How to Have Fun With Your Model A Ford

Introduction

The endurance of the Model A Ford over the past 90+ years is a testament to Henry and Edsel Ford’s engineering genius, their design and use of the best materials for the car, and the latest technology available for that era. The Model A incorporated numerous innovative designs, including a sliding gear transmission, 4-wheel brakes, safety glass, hydraulic shock absorbers on each wheel, and a 40-horsepower engine. They were meant to be driven and then, as now, were expected to provide safe, reliable everyday transportation. With many decades in service, normal wear and tear on the Model A’s mechanical components has in many cases resulted in decreased reliability and various safety issues which the modern-day Model A owner and driver must address.

The following items contain several maintenance tips and small modifications that will improve the safety, reliability, and comfort of your Model A without sacrificing its original concept and design.

Model A Wiring

The electrical system of the Model A consists of 3 separate harnesses that serve different functions:

• Main harness: operation of most lights and horn, provides power to run the system
• Instrument panel to terminal box: ignition
• Terminal box to generator (or alternator): charging

• All wires in each of these harnesses were originally cloth-covered copper wire and color coded for a particular use.
• The electrical system is always “hot”. Each switch when operated grounds that circuit to close it. The system depends on effective grounding to operate correctly.
• There are no wires dedicated to returning current to the battery.
• Many wires use “bullet” end connectors and rubber sleeves to connect various wires together. You must use the correct crimping tool for this type of wire end.

Safety Fuse for the Ignition System

• To protect the electrical system from damage due to a short circuit, a safety fuse should be installed.
• There are 2 types available for the Model A:
  • Starter mounted fuse holder: mounts on top of the starter with 2 machine screws and uses a 30-amp clear glass tube fuse.
  • In-line modern fuse holder: installs in the yellow wire from the starter up to the junction box and uses a blade-type fuse.
• This fuse allows for easy disconnect of the battery from all other electrical components for maintenance or service, eliminating the possibility of fire or accidental shorting out due to sparking.
• Consider a separate circuit for the ignition system.

Modification of Headlight Wiring

• Original headlight wiring used a plastic plug with specified positions for each headlight wire. This plug fit into the conduit and was then plugged into the base of the headlamp bucket.
• This setup can be easily modified by connecting the wires directly to the wires on the socket, abandoning the plastic plugs.
• A separate ground line is also required that runs from the metal socket base down the conduit to a grounding point on the engine/frame (lower mounting screw for the radiator shell).
• All modified wires can be fitted with brass bullet ends and connected with rubber sleeves for a solid connection between the wires.

Advantages

• Better, more solid connections resulting in improved and more dependable headlight operation.
• Separate grounds ensure the lights will actually come on when you want them to.
• Easy connect/disconnect of headlight wiring for radiator service or any other work requiring access to the front of the engine.
• No intermittent/flickering/weak headlight beam.

Timing Gear Covers for the Ford 4-Cylinder Engines

Model A vs. Model B

• Design differences.
• Results in completely different timing procedures.
• Make sure you have a Model A front timing cover on your engine, or a Model B cover with the timing pin hole on the bottom of the oval pad.

Installation of Inline Fuel Filter

• Ensures a clean, steady supply of gasoline to the carburetor.
• Any particle of debris from the tank could block the float valve and prevent proper operation, resulting in a leaking, dripping, or seeping condition.
• Make sure your gas shutoff valve actually stops the flow of gas from the tank through the fuel line and into the carburetor.
• Always turn off the fuel valve at the end of the driving day to guard against the possibility of leaks and gas fumes that could ignite, causing a catastrophe.

Installation of Engine Water Temperature Gauge

Gives you a quick and accurate measure of exact temperatures for the coolant in your engine:

• Cooling efficiency: straight water vs. antifreeze/water mix
• Do I need a thermostat in my Model A?
• Engine operating temperature:
  • 160-190 degrees – normal range of operation
  • 200 degrees – caution range
  • Above 200 degrees for an extended period – engine overheating, stop and cool engine, look for cause of overheated condition

Radiator caps with a Thermo-Quail or Motometer thermometer built in.

Engine Compression Testing

This is a diagnostic procedure to examine the health of your engine, particularly the valves, pistons, and rings. It should be used a first step in diagnosing the possible causes of engine failure.

• Model A engine compression when new from the factory was 76 psi, and each cylinder was within 5 psi of all the other cylinders.
• The range of results and their indications are as follows:
  • Above 65 – excellent condition
  • 55-65 – very good
  • 50-54 – marginal
  • Below 50 – weak engine (time for rebuild)

Original 2-Blade Steel Fan

• Design of the original Model A fan.
• Potential problems resulting from this design.
• If either of the blades weaken and begin to crack, usually around the hub, the blade will eventually separate from the rest of the fan.
• Options:
  • 4-blade truck fan
  • Cast aluminum 2-blade fan (reproduction)
  • 6-blade plastic fan with steel hub

Modification of Model A Distributor

Why should I change my original distributor over to a modified distributor with later style Ford V8 points and condenser?

• Better quality replacement points and condensers are more readily available from local auto parts suppliers.
• Both points and condenser can be changed in a matter of minutes.
• There is no need to re-time the engine because the cam screw is not disturbed.
• The modified distributor can be made to look exactly like the original distributor to satisfy the purist Model A experts.
• No matter which style of distributor you prefer to use, consider carrying a spare distributor in your car for emergency purposes that has been timed to your engine.

Model A Maintenance / Lubrication

• Engine oil – what oil do I use in my Model A engine?
  • Capacity of crankcase is 5 quarts, requires 4 1/2 qts at oil change.
  • Oil change interval – every 500 miles or annually (no filter), every 2000 miles w/filter.
• Differential, transmission, steering gearbox – 600W heavy gear oil.
• Grease all fittings in chassis/suspension.
• Repack all wheel bearings periodically, including large rear hub bearings.
• Fan belt tension/condition – generator vs. alternator.
• Periodically make it a point to tighten every chassis, body and engine bolt you can find, and check for cotter pins wherever they are required.

The objective of this seminar was to provide the Model A owner/operator with some small tips and tricks to help make his/her Model A more reliable, safer, and more comfortable to drive out on the open road. As stated at the beginning, these cars were made to drive...not to sit in a garage. Only the experience of regularly taking your car out for a drive will provide you with a sense of confidence that your Model A Ford will perform satisfactorily for you and will get you back home. The public enjoys seeing these fabulous pieces of automotive history as much as we like showing them off.

Happy Model A’ing!!!

Bill Buckmeyer
Dallas Model A Ford Club / Ft. Worth Cowtown A’s
November 2021