aufrecht and Erhard Melcher bought for DM 9.500,-- the damaged 300 of a doctor ((base price of a 300 SEL 3.5 at that time was DM 32.635,-- without options like auto trans)) as well as an untrimmed body, the engine passed its testing hours in a corrugated-iron hut in a quarry and between the work of the night shift on engine and chassis and the day shift on the body the Mercedes-racer dozens of times rolled over the village streets of Burgstetten on a low wooden cart. Just one week before the planned premiere in Spa the Mercedes-ship was ready to start and after the addition of cost for materials and theoretical payment for day- and night-work represented a value of DM 120.000,--. Until the start in Spa the sentimental value even rose. Helmut Kelleners to be precise, the first captain on board, disfigured the car on the first test drive in Hockenheim that seriously that he could report on the pits in a perfect, even if not fine way: "Here you have the key, throw it away, you don't need it anymore" Hans Werner Aufrecht was told, who not only had to set newly nightshifts, but had to search for a driver for the third time. After Gijs van Lennep and Kurt Ahrens as the first choice were unable to come, ((and)) Kelleners disqualified himself, European Go-cart champion Hans Heyer and Clemens Schickentanz piloted the heavy weight in Spa. A group of six uprights worked on the pit, the pilots drove lap for lap in the training to compensate missing experience of consume of tyres, brakes and fuel. Against the expectations of the experienced competition that the Swabians would be at the end still during the training the AMG-Mercedes passed the race around the clock as second and immediately was engaged for Paul Ricard circuit for a starting fee of DM 10.000,-- - this was the more unusual as the organizers of the 24-hours race on the south French circuit with the hint to the immense prize money on principle didn't want to know anything of starting fees. For similar money the heavy weight went into the ring thrice, was fastest touring car at the four-hour race in Le Mans in 1972 and was stopped with 285 km/h ((176 mph)) on the straight Hunaudieres. For comparison: The fastest BMW-coupe in this year reached 277 km/h ((171 mph)). After only two years of racing and eight starts the career of the AMG-Mercedes 300 SEL 6.8 seemed to be ended. Because from January 1972 at touring car-races only cars with up to five litres displacement were entitled to start.
     Technical Data
Bore         107 mm
Stroke           95 mm
Displacement       6800 ccm
Compression               10:1
Power           428 hp
Max. Speed       285 km/h
Tyres front 4.50/13.00-15
Tyres rear 5.50/13.60-15
Weight          1635 kg
 The future of the car seemed hopeless until a lucky coincidence appointed it into service for lifetime: To imitate aircraft landings and to do measurements Matra on behalf of the French airforce searched for a car which not only could house spacious measuring instruments  inclusive the gear of a jet fighter, but also with this ballast within an distance of only one kilometre could reach 200 km/h. As requested AMG extended the Mercedes-racer 75 centimetres, brought the engine to maximum 428 hp again and handed over the 2400 kg airforce-employee (765 kg more than for racing) into French services. Mercedes had to fear every support of the Burgstetten private initiative could be interpreted as an official engagement. But they didn't left completely Aufrecht, Melcher and co completely in the lurch: The AMG-Mercedes rolled on three sets of loan-rims of the C111-type and through leasing was equipped with
parts of the suspension, rear axle and smaller air-bellows which were not used in Untertuerkheim any more. And the AMG-Mercedes also rolled on 10-inch front- and 12-inch rear-tyres, to whose in contrast to the factory car was given space under five centimetres wide fender flares. 
Photo: Auto Motor und Sport 17/1973    Sorry for low quality
The AMG-300 SEL 6.8 was the touring car of one season although its race successes were within a small scale. It caused quite a stir and was hired for star-fees, because it fueled the invincible Mercedes-racer. The spectacle of its starts proofs that the glory of gone days still today gives any credit to Mercedes. That one one day will have to deal with one in the racing business is more convinced than even amongst the most race-crazy Daimler-engineers. A touring car entrant did bet a tidy little sum that Mercedes-Benz will start again in the 1975 marque-world-championchip. And an American tyre manufacturer reacted to the smallest indication of interest with a free delivery of newest race-tyres in the expected size. 
Helmut Luckner

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Re: 300 SEL 6.8 AMG W109
« Reply #1 on: May 16, 2007, 11:12:17 PM »
more race 109