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GLOSSARY TERMS

B

B-cam
A pattern used to grind pistons in an oval or cam shape with a 0.006 inch (0.152 mm) difference between the face and pinhole side.
B-Dolly Train
A combination of two or more trailers in which the dolly is connected by two or more pintle hooks, couplers, and drawbar connections located between each vehicle, making a rigid connection. The resulting connection has one pivot point.
B-pillar
The structural support just behind the front door.
B-post
A term often used for B-pillar.
B-shim
A valve spring adjuster with a 0.030 inch (0.76 mm) used to balance spring pressure and to correct installed height.
B-train
A combination of two or more trailers in which the rear trailer is connected at a single pivot point, commonly a fifth wheel, which is mounted on an extension of the frame of the lead trailer.
Babbitt
An alloy used to line bearings made up of tin, antimony, copper, and other metals.
Baby Moons
Small chrome-plated wheel covers.
Back Flush
The use of a reverse flow of water, with or without a cleaning agent, to clean out the cooling system of a vehicle.
Back Motor
A mid- or rear-mounted engine.
Back Plane
The main circuit board of a system, containing edge connectors or sockets so other printed circuit boards can be plugged into it.
Back Pressure
Resistance of an exhaust system to the passage of exhaust gases. This can have an adverse effect on performance, fuel economy, and emissions. Excessive back pressure may be caused by a clogged catalytic converter, or a dented or crimped pipe.
The excessive pressure buildup in an engine crankcase.
Back Pressure EGR
Some emissions-control systems use a back-pressure sensor or Diaphragm to monitor back pressure so that exhaust gas recirculating flow can be increased when the engine is under maximum load, and producing maximum back pressure.
Back Seat
The position of a valve stem when turned to the left (ccw) as far as possible back seating a two-seat service valve.
Back Staging
Placing a competition vehicle at the start of a drag race behind the usual staging position. Also referred to as shallow staging.
Backbone Frame
A chassis structure having one boxed member running down the center. It is usually divided into two parallel members at each end to support the power train and suspension system.
Backfire
An explosion in the exhaust system of a motor vehicle caused when an unburned air/fuel mixture is ignited, usually upon deceleration.
An explosion of the air/fuel mixture in the intake manifold, which is evident at the carburetor or throttle body and may be caused by improper ignition timing, crossed spark plug wires, or an intake valve that is stuck open.
The momentary recession of the flame into the welding tip, cutting tip, or flame-spraying gun, followed by immediate reappearance or complete extinction of the flame.
Backfire Suppression Valve
An anti-backfire valve used in the air-injection system of an exhaust emission control.
Backfiring
The pre-explosion of an air/fuel mixture so that the explosion passes back around the opened intake valve, through the intake manifold, and through the carburetor.
The loud explosion of over-rich exhaust gas in the exhaust manifold that exits through the muffler and tailpipe with a loud popping noise.
Backing Plate
Stamped steel plate upon which the wheel cylinder is mounted and the brake shoes are attached; a metal plate that serves as the foundation for the brake shoes and other drum brake hardware.
Backlash
The excessive clearance between the meshing teeth of two gears.
Backlight
The rear window of a vehicle.
Backup Light
Lamps that illuminate the area behind the vehicle and warn others of the driver's intention to back up. All vehicles sold in the United States after 1971 are required to have such lights.
Backyard Mechanic
An amateur mechanic or one with little training. Often called a shade-tree mechanic.
Bad
slang for "Good."
Bad Car
A performance term for an extremely fast car.
Bad Sector
A sector on a computer disk that will not read or write correctly. Usually due to a minor physical flaw in the disk.
Badge Engineering
The act of producing the same car under more than one name.
Baffle
A barrier used to reduce noise in an enclosed system, such as the exhaust system.
A barrier to prevent splashing of liquid in a tank.
Bail
The spring-steel wire loop used to secure a cover, such as on a master cylinder reservoir.
Baja
A Spanish term for lower. The term more generally refers to Mexico's Baja race, which is held in a rugged desert region creating one of the world's toughest off-road courses.
Baja Bug
A Volkswagen Beetle modified for off-road use, developed in the late 1960s by Drino Miller.
Balance
To have all rotating parts in a state of equilibrium.
To balance all rotating parts statically and dynamically in an engine to ensure maximum performance.
Balance Control
A control in a stereo amplifier that adjusts the relative output volume from each of the stereo channels.
Balance Pipe
A pipe that connects the exhaust pipes in a dual exhaust system to equalize the pressures.
A pipe that connects the venturis of dual carburetors.
Balance Shaft
Found primarily in I–4 and V–6 engines, a rotating shaft incorporating a harmonic balancer or vibration damper designed to counteract the natural vibrations of other rotating parts, such as the crankshaft, in an engine.
Balance Tube
A tube to connect the exhaust pipes in a dual exhaust system to equalize the pressures.
A tube to connect the venturis of dual carburetors.
Balanced Carburetor
A carburetor in which the float bowl is vented to the air horn to compensate for the possible effects of a clogged air filter.
Balanced Valve
A type of hydraulic valve that produces a pressure change that is proportional to the variations of spring pressure or the movement of a mechanical linkage.
Balancer
A heavy crankshaft pulley that aids in overall crankshaft balance as it rotates.
Balancing
The process of proportioning weight or force equally on all sides of an object. Most crankshafts, for example, are balanced both statically and dynamically.
Balancing Coil Gauge
An indicating device, such as a fuel gauge, that contains a pair of coils in the instrument-panel unit.
Balk Ring
A rotating device found in a manual transmission that prevents premature engagement of gears while shifting.
Ball and Socket
A term often used for tie rod end.
Ball Bearing
An anti-friction bearing with an inner and outer race having one or more rows of balls between them.
Ball Check Valve
A one-way valve having a ball and seat.
