The myths of Le Mans porsche 917 K
Porsche was pleased with the 1970 edition of the Le Mans 24 Hours, although there were a few regrets. The German brand monopolised the podium with two 917s and a 908, allowing its direct rivals, starting with the Ferrari 512 S, no chance. However, out of all the 917s competing, only the first two classified crossed the finish line.
In 1970, the Porsche 917, which was now homologated in Group 5, proved to be an absolute weapon. This was demonstrated in the first half of the year, when it won the 24 Hours of Daytona, the 1000 km of Brands Hatch and Monza, and Spa. After a disappointing 1969, the credit for these performances was due to the improvements made to the car. The 917 project was built on excellent foundations: the 12-cylinder engine united two cylinder blocks derived from the 911 R in a light-alloy tubular trellis structure with a synthetic body. However, in its first year of competition, the car suffered from stability problems.
That's why the 1970 version started the season with a reduced and redesigned tail, whose top section went up, instead of down, to the tail end. The Porsche technicians modified it during a series of tests after noticing that the front part of the body was covered with midges, whereas the top of the rear part, over which air should flow when the car is pressed to the ground, was not. Realising that the problem was with controlling the flow of air, the engineers shaped the bodywork to increase the pressure and downforce on the rear axle.
This variant, renamed the 917 K for Kurzheck ('short tail'), was to prove its full potential.
1. The sky blue and orange colours, famous in competition in the 1960s and 1970s, were the colours of the Gulf Oil Corporation, sponsor of the J.W. Automotive Engineering team established by the Englishman John Wyer.
2. The engine of the 917 is not a real boxer, but a 180° V12 (flat). Rodriguez and Kinnunen's car no. 21 was fitted with the 4.9-litre version developed during the first half of 1970.
3. In 1970, the tail of the 917 K was raised and enlarged by around ten centimetres to accommodate wider rear tyres.
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From April onwards, in order to compete on equal terms with models such as the Ferrari 512 S, Porsche presented a new 4.9-litre engine producing almost 600 bhp, eventually replacing the 520 bhp 4.5-litre unit. Not many competitors opted for it. The winning car at Le Mans, driven by Richard Attwood and Hans Hermann and managed by Team Salzburg (one of the teams which, like J.W. Automotive Engineering, worked directly with Porsche) was in fact equipped with the 4.5-litre engine.
The second car to finish had an identical option: it was one of the two 917 LHs (Longheck) that were entered, driven by Gérard Larrousse and Willi Kauhsen for the Martini International Racing Team.
1. Among the changes introduced in 1970 was the removal of the transparent top cover that protected the intake ducts and the horizontal extractor used to evacuate the air accumulated underneath the car so that it was more firmly planted on the ground.
2. With its short, truncated, rising tail, the 917 K only covers the engine and suspension, but also helps to cool the V12 engine..
3. Pedro Rodriguez and Leo Kinnunen, the drivers of the No. 21 917 K, also finished second in the Targa Florio in May 1970 with a Porsche 908/03. The Mexican champion was also known for his victory in the 1968 Le Mans 24 Hours in a Ford GT 40 teamed with Lucien Bianchi.
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The 917 Ks that failed to reach the finish also included three crews from the J.W. Automotive Engineering team sponsored by Gulf: Jo Siffert and Brian Redman in the No. 20 car, stopped on lap 156 due to an engine problem; David Hobbs and Mike Hailwood in the No. 22 car, retired after 49 laps due to an accident; and Pedro Rodriguez and Leo Kinnunen in the No. 21 917 K, who withdrew after 22 laps due to a cooling problem. The two cars forced out of the race with mechanical problems were those fitted with the powerful 4.9-litre engine.
A. The dashboard controls include two pairs of ignition switches, plus fuel pump and light switches. On the right there are the windscreen wiper handle and the ignition key. © IXO Collections SAS - Tous droits réservés.
B. The steering wheel is height-adjustable and secured by a bolt. The gear selector is on the right, in the forward position so as not to obstruct access to the vehicle. © IXO Collections SAS - Tous droits réservés.
C. The pit of Team J.W.Automotive Engineering where the three cars are prepared ahead of the race. © IXO Collections SAS - Tous droits réservés.