The Model T Ford Engine
The Engine in the Model T is a 4 cylinder, 4 cycle with 3-3/4 inch bore, 4 inch stroke and rated as 20 horsepower. Rated in accordance with the now generally accepted formula for determining horsepower, d2 x n / 2-1/2, or the square of the diameter of one cylinder multiplied by the number of cylinders and the result divided by 2-1/2, the horsepower of the Model T is 22-1/2. Cylinders are cast in one block and with water jackets and upper half of crank case integral. The water jacketed cylinder head is detachable, rendering easily accessible all pistons, cylinders and valves.
The tower half of the crank case is of pressed steel and extended so as to form the bottom housing for the magneto, flywheel, transmission and universal joint.
The flywheel is back of the transmission and in addition to performing its functions, it serves as a support and rotor for the gears, and likewise supports and revolves the magnets, all of which gears and magnets are included in the weight of the flywheel, thereby materially reducing the weight of the car.
Crank and cam shafts are each made from a single piece of non-welded, drop-forged Vanadium steel, specially heat treated in our own plant.
Pistons are each carefully built to perfect accuracy, with rings of the desired fitness to produce the highest lubrication and compression results. Commutator is in front. Cooling is by thermo-siphon system.
Lubrication is by a combination of splash and gravity that is simple and effective.
The Ford Model T engine is a side-valve design with three main bearings. The cylinders are cast in one block for a displacement of 177 cubic inches, or 2896 cc. Plug firing order is 1-2-4-3. The transmission is joined directly with the engine and shares the same lubrication.
The transmission is controlled by three pedals on the floor, labeled C (clutch), R (reverse) and B (brake).
GENERAL SPECIFICATIONS FOR THE FORD MODEL T
Motor 20 horsepower, 4 cylinder in line L-head side valve with detachable cylinder head and 3 bearing crankshaft. Cylinders cast in one block with water jackets
Bore/Stroke 3 ¾ by 4 inches with a displacement of 2896 cc (177 cubic inches)
Ignition Ford magneto generator, low tension, direct connected to engine drive.
Carburetor Float feed automatic with dash adjustment.
Transmission Ford spur planetary, bathed in oil, - all gears from heat treated Vanadium steel, silent and easy in action.
Lubrication Combination splash and gravity system-simple and sure. Insures against insufficient or excessive lubrication.
Clutch Multiple steel discs, operating in oil. All forward speeds are controlled by foot pedal. Reverse by middle peddal. Spark and throttle on the steering column.
Final Drive By carbon shaft with single universal joint to bevel drive gears in live rear axle. Ford three point system (patented in all countries) with all moving parts enclosed in dust proof casing, running in oil. Vanadium steel throughout.
Front Axle One piece drop forging in I-beam section, specially treated, Vanadium steel.
Steering By Ford reduction gear system; irreversible.
Brakes Two sets: (a) Service band brake operates on the transmission and is controlled by a foot pedal; (b) Emergency brake is controlled by hand lever at side of car acting on the drums of rear wheels.
Wheels Artillery wood type. Hubs extra long. Some are hickory.
Tires Pneumatic; front 30x3 inches (US Cars), rear 30 x 3-1/2 inches. Standard makes. Best quality. Larger tires than ordinarily used for weight of the car, which means longest service and greatest comfort. Note: Canadian Fords use 30 x 3-1/2 tires for both front and rear wheels.
Springs Front and rear, semi-elliptical transverse, all Vanadium.
Wheel Base 100 in., tread 56 in.; 60 in. for Southern roads where ordered.
Gas Tank 10 gallons. Cylindrical gasoline tank mounted directly on frame.
Standard Equipment The Touring Car, Torpedo Runabout, Open Runabout and Roadster include at the fully equipped prices, a top, automatic brass windshield, speedometer, two gas lamps and generator, three oil lamps, tubular horn and a kit of tools. The Town Car and Coupe equipment include three oil lamps, tubular horn and tools only.
Weight 1200 lbs.
Crank Case Upper half integral with cylinder casting. Lower half of pressed steel and extended to form lower housing for magneto and transmission.
Cooling Thermo-siphon and fan.