Ball Joint
A joint or connection where a ball moves within a socket, allowing a rotary motion while the angle of the rotation axis changes.
A suspension component that attaches the steering knuckle to either control arm featuring a ball-and-socket joint to allow pivoting in various directions. Also known as a spherical joint.
Ball Joint angle
The inward tilt of the steering axis from the vertical.
Ball Joint centerline
An imaginary line drawn through the centers of the upper and lower ball joints.
Ball Joint Free Play
The allowable radial and axial motion between the ball-joint housing, checked with the load removed.
Ball Joint Inclination
The inward tilt of the top of the steering axis centerline through the ball joints as viewed from the front of the vehicle.
Ball Joint Internal Lubrication
A ball joint assembly may be pre-lubricated and factory sealed or it may have provision for periodic scheduled lubrication.
Ball Joint Preload
A term relating to certain ball joints, often spring-loaded, having constant friction between the ball-and-joint housing socket.
Ball Joint Seal
A Neoprene rubber seal that fits over a ball-joint stud against the housing to retain lubricating grease and keep unwanted foreign debris, such as sand or dirt, out.
Ball Joint Slack
A term often used for ball joint free play.
Ball Joint Suspension
A type of front suspension in which the wheel spindle is attached directly to the upper and lower suspension arms through the ball joints.
Ball Nut
In a recirculating ball nut steering gear, the ball nut has internal threads that are meshed to the threads of a worm with continuous rows of ball bearings between the two. The ball bearings are recirculated through two outside loops called ball guides. The sliding ball nut has tapered teeth cut on one face that mate with teeth on the cross-shaft sector.
Ball Stud
A stud with a ball-shaped end.
Ball-and-Nut Steering Gear
Another term for recirculating ball-and-nut steering gear.
Ball-and-Trunion joint
A type of universal joint that is combined with the slip joint in one assembly.
Ballast
Material that is added to a racing car chassis to change the weight distribution and/or increase the overall vehicle weight to the minimum class requirement.
Ballast Resistor
A term often used for ignition resistor.
Balloon Foot
A term used to describe a slow driver; one who tends to back off the throttle early.
Band
A hydraulically controlled device installed in an automatic transmission around a clutch drum, used to stop or permit drum turning.
A manual or hydraulic device installed around a drum to provide a braking action.
Banjo Housing
A banjo-shaped case that houses a final drive live axle.
BAR
An acronym for the Bureau of Automotive Repair.
Barb Fitting
A fitting that slips inside a hose and is held in place with a gear-type clamp or pressed-on ferrule.
Bare Electrode
A filler metal electrode that has been produced as a wire, strip, or bar with no coating or covering other than that which is incidental to its manufacture or preservation.
Bare Out
To strip a car body to its basic shell, generally in preparation for its restoration.
BARO
An abbreviation for:
Barometric pressure.
Barometric-pressure sensor.
Barometer.
Barometer
An instrument used for measuring barometric pressure.
Barometric Pressure (BARO)
The pressure exerted by the weight of the earth's atmosphere, equal to one bar, 99.97 kPa, or 14.5 psi at sea level. Barometric pressure changes with the weather and with altitude. Since it affects the density of the air entering the engine and ultimately the air/fuel ratio, some computerized emissions-control systems use a barometric pressure sensor so that the spark advance and exhaust gas recirculate (EGR) valve flow can be regulated to control emissions more precisely.
Barometric Pressure Sensor
A device that senses barometric pressure and sends an electrical signal to the CPU for optimum engine control.
Barrel (BBL)
A term sometimes applied to the cylinders in an engine.
A term used to refer to the number of throttle bores in a carburetor.
Barrel Faced Ring
A compression piston ring with a rounded contact face.
Barrel Finish
The rounded surface on a piston skirt.
Barrel Roll
A vehicle rollover, sideways.
Barrier Hose
A hose constructed with a special liner to prevent refrigerant leakage through its walls. Most air-conditioning systems in vehicles manufactured after 1988 have barrier-type hoses.
Base 10
A base unit in the metric system. All metric units are increased or decreased in units of
One meter, for example, has 10 decimeters, 100 centimeters, or 1,000 millimeters.
Base Circle
The low portion of each cam on the camshaft, concentric with the journal, which is not part of the lobe.
Base Coat
The initial layer of paint.
Base Metal
The largest proportion of metal present in an alloy.
A metal that readily oxidizes, or that dissolves to form ions.
The metal or alloy that is welded, brazed, soldered, or cut.
After welding, that part of the metal that was not melted.
Base Station
The bottom section of a station buck that serves as a reference point in metal working.
Baseline
An initial reference point.
Basic Fuel Metering
The amount of fuel delivered to the injectors in a continuous-flow, fuel-injection system,
Basic Fuel Quality
The amount of fuel delivered to the injectors, in a pulsed, fuel-injection system, based on airflow sensor readings of engine load and rpm.
Basket Of Snakes
A tuned exhaust system with individual intertwined headers.
Bass Compensation
A circuit in an audio amplifier that increases the output of low-end audio frequencies at low listening levels to compensate for the human ear's loss of sensitivity under these conditions.
BAT
An abbreviation for battery.
BAT+
The positive battery terminal.
BAT?
The negative battery terminal.
Batch
A group of records or programs that is considered a single unit for processing on a computer.
Bathtub
An auto body design that resembles an inverted bath tub.
A combustion chamber in an engine with an area that resembles an inverted bath tub with its valves seated at its base.
Battery (BAT)
A device for storing energy in chemical form so it can be released as electricity.
Battery Acid
An electrolyte used in a battery; a mixture of water (H2O) and sulfuric acid (H2SO4).
Battery Backup
Auxiliary power that is provided to a computer so volatile memory information is not lost during a power failure, or when otherwise disconnected from its normal power source.
Battery Capacity
The energy output of a battery measured in amp/hours.
