S/V Ratio
The ratio of the surface area of a combustion chamber to its volume with the piston at TDC.
A designation for an engine lubricating oil that may be used under the mildest of conditions.
The designation for a stock car with an automatic transmission.
Saddle Valve
A term used for saddle-clamp access valve.
Saddle-Clamp Access Valve
A two-part accessory valve that may be clamped around the metal part of a system hose to provide access to the system for diagnostics and service.
Air chambers or openings in the left- and right-front corners of the car body between the kickpads and the exterior of the car. The evaporator is sometimes located in the right saddlebag.
An abbreviation for Society of Automotive Engineers.
SAE Horsepower
The corrected brake horsepower of an engine when tested in accordance with SAE standards.
SAE Standards
A standard for automotive- and aircraft-engine testing and measurement established by the Society of Automotive Engineers.
A limited-slip differential by Pontiac.
Prevention of injury or danger.
Safety Factor
The amount of load that can be absorbed by and through the chassis-frame members of a vehicle.
Safety Glass
Laminated glass used for vehicle windshields and windows; designed to resist shattering on impact.
Safety Glasses
Eye glasses with or without side shields to protect the eyes when working in a hazardous environment and to be worn in a hazardous environment and to be worn at all times when in the automotive shop.
Safety Goggles
For those who wear prescription glasses, eye protection from all sides fitting over the glasses and against the face and forehead to seal and protect the eyes from outside hazards.
Safety Lap
An extra lap taken by the winner of a race to ensure that an error was not made by the official lap scorer.
Safety Ridge
A small, metal ridge just inside the tire-bead section to retain the tire position on the rim in case of a flat or blowout.
Safety Rim
A groove around the outer edge of a rim to provide a lock for the tire bead.
Safety Valve
A valve that opens to release excess pressure or heat.
Safety Wire
A strong wire, usually stainless steel, used to hold pre-drilled nuts or bolts in place, preventing them from turning.
A momentary decrease in throttle rate after the vehicle has gained some speed.
Sail Panel
The roof rear-quarter panel on a notchback body style that extends from the rearmost side window to the rear window.
Sales Representative
One who sells new and used merchandise, such as automobiles, to the general public.
The British term for sedan.
Salt Flats
The dry lake beds in the desert, such as Bonneville, used by hot roders for top-speed runs.
Salvage Yard
A modern term for junkyard, an establishment that sells used auto parts.
Sam Sled
A consistently and unnecessarily slow drag-race driver.
Sand Hole
An unwanted hole in a sand-cast part.
To form a part by pouring molten metal into an impression cavity or mold made by a pattern in sand.
To legally secure equipment without having to pay for it.
To hold back in the staging area of a drag race in an attempt to select a specific opponent during eliminations.
To hold speed down in drag racing in an attempt to fall into a favorable bracket during final eliminations.
To deliberately run slower in road- or oval-track racing in an effort to conserve fuel and/or to psych the competitors.
A bag filled with sand that is used to help shape metal panels.
To clean metal part surfaces by forcing abrasives, usually fine sand, against it with compressed air.
A very clean or well prepared show or race car.
A term short for sanitary.
Saturated Desiccant
A drying agent that contains all of the moisture it can hold at a given temperature.
Saturated Drier
A drier, accumulator-drier, or receiver-drier having a saturated desiccant.
Saturated Point
The point at which matter must change states at any given temperature and pressure.
Saturated Temperature
The boiling point of a substance at a particular pressure.
Saturated Vapor
A term that indicates that the space holds as much vapor as possible and no further vaporization is possible at that particular temperature.
Racing fuel.
An acronym for submerged arc welding.
A designation for lubricating oil that is acceptable for medium-duty engines operated under mild conditions.
An abbreviation for small block.
An abbreviation for single-board engine controller.
The designation for lubricating oil that meets the requirements for 1964–1967 gasoline engines in cars and trucks.
An engine that has literally blown apart.
A reinforced housing around the clutch and flywheel to protect the driver from flying parts.
Scavenge Pump
An oil pump that returns oil to the sump in a dry-sump system.
A powerful car that is difficult to beat in a race.
Scavenger Deposits
White or yellow carbon deposits that normally occur when certain fuels are burned.
The forced removal of exhaust gases from a cylinder during the overlap period.
An abbreviation for Sports Car Club of America.
A map-like drawing of the electrical system that gives the colors and shows the terminal points; used to trace the circuit for troubleshooting.
Schrader Valve
A spring-loaded valve, similar to a tire valve, located inside the service-valve fitting and some control devices to hold vapor or fluid in the system. It requires special adapters for access to the system.
An opening in the hood or body panel used to take in ambient air for cooling or ventilation.
A term used for oscilloscope.
A scratch or small dent in the finished surface of a vehicle.
SCORE International
The actual name for SCORE.
The grooves worn into the friction surface of a brake drum or rotor which may be machined away; if the depth exceedsspecified limits, the drum or rotor must be replaced.
An abbreviation for silicone controlled rectifier.
Scrap Yard
A firm selling used parts.
A firm that accepts scrap metal for recycling.
Scraper Ring
The second ring from the top of a piston used to scrape oil from the cylinder wall.
To spin the drive wheels, usually enough to leave a mark on the road surface.
A mark on the finish of a body surface made by a scribe or other sharp object.
