Mercedes-Benz W 165 racing car, 1939
A very special story underlies the creation of the legendary 1.5-litre Formula W 165 racing car, which was designed specifically to take part in just one race.
The tradition-steeped Gran Premio di Tripoli, which was massively subsidised by the Italian state and had been held since 1933 on the high-speed Mellaha Circuit in the colonial territory of Libya administered by Italy at the time, was on the Mercedes-Benz racing team's schedule for the 1939 season as in previous years. No one doubted that the race, scheduled for 7 May 1939, would be organised for the top category of large Grand Prix cars, but in September 1938 the unexpected happened. In view of the overwhelming dominance of the works teams from Mercedes-Benz and Auto Union, the responsible parties announced, not without a touch of smugness, that the forthcoming edition of the Tripoli Grand Prix would be reserved exclusively for vehicles in the voiturette class, i.e. up to 1500 cc displacement.
The obvious background to this decision was the fact that the works teams of Alfa Romeo and especially Maserati, which played a leading role in the small class, wanted to settle the race between themselves on home soil, as it were.
However, this move by the organisers did not lead to a withdrawal of the Mercedes-Benz racing team, but quite the opposite, it challenged them. It was decided that within the very narrow time window of little more than seven months available, a completely redesigned 1.5-litre Formula racing car would not only be ready to race, but also ready to win. In order to lull not only the competitors from Italy but also the stubborn adversaries from Auto Union in Zwickau into a false sense of security, the development work took place in the strictest secrecy. It was not until mid-April 1939, only three weeks before the race in North Africa, that the actually unimaginable became visible, when the first test drives with the new W 165 racing car took place in Hockenheim.
The focus of the development work was undoubtedly on the newly designed 1.5-litre racing engine called the M 165. The decision was made in favour of a V8 engine with a cylinder bank angle of 90 degrees - the first eight-cylinder engine in a V-configuration in Daimler-Benz history. However, the basic technical architecture of the new high-performance unit, with a cylinder welded into a single unit together with the cylinder head with welded-on cooling jacket made of sheet steel, corresponded to the familiar design philosophy that had already been characteristic of generations of Mercedes-Benz racing engines. The gas cycle was controlled by two overhead, spur gear-driven camshafts per cylinder bank, which operated two intake and exhaust valves per cylinder via rocker arms - another traditional and proven design.
However, the short-stroke cylinder dimensions of a 64 mm bore and a 58 mm stroke represented a premiere. They were necessary in order to be able to use large valve disc diameters that enhanced performance and made it possible to reach previously unknown engine speed regions while at the same time maintaining non-critical values for the mean piston speed. The latter in particular was always a critical point with the long-stroke inline eight-cylinder engines, which with their displacement of well over 5 litres had already reached the limits of their mechanical load-bearing capacity in the mid-1930s at rated speeds of 5800 rpm.
For the M 165, in view of the extremely tight time window available for the development, it was decided to use a single-stage compressor per cylinder bank on the intake side in the tried and tested manner. The transition to a single two-stage compressor, which had been successfully implemented in the W 154's 3-litre V12 engines to increase power, was postponed to a later date - at this point, in early 1939, the 1.5-litre engine was still seen as having a promising future. This also applied to the possible use of a petrol direct injection system, whose development at Bosch - including for the engine speed level of around 9000 rpm targeted for the M 165 - was nearing readiness for use. So for the time being, the tried and tested mixture formation was left as it was - the two Roots blowers were each combined with a Solex carburettor.
The two W 165s used in the race in Tripoli not only had different gear ratios for reasons of racing strategy, but their engines also had markedly different performance data. Whereas Caracciola's car had a shorter 5th gear ratio that resulted in a lower maximum design speed, and furthermore was powered by the M 165 engine with a peak output of 238 hp/175 kW at 7800 rpm, Hermann Lang in the second car was able to enjoy an engine that delivered 263.6 hp/194 kW, around 26 hp/19 kW more.
With a few exceptions, the chassis, suspension and body of the W 165 were very similar to those of its sister car, the W 154 - although everything was visibly smaller and more compact. The design of the fourfold cross-braced oval tube ladder-type frame was basically identical. However, due to the much smaller vehicle dimensions compared to the W 154, with a 280 mm shorter wheelbase and a track width that was 135 mm narrower at the front and 132 mm narrower at the rear, the specific torsional rigidity of the W 165 chassis increased considerably. In combination with the suspension elements adopted from the W 154, a coil-sprung trapezoidal-link front axle and the de Dion rear axle equipped with torsion bars, this resulted in superior handling for the newly designed voiturette car. The weight of the W 165, which at 605 kg was around 250 kg less than that of the W 154, did much to help.