Battery Cell
That part of a battery made from two dissimilar metals and an acid solution. A cell stores chemical energy for use later as electrical energy.
Battery Charge
The restoration of chemical energy to a battery by supplying a measured flow of electrical current to it for a specified time.
Battery Charger
An electrical device that is used for restoring a battery to its original state of charge by passing a current through the battery in a direction opposite of the discharge current flow.
Battery Charging
The act of charging a battery.
Battery Council International (BCI)
A professional association of manufacturers, suppliers, and distributors of lead-acid batteries.
Battery Efficiency
A battery's ability to vary the current it delivers within a wide range, depending on the temperature and the rate of discharge.
Battery Element
A cell.
A group of unlike positive and negative plates assembled with separators.
Battery Maintenance
Generally, preventative maintenance, such as visual inspection, adding water, cleaning top and terminals, tightening hold down, and testing.
Battery Rating Methods
There are several rating methods cold cranking power rating, reserve capacity rating, and twenty-hour rating.
Battery Terminal
A means of connecting the battery to the vehicle's electrical system. The three types of battery terminals are post or top, side, and L.
Bayonet Socket
A lamp socket having two lengthwise slots in its sides, making a right-angled turn at the bottom. A lamp with two pins may be installed by pushing it into the socket and giving it a slight clockwise turn.
BBDC
An abbreviation for before bottom dead center.
BBL
An abbreviation for barrel.
BBM
An abbreviation for break before make, as in a switch.
BCI
An abbreviation for Battery Council International.
BCM
An abbreviation for body control module.
BDC
An abbreviation for bottom dead center.
Bead
That part of a tire that contacts the rim of a wheel.
A narrow half-round pattern where metal has been welded together.
Bead Filler
A rubber piece positioned above the bead to reinforce the sidewall and act as a rim extender.
Bead Lock
A plate that clamps a tire bead to a wheel rim used on circle-dirt-track race cars.
Bead Wire
A group of circular wire strands molded into the inner circumference of a tire to anchor the tire on the rim.
Beam Axle
A shaft that does not transmit power but provides a means of fastening wheels to either, or both, ends.
Beam Solid-mount Suspension
A tandem suspension relying on a pivotal mounted beam, with axles attached at the ends for load equalization.
Beans
Performance term for horsepower.
Bearing
A term used for ball bearing or bushing.
Bearing Block
The outside surface of a bearing that seats against the housing bore.
Bearing Bore
A term often used for housing bore.
Bearing Cap
A device that retains the needle bearings that ride on the trunnion of a U-joint and is pressed into the yoke.
Bearing Cap Register
The cut-out portion of the engine block that keeps the bearing cap aligned to the housing bore.
Bearing Crush
The additional height, manufactured into each bearing half, to ensure complete contact of the bearing back with the housing bore when the engine is assembled.
Bearing Groove
A channel cut into the surface of a bearing to ensure oil distribution.
Bearing ID
The inside diameter of a bearing.
Bearing OD
The outside diameter of a bearing.
Bearing Oil Clearance
A space that is provided between a shaft and a bearing so oil can flow through it.
Bearing Pre-lubricator
A pressurized oil tank attached to the engine-lubrication provisions to maintain oil pressure when the engine is not running.
Bearing Shell
One half of a single rod or main bearing set.
Bearing Spacer
A device that is used to hold a bearing in the housing bore.
Bearing Spin
A bearing that has rotated in its housing or block, generally due to failure as a result of lack of lubrication.
Bearing Spread
The small extra distance across the parting faces of a bearing half in excess of the actual diameter of the bearing bore.
Bearing Upper
The bearing shell that is positioned opposite the bearing cap.
Beater
A car used for everyday transportation.
Beef
A term used for beef up.
Beef Up
To strengthen and/or reinforce.
Beehive Spring
A spring that is wound in the shape of a beehive.
Before Bottom Dead Center
The position of a piston approaching the bottom of its intake or combustion stroke.
Before Top Center (BTC)
A piston as it is approaching the top of its stroke.
Before Top Dead Center (BTDC)
Any position of the piston between bottom dead center and top dead center on its upward stroke.
Bell Housing
A term often used for clutch housing.
Bell-mouthed Drum
A well-worn brake drum that is deformed so that its open end has a larger diameter than its closed end.
Belleville Washer
A circular disk formed into a conical shape. When a load is applied, the disk tends to flatten, constituting a spring action. May be referred to as a coned-disk spring.
Bellows
A flexible chamber that can be expanded to draw a fluid or vapor in and compressed to pressurize the fluid or vapor.
Belly Pan
Body panel(s) covering the bottom of a competition vehicle to reduce the coefficient of drag.
Belly Tank
A tear-shaped, World War II aircraft auxiliary fuel tank used as the body for a lakester.
Belt
In a tire, the belt(s), generally steel, restrict ply movement and provide tread stability and resistance to deformation, providing longer tread wear and reducing heat buildup in the tire.
A device used to drive the water pump and/or other auxiliary devices, such as the alternator, off the engine.
Belt Cover
A nylon cover positioned over the belts in a tire that helps to hold the tire together at high speed, and provides longer tire life.
A rayon, cotton, or nylon cover to protect the interior of a drive belt from the environment and absorb the wear that occurs at the belt-sheave interface.
Belt Dressing
A prepared solution, generally in spray form, formulated for use on automotive V-belts to reduce or eliminate belt noise. It is not generally recommended for serpentine belts.
Belt Pitch
The distance between two adjacent tooth centers as measured on the pitch line of a synchronous belt.
Belt Ride Dimension
A measurement of the distance from the top of the belt to the top of the sheave groove to determine proper belt fit in the groove.
Belt Tension
The tightness of a drive belt, generally measured in ft-lb (N*m).
Belt Width
The distance across a belt measured at the widest point.
