Ford flathead V8 engine

The Ford flathead V8 (often called simply the Ford flathead or flathead Ford) is a V8 engine with a flat cylinder head introduced by the Ford Motor Company in 1932 and built by Ford through 1953. During the engine's first decade of production, when overhead-valve engines were used by only a small minority of makes, it was usually known simply as the Ford V‑8, and the first car model in which it was installed, the Model 18, was (and still is) often called simply the "Ford V-8" after its new engine.

An automotive milestone as the first affordable V8, it ranks as one of the company's most important developments. The engine was intended to be used for big passenger cars and trucks; it was installed in such (with minor, incremental changes) until 1953, making the engine's 21-year production run for the U.S. consumer market longer than the 19-year run of the Ford Model T engine. The Cadillac V8 engine is credited as the first mass-produced V8, and when Ford Motor Company acquired rival luxury marque Lincoln in 1922, the maker was already producing a flathead V8 with fork and blade connecting rods, which remained in production after Ford took over until 1932.

Even though Ford had an engineering team assigned to develop its own V8, many of the ideas and innovations were Henry Ford's. The Model A, its variants (B and 18), and this V8 engine were developed between 1926 and 1932, and this period was the elder Ford's last central contribution to the company's engineering.

An economizing design feature of this engine was the use of three main bearings to support the crankshaft, rather than the customary five used with most V-8s. The flathead mounted the camshaft above the crankshaft, like later pushrod-operated overhead-valve engines. Valves for each bank were mounted inside the triangular area formed by the "vee" of cylinders. The intake manifold fed both banks from inside the vee, but the exhaust ports had to pass between the cylinders to reach the outboard exhaust manifolds, since it did not use a t-head configuration. Such an arrangement transferred exhaust heat to the block, imposing a large cooling load; it required far more coolant and radiator capacity than equivalent overhead-valve V8 engines. Ford flathead V8s were notorious for cracking blocks if their barely adequate cooling systems were overtaxed (such as in trucking or racing). The simple design left much room for improvement, and the power available after even low cost modifications was usually substantially more than could be obtained from an overhead-valve inline six-cylinder engine of similar displacement.

The Ford flathead V8 was manufactured in several countries other than the US, including France, Australia, Germany and Sweden.

The Ford flathead V8 was licensed to other producers. It was used by Simca in France until 1961 and in Brazil until 1964 for cars and until 1990 in the Simca Unic Marmon Bocquet military truck. In the United States, the flathead V8 was replaced by the more modern overhead-valve Ford Y-block engine in 1954. During World War II, the engine was used on the first prototype of the Romanian Mareșal tank destroyer, but was considered too weak and thus replaced by more powerful engines for later versions of the vehicle.

Components

Crankshaft

The crankshaft development for the Ford flathead V8 was pioneering. These new methods were patented. but it had never seen mass production. Making it practical for the latter was an example of the production development needed to bring a V8 engine to the widely affordable segment of the market. Charles E. Sorensen lived up to his longtime nickname at Ford, "Cast-Iron Charlie", by leading this revolution to bring Ford's first V8 to market. The bottom of the block formed the parting line for the main bearing caps. The most complex part of the block was the exhaust passage routing. The exhaust valves were on the inside of the V and exhaust flow was initially downward and passed around the cylinders through the water jacket to exit on the outside of the cylinder block. The routing of the exhaust through the water jacket put an extremely heavy load on the cooling system and led to frequent overheating, especially on early models, if the cooling system was not maintained. Somewhat primitive water pumps used until the advent of the 1948 8RT and 1949 8BA models also contributed to the overheating problem. The space for the exhaust flow was also somewhat restricted, so the exhaust passages were tall and narrow in some locations. The gas flow past the rough sand castings could be greatly improved by polishing the passages. In early blocks, some cylinder walls were extremely thin due to cores shifting during casting.

Bearings

The engines built from 1932 to 1935 had poured main bearings which required skill and machine shop equipment to overhaul. Part of the 1936 production and all production from 1937 to the end of flathead V8 production had both replaceable shell main bearings and connecting rod inserts, enabling straightforward and low cost rebuilding, another reason why the Ford was a favorite of amateur mechanics. These shell main bearings are made of a cadmium silver alloy. It also eliminated a complex oil jet system to feed the rod bearings in the oil pan. As a side benefit to a prospective purchaser of a used vehicle, this also enabled the condition of the connecting rod and main bearings to be determined indirectly by observation of the oil pressure gauge after the vehicle was warmed up, provided that oil of normal viscosity was in use.

Exhaust

The exhaust outlets in the 1932–48 cars and the 1932–47 trucks were near the front of the manifolds aiming down and sometimes out. A Y-pipe took the exhaust gases to the right side of the vehicle to a single muffler, then to a single pipe out the back on the right side. The left side exhaust manifold exhausted to the front in the 1949–53 Ford cars, where a crossover pipe took the exhaust to the forward end of the right side manifold on the car engines and between the 1st and second cylinder on some trucks, in turn exhausting to a single pipe at the rear.