To make a mark on a finished surface using a sharp object, such as a key.
Scratch Built
A vehicle built from the ground up, generally of an original design.
A vehicle with spectacular performance.
The final drive gear.
Screw it On
To rapidly accelerate.
Screw it on the Meter
To install an engine on a dynamometer.
Screw-Thread Pitch Gauge
A thin material with V-shaped notches that, when matched with a thread of a bolt or nut, indicates the number of threads per inch or millimeter, as well as the thread pitch.
A sharp, pointed steel tool with a hardened end for marking lines on metal in laying out work.
An abbreviation for the Society of Collision Repair Specialists.
A term used for tire scrub.
Scrub Radius
The distance between the centerline of the ball joints and the centerline of the tire at the point when the tire contacts the road surface.
Scrub Radius Area
A term used for scrub radius.
A surface that has been roughened by scraping.
Scuff In
To run a new set of racing tires long enough to bring them up to temperature, and wear the manufacturer's protective coating off the tread area. Also known as scuff off.
Scuff Off
A term used for scuff in.
A type of wear between two parts where there is a transfer of material from one part to the other.
New racing tires that have been scuffed in.
The designation for a lubricating oil developed for use in 1968–1971 cars and some trucks.
An abbreviation for spark delay valve.
The designation for a lubricating oil that meets the requirements for use in gasoline engines in 1972 and later cars, and in selected 1971 cars and trucks.
Sea Gull
One at a drag race that complains or squawks all the time.
A device used around a rotating shaft to prevent fluid or vapor leaks.
A gasket-like material used between two or more parts to prevent fluid or vapor leaks.
Seal Weld
A weld designed primarily to provide a specific degree of tightness against leakage.
Sealed Battery
A term used for maintenance-free battery.
Sealed Beam Headlight
A self-contained glass unit made up of a filament, an inner reflector, and an outer glass lens.
Sealed Bearing
A replaceable bearing, such as those found on many rear axle shafts or at the front of alternator rotor shafts, that is lubricated and permanently sealed by the manufacturer to contain the grease while keeping out contaminants.
Sealed Fuel Pump
A permanently sealed, non-serviceable pump that has its body and cover crimped together.
A thick, tacky compound used as a gasket or to seal small openings or irregularities between two mating parts.
Seasoned Part
A part that has been stress relieved.
The surface on which another part rests.
To wear to a good fit.
The bench-like unit one sits on in a vehicle.
Seat Adjuster
A device that permits fore and aft and/or up and down movement of a vehicle's front seat.
Seat Back
The upright portion of a vehicle seat.
Seat Belt Warning System
A warning device to alert the driver and occupants to fasten their seat belts and/or shoulder harness.
Second Gear
The intermediate or kickdown passing-gear range of a transmission.
Second Law of Motion
A body's acceleration is directly proportional to the force applied to it, and the body moves in a straight line away from the force.
Secondary Air
Air that is pumped to the pollution-control devices to promote chemical reactions that reduce exhaust gas pollutants.
Secondary Available Voltage
High voltage that is available to fire the spark plug.
Secondary Brake Shoe
The rear brake shoe in a drum-brake set that is energized by the primary shoe and increases self-energizing action of the brakes.
Secondary Circuit
The electrical circuit on the output side of an ignition coil.
That portion of a welding machine that conducts the secondary current between the welding transformer terminals and the electrodes, or electrode and workpiece.
The secondary passage in a carburetor.
Secondary Lock
A component of a fifth-wheel locking mechanism that can be included as a backup system for the primary locks. The secondary lock is not required for the fifth wheel to function and can be either manually or automatically applied. On some designs, the engagement of the secondary lock can only be accomplished if the primary lock is properly engaged.
Secondary Shoe
The brake shoe located toward the rear of the vehicle, in a dual-servo drum brake, having a longer and thicker lining, and providing most of the braking lining, and providing most of the braking force during forward stops.
Section Height
The straight-distance measurement of a tire from the rim to the tread.
Section Modulus
A measure of the strength of the vehicle-frame side rails.
Section Repair
A body repair that is accomplished using a section of another identical vehicle.
Section Width
The straight distance from one sidewall of a tire to the other sidewall.
A vehicle body that has been lowered by removing a horizontal section of metal all the way around the vehicle.
A component that is not a complete circle, such as the gear on the pitman shaft of many steering systems.
Sector Gear
A gear that converts the rotary motion of the worm in a recirculating ball or worm and sector steering gear to the straight line motion of the pitman arm.
A two- or four-door vehicle with front and back seats that can accommodate four to six persons.
Sedan De Ville
A sedan with an open cockpit and enclosed passenger compartment, intended to be chauffeur driven.
A portion of a larger figure cut off by one or more lines of a plane.
The copper (Cu) bars of a commutator.
Two moving parts that suddenly bind together, usually due to lack of lubricant. Also known as freeze-up.
The stiffening or freezing of a chain joint or shaft as a result of roughness and high friction caused by galling or lack of and high friction caused by galling or lack of lubrication.
A mechanism on a drum brake that compensates for shoe-lining wear and keeps the shoe adjusted close to the drum.
Self-Adjusting Clutch
A mechanism that automatically takes up the slack between the pressure plate and clutch disc.
In automotive computers, especially those for engine control, a program which assesses the condition of the system, including the sensors and the computer itself, and communicates its findings to the technician by means of trouble codes.