Belt-clamping Action
As related to a continuous variable transmission, the action taking place when the V-pulley sheaves clamp the drive belt.
Belt-driven Cooling Fan
A rigid or flexible cooling fan is driven by a belt from the crankshaft in vehicles that have longitudinally mounted engines. Usually the belt-driven cooling fan is mounted to the front of the water pump pulley/hub.
Belted Bias Tire
A tire in which the belts are laid on the bias, cris-crossing each other.
Belted Radial Tire
A tire in which the belts are laid parallel to each other and run perpendicular to the bead.
Beltline
A line down the side of a car defined by the top edge of the lower body and the bottom edge of the roof and window assembly.
Bench Bleeding
A procedure used to bleed the air from a new or rebuilt master cylinder before it is installed in the vehicle.
Bench Race
To talk about racing, generally just after an event.
Bench Seat
A full-width seat that can accommodate two or three persons in a vehicle.
Bench Test
The testing of an engine or component, out of the vehicle, for ease of observation and study.
Bend
A curve or angle that has been bent.
To form a curve or angle by bending.
Bending
The forming of a material, usually metal, into a particular shape.
Bending Sequence
The order in which several bends are made so as not to be blocked by a previous bend.
Bending Stress
A stress, while bending, that involves both tensile and compressive forces that are not equally distributed.
Bendix Drive
A type of starter motor drive that engages, and disengages, the starter and flywheel.
Bendix Folo-Thru Drive
A starter motor drive engaged by initial rotation of the armature, causing the drive pinion to be twisted outward on a threaded sleeve until it is meshed with the flywheel gear. The gears are disengaged automatically at a predetermined speed of about 400 rpm.
Bendix Screw
The helix-grooved shaft of a Bendix drive.
Bent
Not flat or straight, intentionally or unintentionally.
Bent Eight
A V–8 engine.
Bent Six
A V–6 engine.
Bent Stovebolt
A Chevrolet V–8.
Benzine
A highly flammable liquid, C6H6, sometimes found in refined gasoline. Its use, however, is restricted to 3.0% in some areas due to its toxicity.
Benzole
A mixture of aromatic hydrocarbons with a high percentage of benzine, used as a solvent and as a fuel additive.
Berm
A curb-like buildup on the outside of turns on a circular dirt track.
The curb-like buildup of dirt along the edges of an unpaved road.
Bevel Gear
A form of spur gear in which the teeth are cut at an angle to form a cone shape, allowing a gear set to transmit power at an angle.
Bezel
A trim ring, usually around a gauge, to secure the glass cover.
BHP
An abbreviation for brake horsepower.
Bias
A diagonal line of direction.
Bias-belted Tire
A tire that has the ply cords placed diagonally across the tire from bead-to-bead, with alternate ply layers cris-crossing diagonally in opposite directions.
Bias-ply Tire
A term used for bias belted tire.
Big Arm
The throw of a crankshaft that has been stroked.
Sometimes used to identify an engine with a stroked crankshaft.
Big Block
A V–8 engine that displaces more than 400 cubic inches; a muscle car powerplant.
Big Bore
A term often used for big block.
Big End
The crankpin end of a connecting rod.
Big Red Wrench
Slang for an oxyacetylene-cutting rig.
Big Three
The three major United States automobile manufacturers, Chrysler, Ford, and General Motors.
Bigfoot Lifter
A term used for mushroom lifter.
Bigs
Large rear tires.
Bigs and Littles
A combination of large rear tires and small front tires.
Billet
A solid bar of metal.
Billet Camshaft
A camshaft machined from a billet of steel.
Billet Crankshaft
A crankshaft machined from a billet of steel, usually used for racing applications.
Bimetal
A temperature-sensitive strip made up of two metals having different heat expansion rates.
Bimetal Engine
A powerplant with block and head made of different metals, such as a cast iron block and an aluminum head.
Bimetal Spring
A spring made of bimetal, such as a choke spring.
Bimetal Strip
A temperature regulating or indicating device that works on the principle that two dissimilar metals with unequal expansion rates, welded together, will bend as temperature changes.
Bimetallic
Two dissimilar metals fused together; these metals expand and contract at different temperatures to cause a bending effect.
Bimetallic Sensing Element
Another term used for bimetallic sensor.
Bimetallic Sensor
A sensing element having a bimetallic strip or coil.
Bimetallic Temperature Sensor
A bimetallic thermostat.
Bimetallic Thermostat
A thermostat that uses a bimetallic strip instead of a bellows or Diaphragm for making or breaking electrical contact points.
Binary
A system in which numbers are represented as sequences of zeros and ones, which is the basis of digital computing.
Binary Digit
A character that represents one of the two digits in the number system that has a radix of two.
Binary Numeral
The binary representation of a number.
Binder
The paint material that forms the film, so called because it binds the pigment and additives into a solid, durable film.
Binders
A term used for brakes. See hard on the binders.
Binnacle
A console, separate from the dashboard, for switches, instruments, and controls, on or near the steering column.
Birdcage
The plate on an axle housing for attaching suspension components.
The chassis space frame with many small pieces of structural tubing.
Bit
A character that represents one of the two digits in the number system that has a radix of two.
That part of the soldering iron, usually made of copper, that directly transfers heat to the joint.
Bite
Performance term for tire traction.
BK
Black.
BL
Blue.
Black Book
A guide used to determine the value of a used vehicle.
Black Box
A term often used for a central processing unit (CPU).
Black Flag
The signal for a driver to return to the pits for consultation with race officials.
Black Light
An ultraviolet-light system used to detect flaws in metal parts.
Black Smoke
The exhaust that is produced when the air/fuel mixture is too rich.
Blacky Carbon
A term used in disdain for gasoline by drivers using it as a fuel.
Blank
A term often used for billet.
Bleed
To drain fluid.
To remove an air bubble or air lock.
To draw air into a system.
