RACING CARS FROM THE SIXTIES
PORSCHE 908 (1968-9)
GERMAN
The development department at the Porsche factory in Stuttgart has proved very adept at designing and developing new cars very rapidly indeed. Not long ago the team was running 1.5 litre sports cars, picking up class wins with monotonous regularity and often winning races because of sheer reliability. Gradually the engine size increased but even at the beginning of 1968 they were still running the 907 model with its 2.2-litre flat 8 engine but as the engine capacity regulations for Sports/Prototypes were changed for 1968, giving a maximum size of 3 litres, Porsche decided to build a car of this capacity, calling it the 908. It was ready for the Le Mans test day in April 1968 by which time the old 907 had already notched up two successive Championship victories at Daytona and Sebring and a second place at the BOAC 500. Its first racing appearance was at the Monza 1000 Kms where, with something like 350bhp to the 270 of the 907 it was understandably faster but the two 908's both ran into trouble and victory went to Ford. Porsche decided to do some homework on the 908 after that and sent the 907s to do the Targa Florio which Vic Elford won for them. Things went much better on home ground at the Nurburgring rooo Kms and the 908 was given its first race win by Siffert and Elford. In a very wet Spa rooo Kms race Porsche were well beaten by Ford, a 907 finishing second ahead of a 908. At Watkins Glen in the USA wheel-bearing problems decimated the Porsche challenge and the best they could do with a 908 was sixth, with Ford finishing an easy first and second. With stronger wheel bearings the 908 won the Austrian Grand Prix in the hands of Jo Siffert, followed by another 908. The decider for the Championship between Ford and Porsche was the postponed Le Mans 24 Hours but the 9088 ran into a variety of trouble from broken gearboxes to broken alternators and Ford won the race and the Championship, with one of the old 907s in second place.
The 1968 908 was very much a development of the 907, using virtually the same chassis and bodywork but of course the bigger engine and a different gearbox. The 3-litre 908 engine was in fact more a development of the 6-cylinder 906 engine rather than the 907 for the shaft driven camshafts of the 907 were abandoned in favour of gears and chains. The flat 8 air-cooled engine with a very light magnesium crankcase and many strong but light titanium parts such as the crankshaft and connecting rods has a bore and stroke of 85 mm x 66mm for a capacity of 2,996cc. Using a compression ratio of 10.4:1, two valves per cylinder, and Bosch fuel injection the engines originally gave 350 bhp at 8,400 rpm but there is undoubtedly a good deal more on tap now. In 1968 a six-speed gearbox was used, in two different versions, one having a four plate clutch behind the box while the other used a multi plate wet clutch between the engine and gearbox. The tubular steel chassis frame was much the same as that of the 907 as was the double wishbone front suspension and classical single link, lower reversed wishbone and radius arm rear suspension using Bilstein shock absorbers. Disc brakes by the German firm of ATE are fitted all round and 1 sin diameter magnesium cast wheels are used. Glassfibre covered fuel tanks mounted in the cockpit sides are fitted to the cars, the tanks having a capacity of 26 gallons.
For 1969 Porsche made a variety of improvements to the 908 although at the same time they were busily developing the sensational 4.5 - litre 917 for Group 4 racing. No less than three versions of the 908 were developed, the coupe as raced in 1968, a special long tailed version for the faster races and an open bodied type to take advantage of the relaxed rules for 1969 on windscreen height, interior dimensions etc. The latter was intended for short, winding circuits where maximum visibility is needed and top speed less important. The open car was found to be almost 25 mph slower on maximum speed than the long tailed coupe but during the season the drivers, especially Jo Siffert found that they liked this version better than the coupe despite this alleged handicap and Siffert even opted for the open car on the very fast Le Mans circuit and although beaten for speed he led the race for a long while. Mechanically the cars were all similar, having the same dimensions and the same engines although there was a choice of five- and six-speed gearboxes but the external clutch tried in 1968 was abandoned. The bodywork of the coupes was modified for 1969 to accommodate a full width rear moveable spoiler to improve adhesion.
The season started disastrously at Daytona when the five-strong works team of long tailed coupes suffered first from exhaust fumes in the cockpit due to cracking of newly designed exhaust manifolds and then the cars dropped out one by one with broken gearbox quill shafts due to incorrect heat treatment. A team of open cars went to Sebring for the I2-hour race but different disasters overtook them on this bumpy airfield when the chassis frames began to break up on the rough surface, and after a lot of trouble the 908s were lucky to finish third, fifth and seventh, the best car being four laps behind the winning Ford.
Things couldn't have been worse at this stage of the season but back in Europe the victories began to roll in. In England for the BOAC 500 a team of four open cars more or less had things their own way and the Siffert/Redman car led a I, 2, 3, victory. The long tailed coupes were on duty at the fast Monza 1000 Kms and the Siffert/Redman combination led a 1, 2 win which would have been another I, 2, 3, but Elford suffered a big spin when a tyre deflated, and bent the bodywork of the car. The Targa Florio is a Porsche speciality and with a bunch of open cars they swamped the field, finishing 1,2,3,4, led by Gerhard Mitter and Udo Schutz. They were running away with the Championship now, with Siffert/Redman leading a 1,3,4 win in the Spa 1000 Kms followed by a whitewash in the Nurburgring 1000 Kms when they took the first five places despite the fact that the moveable spoilers had to be fixed after the CSI decision on aerofoils after the Monaco GP. This win virtually clinched the Championship but they badly wanted to win Le Mans but the cars dropped out one by one mostly with gearbox trouble until only the Herrmann/Larrousse 908 coupe was left, but in an exciting finish the car was beaten into second place by Jackie Ickx's Ford GT 40.
Even runaway victories in the final two rounds at Watkins Glen and Zeltweg in Austria could not make up for this defeat.
More Le Mans Cars from the 60ies onwards
Author: ArchitectPage
wheelbase 7ft 6 ins
front track 4 ft 10 ins
rear track 4 ft 10.5 ins
height 2 ft 9 ins