The discharging of a battery due to chemical action, although there is no electrical demand.
The placing of brake shoes so that the drum tends to drag the lining along with it, resulting in a wedging action between anchor and drum.
The induction of a voltage in a current-carrying coil of wire, such as an ignition coil.
Self-Locking Screw
A screw configured so that it locks itself in place when tightened.
Self-Sealing Tire
A tire having a special compound on the inner surface that seals punctures when the puncturing object is removed.
Self-Tapping Screw
A screw that cuts its own threads without pre-drilling in sheet metal.
A screw that cuts its own threads in a pre-drilled hole in heavy-gauge metal.
An abbreviation for Specialty Equipment Market Association.
Short for semitractor or semitrailer.
Semi-Independent Rear Suspension
A rear-suspension system in which one rear wheel has a limited amount of movement without affecting the opposite rear wheel.
Semiautomatic Welding
Manual welding with equipment that automatically controls one or more of the welding conditions.
Semicentrifugal Clutch
A clutch having weighted components in the pressure plate, such as rollers or release levers, that apply additional force against the pressure plate to additional force against the pressure plate to hold the disc tighter during high engine rpm.
A solid material, usually germanium (Ge) or silicon (Si), that integrated circuits are made of, with an electrical conductivity between the high conductivity of metals and the low conductivity of insulators used to control the flow of electricity.
Semiconductor Ignition System
A term used for electronic-ignition system.
Refers to the amount that the ends are higher than the center arch of a leaf-spring configuration.
Semielliptical Spring
A leaf spring.
A set of leaf springs of regressive lengths stacked with the longest at the top to the shortest at the bottom.
Semifloating Axle
A popular automotive system in which the axle shaft provides three functions transfers torque to drive the vehicle, supports the car weight, and retains the wheel.
Semifloating Rear Axle
An axle that supports the weight of the vehicle on the axle shaft and transmits the driving force to the rear wheels.
Semiknocked Down (SKD)
A vehicle that is sold in a partially assembled condition.
Semimetallic Brake Lining
A brake lining that is made of an organic resin to bond steel fibers.
A fifth-wheel-type vehicle that oscillates or articulates about an axis perpendicular to the vehicle centerline.
A large truck having a fifth wheel used to tow a semitrailer.
A load-carrying vehicle equipped with one or more axles and constructed so that its front end is attached to, and supported by the fifth wheel of a semitractor that pulls it.
Sending Unit
An electrical or mechanical sensing device that sends information relative to some physical property such as temperature or pressure to a gauge or light. Also known as sensor unit.
Sensible Heat
Heat that causes a change in the temperature of a substance, but does not change the state of the substance that can be felt or measured with a thermometer.
Sensing Voltage
A condition that provides a means for the voltage regulator to monitor and control the battery voltage charge rate.
Sensor Plate
A plate used in the air intake of a continuous-flow, fuel-injection system to measure airflow.
Sensor Unit
A term used for sending unit.
A tank-like device used to remove liquids from a vapor, such as oil from refrigerant.
A nonconductive divider placed between the positive and negative plates of a battery.
Separator Disc
The metal plates in a multi-plate clutch that separates the friction disc.
Sequential Fuel Injection
A term used for sequential-port fuel injection.
Sequential-Port Fuel Injection (SPFI)
A type of multi-port injection system where individual fuel injectors are pulsed sequentially, one after another in the same firing order as the spark plugs, rather than being pulsed simultaneously. This allows more precise fuel control for lower emissions and better performance. Also known as sequential fuel injection.
Series Circuit
A circuit having only one path through which the current or fluid can flow, having to pass through one component before going on to another.
Series Number
A term used for tire aspect ratio.
Series Parallel Circuit
A circuit in which some components are in series while others are in parallel.
Series Parallel System
An arrangement where two 12-volt batteries are connected in such a manner as to provide 24-volts for starting and 12-volts for accessories and charging.
Serpentine Belt
A wide, flat belt having multi-V-grooves to provide frictional contact with the pulleys that winds through all of the engine accessories to drive them off the crankshaft pulley.
Serrated Nut
A self-locking type of nut having serrations on its contact side to prevent it from loosening when tightened.
Serrated Rod Cap
A connecting rod cap that has serrated parting edges to help maintain alignment with the rod.
Service Access Gauge-Port Adapter
An adapter that is used to connect a test gauge to the service port of a system for nonstandard service-port applications.
Service Access Gauge-Port Valve
Fittings found on some service valves and some control devices used to access the system for testing and service.
Service Bay Diagnosis System
A computerized information network system that is connected, often by satellite, to the vehicle manufacturer and used to answer service and diagnostic questions.
Service Bulletin
Technical service information provided by the manufacturer, used as updates for the service manuals and to provide the latest service tips, field repairs, product information, and other related information for the service technician.
Service Hose
A hose that attaches a test gauge set to the service fitting of the system.
Service Manager
The person who is generally responsible for the entire service operation of a dealership.
Service Manual
A manual provided by the manufacturer or other publisher that describes service procedures, troubleshooting and diagnosis, and specifications for a particular car line.
Service Port
An access fitting found on the service valve and some control devices that the gauge set hoses are connected to for service and testing.
Service Procedures
A recommended step-by-step procedure to follow to troubleshoot, disassemble, assemble, or repair an automotive system or component.