Bleed Air Tanks
The process of draining condensation from air tanks to increase air capacity.
Bleed Orifice
A calibrated orifice in a vacuum system that allows ambient air to enter the system to equalize the vacuum.
Bleeder Current
A continuous load placed on a power supply by a resistance load that helps improve regulation and safety.
Bleeder Jar
A glass or transparent plastic container used to detect the escape of air while bleeding brakes.
Bleeder Screw
A small, hollow screw or valve found at drum-brake wheel cylinders, in disc brake calipers, and adjacent to the outlet ports of some master cylinders. It is opened to release pressure and to bleed air and fluid from the hydraulic system.
Bleeding
The slow releasing of pressure in the air-conditioning system by recovering some of its liquid or gas.
The act of removing air from a hydraulic brake system.
A small leak.
When one paint color shows through another.
Bleeding Sequence
The order of bleeding brake systems or other components.
Blend Air
The control of air quality by blending heated and cooled air to the desired temperature.
Blend Air Door
A door in the duct system that controls temperature by mixing heated and cooled air in correct proportions to achieve the desired effect.
Blinky
The timing light at the end of a quarter-mile strip.
Blip
A quick punch to the throttle to rev the engine momentarily.
Blistering
Tire tread separating from the carcass due to high heat.
Bubbles or pinholes that appear in paint.
To go exceptionally fast, as in a blistering pace.
Blistering Pace
To go exceptionally fast.
Bloc-Chek
A device to detect the leakage of exhaust gas into the cooling system.
Block
Main casting of the engine that contains the cylinders; often made of cast iron or aluminum.
Block Check
A device used to detect oil or gasoline in the cooling system.
Block Water
Liquid refuse that must be stored on an RV until it can be disposed at a dump station.
Blow
A performance term for the failure of a transmission or engine, such as blow the engine.
Blow Off
To defeat a competitor.
Blow Off The Doors
To defeat a competitor by a wide margin.
Blow Torch
A jet-powered car for drag or lake competition.
Blowby
Byproducts of combustion, mostly hydrocarbons, that leak out of the combustion chamber, past the piston and piston rings, into the crankcase during the compression and power strokes. In modern engines, blowby vapors are drawn into the intake through the positive crankcase ventilation (PCV) system and are burned in the engine.
Blower
A performance term for a supercharger or turbocharger.
A two-stroke, diesel-engine, intake air compressor.
The fan motor in a heater-air conditioning system.
Blower Belt
A reinforced cover with retaining straps on supercharged engines, required by NHRA to prevent parts from scattering should the supercharger explode.
Blower Circuit
All of the electrical components that are required for blower and blower speed control.
Blower Motor Relay
A relay found in the blower circuit.
Blower Relay
An electrical device used to control the function or speed of a blower motor.
Blower Speed Controller
A solid-state control device that operates the blower motor and, sometimes, the compressor clutch based on signals from the microprocessor.
Blower Switch
A dash-mounted device that allows the operator to turn the blower motor ON/OFF and/or to control its speed.
Blown Engine
An engine that has a supercharger or turbocharger.
A seriously damaged engine.
Blown Head Gasket
A broken head gasket that leaks water, oil, or air and reduces engine performance.
BLU
Blue.
Blue Book
A term given the Kelly Blue Book, a bimonthly publication that lists used car wholesale and retail prices.
Blue Smoke
An exhaust produced when oil has contaminated the air/fuel mixture.
Blue Streak
The trade name of a Goodyear high-performance tire.
Blueprint
To rebuild an engine to original equipment manufacturer (OEM) design specifications.
Bluing
A fluid that produces a blue surface on metal to assist in laying out work on it.
BMC
An abbreviation for Brake Manufacturers Council.
BMEP
An abbreviation for brake mean efficient pressure.
BN
Brown.
Bobbed
Trimmed and shortened.
Bobtail
A vehicle body with a short-rear overhang.
The tractor of a tractor-trailer rig.
The results of a modification of a fad car.
Bobweight
The weight attached to a rod journal to simulate the reciprocating mass when balancing a crankshaft.
Body
The assembly of sheet metal sections and other parts that provide the enclosure of a vehicle.
Body And Frame
The parts of a vehicle that support all components. A frame that supports the engine and drive train and a body that houses the entire vehicle.
Body Control Module (BCM)
A component of self-diagnostic systems used to control vehicle function based on monitored inputs.
Body In White
A new, unpainted, and untrimmed body.
A body that has been completely stripped.
Body Knocker
A person who does body work.
Body Mounting
Rubber cushions, at strategic locations, to dampen noise and vibration.
To place a car body on the chassis.
Body Panels
Sheets of material joined together to form a car body.
Body Pitch
The tendency of a vehicle to dive or squat.
Body Roll
A term often used for roll.
Body Shapes
There are six basic body shapes; sedan, hardtop, convertible top, liftback or hatchback, station wagon, and sports or multipurpose.
Body Shop
A collision-and-damage repair and painting facility.
Body Strength
Body strength depends on the type of vehicle and body structure; factors such as door size and the presence or absence of a center pillar. Also, front body pillar, quarter panels, and roof panels affect how much of an impact is absorbed.
Bog
To lose power and momentarily faulter when coming off the line.
To stall or slow due to soft dirt or sand in off-road racing.
A mud hole.
Bogey
A common way of spelling bogie.
Boggin'
Competitive racing of individual off-road vehicles through a long pre-measured mud hole.
Bogie
The axle-spring suspension arrangement on the rear of a tandem axle tractor.
Boil Tank
A very large tank of boiling solution used for cleaning large parts, such as engine blocks.
Boiling
A rapid change in the state of a liquid to a vapor by adding heat, decreasing pressure, or both.
Boiling Point
The temperature at which a liquid begins to boil.
Boiling The Hides
Smoking the tires during a drag race.
