Two Litre Sports Description
In production: September 1948—May 1950
Chassis numbers: AMC/48/1—AMC/50/15 (and Team Car LMA/48/1)
Gordon Sutherland and Claude Hill had finished building a completely new chassis and body early in 1939. This car was amongst the most advanced designs in the United Kingdom at the time. Few manufacturers had used independent front suspensions. Alvis had gone over to this form of suspension in 1933, though they had dabbled in 1929 with their front wheel drive car. Singer had used a Gordon –Armstrong trailing link system in 1935 to 1937 and the Rootes Group with their Hillman, Humber and Sunbeam Talbot models used a transverse link system in the late 1930s and, of course, Morgan had been wedded to independent front suspension since their beginnings in 1910. Bentley, Invicta and Rover had also put their minds to the inclusion of this concept in their new cars for the late 1940s. So Aston Martin was in illustrious company. To power this new car, Claude Hill had been designed a new 2-litre engine.
For independent suspensions to work at all, the chassis frame must be torsionally stiff, able to resist twisting as well as stiff over its length. So Claude Hill replaced the traditional ladder frame, made using channel sections, with a completely new chassis constructed from rectangular section tubing, stiffened by square section bracing tubes to form an open frame, so designed that the area around scuttle, and suspension mountings was very resistant to twist. To complete the 'stiffening' process, principles worked out in 'Donald Duck' (See J6/703/LS in Prototypes) whereby the body panels were supported on a strong tubular frame, were incorporated into this new design. So when the body frame was assembled to the chassis frame, a very stiff structure resulted onto which to suspend the wheels. Front suspension was independent for the first time on an Aston Martin, using an Armstrong patent of the time, that consisted of short trailing links and coil springs, though semi-elliptic leaf springs were retained for the rear axle. The layout of the divided track rod meant that the steering geometry was unaffected by cornering and bumps in the road. The wheelbase was 8’ 6” (259cm). Fitted initially with a standard pre-war 2-litre engine and a Cotal automatic gearbox (another sign of things to come) the car, which became known as the “Atom” saloon (G40/900, see “Prototypes”) at least by 1942, was used during the war by Gordon Sutherland.
Two or three of Claude Hill’s new four-cylinder 2-litre engines were completed by the end of 1944 and one was fitted to the “Atom”, although it was not announced until towards the end of 1946.
The bore of 82.55 mm and stroke of 92 mm give a capacity of 1,970 c.c., the compression ratio was a modest 7.25:1 and power output was given as 90 b.h.p. at 4,750 r.p.m. The one-piece crankcase and cylinder block and the detachable cylinder head were iron casting. The camshaft was set in the cylinder block, driven by a duplex roller chain which, unusually, was itself driven from the rear of the engine. The valves were operated by push rods and the unusual combustion chambers, which were a development of the earlier wedge shape in Bertelli overhead camshaft engines, but in this case, the valves were set at an angle across the piston, with the inlet valves centred above the pistons, as can be seen from the adjoining drawing. The inlet valve moved vertically to open a fairly normally shaped inlet port, but the the exhaust valve was set at an angle opening to a near vertical port leading to the exhaust manifold. The oil pump and distributor were driven by a cross shaft from the camshaft. Two SU carburettors were fitted. The engine was described in Autocar (October 25, 1946) and Motor (November 6, 1946).
As a matter of interest, the design of a six-cylinder version of the push rod two litres was well on the way by 1946. The Registrar was fortunate to be able to secure a drawing of this light alloy cylinder head, which is dated 4-12-46.
In 1945, Claude Hill started work on a new car, but Gordon Sutherland saw the need for more capital before a new model could be put into production.
The now famous classified advert in The Times announcing the sale of a 'High Class Motor Business' which attracted the eye of an industrialist from Yorkshire, David Brown of the David Brown Corporation, set in motion a train of events that took the pressure off the company. After a small 'wobble' in his resolve, David (later Sir David) Brown bought Aston Martin Ltd. in February 1947 for £20,000. Sutherland and Hill remained as directors. At about the same time the Lagonda Company found itself in difficulties and with much persuasion from a Yorkshire friend, R.A. 'Tony' Scatchard, this organisation also joined under the banner of the David Brown Tractor Division in September.
With financial support thus secured, design work proceeded, assisted by “Jock” St. John Horsfall. The tubular chassis and front suspension of the Two Litre Sports were directly related to the chassis of the "Atom". However, David Brown believed that an 'open' car was the way forward, which caused some problems with the stiffness of the chassis frame which rather depended on the saloon body frame to complete the structure. So the frame area beneath the doors was stiffened by additional, parallel rectangular tubing.
