Power unit design for the Porsche 550 had been led by future company
head Professor Ernst Fuhrmann. It was known as the Typ 547, and
featured four shaft-driven overhead camshafts, two heading each twin-
barrelled cylinder bank. With an aluminium crankcase, the originally
149 cc Åat-4 engine produced a lusty 110bhp at 7, 00rpm. 0t breathed
through two twin-choke downdraught Solex carburettors. The two valves
per cylinder were inclined and the crankshaft was of the Hirth built-up
type, permitted the use of four roller-type main bearing to minimise
frictional loss. The 4-cam engine also featured twin-plug ignition with two
plugs, two coils and two distributors driven from the upper camshafts.
The power unit was of course air-cooled, by a v-belt-driven fan, and it
was mounted ahead of the rear axle line, with the gearbox overhung
at the rear. While the initial 550 Spyders of 1954 used regular Porsche
4-speed gearboxes, Richard von Frankenberg’s entry in the 1955 Tourist
Trophy race at Dundrod, <lster, boasted an experimental 5-speed
transmission. This became standard-equipment for the Spyders
produced from 1956 forward.
Two initial works-entered 550 Coupes finished 1-2 in their class at Le
Mans in 1953, and the cars went on to shine in further great classic races
including the 0talian Mille Miglia, and the great Carrera PanAmericana
Mexico in central America, ultimately achieving completely iconic status
within the wide world of classic Porsches.
When the American ‘Sports Cars Illustrated’ magazine explored the
reality of the Porsche 550 in period, renowned writer Griff Borgeson
declared: “The Porsche Spyder is a fantastic machine. It is fast and
fiercely powerful, one of the most successful competition sports cars
in history, and it has a personality no less complex than Dr Jekyll’s.
At brisk highway speeds it is very easy to drive, docile, perfectly
manageable, superbly responsive.”He continued: ̧There is nothing in the car’s character that makes
it inappropriate for use as a round-town hack. It has enough street
equipment to satisfy the least austere sports car fan: top, windshield,
trafficators, speedometer, windshield, wipers ̄and there’s nothing to
keep you from having radio and heater installed”. And he described
how Ken Miles had a 550 Spyder ̧ ̄that he uses daily in LA traffic, and
he says ‘Why not? Set up for town driving, with soft plugs and the right
Qets, it’s a Qoy to drive ¶ comfortable, roomy, and it goes like a bullet
from a gun when you open the tap...”.In that same feature story, Richie Ginther explained to Borgeson
how his racing 550 Spyder with its 4-cam roller-bearing engine
was “....geared for about 125mph at 7,500rpm, and I turn to 7,800
regularly. At Palm Springs I tried to keep it above 5,500 coming out of
all the corners. There’s a 4,200 feet straight-away on the course and if I
came out onto it clean and fast at about 80, I turned a good 8,000rpm142 | THE GOODWOOD REVIVAL SALE