Bolster Plate
The flat, load-bearing surface under the front of a semitrailer, including the kingpin, which rests firmly on the fifth wheel when coupled.
Bolster Plate Height
The height from the ground to the bolster plate when the trailer is level and unladen.
Bolt
A metal rod, usually with a head at one end and a thread at the other, used to secure parts and assemblies.
Bolt Circle Diameter
The diameter of an imaginary line running through the bolt hole centers.
Bolt Grade
The strength of a bolt.
Bolt Hardness
The hardness of a bolt is identified by the number of lines on the head of the bolt. The more lines, the stronger the bolt.
Bolt On
An aftermarket accessory that can be installed without modification.
Bolt Stretch
When a bolt is elongated and the shank and/or thread diameter is smaller than specifications.
When a bolt is torqued as specified and, as a result, is stretched a predetermined amount.
Bolt Torque
The turning effort required to offset resistance as the bolt is being tightened.
Bomb
Performance term for a vehicle that is capable of extraordinary performance.
Bonded Lining
Brake lining cemented to shoes or bands, eliminating a need for rivets.
Bonding
The process of connecting two or more materials using chemicals or heat, or electrical or mechanical forces.
Bonding Lining
The lining attached to a brake shoe with an oven-cured adhesive.
Bondo
A tradename for a plastic two-part body filler.
Bone Yard
A facility that sells used parts for vehicles.
Bonnet
A safety helmet.
British term for a vehicle hood.
Bonneville
The salt flats in Northwestern Utah; one of the world's most famous courses.
Bookkeeper
One who keeps record books, prepares invoices, writes checks, makes bank deposits, checks bank statements, and is responsible for tax payments.
Boondockin'
Traveling in a remote area, usually with a 4*4 or other off-road vehicle.
Boondocks
A remote, undeveloped area, often the setting for unauthorized, and illegal, auto competition.
Boonies
A slang term for boondocks.
A race driver is off to the boonies if spun off course.
Boost
The increase in intake-manifold pressure, produced by a turbocharger or supercharger.
Booster Battery
A charged battery connected to a discharged battery in order to start the engine.
Booster Cables
A term used for jumper cables.
Booster Venturi
A device in a carburetor that mixes fuel with incoming air.
Boot
Slang for a tire.
A flexible rubber or plastic cover used over the ends of master cylinders, wheel cylinders, transmissions, or constant velocity joints, to keep out water and other matter.
The British term for the rear deck or trunk of a car.
Boots
Performance term for tires.
Borden Tube
A thermo-mechanical device in the fuel injection system that regulates the amount of fuel being injected according to differences in temperature and pressure in the intake manifold.
Borderline Lubrication
Poor lubrication as a result of greasy friction.
Moving parts coated with a thin film of lubricant.
Bore
The diameter of an engine cylinder.
To increase the diameter of a cylinder.
Bore Align
To machine an engine's main bearing journals to assure they are in perfect alignment.
Bore Centers
The center-to-center distance between two bores.
Bore In The Water
To bore a cylinder out far enough to brake through the water passage.
Bored And Stroked
A combination of an enlarged cylinder bore and a lengthened piston stroke to increase an engine's displacement.
Boss
The reinforced extension on a part that holds a mounting pin, bolt, or stud.
A slang term for outstanding quality.
Bottom
The underside; the lowest part.
When a vehicle's chassis hits the lowest point allowed by its suspension system.
When the springs are fully compressed.
Bottom Dead Center (BDC)
Piston position at bottom of stroke.
Bottom End
The crankshaft main bearing and connecting-rod bearing assembly in an engine.
Bottom Out
If a race car settles down tightly on its springs on an oval track as it travels through a baked turn, centrifugal force tends to push the car downward, toward the track's surface, causing its chassis to bottom out.
Bottom U-bolt Plate
A plate that is located on the bottom side of the spring or axle and is held in place when the U-bolts are tightened.
Bottom Valve
A shock absorber component to control the flow of oil into the reservoir during compression and rebound.
Bounce Back
A condition that occurs when particles of paint sprayed on a body panel bounce away from the surface.
Bound
The opposite of rebound. The inward travel of the piston rod in a shock absorber.
Boundary Layer
The thin layer of air along the inner walls of an intake port.
Bourdon Tube
A curved tube that straightens as the pressure inside it is increased. The tube is attached to a needle on a gauge, that senses the movement of the tube and transmits it as a pressure reading.
Bowden Cable
A wire cable inside a metal or rubber housing used to regulate a valve or control it from a remote place.
A small steel cable inside a flexible tube used to transmit mechanical motion from one point to another.
Box Stock
Standard, conforming to OEM specifications.
Boxer
A horizontally opposed engine.
BR
Brown.
Bracket Racing
A handicap system that allows two cars from different classes to compete in drag racing events.
Brain Bucket
A helmet.
Brain Fade
A mental lapse often used as an explanation why a driver looses control of a race car.
Brake
A system used to stop or slow a vehicle and/or prevent it from moving when stopped or parked.
British term for station wagon.
Brake Actuator
A unit that converts hydraulic pressure, air pressure, vacuum, electrical current, or another form of energy to a force that applies a brake.
Brake Anchor
A pivot pin on the brake backing plate against which the brake shoe bears.
Brake Assembly
An assembly of the components of a brake system, including its mechanism for the application of friction forces.
Brake Band
A round, flat metal band with a friction surface on its inner diameter; used primarily in emergency brake systems.
Brake Bias
An excessive brake force at either end of the vehicle causing the brakes at that end to lock before the other end, often leading to loss of control.
Brake Bleeding
Procedure for removing air from lines of a hydraulic brake system.
Brake Booster
A device that uses a supplementary power source to reduce pedal force in a hydraulic brake system.
Brake Chamber
A unit in which a Diaphragm converts pressure to mechanical force for actuation of a brake.
Brake Control Valve
A unit that sends a signal to the computer when the brakes are being applied.
