determining whether the exhaust or intake manifold was 

 permitted to function. 



The ignition timer is mounted adjacent to the engine 

 camshaft, the cam of the timer being driven by the cam- 

 shaft. A spark plug is located in the rear of the cylinder. 

 The original spark plug was made in the Knox factory, as 

 were all ball bearings used in the car. 



The portion of the camshaft that drives the cam of the 

 timer is spirally splined and is free to slide with respect to 

 the rotor, advancing or retarding the ignition as it does so. 

 In addition, the cam itself, which is integral with the splined 

 shaft, is 3-dimensional, which means that as it is moved back 

 and forth with respect to its follower it will advance or re- 

 tard the motion of the follower and consequently the valve 

 timing. The speed of the engine was controlled in this way. 



Mounted on the back of the chassis, next to the intake 

 end of the piston valve, is the carburetor, which is of the 

 constant-level type, with hinged float and needle valve. 

 This is similar to, and has all the essential features of, the 

 modern type of carburetor, the needle valve being located 

 horizontally near the top of the bowl. A jet, which is ad- 

 justed by a metering pin, projects into the intake manifold, 

 which then leads directly to the intake end of the piston 

 valve. The portion of the manifold on the other side of the 

 jet is perforated with many small holes. Air, sucked through 

 these holes as the piston descended, was carried past the jet 

 to form the explosive mixture, which passed by the piston 

 valve and then by the poppet valve. 



Mounted on the carburetor cover plate is a vent tube 

 leading to the float chamber. When starting the engine 

 the operator placed a rubber hose on this tube. Blowing 

 into the hose caused a gasoline mixture to be forced out of 

 the jet and and into the intake manifold. There is no but- 

 terfly control of the carburetor, all speed control of the en- 

 gine being exercised by the sliding camshaft. The exhaust 

 end of the piston valve is connected by a long tube to the 

 muffler, which is transversely mounted next to the chassis 

 cross member in front of the engine. 



A cylindrical sight-glass oil tank is bolted to the front of 

 the crankcase, allowing oil to flow via two oil lines to each 



61 