At first glance, the body of the W 165 looked like a scaled-down version of a 1939 W 154. On closer inspection, however, some differences stood out. The rear end in particular was much more compactly shaped than on the big sister model. The reason was the considerably smaller tank capacity of the 1.5-litre car, which was only 245 litres. The question of how to distribute the enormous fuel volume of over 400 litres between the so-called saddle tank positioned between the rear end of the engine and the cockpit, and the rear tank, which was so critical in the W 154, was of less consequence in the W 165. For the Tripoli Grand Prix, it was initially decided to keep the rear tank very small. The required volume was already accommodated in the area in front of the rear axle and, in contrast to the W 154, the entire rear end did not have to be used as a tank; it could be designed accordingly short and compact. However, with a view to the future planned use of the W 165, the further development after the race in Tripoli resulted in a reversion to the solution practised in the W 154.
Seen from the front, the racing windscreen on the W 165, which was offset to the left as seen in the direction of travel, caught the eye. It was the result of the V8 engine being installed at an angle of 6 degrees to the longitudinal axis of the vehicle. The engine with its complex peripherals could not otherwise be implanted in the cramped installation space of the much smaller car. As a result, the steering column, driver's seat and thus the small racing windscreen had to be moved to the right.
There was no time for more than two test runs on 13 and 16 April before the expected heat race in North Africa. The fact that, despite the immense time pressure under which the newly designed engine was created, no major problems or teething troubles occurred, was testament to the extraordinary achievement of the design team from Untertürkheim - an achievement that probably none of the competitors, including the one from Zwickau, would have managed.
Predictably, the race on the Mellaha Circuit took place under extreme outside conditions. Air temperatures of around 40 degrees prevailed along the route. The huge field of participants in the small voiturette class, in comparison with the large category, comprised around 30 vehicles. Among the more than 20 Maserati cars on the grid were four works cars which, like the six new works Alfa 158s, were among the absolute favourites even from an unbiased point of view, despite the surprising appearance - for their opponents - of two Mercedes-Benz W 165s. After all, Luigi Villoresi had marked the fastest time in practice with one of the factory Maserati 4CLs and started the race from grid position one.
When the flag dropped, the hopes of the Maserati factory racing team were dashed within minutes. Villoresi botched the start due to gearbox problems and had to let the field go, while for two more of the Modena factory cars the end came on the first lap due to defects. Meanwhile, Lang had taken the lead from the start with the more powerful of the two W 165s. At the beginning, Giuseppe Farina in second place in the Alfa 158 was able to keep up with the pace of Lang and Caracciola, who was in third place. Then the heat took its toll on his car and it came to a halt with engine damage on lap 11. From then on, the two Silver Arrows dominated the scene at the front of the field at will and kept pulling away, with Lang also gradually increasing the gap to Caracciola.
After 30 completed laps, Lang had a lead of almost a lap at the finish over his team-mate, who secured second place just as dominantly as the winner. Several minutes behind him, Emilio Villoresi, Luigi's younger brother, came in third in his factory Alfa 158.
The war that broke out some four months later ruined all the plans that those responsible at Daimler-Benz had had for the W 165, such as the systematic further development of the V8 engine in the areas of forced induction and mixture preparation or the construction of a record-setting vehicle. Thus, the legendary triumph In North Africa remained the only use of the 1.5-litre racing car.
After this spectacular success, further technical development of the 1.5-litre car began, but was discontinued in 1940 due to the war. Even after that, however, the W 165 was the subject of extensive activities. The racing star Rudolf Caracciola, who lived in Lugano, travelled to Untertürkheim in July 1941 and suggested to Wilhelm Kissel, Chairman of the Daimler-Benz Board of Management, that he forego his retirement pay and take over one of the unneeded W 165s instead in order to be able to hit the ground running again in motorsport sometime after the end of the war. Since this action would have meant an unauthorised shifting of assets, Kissel could only put Caracciola off and hold out the prospect of the W 165 for him at a later date.
This time seemed to have come at the end of April 1945, shortly before the end of the war, when the two W 165s were shipped by truck from their hiding place near Dresden to Switzerland. There, they were received by the Swiss Mercedes-Benz Import Company, where, however, they were immediately confiscated by the authorities as German property. Then the US-American Pete DePaolo got things moving. The racing driver and racing team owner was the nephew of the successful racing driver Ralph DePalma and, ten years after his uncle, had won the legendary Indy 500 in 1925 and subsequently the AAA National Championship as well. During the Second World War, he was a major stationed in Switzerland, where he was responsible for looking after stranded bomber pilots. DePaolo lobbied for Caracciola to start with one of the two W 165s in the 500-mile race held in Indianapolis on 30 May 1946.
