Mercedes-Benz SL (1963-1971)

The Mercedes-Benz SL, W 113 series (1963-1971)

A comfortable two-seater touring car featuring high performance and optimum handling safety

The Geneva Motor Show of March 1963 was the scene of a remarkable and well-regarded première: Daimler-Benz presented the Mercedes-Benz 230 SL, a new sports car to replace two models of the previous sales range. Its two predecessors, the 190 SL (W 121) and 300 SL (W 198), were extremely popular and successful from the start. The 300 SL in particular was already a living legend.

The new model took a middle course between the concepts of the 190 SL and the 300 SL: the 230 SL, internally designated as W 113 series, held the balance between the sporty tuning of a classic roadster but added to them the comfort of a two-seater touring car featuring high performance and the most advanced features for optimum driving safety.

The 230 SL was available from summer 1963 in three versions: an open-top car with a folding soft top that could be operated with the greatest of ease – that in itself was a minor sensation; an open-top version with hardtop, and finally as hardtop coupé. The hardtop coupé had no soft top and soft-top compartment, but more room for luggage instead. All three versions could be driven with the top open. As an optional extra a rear transverse seat was available, as in the 190 SL.

The exterior of the 230 SL was characterised by clear, straight lines and the unmistakable SL face including the large, centrally positioned Mercedes star. The bonnet had a slight additional bulge in the middle to provide space for the vertically-installed six-cylinder engine. The boot was generously dimensioned. The hardtop with high windows and a roof borne up only by slim pillars conveyed an impression of lightness which simply did not match the stereotype of a sports car. With its inwardly-directed curvature it reminds one of Far Eastern temples, and straightaway the car had a nickname before it really even hit the road: “Pagoda”. In addition, because of its shape the hardtop made it easier to get in and out of the car.

Apart from the wheelbase – the magic number of 2400 millimetres was taken unchanged from the 190 SL and 300 SL models – the new SL had practically nothing in common with its two predecessors. All the same, the W 113 series was not an entirely new design since its technical concept largely conformed to that of the 220 SE (W 111/3). The SL used the “tailfin” frame-floor assembly, albeit shortened and reinforced, including front and rear wheel suspension.

In addition to the standard four-speed manual transmission, for the first time in an SL a four-speed automatic transmission was available as an optional extra. A five-speed manual transmission produced by Zahnradfabrik Friedrichshafen (ZF) was added as third variant in May 1966.

Safety is the new word

The “Pagoda” was the first SL in which sporty speed combined with safety as a design objective. Since its basis was the floor unit of the famed “Tailfin”, the world’s first saloon with a safety body, this SL also had a rigid passenger cell and crumple zones in the form of easily deformable front and rear segments. This design went back to engineer Béla Barényi, responsible for many of the safety features in cars of the Mercedes-Benz brand. As in the saloon the interior was designed so as to reduce injury hazards in accidents, by eliminating hard corners and edges. As in the previous model, seat belts were available as an optional extra. The steering gear was moved from the crash-imperilled front section to the firewall; the steering column yielding to axial compression and additionally featuring a joint that prevented the feared lance effect in an accident. In 1967, the telescoping safety steering column and the impact absorber in the steering wheel were added.

Chassis, engine, and transmission

The chassis, adopted from the 220 SE (W 111) Saloon, was tuned to the requirements of the sporty car, featuring recirculating ball steering, a dual-circuit brake system and disc brakes on the front wheels. The suspension was taut, but for a sports car almost atypically comfortable. Damping was provided by gas-filled shock absorbers, and for the first time a Mercedes-Benz passenger car rode on radial-ply tyres.

The six-cylinder engine, which also came from the saloon, underwent several major changes, the most important of which was the transition from a two-plunger injection pump to a six-plunger unit. This made it possible to “shoot” the fuel directly through the preheated intake port and the opened intake valves into the combustion chamber, and not just into the intake pipe, as before. The M 127 II engine, its bore enlarged to give it a displacement of 2.3 litres, thus developed 150 bhp (110 kW) at 5500 rpm and delivered torque of 196 newton metres at 4200 rpm. Designed very sportily, this drive unit for the SL delighted in high engine speeds but did not take so kindly to underrevving.

