At the Technical Export Fair in Hanover in May 1949 Mercedes-Benz presented two passenger car models that would go on to play a significant role in the model history of Mercedes-Benz: the 170 D and 170 S.
While the 170 S (W 136 IV series, 1949 – 1953) set new standards in terms of ride comfort, the 170 D (W 136 I D, 1949 – 1953) introduced the diesel drive into the large-volume passenger car segment for the first time, thereby making it ‘socially acceptable’. In these two fields – ride comfort and diesel drive – Daimler-Benz continued to introduce innovations that would ultimately benefit the customers of all manufacturers in the decades to come.
The consequences of a world war were still omnipresent in Germany in 1947, in the form of food shortages, high unemployment, a flourishing black market and a scarcity of raw materials. The first half of 1948 was dominated by a mood of uncertainty on account of the imminent currency reform. Although the introduction of the D-Mark (deutschmark) brought with it a certain degree of consolidation, a general shortage of capital prohibited overly euphoric investment plans. This was also true for such established and eminent companies as Daimler-Benz AG. But the founding of the Federal Republic of Germany in 1949 represented a first step towards more normal political and economic circumstances, and even brought with it a revival of demand. Nevertheless, the picture in Germany’s major industrial heartlands was still dominated by the destruction of war. For even if the rubble had been cleared away, new buildings had not yet replaced the ruins.
The German passenger car market had the following look to it in early 1949: Opel had again started producing the 1.5-litre Olympia since 1947 and the Kapitän with 2.5-litre engine since 1948; since October 1948 Ford had once again started building the Taunus with its 1.2-litre engine; and in July 1947 Daimler-Benz started producing the unmodified pre-war version of the Mercedes-Benz 170 V (W 136 I series) as a saloon. But the extent to which this Mercedes met the – traditionally high – expectations of a Daimler-Benz passenger car was limited. On the one hand it was not positioned in the luxury car segment. And on the other, it was not state of the art – nor had it been before the outbreak of war, when it was overtaken by competitors.
That is why in 1938 the engineers designed the W 136 II series, which was conceived as a successor, but in fact was never launched on the market. It had a new, larger and more advanced all-steel body, which borrowed stylistically and technologically from the Mercedes-Benz 230 (W 153, 1938 – 1943) and set new standards. This body was fitted to the unmodified chassis of the 170 V model. Given the increased gross vehicle weight, it was hardly surprising that the unmodified engine from the 170 V with its 38 hp (28 kW) struggled to deliver appropriate performance.
After the war the engineers returned to finish what they had begun. The W 136 II series initially gave rise to the W 136 III series, although this too failed to go into series production. It was an initiative from Rudolf Uhlenhaut that resulted in the vehicle with the desired qualities. The all-improved W 136 IV series, otherwise known as the Mercedes-Benz 170 S, was given the short arm/long arm front suspension and a modified engine with 52 hp (38 kW). These two features went beyond outstanding ride and suspension qualities and catapulted the car into the premier league of the international car world on its debut in 1949.
But on account of the special circumstances of the post-war years, the 170 S took on a role for which it had never been intended. Originally positioned merely as a successor to the 170 V model, the Mercedes-Benz 170 S – for want of anything better – suddenly found itself in the role of a luxury class vehicle and was greeted as such on the market, if only for the limited period until the appearance of the Mercedes-Benz 220 (W 187) at the IAA International Motor Show in 1951. For Daimler-Benz it was a matter of existential importance to be represented from 1949 onwards with a passenger car positioned above the 170 V. This special position was also underpinned by the pricing. The saloon cost DM 9,850 and therefore shared a price tag with the 2.5-litre six-cylinder Opel Kapitän, the most powerful six-cylinder passenger car on the German market at the time. In the case of the 170 S Convertible B at DM 12,500 and the exclusive and very elegant 170 S Convertible A at DM 15,800, the price tags were at the upper limit for German passenger cars in the years 1949 and 1950.
