Friday 29 March 2013
The DB4 is a sports car sold by Aston Martin from 1958 until 1963. It was an entirely different car from the DB Mark III it replaced, though the 3.7 L engine was externally visually related to the 2.9 L unit found in that car. The DB4's unique design and performance would later form the basis for future Aston Martin classics, such as the DB4 GT Zagato, the Lagonda Rapide 4-door saloon, and its ultimate replacement the Aston Martin DB5.
The lightweight superleggera (tube-frame) body was designed by Carrozzeria Touring in Milan, and its Continental looks caused a sensation on its unveiling at the 1958 London Motor Show. Although the design and construction techniques were Italian, the DB4 was the first Aston to be built at the company's Newport Pagnell works in Buckinghamshire, England.
The 3.7 L (3670 cc/223 in³) engine, designed by Tadek Marek, was a double overhead cam straight-6, with cylinder head and block of cast R.R.50 aluminium alloy. The engine was prone to overheating initially, but the 240 hp (179 kW) produced by the twin-SU carburettor version made buyers forgive this unfortunate trait. Servo assisted Disc brakes were fitted all around, with early 11.5 in (292 mm) Dunlops being replaced by Girlings. The independent front suspension used ball-jointed wishbones and coil springs and the live rear axle also using coils springs with location by a Watt's linkage. Rack and pinion steering was used. There was a choice of final drive ratios, the normal one for British and European use was 3.54:1, the United States usually got a 3.77:1 and a 3.31:1 was also available for customers wanting a car with an especially high top speed.
There were five "series" of DB4s, with the most visible changes being the addition of window frames in Series II and the adoption of a barred (rather than eggcrate) grille in Series IV. The Series V cars of September 1962 have a taller and longer body to provide more interior space, though the diameter of the wheels was reduced to keep the overall height the same. The front of the Series V was updated with a more aerodynamic look that was later carried over to the DB5 cars.
The DB4 GT was a special lightweight, high-performance version of the DB4. Introduced in September, 1959, the GT's featured enclosed headlights and a thinner aluminium skin for lighter weight. The wheelbase was also reduced in comparison to the standard car, which resulted in many cars not being fitted with rear seats.
The engine, though, was what made the GT special. Available in 3.7 L (3670 cc/223 in³) and 3.8 L (3750 cc/228 in³) versions, the GT's engine had twin sparkplugs per cylinder with two distributors and three twin-choke Weber carburettors. Modifications to the cylinder head brought compression to 9.0:1 and power output was 302 hp (225 kW). Maximum speed for the GT was 151 mph (246 km/h) with a 6.1 second sprint to 60 mph (97 km/h).
Seventy-five GTs were built with this body style. Nineteen more were modified by the Zagato works in Italy into DB4 GT Zagatos, with plain oval grilles, sans the stock GT's tail fins, and a smoothed out rear end. A single car was also styled by Bertone and dubbed the Bertone Jet.
- engine: V6
- capacity: 3700 cc
- horsepower: 240 HP
- gearbox: 4+1
- top speed: 225 km/h