Service Rating
A designation that indicates the type engine an oil is suited for.
The temperature and/or load rating of a tire.
Service Representative
A manufacturer's agent who works in the local area to provide direct and immediate service to the dealership relative to customer service.
Service Station Dealers of America (SSDA)
A national federation of service station owners.
Service Technician
One actively involved in troubleshooting, maintenance, and repair of the vehicle.
Service Valves
Special manually operated or Schrader-type valves that allow connecting gauge hoses to a pressurized system during servicing procedures.
Service Writer
One who writes the work order.
A device that converts hydraulic pressure to mechanical movement, such as a brake-wheel cylinder.
Servo Action
A method of brake construction in which a primary shoe pushes a secondary shoe to generate self-energization.
Servo Brake
A drum brake in which brake shoes are linked, so that the braking force of one shoe amplifies the input of the other shoe.
Set Screw
A type of screw having a point that fits into the matching recess of a shaft to secure a pulley or gear.
The engine transmission/drivetrain and chassis combination that offers improved performance.
Severe Ring
A piston ring that exerts a high amount of pressure against the cylinder wall, often used in an engine with severe cylinder-wall wear.
Sewing Machine
A small, foreign car.
A swinging support for the rear end of a spring that permits it to vary in length as it deflects.
Shackle Assembly
This assembly is attached to the front spring eye and bushing and is then mounted through a shackle bushing to the frame allowing the leaf spring to pivot up and down.
Shackle Bushing
Insulated bushings to help prevent the transfer of noise and road shock from the suspension to the chassis and vehicle interior.
Shade-Tree Mechanic
An amateur mechanic.
A mechanic with little or no knowledge of the trade.
A rural mechanic that literally works under a shade tree.
Shadow Graph
A scale using reflected light to indicate a difference in the weight of two parts.
Shaft Seal
An assembly that prevents vapor or fluid from escaping around a rotating shaft.
Shaft-Mounted Rocker Arms
Rocker arms that are mounted in a straight row on a shaft.
A hood scoop on some muscle cars that channels directly into the air cleaner.
A Chevrolet among Ford enthusiasts.
Shallow Staging
A term often used for back staging.
A vehicle body with the factory chrome trim removed and the holes filled in and painted.
A cylinder head that has been resurfaced.
Shear Pin
A pin passing through two or more parts, as in securing a gear on a shaft, designed to break, preventing damage if an overload occurs.
Outer spark-plug casing having a threaded end and hexagonal flats for a wrench attachment.
Outer front and/or rear metal container of the power-brake unit.
The sheet metal body structure of a vehicle.
Shielding Gas
Protective gas used to prevent or reduce atmospheric contamination while welding.
Shift Forks
A Y-shaped component located between the low/reverse, first/second, and third/fourth gears on the main shaft of a transmission that causes the gears to engage or disengage via the sliding clutches.
Shift Kit
Parts required to provide high performance of an automatic transmission shifter.
Shift Lever
A lever used to change gears in a transmission.
A lever that moves the starter drive pinion in and out of mesh with the flywheel in some applications.
Shift Rail
A series of grooves in the forks to guide the shift forks, tension balls, and springs to hold the shift forks in gear, allowing them to interlock the rails to prevent the transmission from being shifted into two gears at the same time.
Shift Tower
The main interface between the drive and transmission, a gearshift lever, pivot pin, spring, boot, and housing.
Shift Valve
A valve body component acted on by oil pressure, allowing fluid flow to the involved band and/or clutch at the appropriate time, causing the transmission to upshift or downshift.
Shift Yoke
A term used for shift fork.
Shift-Bar Housing
A component that houses shift rails, shift yokes, detent balls and springs, interlock balls, and pin and neutral shaft; available in standard- and forward-position configurations.
A floor- or steering column-mounted lever on a motor vehicle used to select and/or shift the transmission gears.
Shifting Forks
A term used for shift forks. Also known as shift yoke.
Shifting Rods
The linkage of a manual transmission that connects the shifter to the shift forks.
A hot Chevrolet V-8 engine.
A thin metal spacer used to align the clearance of a part.
A slotted strip of metal used to adjust the front-end alignment on many vehicles.
Shim Stock
Thin metal, usually in a roll, that can be easily cut to be used as a shim.
A harsh, side-to-side vibration of the steering wheel usually due to front wheel imbalance.
A term used for shock absorber.
Shock Absorber
A hydraulic device used at each wheel of the suspension system to help control the up, down, and rolling motion of a car body by dampening the oscillations or jounce of the springs when the car goes over bumps, thereby contributing to vehicle safety and passenger comfort. Also referred to as shock.
Shock Compression
The shock absorber in its shortened position, which occurs when the wheel moves upward.
Shock Fluid
Specially formulated hydraulic fluid used inside of shock absorbers.
Shock Foaming
The mixing of air and shock fluid, due to rapid movement of fluid between the chambers, causing the shock absorber to develop a lag because the piston is moving through an air pocket that offers up resistance. A gas-filled shock absorber is designed to reduce oil foaming.
Shock Hydraulic Principles
Fluid is forced through orifices and/or valves at a controlled rate to provide the desired dampening effect.
Shock Mounting Position
The direction and/or angle at which a shock absorber is mounted vertical, horizontal, or slanted inward at the top.