Control Three foot pedals. By pressing the first pedal "C" the slow speed is applied; by releasing, it is in the high speed. The center pedal "R" is for reversing the car. The third pedal "B" is the brake.
The FORD Model T can be entirely manipulated either by use of the pedals or by the controlling lever at the side of the car. The carburetor lever and throttle just under the steering wheel will regulate the speed of the car from a walk to 40 miles an hour, without shifting a lever or applying the foot pedals.
Shafts Crank and cam, non-welded, drop-forged, heat-treated FORD Vanadium steel, with all surfaces ground to absolute accuracy.
Model T Ford Engine Explained In Detail
The Ford motive power is derived from what is known as an L block, four-cycle and four-cylinder, poppet valve motor (or engine). Its stationary parts are, (1) the cylinders, (2) the crank case. The working parts are, (1) the pistons, (2) the connecting rods, (3) the crank shaft, (4) the flywheel, (5) the valves, cam shaft and time gears. The word “cycle” as it is applied to a gas motor refers to a series of events which are repeated in regular order—and applies to the ideal type of automobile motor. In the Ford motor, four operations are required to complete the series. These operations are, (1) suction, (2) compression, (3) explosion, (4) exhaust. These are repeated in regular order in each of the four cylinders. The piston moves downward during the explosion and intake strokes; it moves upward during the compression and again during the exhaust. The piston receives an impulse (i. e., force of an explosion) once in every two revolutions. On the downward stroke the suction of the piston draws the fresh gas from the carburetor, through the inlet pipe and valve, into the cylinder. The upward movement of the piston compresses the gas into a very small space, between the top of the piston and the depression in the cylinder head, known as the “combustion chamber.” (The compressed gases exert a pressure of approximately 60 pounds per square inch.) At this point the electric spark, generated by the magneto, explodes the gases—driving the piston downward—thus [Model T Ford Engine Top View] producing the power which turns the crank shaft. On the next stroke upward the piston drives the exploded gas out through the exhaust valve and pipe to the muffler. The accompanying cut shows clearly the relative positions of the pistons and valves during the different strokes.
The Cooling System
The Cooling System of the Model T motor is known as the Thermo-Syphon or Gravity system, and acts on the principle that hot water seeks a higher level than cold water, consequently when the water reaches a certain heat, approximately 180 degrees, circulation commences and the water flows from the lower radiator outlet pipe up through the water jackets into the upper radiator water tank, and down through the tubes to the lower tank to repeat the process. During the time that it is passing from the upper to the lower radiator tank it becomes cooled by the air which comes in contact with the fins and tubes of the radiator and which is sucked in by the fan. The rapidity of circulation is governed by the heat of the motor, and not by the speed.
The Ignition System
The source from which the ignition current is obtained is a low tension magneto of the inductor type, which contains but two parts, a stationary armature consisting of a number of coils, which are attached to the cylinder casting, and a set of permanent field magnets of the horseshoe type, which are secured to the flywheel, the whole being incorporated in and a part of the motor. The magnets revolve with the flywheel at a distance of 1/32” from the coils, which collect the current from the magnetic field and shunt it into the spark coil, where it is transformed from low to high tension, and sent to the spark plugs to perform its function of igniting the charge.
The commutator (or timer) , as shown on the right illustration, determines the instant at which the spark plugs must fire. It effects the “make and break” in the primary circuit. The grounded wire in the magneto allows the current to flow through the metal parts to the metal roller in the commutator. Therefore, when the commutator roller in revolving touches the four commutator contact points, to each of which is attached a wire connected with a coil unit, an electrical circuit is passed through the entire system of primary wires. This circuit is only momentary, however, as the roller passes over the contact point very rapidly and sets up the circuit in each unit as the roller touches the contact point connected with that unit. The commutator should be kept
clean and well oiled at all times.
The Gasoline System
This illustration shows the intake and exhaust manifolds. Attached to the intake manifold is the carburetor. The carburetor is the device in which the gasoline and air are combined into a vapor or mixture” in proper proportions to form the “charge,” which is sucked into the engine and there exploded by an electric spark. The carburetor is so constructed as to allow for the varying of the proportions of the air and gasoline, to meet conditions. These proportions are usually about one part gasoline to twelve or fourteen parts air—although the proportion varies according to the conditions of the atmosphere, the speed of the car and the quality of the gasoline.
