CADILLAC COUPE

CADILLAC PROVIDES A GREAT ENGINE AND TRANSMISSION FOR WAR

FAMOUS AMERICAN LUXURY

We speak flippantly, fondly, or derisively of ‘Yank tanks’, but there was a car — a Cadillac, no less — linked closely to that expression for a reason other than its accepted meaning. It wasn’t all bad in 1941. Although much of the world was suffering the tumult of war, the US still prospered. Many of her citizens suspected that they would eventually be drawn into this tragic conflict and probably guessed that it would not be over any time soon. This would result in car production being severely reduced, but, in the meantime, car sales boomed. Cadillac, along with most other marques, enjoyed record sales: up more than 19,000 over 1940.

More than 29,000 of these sales came from the new Series 61 Cadillac, which replaced the La Salle, terminated after a 14-year reign. The La Salle had become too good a car for the money and had eroded sales of the higher profit-margin Cadillac. The Series 61, with its widely copied fastback styling (Bentley, for one) proved to be the best-selling model in the 1941 Cadillac range.

New face, new engine, new transmission

For the first time since 1927, all Cadillac models were powered by the same engine, and what an engine it was: first choice for bootleggers, hot rodders, race drivers, and the army. Three-hundred-and-forty-six cubic inches (5.7 litres) of swept volume gets compressed at a ratio of 7.25:1 in the monobloc, L-head engine, resulting in 150hp (112kw) at 3400rpm. This legendarily smooth-running V8 was introduced in 1936. Its exceptional quietness was due in no small way to General Motors’ (GM) invention of the hydraulic valve-lifter.

Oldsmobile had trialled GM’S new Hydra-matic transmission as an option in 1940 and now offered it as a US$125 Cadillac option. Oldsmobile had also market tested this option. This was an important test at a much higher volume. If the transmission were a dud, the Cadillac reputation would not be compromised. Development of the transmission started in 1934, and it was introduced in October 1939.

The Hydra-matic is the granddaddy of all modern automatics. A glance inside the transmission reveals all the bands, clutches, and valve bodies recognizable in today’s transmissions. Other car manufacturers such as Lincoln, Hudson, Nash, and Rolls-royce used the Hydra-matic, which was only finally superseded in about 1956. It was used in some applications until 1964.

Helping the war effort

With war on the horizon, the US Army still had no ready supply of dedicated tank engines. It knew how good the Cadillac engine was and commissioned the M5 Stuart light tank in November 1941. Two Cadillac engines could handle the 15-tonne weight and powered these tanks to an impressive (official) 36mph (58kph), although their drivers claimed 45mph (72kph) was attainable.

The engines were mounted backwards on either side towards the rear, and power was delivered through two Hydra-matics and drive shafts to a two-speed transfer case. This gave eight forward speeds and two reverse. Speed, manoeuvrability, quietness, reliability, and a 60-degree hill-climbing ability were offset by light armour, lack of firepower, and a high profile.

‘She’s a honey!’

They were so smooth and quiet that tank crews regarded them as stealthy. British soldiers called them ‘Honey’, as in, ‘She’s a honey’. However, despite uprating the rather puny 37mm main gun, too many crews died in them, so their role eventually became mainly reconnaissance and escort duty. Thousands were sent to the Pacific theatre in 1944, where they could beat up the even lighter armoured Japanese tanks.

More than 25,000 Cadillac-powered vehicles were produced for the war effort, and another 10,000 engines went to other armoured-vehicle manufacturers. It is a tribute to the extraordinary might of US industry that the first M5 rolled off the assembly line only 55 days after the last Cadillac.

Development of the Hydra-matic continued throughout the war with many improvements, so many that very few post-war parts interchange with the pre-war version, although they appear identical. Post-war advertising lauded the Hydramatic as “battle-tested”, and so it was; this rugged, reliable transmission was also a favourite of drag racers well into the ’60s.