Shock Mounts
The rubber isolating bushing or grommets attached to the upper shock-mounting piston rod and the lower mounting cylinder tube in which the piston operates.
Shock Operational Check
A method used to check shock efficiency that includes bouncing the vehicle bumper vigorously and observing shock dampening action, or pumping brakes slowly at low speed to see if a vehicle rocking motion is set up.
Shock Piston
The component attached to the bottom of the piston rod containing the rebound valve that moves back and forth inside the inner cylinder.
Shock Rebound
The rebound travel when the shock absorber is in its lengthened position, which occurs when the suspension or spring moves downward.
Shock-Absorber Function
A typical shock absorber has three functions to dampen the effect of spring oscillation in order to control the ride stabilization of a vehicle, to control body sway, and to reduce the tendency of a tire tread to lift off the road surface (a problem often caused by static unbalance).
Shock-Absorber Lag
The incorrect operation of a shock absorber because of aeration due to the mixing of air with oils, causing the shock absorber to produce a poor ride.
Shock-Absorber Ratio
A rating of shock-absorber extension control compared to the amount of compression control, varying from 50/50 to 80/20.
Shock-Absorber Strut Assembly
In a MacPherson strut, the independent rear-suspension system that includes a rubber isolated top mount, upper and lower spring seat, coil spring insulator, and coil spring.
The lining and its steel backing on a drum brake that press against the inside of the brake drum to provide stopping power.
Shoe Box
Any car manufactured in the U.S. having a non-aerodynamic, box-like shape built from the late 1940s through the 1950s.
Shoe Hold-Down Spring
A coiled compression spring that applies pressure to hold the brake shoes against the backing plate.
Shoe Retracting Spring
A coiled tension spring that pulls the shoes away from the brake drum after the pedal is released, forcing the brake fluid back into the master cylinder.
To spray paint, as in painting a vehicle.
Shop Housekeeping
A term used for housekeeping.
Short and Long A-Arms
A double A-arm suspension where one arm is smaller than the other.
Short Arm
The throw of a crankshaft that has not been stroked.
Short Arm, Long Arm Suspension
A conventional front-suspension system that uses a short upper-control arm and a long lower-control arm.
Short Bed
The cargo area of a short-wheelbase pickup truck, usually about six feet (1.83 meters) long.
Short Block
A new or rebuilt engine block with all internal parts.
Short Circuit
The intentional or unintentional grounding of an electrical circuit.
Short Course
To take a shortcut that bypasses a part of the official course in an off-road racing event.
Short Course Off-Road Enterprises (SCORE)
More commonly known as SCORE International, an organization involved in long- distance desert competition events.
Short Cycling
A rapid cycling of the clutch resulting in poor cooling condition of the air conditioner that can be caused by poor refrigerant and/or air circulation or a maladjusted thermostat.
An electrical condition where the device goes on and off as cycled by a circuit breaker due to a malfunction.
Short Deck Engine
An engine block designed to accommodate a short-stroke crankshaft.
Short Gear
A final drive with low gearing.
Short Side Radius
The small radius in a port between the bottom of the port runner of the intake manifold and the bowl area.
Short Ton
A standard English weight equal to 2,000 pounds.
Short Track
An oval race track that is less than one kilometer (5/8 mile).
Short, Long-Arm Suspension
A conventional front-suspension system that uses a short upper-control arm and a long lower-control arm.
Shorted Circuit
A circuit that allows current to bypass part of the normal path.
Pellets used with air pressure to clean parts.
Shot Bag
A leather bag filled with #9 birdshot used by metal workers to help shape and form metal panels.
Shot Peen
To harden the surface of a metal part by bombarding it with metal shot using high air pressure.
Shot Rodder
One who is a discredit to the sport of hot rodding.
Shotgun Motor
A rare Ford big block 429 cid Hemi, offered in 1969 and 1970.
Show 'n' Shine
To display a hot rod or custom car in a car show.
Show Car
A custom-built car for show and not for driving, though driveable.
Show Through
The appearance of a sanding pattern after the vehicle has been painted.
Showroom Stock
A factory-stock vehicle with minor modifications and safety equipment under SCCA rules.
To reduce an area of a piece of metal by heating and hammering it.
Shrink Fit
A tight or snug fit accomplished by shrinking a part.
Shrink Wrap
A shrink-fit tubing used to protect wires, wire splices, and terminals of an automotive electrical system.
Shrink-Fit Tubing
An insulated tubing that shrinks to about half its original diameter when heated.
Shrinking Hammer
A special hammer that is used to shrink spots that have been stretched by excessive hammering.
A metal or plastic duct that directs ambient air to the radiator cooling fan.
A hood-like device placed around an engine fan to improve air flow.
An obstruction, such as carbon buildup, around a valve in the combustion chamber that interferes with the proper air flow.
A British term for vehicle accident.
To bump or shove another car in an oval track or road race.
A parallel electrical connection or circuit.
Shunt Winding
Bypass winding found on some alternators.
Shut Down
To defeat a competitor.
To stop an engine.
Shut Down Valve
A valve which is used to shut down an engine by interrupting the fuel supply; a safety requirement for many competitive vehicles.
Shut Off
To slow a vehicle by releasing the accelerator or throttle.
Shut Off Area
An area beyond the measured distance of competition where the vehicle may be safely brought to a stop.
