Porsche 917 - History

Porsche reaches out to achieve leadership. As the year starts, using the 908 models, the intensive testing on the 917 takes place, for all of their hopes are on such car…

Ferrari returns to the Championship, and Porsche is determined to achieve results and worked hard to obtain them.

The German house tests a 908 in Monza, with the objective of racing it as hard as possible during 18 straight hours to detect possible faults. Porsche engineers had decided to substitute the extremely heavy, but very solid six-speed gearbox for a lighter, and equally effective 5-speed gearbox. During the test, Hans Hermann went off track and destroyed the car; hence the test was early interrupted. The only parts that were saved were the engine and gearbox, which were unassembled for inspection of possible premature damages. Nothing abnormal was found, and it was considered that everything was OK for the beginning of the season.

Not withstanding these preparations with the already effective-proven 908; it was during the winter of 1968-69 that Porsche was discretely preparing it’s new model, based on a 12-cylinder engine and 4,494 cm3 to fully benefit from the freedom of the World Manufacturers Championship regulations.

Under the command of engineer Ferdinand Piech (actual president of Volkswagen Group), the 917 was presented to society at the Geneva Motor Show, on March 12^th, 1969.

The display model was painted in white with green livery on the front end of the car, and the informative pamphlet quoted a retail price of 16,000 sterling pounds.

The F.I.A. representative Dean Delamont instructs Porsche that prior to homologation, and according to the new regulations, they must physically present the 25 units required. The term for such inspection was set in a four-week period.

A month later, in April 1969, the C.S.I. had inspected 25 fully finished Porsche 917´s, minimum quantity required for the homologation. Engineer Piech felt so proud, that offered Delamont to take a ride in any of the units, gesture that he declined.

On May 1^st, 1969 the Porsche 917 was officially accepted by the F.I.A. to race.

The brand new 917 had a multi-tubular structure made out of a lightweight material on which the German automaker had been previously experimenting; glass fiber body and epoxy resin, which made it extremely lightweight.

Hans Mezger, who had previously collaborated in the design of the engine for the 908, designed the engine. It was a flat-12 horizontally opposed, which resulted from |”putting together” two 6 cylinder, 2.2-litre engines from the 911. The engine intake was located in the middle of the crankshaft in order to avoid unwanted torsional vibrations. The cylinders were chromed, and the connecting rods were made of forged titanium. It pumped out 520 bhp, although later, it evolved, and easily reached 600bhp .

On February 2^nd, Porsche introduces 4 works 908 long tails, but none of them achieves to finish the race. Nevertheless, when the last Porsche abandoned in the 18^th hour of the race, such car was leading with 45 laps of advantage over Mark Donahue’s Lola T70 Chevrolet, who was in 2^nd place.

In spite of the abandons, the power of the 908´s was more than proven. Rico Steinemann (Porsche director at the time) was quoted: ”We have proven that we have the best cars, but that’s not enough”.

All four cars retired due to failures of the crankshaft timing drive gear which also drives the oil pump. Once in Stuttgart, the gears were replaced with a more durable steel alloy. It was evident that had the Monza tests not been interrupted, the problem could have been remedied without the price of leaving Daytona empty-handed.

Another problem that had arisen, was the entry of combustion gases to the cockpit, which made the drivers suffer from mild intoxication. The engine vibrations under heavy demand, loosened the exhaust connections, and toxic gases entered the driver’s habitat, making the cockpits true “gas chambers”.

During the Monza testing, this could not been detected, because of the high-speed configuration of the circuit, larger ratios were used, hence, the engine were not as demanded as Daytona.

In synthesis, Jo Siffert, got the Pole Position with the 908 Long Tail, but the race was won by one of Roger Penske´s Lola T70 Mk3b.

In this race, the Porsche 908 Spyder Sebring were introduced, honoring the circuit where the 908 made its debut.

This new model, had been successfully tested in January, but nevertheless, another testing was scheduled prior to the race, this time in Weissach, but snow made it impossible, so the team headed to Sebring, with intentions of testing there. On test day, 100kp/h winds and heavy rains made the test, once again, impossible to take place, which is why they decided to take advantage of the full 5 hours of the official practices. To make matters worse, in only five hours, they had to find the appropriate set-up for the car, and the drivers to familiarize with the new car.

The chassis problems

During the official practices, one of the 908 suffered a broken chassis in a place where diverse structural tubing connected in the front of the car. (see the arrow in the picture).

At the early stages of the race, the 908 of Hans Herrmann and Kurt Ahrens made a pit stop with a broken chassis in the same place where the other unit had suffered days before. A few minutes later, Jo Siffert, who had pitted earlier due to a front suspension problem caused by an off-track encounter with the guardrail, suffered the exact same broken chassis problem; and a while later, Mitter’s car and the 2-litre 907 of Rolf Stommelen-Joe Buzzeta unit suffered the same inconvenient, nevertheless, the Stommelen-Buzzeta car was able to continue after an emergency repair, and managed to finish third overall achieving the first 4 points of the year in the World Manufacturers Championship.

The only 908 that didn’t suffer the fatidic chassis problem, was the one drove by Vic Elford-Richard Atwood, but one of the vertical fins was broken due to the aforementioned vibrations, and perforated the fuel cell, which obviously damaged their performance.

Rico Steinemann suggested that the fault for the defective chassis was due to the extreme roughness of the circuit –an American airfield, even though later he surely was grateful that the problem appeared in such an acute way, for it resulted in Porsche redoubling it’s efforts, and improved the cars in great measure.

In synthesis, the Pole Position was for Chris Amon in the Ferrari 312P, but managed only 2^nd place in the race, which was won by a Ford GT40 (Ickx-Oliver). The best finish for Porsche was third place.