An American vintage sports car

From Theodore F Robertson, President of the Sports Car Club of America, comes some information about his 1918 Series 4 L-head sports Mercer, which has a 4-cylinder side-valve engine of 33/4 in by 63/4 in (298.2 cu in) and so came within the 300 cu in class. The valves have a clear opening of 21/4 in, carburation is by a Zenith carburetter ported through the block, and ignition is by a Bosch ZU4 magneto. The gearbox gives a direct drive on top and has ratios of 11.91, 6.88, 4.72 and 3.22 to 1. Transmission is by open shaft. The chassis is sprung on 21/2 in by 39 in 1/2-elliptics at the front and 23/4 in by 52 in 1/2 eliptics at the back. The wheelbase is 9 ft 7 in, the track 4 ft 10 in, and the wheels are 80 mm Rudge, with 21 in, and 24 in rims, carrying 6 in section tyres. The foot-brake operates on the transmission and the hand-brake on 16 in rear wheel brakes. The 1915 catalogue guaranteed 1 mile in 48 secs. (ie, 75 mph), and in the amateur race at Chicago in May, 1916, Mercers of this type won at 86.8 mph, for the 30-mile race and 86.7 mph for the 50 mile race, putting up the fastest lap of the 2 mile circuit at 94.0 mph, these achievements going to the credit of three different cars.