‘ve been nattering about this project for a few years now, as the plans have morphed based on my resources. Last month, I unveiled the first installment in a series of articles discussing, in depth, the recipe I’ve worked out with my friend Clayton Paddison to turn a well-preserved 1921 Ford Model T touring car into something capable of running on modern roads without hanging an orange triangle on the back.
The blueprint we’ve laid out uses 1920s and ’30s technology to expand the capabilities of the Model T’s 1900s design in much the same way a driver in that era might have done so. The previous installment dealt with the chassis and brakes. This month, I want to explain our plans for the powertrain: engine, transmission, rear axle, and driveline.
The engine on a hot rod should never be an afterthought, yet on my car it’s getting only mild attention. That’s because it’s an original, 99-year-old (June 1921) engine that still runs well.
I know that if I were to start hotting it up, it would quickly collapse under the strain. On a pre-1927 Model T engine (engines stayed in production through December 1941), the biggest weakness is the “bent-paperclip” crankshaft.Eventually, when the reservoir of fun tickets has refilled, I will build the “big” engine—starting with a 1926-’27 block and EE-series crank and capped off with a pair of Stromberg 81s on an Evans intake. Beyond that, who knows? Maybe by then I’ll have acquired the Rajo Model A head I’ve always wanted.
Alternately, I’ve also got a ’28 Chevrolet head bumping around here that I can’t bear to part with.Until then, a set of aluminum pistons and a few mild bolt-ons will suffice. The original intake manifold and Kingston L4 will be set aside and replaced with a “straight-through” Holley NH and an aftermarket high-volume intake manifold.
The straight-through NH was a short-lived version of the common Model T carburetor that flows slightly better than the norm and the high-volume intake is a necessity to take advantage of its potential.Bigger, one-piece valves and a high-lift camshaft will further the performance enhancements, permitting more mixture into the cylinders.
To make sure that charge is properly tumbled and squeezed, I’ve also sent Clayton an aluminum “Z” Head which has about 6:1 compression (stock was 4.5:1—gas wasn’t great in the ’20s—and the practical maximum for an L-head engine is around 7 or 7.5:1, but that’s awful hard on the bottom end of a stockish T engine) and the efficient combustion chambers advocated by the great Harry Ricardo.