The first Ford passenger car with overhead valves wasn’t a V8. It was the Mileage Maker Six introduced in 1952, and it was a thoroughly up-to-date design.
It was an accepted fact in Motor City lore that Henry Ford didn’t care for six-cylinder engines, even though that likely wasn’t true. But in 1941 Ford introduced a six, and it served the company well for a decade (see our feature here). There were no doubt many good reasons for a replacement by 1952, but according to Ford chief engineer Earle S. MacPherson (yes, the father of the MacPherson strut) the best reason was a simple one. The tooling for the old L-head six had simply worn out by then, and it made more sense to design a new engine at that point than to invest in expensive new equipment for the old one.
In much the same manner as Ford’s familiar Y-Block concept, the new Ford six was termed an I-Block, with a deep-skirted crankcase that extended well below the crankshaft centerline. The trusty flathead V8 introduced back in ’32 was a centerline design with some recognized shortcomings including clutch chatter, and Ford required an engine suitable for both passenger cars and heavy-duty trucks. So the I-Block extended a full 2.25 inches below the crank, allowing a more rigid driveline, while the bottom end was robust throughout with 2.5-in main bearings, 2.25 rod journals, and a cast crankshaft in alloy steel using Ford’s well-tested shell-molding process.
It’s a neat quirk in history that the first Ford passenger car engine with overhead valves wasn’t a V8, but the 1952 Mileage Maker Six. (A Lincoln OHV V8 was also introduced that year.) The layout was latest practice for the Motor City at the time, featuring a turbulent wedge combustion chamber with generous squish and quench area. Pistons were up to date as well: Nelson-type cast aluminum with autothermic Invar nickel-iron struts and a modern three-ring package.
In its initial form the Mileage Marker displaced 215 cubic inches, with nearly square bore and stroke dimensions of 3.56-in by 3.60-in. This was a marked improvement over the L-head six with its long 4.40-in stroke, since mean piston speed was lowered by nearly 20 percent, reducing cylinder bore wear and extending engine life. The Mileage Maker was a great deal for Ford buyers: With 101 hp and 185 lb-ft of torque, the output was comparable to the flathead V8, and for $75 less. And they were getting a far more modern engine to boot. Motor Trend magazine reported that the six was actually quicker.
Marketed under various names including Cost Clipper and Big Job Six, the Mileage Maker was enlarged to 223 CID in 1954 and to 261 CID in 1961 for big trucks. The engine did have one rather famous defect: a tendency for an internal oil galley to clog up with carbon, starving the upper end for lubrication and producing a telltale clatter. But there was an easy field fix, the addition of an external oil line from the oil sending unit in the block to the rocker shaft up top. The Mileage Maker remained in production through 1964, when it was replaced by the 240 and 300 cubic inch Big Six family.
