In 1931, American LaFrance astounded the fire service – and the rest of the fire apparatus industry – with its surprise announcement of a V-12 engine. Designed for the unique requirements of the fire service, the 312-A engine had been under development at Elmira for more than three years.
With four-inch bore and five-inch stroke, the big V-12 displaced 754 cubic inches (ca. 12 l) and delivered an impressive 240 horsepower. Actually two six-cylinder engines sharing a common crankshaft, the 312-A engine had an extremely narrow bank angle of 30 degrees.
The first production American LaFrance V-12 pumper was delivered to Winfield, Kansas, in August, 1931. With the new V-12, American LaFrance replaced the 1929-1931 Master Series with a new 300 Series. The 240-horsepower 312-A engine also permitted American LaFrance to market its first high-capacity 1500 gallon-per-minute pumpers, the first two of which were constructed for New York City.
During the early to mid-1930s, American LaFrance abandoned its long-favored rotary gear pump in favor of a single-stage centrifugal pump purchased from the Buffalo Steam Pump Co. The company also converted from outdated chain-drive to more efficient bevel gear shaft drive propulsion for its motor fire apparatus.