Porsche 917 K-70
Premiere: January 10, 1970 qualification for Buenos Aires 1000 km
Le Mans winner 1970, Interserie winner 1970
Manufacturers' World Championship for Porsche in 1970
Engines
| 4.5F12 | 428 kW | 375 lb-ft | 510 Nm |
| 4.9F12 | 441 kW | 404 lb-ft | 550 Nm |
| 5.0F12 | 458 kW | 419 lb-ft | 570 Nm |
While the 1969 917 K was unstable and very difficult to drive, the rear end was completely redesigned for 1970, to finally generate downforce instead of unintended lift. The 1970 car was sorted and ready to take on the competitors. The cars built in 1969 were converted to 1970 specs. The first major victory arrived right in the beginning of the season - the Daytona 24 hour race saw a 917 K 1-2 finish by team John Wyer Engineering.
The 917 K-70 of the J. W. Automotive Engineering team + Leo Kinnunen & Pedro Rodriguez proved to be the winning formula. They took already the third major win in the season - after Daytona 24H and Brands Hatch 1000 km, also the Monza 1000 km. Another evolution to the 917 is seen at the Monza 1000 km - the 4.9-litre engine.
The added power and torque of the 4.9-litre engine compared to the final version of the 4.5-litre wasn't significant, but of course any increase in performance is beneficial in the races where rivals' cars are not failing for technical reasons or because of accidents. The first victory for the 4.9-litre 917 comes at the Spa 1000 km race.
By 1970 Porsches were so famous racing cars that majority of privateers used Porsches. This meant that the starting grid of the 1970 Le Mans 24H saw 24 Porsches and 27 other cars. What can be better for marketing - now everybody wanted a Porsche.
One and half hours to the race it started raining. Soon after there was an incident with four Ferrari 512 - three of them involved in a crash which eliminated them and the engine in the fourth was ruined with unintended over-revving during the close escape manouvre. At that point already seven of top ten qualifiers were out of the race. The rain got heavier and Jacky Ickx was driving the last surviving factory entered Ferrari in the night from 6th place to the second when he crashed, killing a marschal as a consequence. By dawn the weather turned from rain to storm. Despite the "Le Mans-special" longtail 917 LH-70 4.9 of Vic Elford/Kurt Ahrens Jr. was the fastest in qualification and started from the pole position, in the morning they had to retire due to engine failure. The race was won by Porsche Salzburg entered 917 K-70 4.5 (chassis 917-023) #23 driven by Richard Attwood/Hans Hermann. They were followed by two cars from Martini Racing, the second place went to 917 LH-70 4.5 #3 of Gérard Larrousse/Willy Kauhsen and third to 908/02 LH Flunder Spyder.
Because of the awful weather conditions only 16 cars finished. As many of them were too many laps behind, only seven cars were finally classified. Porsche had won all the four classes that had finishers: 5-litre sports car class with the 917, 3-litre prototype class with the 908, 2-litre GT class with the 914 and finally the 2.5-litre GT class with the 911 S/T 2.3. The 914 was 6th and 911 7th overall.
The 1970 Le Mans proved again - in a long distance race the main factor is the durability of the car, not only its speed. The long tail 917 is quicker at the very fast Le Mans track as is the 4.9-litre a bit faster than the 4.5-litre, but still the race was won by the more durable 4.5-litre and the less aerodynamic short tail body. None of the 4.9-litre engines survived the 24 hours. The winning 917-023 had started the season with the 4.5-litre engine, then used the 4.9-litre for two 1000 km races and was equipped again with the 4.5-litre for the Le Mans.
Pedro Rodriguez/Leo Kinnunen won the 1970 Watkins Glen 6 hour race on July 11. A day later, the 5.0-litre engine is first seen racing at Can-Am Watkins Glen race. The engine has approx. 458 kW and makes the power leap from 4.9 to 5.0 as strong as it was from 4.5 to 4.9. The first victory for the 5-litre 917 comes at Zeltweg 1000 km race in Austria in October driven by Jo Siffert/Brian Redman. Interestingly, the 917 with chassis number 023, that had won the Le Mans a few months ago, is also equipped with the 5-litre engine and entered under #21 for the Zeltweg 1000 km race. It scores 4th. The fact that the car was not put in the storage after Le Mans victory, but was instead raced again and soon even sold, was the reason of many factors: in 1970 the Le Mans race was not yet as important as it would be years later, there was no Porsche Museum, and the racing department needed to cash in as it had spent vast amounts of money under the direction of "no compromises" engineering genius Ferdinand Piëch.
The 1970 Interserie was won by Jürgen Neuhaus and 917 K-70, chassis 007. In the Interserie the races were up to 300 miles long and all races took place in Europe, so it was much cheaper series than the Manufacturers' World Championship which took place all over the world and where the shortest race was the Targa Florio with its around 800 km distance. The 1970 MWC consisted of the following races: Daytona 24H, Sebring 12H, Brands Hatch 1000km, Monza 1000km, Targa Florio, Spa 1000km, Nürburgring 1000 km, Le Mans 24H, Watkins Glen 6H and Zeltweg 1000km. Porsche became the Manufacturers' World Champion already in 1969, and again in 1970, now thanks to the 917.
Although the factory team cars receive new body with rear fins for the 1971 season, many private cars were campaigned in their 1970 trim also in 1971.
On October 17, 1971, a non-championship Paris 1000 km race is won by 917 K-70 5.0 of J. W. Automotive driven by Derek Bell/Gijs van Lennep.
Porsche racing driver Jo Siffert joined the Formula 1 championship with BRM in 1971. The last championship race was on October 3 and he scored 5th in the season. After the season he joined a non-championship F1 race on October 24 and lost his life in the fire following a crash. In the funeral, the hearse was leaded by a Porsche 917 K-70. Siffert would have appreciated this.
The 1970 Le Mans-winning 917, chassis 023, was sold already after the 1970 season to Martini Racing and instead of its now famous Salzburg livery was painted silver and covered with Martini stripes. From Martini Racing the car went on to private collection and has changed hands a few times. The 917-023 has been restored back to the 1970 Le Mans trim. The car in the Porsche Museum storage, is an official clone they made from chassis 001 or 009.
Two 917 were converted for street use in the seventies, the 917-021 and 030. The white Martini Racing 917 K-71 (917-030) that crashed at the 1971 Zeltweg 1000 km, was years later fitted with the K-70 rear end, street car equipment and painted silver for Gregorio Rossi di Montelera of Martini & Rossi. The 917-021 was extensively raced and crashed. It was restored by Joachim Grossmann into street legal car and painted white. It later changed hands a few times and was converted back to racing trim. So, the 917-030 is the only street legal 917.
Article © James Herne / Stuttcars.com
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