Mercedes-Benz 300SEL 6.3 vs Daimler Double Six (Part 1)

The 300SEL 6.3 and the Double Six offered unparalleled power on the QT. Robert C. finds out which moves him most, as well as fastest

A freezing winter’s night in central London and the roads of the nation’s capital are, for once, deserted. An opportunity too good to pass up. But the icy weather is not really suitable for rorty, snorty sports cars.

No, this is a night for a different sort of automotive conveyance, and a pair of discreet saloons swish along the boulevard towards me. For a second the Georgian streetlamps pickouttwobadges:‘6.3’and‘DoubleSix’.Ah, a bit of rorty, snorty sportiness might well be on the cards after all…

Rewind to the mid-1960s and the industrial town of Stuttgart, Germany. Engineers bent over their drawing boards at Mercedes-Benz are developing reliable, well-made cars. The company has long since withdrawn from motor sport, and production of the exciting Gullwing is also now in the rear-view mirror. The solid Fintails and rather girly Pagodas have been selling well, and the next iteration of the boxy Merc saloon is taking shape. Beirut taxi drivers are not holding their breath.

Rudolf Uhlenhaut, the head of the all-conquering Mercedes-Benz Rennabteilung (racing department) of the late ’30s, the man who designed the W194 300SL racing car, is running the engineering department. One of his employees is a bright young racer named Erich Waxenberger, a renowned press-on driver who is interested in fast cars, not stolid saloons. He once embarrassed test driver Mike Parkes at the Nürburgring, lapping the infamous circuit in a dainty Pagoda just a few seconds behind Mike’s V12 Ferrari 250GT Berlinetta. ‘Wax’ means business.

The Mercedes-Benz 300SEL of 1965 is the company’s top autobahn express, its 3.0-liter straight-six producing an adequate 168bhp and enabling a comfortable cruising speed of 100mph. Not bad, but not good enough for Heinz-Ulrich Wieselmann, editor of the influential magazine Auto Motor und Sport, who criticizes Mercedes-Benz for producing derivative cars for executives, farmers and retirees. Wax is not amused.

Mercedes-Benz 300SEL 6.3

Fortuitously, a 250SE Coupé body shell happens to ‘fall off’ the production line and Wax grabs it and secretes it away in the experimental department. He and his team set to the shell with crowbars und hammers and shoehorn in the huge 6332cc V8 engine from the Grosser 600 Pullman. The result is startling: here is an engine that produces an easy 250bhp at just 4000rpm and a stonking 365lb ft at a mere 2800rpm – incredible figures in the ’60s – stuffed into a light production car shell.

Uhlenhaut gets wind of what Wax is up to and insists on a test drive. He instantly loves the hot rod and convinces the conservative board to sign off the production of a four-door, 6.3-litre-engined 300SEL saloon. They think 500 examples or so might sell. A satisfactory ‘halo’ model. When production ceases in 1972, some 6526 300SELs have been sold, each of them more expensive than a Ferrari 365GT 2+2.

The 300SEL 6.3 makes its debut at the Geneva show in March 1968 to the delight of the motoring press. At last Mercedes-Benz is producing a properly fast autobahn stormer. Germany has its new 130mph cruise missile.

Germany has its new 130mph cruise missile.

In the ever-so-important American market, the 6.3 is launched at Laguna Seca racetrack (!) in June 1968. The Merc is timed at 14.25sec for the quarter-mile dash, with the 0-60mph sprint dispatched in 6.8sec and a top speed of 140mph recorded. This is an ‘isn’t no substitute for cubic inches’ car that is actually well engineered, boasting a four-speed automatic gearbox, air suspension and effective air-con. How could the Americans fail to love it? Well-heeled petrol heads line up to buy this discreet German dragster, a saloon faster than the hot Porsche 911S and Ferrari 330GTC.