Shut the Gate
To pass a competitor in closed-course racing then immediately cut in front.
To prevent an opponent from passing on the inside of a turn by blocking the apex.
An abbreviation for spark ignition.
An abbreviation for Système Internationale des Unités.
Siamese Ports
Intake or exhaust ports inside the cylinder head where two cylinders are feeding through the one port.
1.Two exhaust pipes joined together.
Cylinders in an engine block that are cast so close together that there is no room for a coolant passage between them.
Two adjacent valves in a cylinder head that is served by a single port.
Side Bolt Mains
Side-mounted main bearing bolts that increase the rigidity of the lower end.
Side Clearance
The clearance between the cheeks of the crankshaft journal and the connecting rod.
Side Gears
Bevel gears that transfer power from the differential pinion gears to the splined axle shafts, providing differential action during turns.
Side Guard Door Beam
The structural member of a vehicle door that prevents it from being pushed inward if struck.
Side Lead
The effects of centrifugal force as a vehicle rounds a turn.
Side Marker Light
Lamps installed in all vehicles sold in the United States since 1969 that permit the vehicle to be seen when entering a roadway from the side and to provide a means for other drivers to determine vehicle length (clearance).
Side Molding
The trim on the sides of a vehicle that offer protection or to improve the appearance.
Side Oiler
A Ford big block V–8 having a main oil gallery relocated on the low left side of the block.
Side Shift
A steering-column mounted transmission gear-shift lever.
Side Step
The act of slipping one's foot on the clutch pedal suddenly while revving the engine in drag racing.
Side Valve
An engine having intake and exhaust valves in the block beside the cylinders.
Side-Dash Components
The installation of heating and air-conditioning components that have the evaporator mounted on the curb side of the firewall in the engine compartment and the heater core in the duct in the passenger compartment.
Side-Draft Carburetor
A carburetor having one or more horizontal barrels.
Side-Mount Battery
A battery having terminals on the side.
The side of a tire between the bead and the tread.
Sidewall Information
Certain information required by the Department of Transportation to be imprinted on each tire, such as size, load rating/inflation pressure maximums, generic name of each cord material in the sidewalls and tread areas, actual number of plies in the sidewall and tread area, the words tubeless or tube type, as applicable, the word radial, if applicable, and the manufacturing code to determine who made the tire, where it was made, and when it was made.
A vehicle having an engine that is mounted transversely.
Sight Glass
A glass window in the liquid line or top of the receiver-drier used to observe the liquid refrigerant flow in an air-conditioning system.
An abbreviation for Society of Independent Gasoline Marketers of America.
Significant New Alternatives Policy (SNAP)
A rule established in 1994, under Section 612 of the 1990 Clean Air Act (CAA) to initiate a program in which the Environmental Protection Agency (EPA) is to evaluate applications for use of substitute chemicals and technology designated to replace ozone depleters in specific uses, including flammability, chemical toxicity, global-warming potential, exposure of workers, consumers, the general public, and aquatic life.
A device, such as a muffler, designed to reduce noise.
Silent Block
A rubber mount designed to reduce noise due to vibration.
Silhouette Car
A modern, front-drive 4- or 6-cylinder car that has been converted to a rear-drive V–8 car.
Silica Gel
A drying agent used in many automotive applications, such as an air-conditioner desiccant because of its ability to absorb large quantities of water.
A chemical element (Si).
Silicon-Killed Steel
A steel alloy that has been killed with silicon in the molten stage to refine its grain structure.
A group of organic compounds based on the non-metallic element, silicon (Si).
Silicone Controlled Rectifier (SCR)
A semiconductor diode device used in controlling large amounts of DC current or voltage.
Silicone Fluid
Fluid made of chemicals with a silicone carbon bond; adaptable for many industrial uses.
Silicone Jackets
High-temperature coverings for spark plugs.
Silver Solder
A filler alloy that contains up to 45% silver (AG), that melts at 1,120°F (604°C) and flows at 1,145°F (618°C).
Silver Tape
A term used for duct tape.
Simple Planetary Gear Set
Gear set with a sun gear, planetary pinions, planetary carrier, and ring gear.
Simpson Gear Set
A gear set having two simple planetary gears mounted on a common sun gear.
Single Chamber Capacity
The measure of the maximum volume or displacement of the rotor chamber of a Wankel engine.
Single Leaf Spring
A spring having one leaf that may by tapered thinner and wider toward the ends, allowing a variable flexing rate.
Single Overhead Camshaft (SOHC)
An engine having one overhead camshaft.
Single Overhead Camshaft engine
An engine having a single camshaft mounted over each cylinder head.
Single Pass
A term applicable to a refrigerant recovery unit that removes refrigerant from the air conditioner and passes it through only one time on its way to the recovery cylinder.
Single Rear Wheels (SRW)
Single wheels on either side of the drive axle of a rear-drive vehicle.
Single Reduction Axle
An axle assembly that has but one gear reduction through its differental carrier assembly.
Single Wrap
A transmission brake with a circular steel strap that is lined internally with friction material.
Single-Board Engine Controller (SBEC)
A single microprocessor used to control engine functions.
Single-Pivot Control Arm
A term used for control arm.
Single-Plane Crankshaft
A crankshaft having throws on the opposite side of the same plane, at 180 degrees.
