International Description

With more short chassis cars than tourers being produced in 1929, the efforts of the Aston Martin works were clearly going towards the sports end of the market. By the end of the year the ‘Standard Sports Model’ had developed into the ‘Four-seater “International” Sports Model’, more commonly known simply as the “International”. It was quickly and widely regarded as one of the best light sports cars of the day. The name “International” was coined to cash in on the works’ racing efforts. The appearance of the cars at Brooklands race track and in rallies, sprints and hill climbs all around the country alongside the works team cars, increased the cars’ sporting reputation. The “International” was truly a sports car in the best tradition of the earlier Bamford and Martin cars. Now with twin 1?” carburetors it had dry sump lubrication as standard, which kept the temperature of the oil at least 10 degrees cooler than in the wet sump engines. It was fitted with relatively large fourteen inch diameter brakes operated by Perrot shafts at the front. The “International” was expensive but performance was good enough for the motoring press to praise the car highly. A significant amount of advertising was placed in the popular motoring press highlighting competition successes.

The “International” had a similar but dimensionally different chassis to the ‘Standard Sports Model’. Also slightly different, was the brake arrangement, and the gearbox was moved back in the chassis to leave more room in the driver’s side foot-well. These small modifications were typical of the subtle development that all the Bertelli cars went through. This was in part a result of Bertelli driving the cars himself in competition. For example, he would have been well aware that the gearbox of the early cars needed to be moved back; he would have had a pain in his left leg where it constantly rubbed against it!

Renwick and Bertelli had designed and developed a simple yet rugged 1½ litre sports car. The build quality was very high with the best standard of materials used throughout. The entire car (with the exception of the steering box) was designed and built at the factory (from November 1929, now Aston Martin Ltd). It was very carefully assembled with engines, rear axles and gearboxes all tested on their own dynamometers, after which they were stripped and checked. This made it very expensive to produce. However, the simplicity and elegance of the design made for an efficient little sports car, which had the legs of many of its competitors.

International Derivatives

Two Seater International Sports

Using the same chassis and mechanical specification of the Four Seater ‘International’ Sports, E. Bertelli Ltd. built six, two-seater bodied cars. Almost identical to the four-seater up to the scuttle, they had stubby tails, very similar to the earlier two seater ‘Standard Sports Model’, but with the spare wheel mounted at the extreme rear. The hood, in a bag, simply sat on the rear of the bodywork. It must have been quite claustrophobic with the hood erected.

Four Seater International Sports

Built on the short chassis, most of the first series cars were bodied by E. Bertelli Ltd. The standard “International “coachwork was a slightly perpendicular open 2/4 seater, with minimal space in the back for passengers. It was characterized by a rather high profile stemming from a tall ‘wet case’ radiator (the shell forming the water tank) which was further emphasized by the 21” wheels. The fuel tank was enclosed beneath the rear of the body and the spare wheel bracketed on to the body at the extreme rear. The exhaust system was taken from the cylinder head in a simple manifold with the downpipe going down inside the bonnet to the tail pipe and exhaust box below the car. The windscreen folded forward from the base, not flat onto the scuttle (with the exception of the “International Le Mans” model).

Four-seater Open Tourer

The long chassis cars were rather heavy for a 1½ litre engine and were not a great success. They were bodied as rather cumbersome looking four door tourers, many with a large trunk over the rear mounted fuel tank. Some had a rather unsightly bulge at the back to enclose luggage, which could be accessed behind the rear seat.

Two Door Saloon

Heavier still than the Tourer, the Saloon must have been the slowest of all pre-war Aston Martins; only one example is known to survive. In fact, only one 2 door example was built. It was however, very well finished, both inside and out and was upholstered in best quality ‘furniture hide’. At £595 it was the price of a large family home and was certainly amongst the more expensive medium sized saloons available at the time.

Four Door Saloon

Almost identical to the two door saloon, but with the rear doors hinged at the ‘B’ post (opening the modern conventional way). This did however cost more to build.

The “Le Mans” Two-Seater Sports Model

Towards the end of the first series, a small number of replicas of the two seater team cars were built, known as the “International” Le Mans (not to be confused with the later 1933 “Le Mans” model). Five were built with two seater coachwork similar to the works’ team cars, with fold flat windscreens, but with doors. The ”Le Mans” Two-Seater Sports Model had the 4½” lower radiators of the team cars which gave them a particularly sporting appearance, and a close ratio gearbox which gave them a performance to match their looks. The exhaust exited the bonnet in two downpipes and entered a ‘Brooklands’ exhaust box and was finished in a fishtail. It had only a single filler cap to the fuel tank. One of these cars had outside gearlever and handbrake (an option, but one very rarely taken up) outboard of a ‘dummy’ door, by special order. Two out of the seven produced by Bertelli were fitted with 2/4 seater coachwork similar to the short chassis “International” but with pronounced humped scuttle and external slab fuel tank at the rear. This body shape was effectively the prototype for the 1933 “Le Mans”. A third body was fitted to the works team car, (chassis no LM5), in 1932. Freestone and Webb also built a very similar body on one of the five original two seater cars, so that in total, four cars had very similar 2/4 seater humped scuttle coachwork. It was equipped as standard with six inch Jaeger instruments, and radiator and headlamp stone guards. The headlamps were fitted with double filament bulbs.

The ‘Coupe’

Lance Prideaux-Brune, owner of the Automobile Service Company at the Winter Garden Garages, admired the new Aston Martin. He was later to give financial assistance to the company and become a director. He was also a keen rally competitor and ordered a one off coupe from Aston Martin to participate in the 1932 RAC rally. Harry Bertelli designed a handsome drop head coupe body on the short “International” chassis. It was very expensive at £715 and no more than two examples were produced, however at least two very similar cars were bodied by outside coachbuilders.

