The anti-piston concept is not revolutionary; The Fairbanks-Morse 38 1/8 has been supporting naval vessels since World War II. A French engineer named Eugene Brillié developed anti-piston engines in the early 1920s. The DS3 engine used by Commer was built by the Rootes group, which included the Hillman and Humber brands and, in some cases, it builds bodies for Rolls-Royce and Daimler, among others.
The Commer Knocker differed from other opposed piston engines in that it had one crankshaft instead of two. In TS3, one piston is designated as the exhaust piston, and the other as the intake piston. The exhaust piston had a very short travel distance to ensure that its port was closed when air was drawn into the cylinder. This set the TS3 apart from other reciprocating piston engines, along with a large lobe-shaped blower that captured the exhaust gases and forced them back through the manifold.
The design was very powerful for its size: the original 3.25 liter TS3 produced 105 horsepower and 270 lb-ft of torque, and a 1964 upgrade raised those numbers to 117 hp and 310 lb-ft.
The TS3 remained in production until 1972, when the four-cylinder TS4 replaced it. By that time, Chrysler’s gradual acquisition of the Rootes group had already begun, translating into Commer Knocker’s final words.