1959-1964 Daimler SP250 Design
The 1959-1964 Daimler SP250 design was little changed from the pre-production machine, except that a front bumper had been added as an extra-cost option. Daimler made it clear that SP250 sales were specifically aimed at North America and that most of its first year’s production, projected at 10 units per day, would go to the U.S. and Canada.
The box-section chassis was almost totally cribbed from the TR3A; it used the same coil spring and wishbone front suspension (the components even came from the same supplier), had cruciform cross bracing under the seats, and was underslung at the rear, which is to say that the back axle assembly rode above the side members.
Compared to the TR3A, however, the wheelbase measured four inches longer (at 92 inches), while the front and rear tracks were spread five and two inches wider, respectively. The dimensions promised more space in the passenger cabin and, perhaps, better roadholding.
The SP250’s most outstanding feature, of course, was Edward Turner’s magnificent V-8. Powerful and torquey, it looked mean in the same way that Chrysler’s hemi always looked more purposeful than other Detroit V-8s -- the Daimler V-8 looked ready to smoke the tires off the nearest dragster or single-seat racer.
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The swoop lines and wide grille of the SP250 looked better with the bumper removed.
Behind the engine lurked another bit of plagiarism: the gearbox. Not only was this the first conventional four-speed manual to be offered by Daimler for 30 years (postwar Daimlers always used either a pre-selector or a fully automatic transmission), but it was a dead ringer for the Triumph TR3A design.
In Daimler’s case, however, the internal ratios differed. Daimler also offered a Borg Warner automatic, something not seen on a sporting Triumph until the TRs of the mid-1970s.
To keep the performance in check, Daimler chose Girling disc brakes on front and rear wheels. All in all (and if one hadn’t already studied the design of the popular Triumph), this was a neat and workmanlike chassis and drivetrain.
Daimler, unfortunately, had not stooped to studying its rivals’ body styling with enough care. The best that could ever be said of the SP250’s looks is that it was unique, and quite impossible to mistake for any other car.
Think of a late-1950s gimmick, and the SP250 had it -- a rather MGA-like droopy nose, with a wide-grin TR3A-like grille, a set of tail fins, and a semi-wraparound windscreen like that of the contemporary Sunbeam Alpine, but with wind-up windows and sidelamps fixed immediately above the headlamps to accord with latest Daimler policy.
Since the company did not expect to sell the SP250 in large numbers (at least by Triumph standards), they chose to build the bodies from fiberglass (as used at the time by Corvette in the U.S. and Lotus in the UK). At least it helped them form the complex contours of the body without resorting to expensive press tooling, but it didn’t help raise the standards of rigidity or product quality.
One result of Daimler’s management upheaval in the 1950s was that motorcycle designer Edward Turner joined the board of directors. Since the company desperately needed a range of new engines, Turner schemed out a pair of 90-degree V-8s that were similar in layout but utterly different in detail.
For the SP250, he designed a 2548-cc unit, and for the larger cars (the Majestic Major) there was a 4561-cc unit. Since the numbers involved were small, little production tooling was needed, or provided -- as Jaguar discovered to their dismay when they took Daimler over in 1960.
Edward Turner’s design philosophy was floated in a British magazine, The Motor, in April, 1958, by which time the 2548-cc engine was already designed. The central feature was the use of light-alloy cylinder heads, part-spherical combustion chambers, and overhead valves opposed at an angle of 70 degrees, with operation from a single camshaft mounted high in the cast iron cylinder block.
Naturally, there was cross-flow breathing, and twin semi-downdraught SU carburetors nestled in the center of the vee. It was an extremely free revving engine, with maximum power coming on at 5800 rpm, although the unit could be wound well beyond that if the driver insisted.
Find out more about 1959-1964 Daimler SP250 performance on the next page.
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