Dictionary of Automotive Terms: F

°F: Temperature measurement in degrees Fahrenheit.

FAHRENHEIT: Thermometer on which boiling point of water is 212 deg. and freezing point is 32 deg. above zero.

FAN: A device designed to create a moving stream of air. Generally employed for cooling purposes.

FARAD: Unit of capacitance; capacitance of condenser retaining one coulomb of charge with one volt difference of potential.

FEELER GAUGE: Thin strip of hardened steel, ground to an exact thickness, used to check clearances between parts.

FENDER SKIRT: Plate designed to cover portion of rear fender wheel opening.

FERROUS METAL: Metal containing iron or steel.

F-HEAD ENGINE: Engine having one valve in the head and the other in the block.

FIBERGLASS: Mixture of glass fibers and resin that when cured (hardened) produces a very light and strong material. Used to build boats, car bodies, repair damaged areas, etc.

FIELD: Area covered or filled with a magnetic force.

FIELD COIL: Insulated wire wrapped around an iron or steel core. When current flows through wire, strong magnetic force field is built up.

FIELD FRAME: That portion of an electrical generator or motor upon which field coil is wound.

FILAMENT: Fine wire inside light bulb that heats to incandescence when current passes through it. The filament produces the light.

FILLET: Rounding joint between two parts connected at an angle.

FILTER: Device designed to remove foreign substances from air, oil, gasoline, water, etc.

FINAL DRIVE RATIO: Overall gear reduction (includes transmission, overdrive, auxiliary transmission, etc., gear ratio as well as rear axle ratio) at rear wheels.

FINISHING STONE (Hone): Fine stone used for final finishing during honing.

FIRE WALL: Metal partition between driver’s compartment and engine compartment.

FIRING ORDER: Order in which cylinders must be fired -- 1, 5, 3, 6, 2, 4, etc.

FIT: Contact area between two parts.

FLARING TOOL: Tool used to form flare connections on tubing.

FLASH POINT: The point in the temperature range at which a given oil will ignite and flash into flame.

FLAT HEAD: Engine with all the valves in block.

FLAT SPOT: Refers to a spot experienced during an acceleration period where the engine seems to “fall on its face” for a second or so and will then begin to pull again.

FLOAT: Unit in carburetor bowl that floats on top of fuel. It controls inlet needle valve to produce proper fuel level in bowl, can be of hollow metal, plastic, or cork.

FLOAT BOWL: The part of the carburetor that acts as a reservoir for gasoline and in which the float is placed.

FLOAT CIRCUIT: That portion of the carburetor devoted to maintaining a constant level of fuel in carburetor. Consists of float bowl, float, inlet valve, etc.

FLOAT LEVEL: Height of fuel in carburetor float bowl. Also refers to specific float set ting that will produce correct fuel level.

FLOODING: Condition where fuel mixture is overly rich or an excessive amount has reached cylinders. Starting will be difficult and sometimes impossible until condition is corrected.

FLOW METER: Sensing device which measures flow of air or liquid.

FLUID COUPLING: Unit that transfers engine torque to transmission input shaft through use of two vaned units (called a torus) operating very close together in a bath of oil.

FLUTE: Groove in cutting tool that forms a passageway for exit of chips removed during the cutting process.

FLUX (Magnetic): Lines of magnetic force moving through magnetic field.

FLUX (Soldering, Brazing): Ingredient placed on metal being soldered or brazed, to re move and prevent formation of surface oxidation which would make soldering or brazing difficult.

FLYWHEEL: Relatively large wheel that's attached to crankshaft to smooth out firing impulses. It provides inertia to keep crankshaft turning smoothly during periods when no power is being applied. It also forms a base for starter ring gear and in many instances, for clutch assembly.

FLYWHEEL RING GEAR: Gear on outer circumference of flywheel. Starter drive gear engages ring gear and cranks engine.

FOG LIGHTS: Amber or clear lamps specially designed to provide better visibility in fog. Are usually mounted as close to road as is feasible.

FOOT POUND: Measurement of work involved in lifting one pound one foot.

FOOT POUND (Tightening): One pound pull one foot from center of an object.

FORCE: Pressure (pull, push, etc.) acting upon body that tends to change state of motion, or rest, of the body.

FORCE-FIT: Same as drive-fit.

FORGE: To force piece of hot metal into desired shape by hammering.

FOUR BANGER, SIX BANGER, ETC.: Four cylinder, six cylinder engine, etc.