The carburetor is of the automatic float feed type, having but one adjustment—the gasoline needle valve. The cross section diagram of carburetor (Cut No. 14) is not a detail drawing but simply shows how the gasoline enters the carburetor, is vaporized by a current of air, and passes through the inlet pipe to the engine in the form of an explosive mixture. The gasoline, entering the bowl of the carburetor, gradually raises the float to a point where the inlet needle lowers into its seat, thus cutting off the flow of gasoline. As the gasoline in the bowl recedes, the float lowers and lifts the needle from its seat and the flow of gasoline is resumed. It is plain to see that a constant level of gasoline is maintained in the carburetor by the automatic action of float and needle. The quantity of gasoline entering into the mixture is governed by the needle valve. The volume of gas mixture entering the intake pipe is controlled by opening and closing the throttle’ according to the speed desired by the driver.
The Model T Ford Transmission
The Ford Model T transmission is of the planetary type. A planetary transmission uses groups of gears that always remain in mesh and revolve around a main axis. The different sets of gears are brought into action by stopping the revolution of the parts which support the gears. By means of bands (similar to brake bands) the rotation of the different parts is stopped.
The clutch is controlled by the left pedal at the driver’s feet (see below). If the clutch pedal, when pushed forward into slow speed, has a tendency to stick and not to come back readily into high, tighten up the slow speed band. Should the machine have an inclination to creep forward when cranking, it indicates that the clutch lever screw which bears on the clutch lever cam has worn, and requires an extra turn to hold the clutch in neutral position.
[Ford Model T Transmission]
The Ford Model T Front and Rear Axles
The illustration to the right shows the Ford Model T front axle and spindle bodies.
The wheel hubs are placed onto the spindle ends along with bearings.
The rear axle uses a "3-point drive" system, unique to Ford. This type of construction necessitates the use of only a single universal joint and permits of the housing of the entire driving mechanism in a dust proof, oil tight case. If plenty of oil is supplied to these parts there should be no trouble during the natural life of the gears, made as they are of the best special alloy steel obtainable, carefully cut and case hardened. The rear axle runs on Hyatt roller bearings. End thrust tendencies of the large bevel gear are taken by fiber discs between hardened and ground steel discs—the best possible construction for this service. The propeller shaft runs in babbitt bearings at both ends. Gears ride in an oil bath and the very early T's are lubricated by a copper tube which leads from the oiler and enters at the ball joint. The oil flows down through the tubular torsion tube to the gears and finally to the Hyatt roller axle-bearings. These bearings are spiral rollers and each alternate spiral is reversed so that they distribute the oil [Model T Ford Differential] automatically over all parts of the bearing surface. Dope cups are installed on each drive shaft bearing and the four rear axle bearings to assist lubrication, as dope will be retained longer and therefore gives better results than oil. Note: The rear hub brakes are intended to perform the function of emergency brakes as their name implies and consequently they take hold severely. Used only in emergency they should outlive the rest of the car. Many theories to the contrary notwithstanding, the transmission brake is not injurious to the driving gears if used judiciously, as every other part of the car should be used. And inasmuch as this brake equalizes the forces between the two rear wheels uniformly, is more easily lubricated, inspected and adjusted, it is better practice to use it for service than the hub brakes.
U.S. Ford Model T Engine Serial Numbers
The following table shows engine serial numbers for the Ford Model T, gleaned from production records at the Ford Motor Company. These numbers represent calendar year production, not model year.
Technical Data Links
Coils / Ignition / Timing
Engine / Transmission
For More Parts Suppliers, visit the Model T Ford Club of America
Website At: http://www.mtfca.com/suppliers/Suppliers.htm
Ford Model T Plant on You Tube: http://youtu.be/S4KrIMZpwCY
How to Start a Model T on You Tube: http://youtu.be/OfQWnaWLDeQ
How to Drive a Model T on You Tube: http://youtu.be/n0hQh_Ej_34 and another....