Single-Plane Manifold
An intake manifold having a single plenum between the carburetor and intake ports.
Single-Wire Circuit
A circuit using a single wire that relies on the metal structures of the vehicle, such as the frame or body, as a ground.
A somewhat porous metallic bearing formed by pressing particles of powdered metal to a temperature at which they adhere to each other.
Sintered Brake Lining
A term used for metallic brake lining.
Six Holer
A six-cylinder engine.
Six Pack
A carburetor setup having a total of six barrels.
Six-Stroke Cycle
The stroke cycle of an experimental engine by Toyota where combustion occurs every third revolution of the crankshaft.
Sixty Foot Time
The time it takes to cover the first sixty feet (18.3 meters) from the starting line in a drag race.
SK Steel
A shortened term for silicon-killed steel.
An abbreviation for semiknocked down.
Skid Control
A device that prevents wheel lockup during braking, to prevent skidding.
Skid Control System
A system designed to respond to a locking wheel by relieving hydraulic pressure to the locking brake.
Skid Pad
A flat area of pavement with a painted circle 300 feet (91 meters) in diameter used to determine a vehicle's lateral grip and lateral acceleration.
Skid Plate
A shield under the power train of an off-road vehicle to protect the engine and transmission.
The surface hardening of RTV or some body fillers.
The outer sheet metal of a vehicle.
Skin Effect
The tendency of current to crowd toward the outer surface of a conductor; increases with conductor diameter and frequency.
A thin, unburned layer of air/fuel mixture next to the combustion camber surface.
Narrow front wheels and tires.
The removal of insulation from electrical conductors before making splices or connections.
A term used for piston skirt.
The unmelted residue from a filler metal when welding.
Skunk Works
A small, secretive group within the research and development department of a large organization that focuses on more advanced research and development.
A contest of speed and maneuverability through a tight course marked off with pylons.
To modify a vehicle's suspension to make it lower.
Slam the Door
Beating another vehicle in competition.
Preventing a competitive vehicle from passing.
Slant Six
A six-cylinder engine design offered on some Chrysler car lines in the 1960s and 1970s.
Slave Valve
An air-pressure operated device that helps to protect gears and components in the transmission's auxiliary section by permitting range shifts to occur only when the transmission's main gearbox is in neutral.
Sled Runner
The taper of the skirt of a piston to compensate for heat expansion.
A vehicle that looks ordinary but is actually a high performer.
A term used for cylinder sleeve.
Sleeve Bearing
A plain bearing.
A smooth, treadless racing tire.
Slide Travel
The distance that a sliding fifth wheel is designed to move.
Slider Clutch
A special clutch used in drag race cars that slips to allow the engine to rev up before engaging.
Sliding Caliper
A disc-brake caliper that has a piston(s) on one side of the disc only that moves sideways on machined ways or keys to press the pad on the other side against the disc.
Sliding Fifth Wheel
A specialized fifth wheel design that incorporates provisionsto readily relocate the kingpin center forward and rearward, which affects the weight distribution on the tractor axles and/or overall length of the tractor and trailer.
A loop of rope, cable, or chain used in hoisting heavy material.
A metal disc attached to the crankshaft to keep engine oil away from the front seal.
Slip Angle
The difference in the path the wheels follow during a turn compared to the actual direction they are pointing, caused by centrifugal force at higher speeds.
Slip Joint
A term used for slip yoke.
Slip Rings
The electrical contact area for the brushes in an alternator.
Slip Stream
A partial vacuum that is created behind a vehicle traveling at a high speed.
Slip Yoke
A component having internal splines that slide on the transmission output-shaft external splines, allowing the drive line to adjust for variations in length as the rear axle assembly moves.
A part that fits without modification or adjustment.
A condition that occurs with a tractor-trailer when pulling with full power or decelerating with the load; tapered or worn clutch teeth tend to walk as they rotate, causing the sliding gear and clutch to slip out of engagement.
Slipper Skirt
A term used for slipper skirt piston.
Slipper Skirt Piston
A piston that has a cutaway skirt so that the piston can come closer to the counterweights reducing the overall size of the engine. Also known as slipper skirt.
A streamlined, aerodynamically efficient vehicle.
A fastback body type.
Slow Reverse
A simple planetary gear combination with sun gear as input, planetary carrier held, and ring gear as output.
A buildup of combustion by-products that can clog oil lines and interfere with proper lubrication.
A piston.
The return of liquid refrigerant or oil to the compressor.
The act of adding a separate piece(s) of material in a joint before or during welding that results in a welded joint not complying with design, drawing, or specification requirements.
Slush Pump
An automatic transmission.
Small Block (SB)
A V–8 engine of 400 cid (6.5 liters) or less.
Air pollution, especially the photochemical variety formed when sunlight causes chemical reactions in air pollutants, resulting in the formation of ozone and other compounds.
Smog Check
To measure the emissions level of a vehicle's exhaust gases.
Smog Motor
A vehicle engine with exhaust emissions controls.
Smog Pump
An air-injection system pump.
Smog Test
A term used for smog check.
To defeat a racing competitor.
The color of the vapor coming out of the vehicle's exhaust system.
Smoke in Exhaust
A visible blue or black substance often present in the vehicle exhaust.
Smoke it Over
To discuss, analyze, and give careful consideration to a concept, idea, or problem.