FOUR-ON-THE-FLOOR: Four-speed manual transmission with floor mounted shift.

FOUR-STROKE CYCLE ENGINE: Engine requiring two complete revolutions of crankshaft to fire each piston once.

FOUR-WHEEL DRIVE: Vehicle, such as Jeep, in which front wheels, as well as rear, may be driven.

FRAME: Portion of automobile upon which body rests and to which engine and springs are attached. Generally constructed of steel channels.

FRAME (Conventional): Strong, steel members run from front to rear of body.

FRAME (Integral): Car body serves as portion or all of frame.

FRAME RAILS: Structural sections of the car frame. Often specifically used to refer to two outside longitudinal sections.

FREE ELECTRONS: Electrons in outer or bits around nucleus of atom. They can be moved out of orbit comparatively easy.

FREEWHEEL: Usually refers to action of car on downgrade when overdrive over running clutch is slipping with resultant loss of engine braking. This condition will only occur after overdrive unit is engaged but before balk ring has activated planetary gearset.

FREEZING: When two parts that are rubbing together heat up and force lubricant out of area, they will gall and finally freeze or stick together.

FREON-12: Gas used as cooling medium in air conditioning and refrigeration systems.

FREQUENCY: The rate of change in direction, oscillation, cycles, etc., in a given time span.

FRICTION: Resistance to movement between any two Objects when placed in con tact with each other. Friction is not constant but depends on type of surface, pressure holding two objects together, etc.

FRICTION BEARING: Bearing made of babbitt, bronze, etc. There are no moving parts and shaft that rests in bearing merely rubs against friction material in bearing.

FTC: Federal Trade Commission.

FUEL: Combustible substance that's burned within (internal) or without (external) an engine so as to impart motion to pistons, vanes, etc.

FUEL ACCUMULATOR: Spring loaded diaphragm device which dampens fuel pressure pulsations, muffles noise, and helps maintain residual pressure with engine off.

FUEL BOWL: Storage area in carburetor for extra fuel.

FUEL DISTRIBUTOR: Device which meters fuel to injectors at correct rate of flow for engine conditions.

FUEL FILTER: A device that removes dirt, rust particles, and in some cases, water from fuel before it moves into carburetor or fuel injection system.

FUEL GAUGE: A device to indicate the approximate amount of fuel in tank.

FUEL INJECTION: Fuel system that uses no carburetor but sprays fuel either directly into cylinders or into intake manifold just ahead of cylinders.

FUEL LINE: That portion of the fuel system, consisting of tubing and hose, that carries fuel from tank to carburetor or injection system.

FUEL MIXTURE: Mixture of gasoline and air. An average mixture, by weight, would contain 16 parts of air to one part of gasoline.

FUEL PULSATION: Fuel pressure variations due to fuel pump action.

FUEL PUMP: Vacuum device, operated either mechanically or electrically, that's used to draw gasoline from tank and force it into carburetor.

FUEL TANK: A large tank of steel or plastic, used to store a supply of fuel aboard vehicle.

FULCRUM: Support on which a lever pivots in raising an object.

FULL-FLOATING AXLE: Rear drive axle that does not hold wheel on nor does it hold wheel in line or support any weight. It merely drives wheel. Used primarily on trucks.

FULL-FLOW OIL FILTER: Oil filter that filters ALL of oil passing through engine — before it reaches the bearings.

FULL HOUSE: Engine that's fully modified and equipped for all-out performance.

FULL PRESSURE SYSTEM: Type of oiling or lubrication system using an oil pump to draw oil out of a sump and force it through passages in engine.

FULL-TIME FOUR-WHEEL DRIVE: Setup in which all four wheels are driven — all the time — off road or on. Addition of a third differential, located at transfer case, permits front and rear wheels to operate at different speeds.

FULL-TIME TRANSFER CASE: Four- wheel drive transfer case that drives all four wheels all the time. Two-wheel drive is not possible. Such systems permit four-wheel drive on dry, hard surfaced roads by incorporating a differential in transfer case unit.

FUSE: Protective device that will break flow of current when current draw exceeds capacity of fuse.

FUSIBLE LINK: A special wire inserted into a circuit to provide protection in event of overloading, shorts, etc. Overloads will melt wire and break circuit. Unlike a regular fuse, fusible link will permit overloading for a short time before melting.

FUSION: Two metals reaching the melting point and flowing or welding themselves together.