When we talk about engine development, we mean it. Development is a process in which we take everything we know and we try something new. Sometimes it works and sometimes it doesn’t, but without an understanding of all the steps that have gone before, how do you get a clue about the next step to take?
That’s the idea behind the next series of articles you’re going to find here at EngineLabs. We’re going to take a look at the great engines of the past, and see what those engines have to offer us today – even if it’s a cautionary tale of what not to do. The Historic Engines series will take it all in, and put today’s best engines in context.
If you have an idea of an engine we should cover, please send it along and we’ll get it on the list.
We decided to start almost at the beginning, with Ford’s original mass-market engine, delivered in almost 16 million units of the Model T. Between its introduction in 1908 and the end of production in 1927, the basic engine in the Model T hardly changed at all, and it continued to be used in a wide variety of applications after Ford moved on. Millions of Model T engines are still running today, about 100 years later.
The Model T was the car that put America on wheels, and the engine is central to the success of the vehicle. Henry Ford was a maniac about cutting costs everywhere a penny could be saved. He even had farms raising cattle to provide leather for his seats and beef for his workers to eat at lunchtime. Ford put pressure on his engineers to build the Model T engine to be versatile, reliable, and inexpensive. The results they achieved are pure genius.
The Model T engine is as simple as an engine can possibly be. It’s an inline 4-cylinder flathead design – specifically an L-Head configuration. That means that the valves are next to the pistons, pointed upwards. The head is not truly flat, having four spade-shaped combustion chambers to accommodate the valves. But there’s no chance of valve/piston interference – remember that.
The T engine displaces 2.9 liters (177 cubic inches), and has a bore of 3.75 inches and a 4-inch stroke. The compression ratio was a mere 4.5:1, creating normal cylinder pressures of only 50-75 psi. As a result, the engine develops about 20 horsepower, but it makes 83 pound-feet of torque due to the long stroke and relatively large displacement.
The genius of the Model T engine is not in what it has, but rather what it lacks. There is no oil pump – all lubrication happens by splashing the crank through the oil pan, drenching the three main bearings, the cam, and the lifters with oil.
There’s no water pump, either. Ford’s engineers realized that hot water rises, and they created an unpressurized cooling system that feeds cooled water from the radiator into the bottom of the block, relying on convection to push the hot water out the top and into the radiator. It works, sort of. Model T drivers know to carry extra water.
Don’t look for a fuel pump, either. It’s all gravity-fed from a tank under the seat to a simple carburetor with two adjustments: an idle stop and a mixture needle. The driver can adjust the mixture from the cockpit. There’s a basic choke, accessible from the front of the car near the crank, and from the driver’s seat if the Model T has electric start capability. The throttle is a lever mounted by the steering wheel, like a tractor.
The ignition system is also a marvel of easy design. There is a basic distributor mechanism on the front of the engine, driven directly off the camshaft. The driver sets the spark timing by means of a second lever near the steering wheel, which rotates the distributor cap. Timing can be adjusted by bending the metal rod that connects the lever to the distributor.
In practice, you want the spark to be fully retarded to after top dead center to start the engine, then you advance it as soon as the engine is started. This is to avoid kickback through the hand crank and to make the engine easier to start. Four separate box coils are actuated by the commutator in the distributor housing, and each emits a short buzz when sparking.
Because of the extremely basic design of the Model T engine, owners could run the car on gasoline, kerosene, or grain alcohol (pure ethanol). This “multifuel” capability was also done by design, to allow farmers to create their own fuel with excess corn. You can literally run a Model T on Moonshine! A generator and electric starter became standard equipment on 1920 models, but before that the only accessory on the engine was a simple fan driven by a flat belt.
Here’s something you probably don’t know – the Model T was single-handedly responsible for the birth of aftermarket speed equipment. Remember that the Model T engine cannot have any interference between the valves and pistons? That opened the door for companies like RAJO to make high compression heads that boosted compression for more power. Other companies made upgrade “Rocky Mountain” brake kits, Ruckstell made two-speed rear axles that enabled speeds up to 60 MPH, and other people created a full list of aftermarket gear to customize your Model T.
The Model T engine almost looks like a toy by modern standards, but if you put in four quarts of modern synthetic oil, this machine will keep running effectively forever. Henry Ford eventually cut the price of a new Model T from $850 in 1908 to just $260 for a roadster in 1925. That’s about $3,500 in today’s dollars, for a brand new car. Today, typical prices for an unmodified and good condition Model T range from about $5,000 to $10,000.