Brake Cylinder
That part in which a piston converts pressure to mechanical force for actuation of the brake shoes.
Brake Disc
The parallel-faced, circular, rotational member of a brake, acted upon by the friction material of the brake pads.
Brake Disc Minimum Thickness
A term sometimes used to indicate disc minimum thickness.
Brake Dive
A term used for dive.
Brake Drag
A light, but constant, contact of the brake shoes with the drum or rotor, resulting in early failure due to excessive heat.
Brake Drum
The cylindrical part that rotates with the wheel and surrounds the brake shoes.
Brake Drum Glaze
A brake drum with an excessively smooth surface that lowers friction and, therefore, efficiency.
Brake Equalizer
A device used in the parking-brake systems to equalize the pull of both rear-brake cables.
Brake Fade
A condition whereby repeated severe application of the brakes, over a short time period, cause an expansion of the brake drum and/or loss of frictional ability, which results in impaired braking efficiency.
Brake Fanning
Applying and releasing the brakes in rapid succession on a long downgrade.
Brake Feel
A term relating to the driver's ability to determine the amount of braking force exerted or required during a stop.
Brake Fluid
A specially formulated liquid used to transmit brake pedal pressure from the master cylinder to the wheel cylinders.
Brake Flushing
The removal of fluid from a brake system, washing out sediment by flushing with denatured alcohol or clean brake fluid, and refilling the system with fresh brake fluid.
Brake Grab
The sudden increase in the braking of a wheel, often caused by a contaminated lining due to a leaking wheel cylinder.
Brake Hop
A condition that occurs when the swing-arm length of the rear suspension is too short, causing the rear wheels to repeatedly leave the ground during braking.
Brake Horsepower (bhp)
A measurement of horsepower (hp) delivered at the engine crankshaft. A prony brake or an engine dynamometer is used to determine brake horsepower.
Brake Hose
A flexible tubular conduit for the transmission of fluid pressure in the brake system.
Brake Light Switch
An electrical switch, operated either mechanically or hydraulically when the brakes are applied, that causes the brake lights to light up.
Brake Lights
Red lamps at the rear of the vehicle that light up when the brakes are applied.
Brake Line
Small-diameter, rigid-steel tubing, or flexible, rubber, reinforced hose, used to channel brake fluid from the master cylinder to the wheel cylinders or calipers when the brakes are applied.
Brake Lining
A special friction material that will withstand high temperature and pressure, used for lining the brake shoes or pads, either by riveting or bonding.
Brake Lining Pad
The friction lining and plate assembly that is forced against the rotor to cause braking action in a disc brake.
Brake Machining
The practice of turning a drum or a rotor on a special lathe to remove surface imperfections such as scoring, and to eliminate runout and other dimensional problems.
Brake Mean Effective Pressure
The average effective pressure in an engine's cylinders at a specific brake horsepower and speed.
Brake Pad
The pad of friction material applied by the caliper to the disc, to slow or stop a vehicle.
A term often used for brake lining.
Brake Power Assist
A device installed in a hydraulic brake system that reduces pedal effort and affords better braking.
Brake Shoe
The curved metal part, faced with brake lining, that is forced against the brake drum to produce braking action.
Brake Shoe Heel
The end of brake shoe opposite the anchor pin.
Brake Shoe Toe
The end of brake shoe nearest the anchor pin.
Brake Specific Fuel Consumption
The measure of an engine's fuel efficiency during dynamometer testing.
Brake Stopping Distance
The distance traveled from the application of the brakes to the point at which the vehicle comes to a complete stop.
Brake System
The system in a vehicle that is used to slow or stop the vehicle.
Brake Torque
The engine output at the flywheel as measured on a dynamometer.
Brake Warning Light
An instrument-panel light that warns of brake-system malfunction.
Branch Circuit
A portion of a wiring system extending beyond the final over-current protective device in a circuit.
Braze
A weld produced by heating an assembly to above 840°F (450°C) but below the solidus of the base metal.
Break
To damage a car in any way.
To open, as a set of points.
Break Before Make (BBM)
A switch, such as a headlamp dimmer, that breaks one circuit before making another.
Break Rule
A regulation in drag racing that permits a car, defeated in an elimination, to return to competition if the car that beat it is not able to get to the line for its next round.
Break-in
The operation of a new vehicle at a constant and even speed to assure even initial wear of all engine parts.
Breaker
A spring-loaded switch in a conventional distributor ignition system that opens (breaks) and closes (makes) the primary circuit.
Breaker Cam
The rotating part, located near the top of the conventional distributor, that has lobes that cause the breaker points to open and close.
Breaker Point Gap
The space between the fully opened breaker points in a conventional distributor.
Breaker Points
In a conventional ignition system, an electrical switch that opens to interrupt current flow in the primary circuit. Often called contact points.
Breaker Trigger System
Any ignition system that utilizes conventional breaker contacts to time and trigger the system.
Breakerless System
An electronic ignition system that does not use conventional breaker points to time and trigger the primary voltage but retains the distributor for secondary voltage distribution.
Breakout
The point at which conductor(s) are taken out of a multi-conductor assembly.
The point at which a branch circuit departs from the main wiring harness.
Breakover Angle
A term often used for ramp angle.
Breathing
The ability of an engine to draw in air and exhaust gases. The better the breathing, the better the performance.
Brickyard
The Indianapolis Motor Speedway.
Bridge Rectifier
A full-wave rectifier in which the diodes are connected in a bridge circuit allowing current flow to the load during both positive and negative alternation of the supply voltage.
Brinell Test
A technique for testing the hardness of a metal.
Brinelling
A steel-shim head gasket torqued in place on an engine block.
British Imperial System
A system of measurement used in the United Kingdom.
British Thermal Unit
A measure of heat energy where one Btu is the amount of heat necessary to raise 1 pound of water 1°F.
