| Ford Sidevalve engine | |
| Aka: | Ford Flathead engine |
| Manufacturer: | Ford Motor Company |
| Production: | 1932 - 1962 |
| Predecessor: | None |
| Successor: | Ford Kent engine Ford Taunus V4 engine |
| Configuration: | Naturally aspirated straight 4 |
| Displacement: | 9331NaN1 11721NaN1 |
| Block: | Cast iron |
| Head: | Cast iron |
| Valvetrain: | Sidevalve 2 valves per cyl. |
| Fuelsystem: | Carburettor |
| Fueltype: | Leaded Gasoline |
| Coolingsystem: | Thermosiphon (pump was only fitted after 1953) |
| Power: | 36hp |
| Compression: | 6.0:1 |
The Ford Sidevalve is a side valve (flathead engine) from the British arm of the Ford Motor Company, often also referred to as the "English Sidevalve". The engine had its origins in the 1930s Ford Model Y, and was made in two sizes, 9331NaN1 or "8 HP", and 11721NaN1 or "10 HP". The early engines did not have a water pump as standard, instead relying on thermosiphon cooling as the Model T engine had. A water pump was added in 1953 for the 100E models when the engine was re-engineered to the point that few specifications are identical between the early and the later series. The Sidevalve engine was used in many smaller Fords as well as farm vehicles, commercial vehicles and a marine version in boats. Production of the engine was stopped in 1962. Windscreen wipers were often driven by the vacuum generated in the inlet manifold.
The Sidevalve Engine was also used in German Fords, starting with the Ford Köln in 1932 and ending with the last rear-wheel drive Ford Taunus 12M (G13/G13AL) in 1962. Early further research and development were being carried out at the German Ford engine plant in Cologne to improve the engine for ease of use in the Taunus line of cars, including a 44 hp 1.5 developed from the 1172cc for the Taunus G93A but this work was finally halted in 1942.
Ford of Germany would later make use of the work on the 1.5 development of the 1.2 Sidevalve and convert it to a 55 hp 1498 cc Overhead-Valve design for the 1955 Ford Taunus 15M P1, which would later be further enlarged to a 59 hp 1698 cc for the 1957 Ford Taunus 17M P2 and 69-74 hp 1758cc for the 1960 Ford Taunus 17M/TS 1750 P3 until production ceased in 1964.
It was replaced by the Kent engine in Britain and by the Taunus V4 engine in Germany.
Many ways were explored to enhance the power output of the standard engine, most notably special exhaust manifolds, twin carburettors, stiffer valve springs, thinner cylinder head gaskets and modified camshafts. The most hardcore performance tuning available was the Overhead Inlet Valve head conversion from Wilmont and Elva, which could be built to produce 70+ BHP [1]
The nominal horsepower quoted for each engine size comes from the British method of power calculation for road taxation purposes, and bears no relationship with the actual power output. Displacement, cylinder diameter, stroke, and number of cylinders determined the power for road taxation purposes.
A three-speed gearbox was fitted as standard; three forward and one reverse. Several ways of improving the performance through modifications to the gearbox and transmission train were applied; replacement close ratio gears fitted to gearbox, overdrive gears fitted behind the original gearbox and higher ratio crown & pinion gears fitted to the differential unit on the back axle.