The spark plug was installed horizontally into the rear of the cylinder at the top but had no connecting high-voltage wire. An internal-tooth ring gear mounted on the engine drove a stationary magneto mounted on the firewall, whose high-voltage output terminal was in close proximity to the spark plug terminals as they passed by. This arrangement eliminated the need for distributor and high-voltage wiring found in conventional mechanically timed ignition systems. This ring gear also drove the oil pump, which supplied oil to all bearings, and through hollow pushrods to the rockers and valves and also drove an air pump which pressurized the fuel tank. The later Gnome 9N engines had dual ignition systems for safety, with twin spark plugs per cylinder which "were" electrically wired, with the wires routed onto the crankcase and a central pair of magnetos driven by the spinning engine crankcase.