Flathead Ford V8
Article by Mark Trotta
In December of 1931, in the midst of America's Great Depression, Ford Motor Company stopped production of their four-cylinder engine and began manufacturing a new flathead V8.
Advantages of a flathead (side-valve) engine over an overhead valve engine were cost of manufacture and simplicity. With valves positioned in the engine block beside the piston (instead of in the cylinder head, as in an OHV engine), push-rods and rocker arms were not needed. Additionally, cylinder heads need only be a simple casting with threaded holes for the spark plugs.
Unlike other V8's of the day (Cadillac, LaSalle, Lincoln), in which the engine block and crankcase were bolted together, Ford designed a one-piece casting with bolt-on exhaust manifolds. The 90-degree, flathead V8 used a 0.265" offset crankshaft for reducing piston slap, which made for a smoother running lower end.
1932-1938 Ford Flathead V8
The first-design flathead Ford V8 engines had 21 cylinder-head studs and are known as "21 stud" motors. The bell housing was cast as part of the block. Until mid 1936, poured Babbit main-bearings were used.
Most easily recognized by the two water pumps mounted to the front of the heads, production of the original 221ci Ford flathead ran from 1932 to 1936.
Several issues plagued the early Ford flathead blocks, including overheating, casting porosity and cracking near the valve ports. Early flathead Ford V8 water pumps were actually Model A units, designed to fit the new engine to save cost and retooling.
Early Ford flathead V8's are hard to upgrade, but are highly prized by collector car restorers.
An updated design in 1937 had the water outlets relocated from the front of the heads to the top center of the heads. These were produced in 1937 and early 1938.
A smaller, 136ci V8 flathead engine was introduced in 1937. Known as the "V8-60", it's meager 60 horsepower output made it an unpopular engine choice in American-built cars and trucks. Although dropped from U.S. made models several years later, the V8-60 powered several French and British-built Fords up into the 1950s.
Read: Woodie Wagons History
1938-1948 Ford Flathead V8
Needing a more powerful motor for their new Mercury line of cars, Ford introduced the 239ci "24 stud" engine (twenty-four studs holding down each cylinder head) in late 1938. Producing 95-horsepower and 170 lb/ft of torque, these engines were used through 1942 for civilian use and also World War Two military vehicles. These second-design blocks (often referred to as 59A castings) retained the integral cast-in bell housing,
The 1939-1948 Ford flatheads had insert-style main bearings, but still used full-floating rod bearings (one bearing shell for each rod pair). A direct camshaft-driven front-mount distributor mounted flush to the cover, with a horizontal shaft on the front of the engine.
1949-1953 Ford Flathead V8
The third-design "8BA" engines (8RT for Ford trucks) were produced from 1949 to 1953. The block itself was the same for both Ford and Mercury, and had a higher 6.8:1 compression and bolt-on bell housing. The 24 studs and nuts that attached the heads on the block were replaced by 24 bolts, and left and right heads had different gaskets.
A revised cooling system had the water inlets and thermostat housings moved to the front end of the heads. The gear-driven distributor was now vertically mounted on the right-front of the engine. Early and late distributor styles can be interchanged by using the corresponding front engine covers and cam drive.
Flathead V8 motors were available in early F-series Ford trucks.
The End of Flathead Production
After 22 years of production, Ford's venerable flathead V-8 was discontinued in favor of an overhead-valve V-8. The new V8 displaced the same 239 cubic-inches as the flathead, but with a 15% increase in horsepower.
Although the flathead was discontinued in U.S. cars and trucks, production continued in other countries. The Ford Flathead V8 engine continued to be used in French military vehicles through the 1990s, with a good supply of new flatheads still available.
Flathead Ford Legacy
From 1932 until 1953, the Ford Flathead V8 was original equipment in over 25 million cars and trucks. The engine's 21-year production is on "Ward's List of the Ten Best engines of the 20th century".
New Ford Flathead repair manual covers disassembly, inspection and repair, assembly of engine and tolerances. Contains info for 221ci and 239ci Flathead V-8 Engines (78-81A-59A Series).
Shop: Ford Flathead V8 Engine Repair Service Manual
In 1963, legendary rock group the Beach Boys immortalized the Ford flathead in their hit single, "Little Deuce Coupe."
Flathead Ford Performance
Being cheap and plentiful, the aftermarket embraced the Ford flathead engine with a plethora of performance parts, including multiple carb and manifold setups, exhaust headers, and more radical camshafts.
Read: Flathead Ford Performance