AC Royal Six

Manufacturer	AC
Production	1926 to 1928
Class	Sports Car
Body style	2 -door / 4-door saloon, drophead coupé, tourer
Layout	FR layout
Engine	1991cc straight six
Curb weight	2,912 lb (1,321 kg)

The AC Royal was a British car from the 1920s, this came built like many cars from the time with ash-framed bodt structure covered with lightweight aluminium outer panels, but still the cheapest model in the range from the time.

The Famous AC cars after World War l. Four-cylinder engines were used at first, joined by a six in 1920. An advanced six Designed by John Weller, the 1.5 litre six-cylinder engine was an advanced unit,with aluminium alloy block and crankcase. wet cylinder liners and a cast-iron cylinder head. The slightly inclined Overhead valves were operated by a single over-head camshaft 1922 Capacity went up to 1991 cc and power to 40 bhp.
The cars in which the six-cylinder engine was fitted (there was also a 1.5 litre four until 1927) with rounded radiators and bodies often of polished aluminium,Front wheel brakes did not come until 1927, and apart from racing cars there was no four-speed AC until 1933. when the old the-speed box in unit with the rear axle gave way to a conventional. four speed. in 1928 the name Aceca appeared for the first time, as a drophead coupé; this was priced at £475, while the cheapest model in the range was the Royal  open 2/3-seater at £350. Power output had been increased to 56 b.h.p. from 40  and the crankshaft line was stiffened by the addition of a fifth main bearing.