So for Mercedes-Benz and customers in 1949, the 170 S was a vehicle with signal effect. With this vehicle model the brand was very deliberately demonstrating its membership of the automotive luxury class for the first time since the end of the Second World War, and expressed this membership with a letter “S” in the model designation. The “S” was a throwback to the initiative of Haspel, who intended others to see it as an abbreviation for “special” or “super”.
Mercedes-Benz 170 D: Difficult birth with sustainable impact
In spite of all the problems, development of the Mercedes-Benz 170 S went according to plan – unlike the 170 D, whose evolution could only be explained in the context of post-war confusion. The former design chief for marine engines, Julius Witzky, initially found himself without a field of operation in 1945 – Daimler-Benz no longer had a market either for motorboat engines, no matter how exceptional their reputation, nor for its legendary aeroengines. Witzky transferred his experience of large diesel engine design to development of a high-speed diesel engine for passenger car use. After the war, Daimler-Benz had already built a great tradition as a manufacturer of diesel engine for trucks, motorboats and airships, but until then it had only one diesel-engined passenger car in its range, the Mercedes-Benz 260 D. This came on the market in modest unit numbers between 1936 and 1939, above all as a taxi variant.
Although its engine made no great impression on the market at the time on account of its rustic running nature and rather phlegmatic temperament, it could not have had a better introduction thanks to its use also in light trucks. After the war Daimler-Benz set up an engine reconditioning facility in Untertürkheim, since quite a number of diesel vehicles had survived the Second World War – the German Army had decided against requisitioning diesel-powered passenger cars. A count conducted in Germany on 3 May 1947 revealed 713 vehicles of the type 260 D and 2,565 light commercial vehicles.
From 1945 onwards Witzky began implementing in the basic M 136 engine of the Mercedes-Benz 170 V the excellent prechamber results he had enjoyed using an annular intake burner in his motorboat engine designs.
It should be mentioned here that this had been a petrol engine of very simple design, with vertical valves and a triple-bearing crankshaft. But in order to turn this into a diesel engine, Witzky developed an entirely new cylinder head that no longer had anything in common with the original assembly. Initially Witzky made two cylinder heads for the new compact diesel engine’s two cylinders. And he aimed to achieve the same output as for the petrol engine – 38 hp (28 kW). His project received the support of former Board of Management members Otto Hoppe and Walter Kaufmann, as well as Dr. Carl-Heinrich Jahr, who was responsible for engine sales. Jahr was confident of good sales for the diesel engine as a replacement engine for the many 170 V passenger cars that had survived the war on account of their robust design, as well as for the recently launched production of the 170 V as a delivery van.
Test cars equipped with the new compact OM 636 diesel engine successfully completed several hundred thousand kilometres and the desired power output was also achieved. With that, it seemed nothing could now stand in the way of its market launch. An additional boost came in the form of an order during the second half of 1947 from the company Boehringer in Göppingen, which required one hundred engines for its Unimog.
When Haspel returned to his former office at the turn of the year 1947/48, he was initially rather dismissive of plans for diesel engine production, citing the following reasons: “I am in no doubt that this engine is a very good design solution and that it is highly attractive in the current climate. But having looked closely at our operations and established the circumstances in which we find ourselves in terms of men and machines, I have reached the conclusion that anything done on top of what we are already doing would be enough to bankrupt our company. If we do not take action to make ourselves price competitive with the 170 V and turn out at least 1000 vehicles per month, then this factory will perish, even if we were to build a diesel engine with such low fuel consumption. Today we are currently producing an average of 100 vehicles per month. This raises the real question of whether, given such a shortfall, the factory may have to close. In a year the situation could perhaps be different.”
