1955 Austin-Healey 100S

The Austin-Healey 100S (was essentially a purpose-built racing version of the Austin-Healey 100 with 50 examples built (excluding prototypes and 'Special Test Cars') to '100S' specification. Approximately half of the production was despatched to the United States with the first deliveries arriving in time for the 155 Sebring 12 Hour race. The 'S' stood for 'Sebring', in honor of the factory entered and 100-based Special Test Car's success with Lance Macklin and George Huntoon at the 1954 Sebring 12-Hours, where it finished 3rd overall and 1st in class.

The Austin-Healey 100 was produced from 1953 until 1956 and was based upon Austin A90 Atlantic mechanicals. A Healey 'Hundred' was displayed at the 1952 Lonon Motor Show and caught the attention of Austin managing director Leonard Lord, who was seeking a replacement for the unsuccessful A90. It was called the '100' due to its ability to reach 100 mph. Its body was styled by Gerry Coker and the chassis was by Barry Bilbie. It achieved a low overall height due to its underslung rear axle, with the chassis frame passing beneath the rear axle assembly.

The competition-derived aluminum-bodied '100S' model produced 132 horsepower at 4,700 RPM - a 30-percent increase over the standard engine's output. The standard cast-iron cylinder head was replaced by a bespoke Weslake-designed eight-port aluminum unit that required the intake and exhaust manifolds to be on opposite sides from those of the production cars. These engines were built at the Morris engine plant in Coventry - although they were still an 'Austin' engine. Dunlop hydraulic disc brakes were placed at all four corners and replaced the previous drums. The early Dunlop system used a Plessey mechanical pump to energize the braking system. This pump system was later believed to be unnecessary due to the advances in disc brake design, and Healey and Dunlop installed a new design in the Cooper 100S chassis. Following additional testing and development, the optimal setup was determined and installed on the subsequent 100S Healeys.

Weight reduction was an integral part of the 100S, including the all-alloy bodywork and alloy substructure. The standard car's overdrive unit was not installed, bumpers and the large glass windscreen were removed, and was devoid of the non-essential 'weather equipment' including the side curtains and the top. The result was a reduction of approximately 200 lbs. Most of the 100S received a two-tone color scheme of white with Lobelia Blue sides. A single example was painted black, and a small number were sold in Spruce Green and red.

The 100S were hand-built by the Donald Healey Motor Company at Warwick, had 'AHS' chassis number prefix, and were delivered between February and November of 1955.

by Daniel Vaughan | Aug 2020

The Austin Healey 100 was introduced in October of 1952 at the Earls Court Motor Show. The first Austin Healey 100's were known as 100-4 or BN1. The name 100 came-about by being able to break the 100 mph barrier. The BN also had meaning. The B represented the engine class which meant it had between 2000 and 3000 cc. The N represented the body-style configuration, two-seat and open-top. The 100 was powered by a A90, 2660 cc, four-cylinder engine capable of producing 94 horsepower. The manual three-speed transmission was also borrowed from the A90. However, the first gear was blocked off and was fitted with overdrive on the second and third gears to provide extra power.

The name 'Austin Healey' was formed by a partnership comprising of the designer, Donald Mitchell Healey, and the manufacturer, Austin.

During its total production cycle, 10,688 examples of the BN1 were produced.

In October of 1955, the BN2 was introduced. The BN2 was similar to the BN1 in design but now featured larger drum brakes and a new four-speed transmission with overdrive.

During its production run, 3,924 examples of the BN2 were produced.

The Austin Healey 100S was produced in limited numbers, only 55. Their primary purpose was for competing in racing and rally events as well as for development and marketing purposes. They were entered into races such as Sebring, Mille Miglia, and Le Mans. They were copies of special factory test car that Stirling Moss raced in the 1954 12-hour Sebring race where he placed third. The 100S's were produced at the Healey Warwick factory and most were decorated with the American racing colors, white and blue. Of the 55 that were built, only 10 remain unaccounted for. The 100S, when compared with the 100, featured Dunlop disc brakes on all four wheels, different cylinder head and internal engine modifications, four-speed gearbox without overdrive, and a light-alloy body shell.

The 100S was followed by the 100M. The 100M was a Le Mans variation of the BN2 with an increased horsepower rating of 100-110. It featured bigger carburetors and modified distributor. Valve springs and anti-roll bars were added to the suspension. During its production run, 1100 of the Le Mans BN2's were produced.

Over time, about 100 BN2 were later modified but in order to qualify for the Le Mans configuration the vehicles needed to meet specific standards. These standards included a 1.75 inch H6, SU carburetors, cold air box and air tube, Le Mans regulation strap and a factory style louvered hood.

The four cylinder engine was used from 1952 through 1956, after which a BMC six-cylinder engine was used. The car was dubbed the '100 Six'. Three years and a few engine modifications later, the car was named the '3000' and today is known as the 'Big Healey'. Over the production lifespan of the 3000, it could be assembled with multiple options such as a two-seater or 2+2, hard-tops, single or duo-tone paint schemes, overdrive, and more.

In 1962 the body was redesigned with a curved screen and wind up windows. The interior of the vehicle was revamped in 1964 and also received more ground clearance.

The 3000 was produced from 1959 through 1968. The original engine produced 124 horsepower and was capable of about 114 mph. Modifications to the engine throughout the years increased the horsepower to around 148 and the top speed to 121 mph. The size of the car, the power of the engine, and weighing in at around 2400 lbs made this car responsive, competitive and fun to drive.

In all, there were around 73,000 100's and 3000's produced with 58,000 featuring the six-cylinder engine.

by Daniel Vaughan | Jun 2005