However, there were fa few hurdles to overcome first: Caracciola needed a visa for the USA - which was no easy task for a German at the time; the cars stored in the cellar of the Mercedes-Benz distributor had to be repaired, and spare parts procured in Germany expedited to Switzerland together with an experienced racing car mechanic from the factory. Finally, the driver, car and mechanic had to be allowed to travel to the USA and, as the biggest hurdle of all, the Allied Control Council had to be convinced to approve the project.
Initially, there were definite grounds for optimism: the parts needed for the repair could be procured - partly from the second W 165, partly from the factory - and installed with the help of a mechanic from the Bern distributor; even a transport box for the racing car was made and delivered at a price of 1200 francs. The Swiss authorities were also very accommodating: the Zurich police allowed the racing car to be tested, closed off a suburban street early in the morning on the appointed day, and let Caracciola test drive the car in whatever way he wanted. Although the German racing car mechanic assigned to look after the car had not received a visa, a solution was found for this too; DePaolo had organised an Air Force transport plane and the crate with the W 165 was ready for loading on the truck. That's when the notice arrived from England that the permit would not be granted.
Nevertheless, Caracciola flew to the USA and accepted the invitation of racing team owner Joel Thorne to contest the race in one of his two Thorne Engineering Specials. During qualifying, Caracciola had a serious accident, was thrown out of the car and lost consciousness. George Robson won the race in the end in the second Thorne Engineering Special. Caracciola was slow to recover from his accident and did not compete again until 1952 - in the Monte Carlo Rally.
in 1948, the Swiss Clearing House instigated a lawsuit in the Zurich District Court to clarify the ownership of the W 165, which was still confiscated. The court first determined that Caracciola, to whom both cars had been verbally promised by Wilhelm Kissel, was the rightful owner. However, at the appeal hearing before the Supreme Court, the Mercedes-Benz import and sales company was ordered to hand over the cars to the Clearing House, as they were considered German property and therefore to be confiscated. The testimony of Kissel's successor Wilhelm Haspel was not able to change this. In 1950, the Swiss authorities offered the two vehicles for sale to the highest bidder via an advertisement in daily newspapers and trade journals. In the end, the Swiss sales company submitted the highest bid, and so the two historically valuable cars could be returned to their place of origin.
They were almost used for racing again after the CSI (Commission Sportive Internationale) of the newly founded Fédération Internationale d'Automobile (FIA) had defined the Grand Prix formula to be valid from 1947 at its first meeting in February 1946. Naturally aspirated engines with a displacement of 4.5 litres and 1.5-litre supercharged engines were now permitted.
On 15 June 1951, the Daimler-Benz Board of Management decided by management resolution to re-enter five W 165 racing cars and five additional engines. Neubauer noted in his notebook: "Racing cars and sports cars are being built!". This decision was modified a short time later, however, after some lessons learned during a visit to the German Grand Prix held on the Nürburgring on 29 July 1951, which Neubauer summarised in a memo two days later: "The construction of our W 165 racing car is no longer an option, since this design promises equivalence at best, but not superiority. The re-entry [...] must therefore be regarded as obsolete and applied mutatis mutandis to the new design".
This meant that the W 165 was finally history, and it was replaced by the W 195 - a 1.5-litre V12 racing car with a supercharged engine, the starting signal for which had already been given in November 1950 together with a variant with a 4.5-litre naturally aspirated engine. In his memo of 29 July 1951, Neubauer writes about this: "Successful racing seems to be possible only through the redesign of a car that already exists as a draft [...]. Since, as things stand with regard to the International Racing Formula, it has not been determined in any way whether the existing formula will be renewed or replaced by a new formula, work will be carried out on the 12-cylinder that is currently in the planning stage. The October meeting of the FIA on the occasion of the Paris Motor Show will be decisive for whether the car will actually be built [...]."
On 22 September 1951, however, Chief Technical Officer Nallinger pulled the plug and instructed the colleagues and employees directly affected to stop all further work on the W 195 due to the uncertain period of validity of the Formula 1 regulations. The background to this was the justified fear that the car would not be ready for use until the summer of 1952 at the earliest and not competitive until the start of the 1953 season and could therefore only be used for one season if the 1.5-litre formula was not extended beyond the end of the 1951 season. In this case, the investment for the new racing car would not have been justifiable.
Since their interlude in Zurich, the two W 165s built in 1939 have been part of the company's vehicle collection for decades: Lang's winning car is on display in the Mercedes-Benz Museum, while the W 165 driven by Caracciola is used time and again on a wide variety of occasions at exhibitions and driving events.