The four-speed transmission, likewise from the saloon construction kit, was designed with a slightly lower ratio in 1st gear to achieve sportier acceleration. It sprinted from 0 to 100 km/h in 9.7 seconds. The top speed of the fabric-roofed 230 SL was 200 km/h, the hard-top version only marginally lower at 196 km/h. The variant with the optional automatic transmission reached a top speed of 195 km/h. In the eyes of sports car purists the automatic is almost immoral. But history teaches us a different lesson: by the time the “Pagoda” was discontinued the automatic transmission’s share was around 77 per cent. It was much the same with the power steering that was also available at extra cost. The W 113 series was a pioneer also on that score: all subsequent SL models always pair exceptionally good performance with highest levels of comfort. The respectable number of 19,831 units of the 230 SL were built.

Successors with higher displacements

On 27 February 1967, Mercedes-Benz presented the 250 SL, which replaced the 230 SL that had been produced for four years. On the outside the new car, whose series production had already begun in December 1966, was indistinguishable from its predecessor. The changes concerned mainly the engine and the brake system. Both were taken, slightly modified, from the 250 SE (W 108 III). The M 129 III engine, its displacement enlarged by 200 cubic centimetres, had the same output as the 230 SL, 150 bhp (110 kW) at 5500 rpm, but 10 per cent more torque and a flatter torque curve. It was now provided with seven crankshaft bearings for smoother operation, and with an oil/water heat exchanger as well; only the future 280 SL would be fitted with an air/oil cooler. The 250 SL thus was appreciably more flexible in operation, but did not quite reach the previous model’s top speed owing to its higher weight. The 250 SL’s top speed with four-speed manual transmission was 195 km/h or 200 km/h depending on the final drive ratio (standard: 1:3.92; optional: 1:3.69; automatic transmission: 190 km/h or 195 km/h). With five-speed manual transmission it was available in only one variant (1:4.08), which reached 200 km/h.

The changes to the brake system included disc brakes on the rear wheels as well, larger brake discs at the front, and the fitting of a brake power regulator to prevent rear wheel overbraking. As an optional extra a differential lock was now available. A fuel tank capacity of 82 litres instead of the previous 65 permitted an extended cruising range. In addition to the three body versions known from the 230 SL, the 250 SL was available as an optional extra in a fourth version, a coupé with rear seat bench, which was shown for the first time in March 1967 at the Geneva Motor Show. In this so-called California version, the necessary space for the rear bench seat had been obtained by eliminating soft top and soft-top compartment. Since the soft top could not be retrofitted, this variant promised unspoilt driving pleasure only in dry regions or with mounted coupé roof.

Less than a year after the presentation of the 250 SL, after 5196 units had been built it was replaced by the 280 SL. Apart from the model plate it could only be distinguished from the two preceding models on the outside by the different wheel hub caps.

In the wake of the market launch of the intermediate range models of the 114/115 series, not only the luxury-class saloons, coupés and cabriolets, but also the SL was powered by a 2.8-litre engine. Thanks to a camshaft with changed valve timing, the variant of the M 130 engine used in the 280 SL mobilised 10 bhp (7.4 kW) more than the base version of the 280 SE, developing 170 bhp (125 kW) at 5750 rpm.

Compared with the 250 SL the power had been increased by around 20 bhp (15 kW) and torque by 10 per cent. For the first time the radiator fan was fitted with a viscous coupling which limited the rotational speed. The 0 to 100 km/h was in the vicinity of nine seconds and the top speed again came up to the level of the 230 SL, i.e., 200 km/h in the fabric-top version. Its suspension, designed for further enhanced comfort, was softer. The service intervals were 10,000 kilometres instead of 3000.

23,885 units of the fast and reliable Mercedes-Benz 280 SL rolled off the assembly line. All in all, from 1963 to 1971 a total of 48,912 “Pagodas” were built – remarkable for a sports car with such high standards. Today its high overall quality, its elegance and its clear lines make the W 113 series a coveted item among restorers and collectors.

Highlights of the Mercedes-Benz SL, W 113 series

Extremely easy-to-handle folding top
Six-cylinder engine with six-plunger fuel injection pump
For the first time, automatic transmission available for an SL
Safety bodywork with rigid passenger cell and deformable front and rear segments
Numerous further safety features such as interior devoid of sharp edges and angled steering column
Disc brakes on front axle, from 1967 onwards, on rear axle as well