Design Project 'DP2155', The Works Service developed 1959 4.7-litre Aston Martin DB4 Works Prototype Registration no. UAW 707 Chassis no. DB4/207/R re-designated DP2155 Engine no. 370/682
Early in 1990 former Aston Martin chairman, Victor Gauntlett, and the General Manager for Service and Parts, Kingsley Riding-Felce, discussed the possibility of Aston Martin Lagonda Ltd purchasing a DB4 for restoration within the factory Service Department (Works Service). However, this was to be no ordinary restoration, for the project was to incorporate a number of significant developments and ideas to make a unique and interesting motor car.
In March 1990 a DB4 in poor condition, chassis number 'DB4/207/R', registration 'UAW 707' was purchased. This car had first been registered on 21st December 1959 to a Mr Tom Leake, a well-known Aston Martin owner and journalist, and was given the works Design Project designation 'DP2155', joining the ranks of many previous, and now legendarily famous, 'project' Aston Martins.
The first task was to dismantle the vehicle and remove the body panels from the chassis, which was then fully shot blasted. The chassis was then fixed to a jig and shortened by 5" to DB4GT specification. Any corroded metalwork was cut out and new panels made and fitted as required. This work included fitting special lightweight inner sills and the installation of a rear cross-mounting bar to take telescopic shock absorber mountings to the same specification as the DB4GT Prototype 'DP199'. The chassis was then completely re-coated in red oxide and undersealed. New aluminium panels were made for the bodywork, again to DB4GT specification. During this work consideration was given to the larger oil cooler and full-flow oil filter installation, in addition to the larger water radiator. Once the panel work had been completed, a new 30-gallon fuel tank was made to the original specification and fitted at the same time as a six-point removable roll cage. The entire car was then painted in the familiar Aston Green, and the special seats and interior trimmed in new black hides.
While considerable work was being carried out to fully restore the car and bring it to DB4GT specification, discussions were taking place about its suitability to become the prototype for a newly developed independent rear suspension conversion suitable for models DB4, 5 and 6. The concept consisted of proven and well-known components, including a Ford differential, being engineered into an independent rear suspension assembly mounted on a subframe. This form of installation would allow the standard axle to be removed and the independent assembly fitted onto the same locating points without having to change or modify the car's original structure. Thus the conversion could easily be removed at any stage and the suspension returned to standard specification if desired. The benefits of up-rating this unique car to independent rear suspension from the original live axle include dramatically improved roadholding and handling, together with greater ride comfort. Moreover, with a significantly up-rated engine being planned, it was felt that this was the only way of coping with the expected substantial increase in power.
It was agreed that 'DP2155'would be fitted with the prototype IRS installation and a ZF five-speed gearbox. A great many changes were made to the front suspension to match the rear suspension geometry changes. These consisted of fitting new-specification front road springs with adjustable Koni dampers and adjustable abutments. In addition, a rose-jointed front anti-roll bar and four rose-jointed (but rubber-mounted) adjustable top wishbones were fitted to enable the camber to be finely adjusted. Modified original kingpin posts were fitted to alter the roll centre, together with modified lower wishbones to accept the rose-jointed roll bar. Modifications to the steering arms, track-rod ends, top wishbone spindles and steering rack mountings were made to dial out bump steer. New and enlarged brakes were fitted to complement the additional power and available grip, consisting of 13" front discs with Brembo calipers, new brake pipe runs and a special handbrake cable installation. As work progressed the restored dashboard and a new wiring loom were installed and the interior re-trim completed.
Turning to the engine, it had been agreed that it would be appropriate for 'DP2155' to be fitted with an exciting new project: a 4.7-litre conversion that could also be offered to customers. As the car was now in effect a DB4GT fitted with IRS, it was decided that the engine conversion should include a new twin-plug cylinder head casting to correct DB4GT specification. It was agreed that the performance figures should exceed the best output from the most powerful standard Aston 'six', that of the DB4GT, which produced 270bhp at 6,000rpm and 261ft/lbs of torque at 5,000 revs.
The Aston Martin six-cylinder twin-overhead-camshaft engine, originally designed by Tadek Marek in 3.7-litre form, has been extensively modified for this enhancement. Its bottom-end consists of a fully counter-balanced, steel billet crankshaft with an increased stroke, while the cylinder block has been specially braced to accept purpose-made liners of revised bore for a capacity of 4,670cc. The pistons are manufactured by Cosworth and the connecting rods by Carrillo, both of whom are foremost specialists in their respective fields. Apart from the bracing, other significant modifications to the cylinder block and head include the flowing of all oil and waterways. The engine has a compression ratio of 9.1:1 and has been set up to run on super unleaded fuel, but with adjustment to the ignition timing can accept ordinary unleaded.
Reassembled, the engine was connected to the dynamometer for testing to start. After considerable optimising of the ignition and fuel settings, the outstanding figures of 351bhp at 6,000rpm and 334lb/ft of torque at 3,500 revs were achieved and the engine reinstalled in the car. Finally, a considerable amount of work was carried out to fine-tune the suspension geometry to exploit the benefits of the tyres and to optimise the engine in the chassis. After seven years work this unique blend of chassis, engine, IRS and brakes resulted in a most effective and exciting DB4GT that is equally at home as a fast road/rally or circuit car. Aston Martin Lagonda Works Service is justifiably proud of 'DP2155' and whether another will ever be built at Newport Pagnell remains to be seen.
The preceding owner acquired 'DP2155' directly from the factory and enjoyed the Aston immensely, using it for occasional track days and road use when time allowed, the car being maintained regardless of cost.
The current owner purchased 'DP2155' at Brooks' (as we were then known) inaugural sale at Works Service, Newport Pagnell in May 2000 where it achieved more than a DB4GT and an AMR1 Group C Endurance racer. Maintained to the highest standards, 'DP2155' is offered fresh from a major service at R S Williams, carried out in March 2010 at a cost of almost £19,000 (bill on file) and is presented in commensurately good condition. In April of this year, the car was road-tested by Steve Wakefield of classicdriver.com. Steve described the car as "very fast but, to repeat, very usable and not in any way a 'racing car for the road'", and that the "all-new rear suspension fully justifies Riding-Felce's decision to commence the project." A report can be viewed via www.classicdriver.com/uk/magazine/3600.asp?id=14580.
The car also comes with a beautiful bound file that Works Service supplied upon completion of the project, and another extensive file containing current MoT, Swansea V5 and sundry other invoices.
Kingsley Riding-Felce, Director Works Service and Parts Operations at Aston Martin Lagonda Ltd, has on occasion been asked what the best aspect of his position within the company is, and his reply has always been to build cars that he would like to own himself. That statement could never be truer than in the case of this unique car, 'DP2155'.
Kingsley says, 'Of all the DB heritage cars this is the one I would like to own more than any other. With Victor Gauntlett's permission, I built my - and many others' - dream car: independent rear suspension (at last and as always wanted by designer Harold Beach); the DB4GT wheelbase; 4.7-litre GT-specification engine with tremendous torque; upgraded brakes and suspension; and that purposeful stance with the flared wheel arches - it has the best of everything and it doesn't get much better. It is also worth noting that this car was the last to be allocated a genuine and traditional DP (Design Project) number from the company register.'
With an endorsement like that, there is very little more to add.