The front suspension followed the system found on 'Atom' but was redesigned 'in house' still using coil springs, short trailing arms and Armstrong shock absorbers, but with a strong torsion bar in an oil-filled transverse tube. The rear suspension, however, was new with the leaf springs be discarded in favour of coil springs, the live axle being located transversely by a Panhard rod and, fore and aft, by parallel linkages. After extensive testing, including road work using an almost bare chassis (probably AMC/48/1) the new car was announced at the London Motor Show later that year. It was described simply as a “Two Litre Sports”, but after the DB2 had been introduced, it became known as the DB1, to the annoyance of many. The car that had won at the 1948 Spa 24 hour race (See Team Cars in this volume) was rebuilt as the “Spa Replica” and was also on the stand shared by Aston Martin and Lagonda at the 1948 London Motor Show, but there was insufficient interest (at the price!) to warrant a production run
Transmission was through a Borg and Beck single-plate clutch to a David Brown four-speed gearbox and a hypoid bevel final drive. Overall ratios were 4.1, 5.17, 7.7 and 12:1 (for both first and reverse gears). Girling 12 drum brakes were fitted all round and the tyres were 5.75” 16”. In top gear, 1,000 r.p.m. was equivalent to 19.2 m.p.h. Fuel tank capacity was 14½ gall. All but one of the 14 production cars sold were drop-head coupés, the exception was AMC/49/8, which was originally fitted with saloon bodywork modelled on the “Atom”.
A higher compression “Spa” head, which increased the power output to 95 b.h.p., was offered as an optional extra. The Two Litre Sports was not road tested, but descriptions were published in Autocar (March 12 and April 4, 1948) and Motor (May 12 and October 6, 1948), and the “Atom” was described in Motor (October 4, 1940 and July 22, 1942), Motor Sport (June, 1942) and Autocar (October 4, 1940 and July 18, 1941). For detailed account of the engines, see AM, Vol. 21, No. 91, p.13, 1985.
Two Litre Sports Derivatives
After responding to an advertisement in The Times - 'Sports Car company for sale', the wealthy Yorkshire businessman and industrialist, David Brown, bought Aston Martin in February 1947 for £20,000. For this comically tiny sum, DB got the Aston Martin name, the Atom prototype and the bomb damaged factory in Victoria Road, Feltham.
At this time, the company were working on the first post war Aston Martin, based on the wartime Atom prototype with a chassis and 4 cylinder, 2 litre pushrod engine designed by Claude Hill. After thorough road testing of a virtually bare chassis by Claude Hill and AM test driver St John (Jock) Horsfall, it was decided that the best way to thoroughly evaluate the new car was to enter it into the 1948 Spa 24 hour race in the hands of Horsfall and Leslie Johnson.
David Brown must have been elated when the car came in 1st overall and it was quickly rebuilt for the 1948 London Motor Show and offered for sale as ‘The Spa Replica’. Sadly in post-war Britain, money was in short supply and no-one placed orders since, with sales tax, the price was in excess of £3,100, a massive amount at the time, sufficient to buy a very nice house.
The car spent many decades in car museums in both Belgium and the Netherlands but more recently was returned to the UK where it has been sympathetically restored by it’s new owner. The first time that it was seen in public in the UK for decades was appropriately at the 2006 AMOC Horsfall race meeting.
One element of the Spa Replica is in my opinion very special indeed. Look at the shape of the (three part) grille – which after countless re-designs, is still the most familiar AM design cue.
The car remains unique and is a special and important piece of Aston Martin history.
As well as the Spa Replica, Aston Martin premiered the Two Litre Sports on their stand at the 1948 London Motor Show. It was also based on a chassis very much like that of the Atom and was powered by Claude Hill's 2 litre 4 cylinder push rod engine. Partly due to the weight of the 2 seater open coachwork, post-war low octane pool petrol and the modest power output of 90 bhp, maximum speed was only 93 mph.
Sadly, only 14 examples were built, 13 with the open 2 seater coachwork, and a single example sold chassis only. They are very rarely seen indeed. The first that I have ever seen was in the showroom of Aston Workshop in Beamish during March 2006. This particular car was the last one to be made. It took until 2013 and the Centenary Celebration at Kensington Gardens for me to see my second 2 litre sports.
But one distinctive feature of the 2 Litre Sports can still be seen Aston Martins to the present day. It’s possible to see a familiar shape in the three piece grille.
After the DB2 was first announced in 1950, the 2 litre Sports become known retrospectively as the DB1.