Low fuel costs the ultimate argument in favour of diesel engines
The currency reform brought with it a general wave of rising prices, which opened up new prospects for the diesel engine with its low fuel costs. Haspel revised his almost apodictic “no” to the diesel engine, when he asserted in June 1948: “As far as problems with the diesel engine are concerned, current circumstances necessitate a rethinking. In view of the expected and significant increase in the price of petrol, once must seriously consider the idea of bringing the diesel engine in line with the petrol engine after all.” This thinking was also shared by other members of the Board of Management, in particular by Head of Production Karl C. Müller and Chief Engineer Fritz Nallinger. The two men agreed that the 170 D could expect a production share of up to 30 percent.
The diesel project was also fuelled by another factor. Since the 170 V was now to remain in the range for the time being, the well-practised composite body production (wood/steel design) would also be available for the 170 D. This fact brought the prospect of high-yield unit numbers. For although demand for the 170 V was down following introduction of the all-steel 170 S, the Mercedes-Benz 170 D helped to maintain overall unit numbers between 1949 and 1951, and subsequently even to considerably expand them, thus making optimum use of production facilities. 1949 saw production of 17,164 passenger cars of the models 170 V, 170 D and 170 S. In 1950 numbers expanded to 33,906 units, and 38,350 units in 1951.
For Daimler-Benz, therefore, the Mercedes-Benz 170 D opened up an opportunity for a successful multi-model strategy. At the same time, the vehicle laid the foundations for the success of the diesel engine in passenger cars. For strictly speaking it was the Mercedes-Benz 170 D that first made the diesel-powered passenger car socially acceptable. On account of its low unit numbers, for which the high price tag was partly responsible, (170 V: 3,750 Reichmarks, 260 D: 6,800 Reichmarks), the 260 D was more of a fringe phenomenon.
With the introduction of the Mercedes-Benz 170 D in Hanover, too, the company at first operated with a relatively high sale price in order to dampen the initial enthusiasm on the part of customers. The 170 V had a price tag of 8,182.75 DM, and the 170 D was priced at 9,200 DM. The reason for such damping measures was to do with the initially limited availability of Bosch injection pumps; but it was also an attempt first to place a focus attention on the 170 S. When it was launched in 1950, the 170 Da was already considerably cheaper, priced at 8,620 DM.
Despite the euphoria triggered by the Mercedes-Benz 170 S in Hanover, the unassuming sustainability of the 170 D also well and truly caught the public imagination. Even trade journalists with a pronounced leaning towards speed took a liking to the vehicle. For example, in a test report about the compact diesel novice, published in the trade magazine Das Auto in 1949, Paul Pietsch enthused: “As with the 170 V, the body is unfortunately rather narrow. The boot is too limited in size and not easily accessible. In terms of liveliness, the engine certainly outperforms the 170 V, in other words the petrol version. Its torque is particularly noticeable on winding stretches of road. Even if one kicks down hard on the accelerator at 100 km/h, there is no noticeable flat spot and the engine responds powerfully, accelerating up to 105 km/h, or even 110 km/h in favourable circumstances. [Note: The maximum speed for the 170 V given by the factory is 108 km/h.] Apologies, that was not said for the benefit of those living with speed restrictions in the American and British zones, but was tested in our unrestricted French zone. We would like to take this opportunity to put on record that we have seldom approached a car with more prejudice than in the case of the MB 170 D; and yet rarely have we been more excited about an engine than this one. Indeed, we got to like the car so much we were reluctant to return it to the plant.”
Motor Rundschau established a new top speed for the Mercedes-Benz 170 D of 102 km/h and 105 km/h for the 170 Da with an additional 2 hp. For both vehicles, touring fuel consumption figures of between 6.5 and 7.5 litres per 100 kilometres were returned. By comparison, the Mercedes-Benz 170 V achieved between 10 and 11 litres per 100 kilometres.
So these were two vehicles with a wide range of merits, not least among them the fact that the 170 S and 170 D enabled Mercedes-Benz to get through the post-war years successfully. With these and with the 170 V, the brand established the basis within the passenger car portfolio for sustainable success in the decades to come.
Source: Daimler AG