The Sportsman’s Coupe

The’ Sportsman coupe’, was a slightly ungainly fixed head design, based on the long “International” chassis. It had louvred valances to cover the chassis, and at least one had shutters over the radiator. One of them had its interior upholstered in pigskin, and another painted bright yellow with black wings. They were even more expensive at £750 and only three were made.

The Fixed Head Coupe

A one off fixed head coupe car was ordered by wealthy ship owner W. S. Headlam. Though rather cramped inside due to it being built on a short chassis, the car was nevertheless one of Harry Bertelli’s finest creations and a perfect example of English coach building at its very best.

International Specifications

Four- seater “International” Sports

Steel channel section, 11’ 6” in length. Tapering at both ends, and to the rear cross tube 8’ from the front requiring 5¾” extensions to the rear cross tube to mount the rear springs. Six tubular cross members and one channel cross member. The fourth tubular cross member from the front, which provided the support for the front gearbox mounting, was 4” further towards the rear, moving the gearbox back by this amount and giving far more room for the driver’s feet in the foot-well. The drive shafts were correspondingly shorter to the rear axle but longer between the engine and the gearbox. The rear brake lever cross shaft was 6” further to the rear of the car and the arrangement of brake rods and levers different from the earlier cars. An aluminium casting the full width of the chassis supported two brackets for the dashboard and the aluminium clad ½” plywood firewall.
Wheelbase: 8’ 7”. Track: 4’ 4”
The Renwick& Bertelli designed overhead camshaft 4 cylinder 8 valve engine. Dry sump as per the ‘Standard Sports Model’
Bore: 63.9 mm, stroke: 99 mm, 1495 cc
Compression ratio: 6.5:1
Power: approximately 60 bhp at 4750 rpm
Torque: approximately 55 lbft
Twin SU 1?” side draught carburettor
Magneto ignition
Two ‘Autopulse’ fuel pumps mounted on the rear of the chassis
Aston Martin designed 4 speed crash gearbox with straight cut gears, constant mesh main shaft and layshaft, dog clutch 4th speed and reverse. The gearbox was mounted 4” further back in the chassis allowing more room for the feet in the foot-wells. The clutch eas the later type ‘push-off’ Borg and Beck with single large coil spring
Ratios: 16.31:1, 10.48:1, 6.43:1, 4.66:1
‘Bishop Cam’ box, by worm and peg
Wheels and Tyres
Rudge Whitworth’ 52mm x 21”, well base, 60 spoke wheels with 2?” wide rim, fitted with 4.50 x 21” tyres
14” aluminium drums with shrunk in steel liners and 1?” wide cam operated shoes mounted on a single pivot, actuated by rods. Perrot operated at the front. Handbrake operated all four brakes. Rear brake lever cross shaft moved 4” further back shortening the rear brake rod. From 1929 the front axle was fitted with a torque reaction cable to prevent wind up of the front axle under hard braking
Wheelbase: 8’6”
Track: 4’ 4”
Length: 12”
Width: 5’ 3”
Height: 4’ 4” (hood raised), Saloon 5’ 2”
Weight: 18 cwt
Fuel tank capacity: 20 gallons
Performance: approximately 80 mph. 65 mph (saloon)
price (1932)

Four -seater Tourer

As International Four Seater Sports, but chassis length increased to 9’ 10” and overall length 13’ 4”. Weight was 19 cwt. Being very heavy, top speed was not more than 70 mph

Gearbox ratios: 17.85:1, 11.47:1, 7.03:1, 5.1:1

Price (1932) £630

Two Door Saloon

As four seater tourer, but with full closed saloon coachwork. Price £725

Four Door Saloon

As Two Door Saloon, but the extra cost of making and fitting two extra doors bought the price up to £745

“Le Mans” Two-Seater Sports Model

As Four-Seater “International” Sports Model, but with lower radiator, outside exhaust and a gas flowed cylinder head. They were fitted with a pair of 1¼” carburettors

Gear box ratios were closer and slightly more sporting: 14.02:1 8.74:1 5.93:1 4.66:1. Electron was substituted in place of aluminium wherever possible.

Price £650

The ‘Coupe’

As Four-Seater “International” Sports Model

The Sportsman’s Coupe

As Two Door Saloon

The Fixed Head Coupe

As Four Seater “International” Sports Model

The two seater ‘International’ Sports

As Four-Seater “International” Sports Model

The Ulster Engine

From 1930, an ‘Ulster’ version of the ‘International’ engine was offered for an extra £50. The top of the combustion chamber was lowered by ?” and the ports tidied up, thereby improving the gas flow and increasing the compression ratio. This gave 56 bhp at 4500 rpm and would have made the lower and lighter “Le Mans” Two-Seater Sports model respectably fast for its day (particularly for a 1½ litre car) with up to 90 mph possible. This ’Ulster’ engine was an early example of Bertelli taking advantage of his racing programme to promote his production cars, and ‘Ulster’ was of course later to be used to name the racing version of the ‘Mark II’

In 1931 the Supercharged ‘International’ Sports Chassis was catalogued, but none were ever produced. At £720 pounds for the rolling chassis only, it was very expensive. A Power Plus supercharger was to be fitted between the dumb irons and driven from the front end of the crankshaft. Still dry sump, no mention was made of where the oil tank would be re-located. It was also advertised as having ‘Central Control’ to ‘provide greater rigidity as well as to save weight, and enables a narrower body to be used without either cramping the driver or putting the levers outside’. It is not clear whether this meant a central single seat body, but a footnote in the catalogue noted ‘We shall be pleased to discuss details of any type of body required and submit drawings or photographs, together with quotation for body to customers’ ideas.’

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