Jaguar has long been in competition with Mercedes-Benz. Since the heyday of Le Mans in the ’50s, Coventry has locked horns with Stuttgart. Jaguar, too, has failed to produce a proper sports car since the superbly advanced E–type was introduced in 1961. Popular saloons like the S-type and later versions of the venerable Mk2 are being churned out at Browns Lane, and the emerging middle class is lapping them up. But the Coventry engineers are getting restless…

The XJ6 is launched in September 1968 in both 2.8- and 4.2-litre versions. With fully independent rubber-mounted suspension, automatic transmission, leather upholstery (in the 4.2, at least) and air conditioning, this is ‘the finest Jaguar ever’, Sir William Lyons announces on television. And he is correct. CAR magazine awards the Jaguar its coveted ‘Car of the Year’ accolade. It is incredibly sophisticated and refined, a spectacular engineering accomplishment.

Jaguar has long been in competition with Mercedes-Benz. Since the heyday of Le Mans in the ’50s, Coventry has locked horns with Stuttgart.

The Germans are shocked. The new Jaguar is a well-priced car that offers doctors, solicitors, bank managers and assorted moneyed-up scoundrels the most impressive of drives; the XJ6 makes the outgoing 420 look like a suet pudding. It is modern and lithe… and yet, the somewhat asthmatic straight-six does not quite deliver the performance promised by the elegant packaging. The 2.8-litre produces a middling 120bhp or so and the 4.2-litre only manages a real 200bhp, not the 245bhp quoted. So the svelte 4.2 XJ6 can only manage 0-60mph in nine seconds and it tops out at 120mph in automatic guise. Just a tad disappointing.

Someone at Browns Lane has been keeping an eye on the autobahn-storming Germans and their 300SEL 6.3. Jaguar’s supreme 5.3-litre, all-alloy V12, the creation of Walter Hassan and Harry Weslake, was developed for the E-type Series III and it weighs just 36kg more than the old-fashioned iron straight-six that has underwhelmed in the XJ6. Here, then, is an opportunity .

The XJ12 is launched at the Earls Court Motor Show in 1972 and the Germans, once again, are shocked. A V12 super-saloon that can crack 145mph and rush from ought to 60mph in 7.4sec, all for just $5580? One third of the cost of a Rolls-Royce Silver Shadow and half the price of the Benz 6.3? Unbelievable. Fuel consumption is outrageous, of course, but in the days (just) before the oil crisis, fuel is affordable, especially if you are a chap who resides in Mayfair.

Jaguar had looked at producing double-overhead-cam heads for the V12 but the SOHC arrangement produced so much torque that the added complication was not necessary . A V8 engine was considered too, but in the US market the home-grown V8s were excellent, and Jaguar wanted something rather more special – something exotic enough to compete with the Ferraris and smooth-running enough to challenge the likes of Rolls-Royce. Fuel injection by AE Brico was mooted early in development, but four Zenith 175 CDSE variable-choke, side draught carburetors were ultimately chosen for production.

When the Daimler version of the Series I XJ12 emerges, it is externally identical to the Jaguar apart from the signature fluted radiator surround and a ‘Double Six’ badge on the rear. Stiffened front springs support the extra weight of the V12 engine and vented disc brakes cope with the increased performance. A Borg-Warner Model 12 three-speed auto is the only transmission offered; it is the only one that can cope with the V12’s mighty 304lb ft of torque. It is a monster of a car, but somehow it flies way under the radar: only 534 examples are ever sold.

And now to our chilly winter’s evening in London. Commuters are at home in front of their televisions eating their low-calorie Marks & Spencer microwave meals and the roads are clear. Time to see how two super-saloons fare some 40 years on…

The arrival of the Mercedes-Benz 300SEL 6.3 is heralded by a V8 rumble. That deep bass note is the sound of serious cubic inches. It’s not overtly noisy, just quietly powerful. As the car pulls closer you can hear induction suction, pressurized fuel injection and general whirring from deep within its engine room, and a tough, resonating rasp coming from the twin tail pipes.