A common conversion for the 1949–53 Ford cars and 1952–53 Mercurys was to block off the right forward manifold entrance and route the left side exhaust to a new pipe to form a dual exhaust system with better flow characteristics. These typically involved installation of free-flowing mufflers, which if at a legal noise level still allowed low frequency sounds to pass, giving a characteristic rumbling dual exhaust sound to these systems. In the 1950s shortcut exhaust outlets with manually removed covers were added to street machines in emulation of vehicles intended for high speed straight line racing on dry lake beds, typically located just behind the front wheel, although chromed external runners sometimes extended to just forward of the rear wheel. These covers were referred to as lake plugs, the pipes as lake pipes. This style exhaust was also used legally in sanctioned drag racing and illegally in unsanctioned performance demonstrations.

Internal Air flow

More extreme modifications were to improve the airflow by removing material from the top of the block between the valves and the cylinders (called relieving), increasing the size of the inlet and exhaust passages (called porting), and by polishing the sand-cast surfaces to improve air flow. Increased compression ratios could be cheaply obtained by milling material from the head or by obtaining aluminum heads as aftermarket parts. Higher capacity intake manifolds were similarly available. Changing the camshaft to a higher performance version required head removal so that the valves could be held up out of the way, so this was usually done only as part of a substantial rework of the basic engine.

Overhead-valve kits

A popular modification for the flathead was conversion to an overhead-valve configuration, and many such modification kits were available, including the Ardun heads from Zora Arkus-Duntov who was to go on to fame as the "father of the Corvette". These conversions were not initially demanded by hot rodders looking for extra power, as they had not yet exhausted the capabilities of the flathead configuration, but were demanded by users of the engine in trucks and other such high load applications, where the constant flow of hot exhaust through the block to the exhaust manifolds caused the entire engine to overheat; the overhead-valve heads routed the exhaust out more directly, and away from the block.

Hot-rodding applications

In the early 1950s, many hot-rodders could not afford to purchase and modify even a "cheap" flathead V-8, and a large investment in machine work and aftermarket parts was necessary to bring a Ford flathead V-8 to even the performance levels of most stock OHV V-8s available at the time. Even many inline six-cylinder engines from that period could be modified to produce more reliable and practical power than Ford V-8s, as the Ford flathead V-8 is saddled with many design features that make modifying it for true high-performance use difficult and expensive compared with other V-8s.

As modern OHV V-8s became available and affordable in salvage yards, the Ford flathead V-8 rapidly disappeared from the hot-rodding scene. Hot-rodding in general moved away from the salvage-yard car builds as parts and labor became more expensive and many hot-rod shops priced themselves out of business. The modern OHV V-8 powered vehicles available also contributed to the demise of hot-rodding's original culture (affordable modifications by working-class car owners), as new factory cars became capable of much higher performance than most hot-rods.

Today the flat-head Ford is mainly used in "retro" hot-rod builds by builders more interested in an historic feel and recreating history than performance. Even four-cylinder Ford engines are used to make a retro hot-rod "correct".

thumb|Ford flathead V-8 with an aftermarket twin plug cylinder head & Stromberg carburettors

Modern performance flatheads

Ford flatheads are still hot rodded today, with a special land speed record class for flathead engines. The current record holder achieves and . The current land speed record for a Ford flathead V8 stands at 302.462mph.

Tractor conversions

During the 1930s to 1950s, the farm market in North America and parts of Europe demanded ever-increasing power output from farm tractors. It was in this climate that Ford experimented with V-8 tractor designs, some individual farmers converted their 4-cylinder tractors to Ford inline-6 or V-8 engines, and a few aftermarket companies offered such conversions for sale. Among the latter, the best-known were Funk conversions by brothers Joe and Howard Funk. In the 1930s, the Funk brothers built aircraft—including the Funk B, which used an engine design based on Ford engines. In the late 1940s, their aircraft line became unprofitable, but they found renewed profitability in aftermarket parts for tractors—transmissions, engines, and accessories. They sold many converted Ford N-Series tractors and conversion kits using Ford industrial inline-6 engines and Ford flathead V-8 engines. The block was cast as a single piece (monobloc) for durability, and a single-barrel carburetor fed the engine. The 1932 V8-18 with 5.5:1 compression Simca do Brasil introduced a version in May 1962 but the real surprise was the "Emi-Sul" of April 1966. This engine has overhead valves and hemispherical combustion chambers; it produced in its most powerful version. In addition, rodders in the 1950s routinely bored them out by (to ).

Vehicles used
Lincoln (EL-series)
Lincoln Cosmopolitan
Ford F-Series "Big Job"

References

Sources

Shelton, Chris. "Then, Now, and Forever" in Hot Rod, March 2017, pp. 16–29.

Bibliography

External links

Newly Engineered Flathead Block
Ford Flathead V8 Engine Guide