Cadillac V16 Engine - Series 90

Series 90

The second generation of V16 used an unusually wide vee-angle of 135°, giving a wide but much lower engine to suit the styling tastes of the late 1930s. The two carburetors, one on each bank, and air cleaners were mounted on top of the engine block in this design. These engines had 'square' proportions; bore and stroke were both 3+1⁄₄ in (82.6 mm), giving an overall displacement of 431 cubic inches (7.1 L). Cadillac rated these engines at the same 185 bhp (138 kW) as the previous series. These engines were known as the Series 90, as were the cars that used them. The Series 90 V16 was produced from 1938 through 1940.

This engine was used in the 1938-1940 Series 90.

The 431-cubic-inch displacement 1938-40 Cadillac V16 was one of the last new American auto engine designs prior to World War Two. As such, it incorporated some of the latest thinking. Nine main bearings provided a crankshaft main bearing support between each 135 degree opposing pair of cylinders. The square bore and stroke lowered piston speed and promoted crankshaft rigidity, no small matter for an engine with eight cylinders in line per cylinder bank. The side valve engine design was no handicap for the time because the era's typical top engine speed of 3400-3700 rpm provided little opportunity to exploit the high speed breathing efficiency of overhead valves. Luxury car drivers presumably valued smoothness and silence more than high speed power. Hydraulic valve lifters promoted silent running and an absence of periodic adjustment. Unlike most cars of the era, an external oil filter safeguarded the precision valve lifters. Despite the use of side valves, the engine produced as much power as the prior 45 degree V16, and with much less complexity. The earliest engines produced featured an innovative friction wheel drive to the generator. This was soon replaced by a conventional V belt drive. Cadillac claimed that the 1938, 1939, and 1940 Series 90 Sixteen had the best performance of any production car in the world at the time and would accelerate 10-60 in high gear only in 16 seconds. The definitive engineering report on the 135 degree Cadillac V16 engine is "The Evolution of the Cadillac Sixteen engine," by E.W. Seaholm, in charge of Cadillac engine design. It was published by the industry journal "Automotive Industries," November 27, 1937.