Brittleness
The quality of a material that leads to fracture without appreciable deformation.
BRN
Brown.
Broach
A tool used for reshaping or resizing parts.
Brody
A controlled, rear-wheel skid often used on dirt tracks for fast cornering.
Bronze
A copper-rich, copper-tin alloy with or without small proportions of other elements such as zinc and phosphorus often used for bearings or bushings.
Bronze Guide
A valve guide made of bronze alloy.
Bronze Guide liner
A thin valve guide, easy to install, but must be broached to stay in place.
Bronzewall
A type of thread-like, valve-guide repair insert that must be reamed to size after installation.
Brush
A block of conducting material, such as carbon, held against an armature commutator or rotor slip ring to form a continuous electrical path.
Brush Holder
Adjustable arms for holding the commutator brushes of a generator against the commutator, feeding them forward to maintain proper contact as they wear and permitting them to be lifted from contact when necessary.
BSFC
An abbreviation for brake-specific fuel consumption.
BTC
An abbreviation for before top center.
BTDC
An abbreviation for before top dead center.
Bubble
The slowest qualifying position for a race.
Bubble Balancer
A wheel balancer using an air bubble to show static balance. The tire and wheel are considered balanced if the bubble is centered in its area.
Bubble Gum Machine
Slang for a blue and/or red police-car roof light.
Bubble Memory
A method by which information is stored as magnetized dots (bubbles), that rest on a thin film of semiconductor material.
Bubble Top
A transparent roof on an automobile.
Buck
Jargon for 100 miles per hour.
Bucket
The passenger compartment of a roadster.
Overhead camshaft valve lifters.
An individual driver or passenger seat.
Buckling
The bowing or lateral displacement of a compression spring.
Bucks Down
To have not.
Bucks Up
To have.
Bucks Up, Bucks Down
To have and to have not.
Buff
An enthusiast.
Buff Book
A magazine for car enthusiasts.
Buffing
A surface-finishing process that produces a smooth, lustrous appearance generally free of defined line patterns.
Bug
A minor flaw, imperfection, or malfunction.
A Volkswagen Beetle.
Bug Catcher
A scoop-like intake on a fuel-injection or blower system.
Buggy
A small, lightweight, off-road vehicle.
Build
As its name implies; for example, to modify an engine for racing it is to build it.
Buildup Time
The time required to form a magnetic field around the primary winding of the coil when current is allowed to flow through it in a conventional ignition system.
Bulb
The glass envelope that contains an incandescent lamp or an electronic tube.
Bulge
A high spot or crown in stretched metal.
Bulkhead Connector
A connector for wires or hoses located where they must pass through a partition or lead to another area.
Bull Ring
A dirt, oval track, generally one-half mile or less.
Bulletproof
Indestructible.
Bullnose
The smooth nose of a hood when the ornament has been removed and the holes filled in.
Bump
To be forced out of a racing lineup by a faster qualifier.
Bump Shop
An auto body repair facility.
Bump Spot
The slowest qualifying position for a race.
Bump Steer
The tendency of the steering to veer suddenly in one direction when one or both of the front wheels strikes a bump.
Bump Stick
The camshaft.
Bump Stop
A block, usually rubber, to limit suspension system deflection when a tire hits a bump.
Bumpin'
Cruising in a lowered vehicle, such as a low rider. Some have hydraulics that assist in bouncing up and down.
Bunch Of Bananas
A tuned exhaust system with intertwined headers.
Bunting Bronze
A trade name for a type of bronze used for bushings.
Bureau Of Automotive Repair (BAR)
A state agency that regulates the auto service and repair industry in California.
Burette
A glass container used to measure liquid in cubic centimeters (cc).
Burn
A visible discoloration or sub-surface damage from an excessively high temperature, generally produced by grinding.
Burn Rubber
To accelerate at a rate that the traction tires leave black streaks on the pavement.
Burn Time
Time required for a given amount of air/fuel mixture in the combustion chamber to burn.
Burnout
The moment of final oxidation or combustion of fuel in an engine.
Burnt
Permanently damaged material caused by heating conditions producing incipient melting or intergranular oxidation.
Burr
A feather edge left on metal after being cut or filed.
Bus
A large enclosed vehicle for carrying passengers, usually for hire.
Slang for a family car.
Bushing
A one-piece sleeve, usually bronze, inserted into a bore to serve as a bearing.
Business Coupe
An inexpensive two-door body type with no rear seat, last available in the mid 1940s.
Butane
A gaseous, highly flammable fuel (C4H10) that becomes liquid when it is compressed.
Butt Gap
The distance between the ends of a piston ring.
Butt Weld
A type of weld that joins two pieces of metal by fusion.
Butterfly
A type of valve used for the choke and throttle valve in a carburetor; a moveable plate that controls the amount of air permitted to enter the carburetor.
Butyl
The trade name of a synthetic rubber.
Buzz Box
A small car with a noisy engine.
Buzzer
An electric sound generator that makes a buzzing noise when activated. It operates on the same principle as a vibrating bell. Sometimes used to warn the driver of possible safety hazards, such as when the seat belt is not fastened.
Buzzword
A word or phrase that happens to be a popular cliché of a group of people, such as race car drivers.
Bye
A solo run during drag eliminations.
Bypass
A passageway between the head and block or behind the water pump that allows a water pump to circulate coolant throughout the cylinder head and engine block before the thermostat opens.
A valve that is used to regulate pressure or control the quantity of a liquid or gas.
Bypass Capacitor
A capacitor that provides a low impedance path (usually to ground) to remove unwanted signals from the main signal path.
Bypass Control Valve
A valve used in a bypass system.
Bypass Line
A line or hose used in a bypass system to transfer liquid or gas.
Bypass Tube
A tube directly in front of the thermostat. The coolant bypasses the radiator through this tube when cold.
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