Smoke Off
To leave the starting line in a drag race with the rear wheels smoking.
Smoking Rules
Rules concerning smoking, such as, NO SMOKING or SMOKE ONLY IN DESIGNATED SMOKING AREAS. Fumes in the shop may be ignited if these rules are not followed.
A body panel with trim removed and the holes filled.
An acronym for Significant New Alternatives Policy.
Snap Ring
A circular retaining clip used inside or outside a shaft or part to secure a shaft, such as a floating wrist pin.
Snell Foundation
An organization that sets safety standards for racing helmets that are adhered to by most race-sanctioning bodies.
An exhaust-gas analyzer used in making a smog check.
A pipe that is placed on a wrench to increase leverage; generally an unsafe practice.
Snorkel Tube
A long, narrow tube attached to the air cleaner, used to direct air into the air filter.
A slippery surface.
Snow-and-Mud Tire
A tire, identified with an MS suffix, having treads designed to provide traction when driving in mud or snow; available in various ply and belt designs.
Society of Automobile Engineers (SAE)
A professional organization established in 1905 and now known as the Society of Automotive Engineers.
Society of Automotive Engineers (SAE)
A professional organization of the automotive industry founded in 1905, the SAE is dedicated to providing technical information and standards to the automotive industry.
Society of Collision Repair Specialists (SCRS)
A trade association of those involved in the collision-repair industry.
Society of Independent Gasoline Marketers of America (SIGMA)
A trade association of wholesale and retail private-brand gasoline marketers.
Sodium Bicarbonate
Baking soda (NaHCO) used to neutralize battery acid.
Sodium Hydroxide
A caustic soda (NaOH) that makes a good parts cleaner when mixed with water.
Sodium Silicate
A white, grey, or colorless compound sometimes used to seal small cracks or leaks in the cooling system.
Sodium-Cooled Valve
A partially hollow valve containing metallic sodium that melts at a low temperature (208°F) 97.8°C and when in its liquid state at operating temperatures splashes around inside the valve, transferring heat away from the valve head.
Soft Plug
A term used for core plug.
Soft Solder 95/5
A lead-free metallic alloy of 95% tin (Sn) and 5% antimony (Sb); used to repair or join ferrous metal parts for repair or join ferrous metal parts for temperatures below 350°F (176°C).
Soft Top
A convertible top.
A vehicle having a convertible top.
An abbreviation for single overhead camshaft.
Solar Cell
A semiconductor that converts sunlight to electrical energy.
Solar Power
Electricity that is generated by solar cells.
A filler metal used in joining two or more parts that has a liquidus state not exceeding 840°F (450°C).
A welding process that produces consolidation of materials by heating them to the proper temperature and using a filler metal having a liquidus not exceeding 840°F (450°C) and below the solidus of the base metals.
An electro-mechanical device used to effect a push-pull mechanical operation using electrical current.
Solenoid Relay
A relay that connects a solenoid to an electrical circuit, such as a starter-motor solenoid relay.
Solenoid Switch
An electrical switch that is opened and closed mechanically by the movement of a solenoid core.
Solid Axle
A term used for beam axle or rigid axle.
Solid Pushrod
A pushrod made from solid stock.
Solid State Device
A semiconductor.
Solid State Ignition
An ignition system using diodes and transistors to control spark timing.
Solid State Regulator
An alternator regulator having no moving parts.
Solid Valve Lifter
A term used for mechanical valve lifter.
Solid Wire
A single stranded conductor, usually insulated.
Solid-Axle Suspension
Suspension system in which the wheels are mounted at each end of a solid, or undivided, axle or axle housing.
A type of paint pigment.
A solid or mechanical valve lifter.
The highest temperature at which a metal or an alloy is completely solid.
By oneself.
A run made by a single car during a drag-race elimination.
A substance that will dissolve in a solvent.
A liquid substance, such as water, in which other substances can dissolve.
A petrochemical liquid that will dissolve oil and grease.
A paint cleaner and thinner.
Sonic Testing
A procedure for testing the integrity of engine blocks, using sound waves.
An abbreviation for standard operating procedure.
An abbreviation for seat of the pants.
SOP Rally
A competitive event in which instruments cannot be used by the contestant to check time or distance.
A desiccant.
Sorted Out
Corrected, such as a problem that has been corrected.
A special racing-fuel mixture.
To increase the output of an engine.
South Pole
The pole or end at which magnetic lines of force enter a magnet.
Southern California Timing Association (SCTA)
A sanctioning body concerned with the annual Bonneville speed trials.
Space Frame
A light-weight race car frame constructed of small-diameter metal tubing that is welded together in such a manner as to provide high rigidity.
Space-Saver Spare Tire
A deflated, compact spare tire that must be inflated to 35 psi (241 kPa) with a vehicle-battery powered air compressor or a can of compressed air.
An inflated spare tire which is smaller and narrower than those on the vehicle that is to be used in an emergency only.
Space-Saver Tire
A term used for space-saver spare tire.
A device, such as a shim or washer, that is used to increase the space between two mating surfaces or parts.
A condition where chips, flakes, or scales of metal break off a part due to fatigue rather than by wear.
The width of an air foil.
The British term for wrench.
Not in regular use or immediately needed.
Extra or reserve.
A term used for spare tire.
Spare Tire
A full-size replacement tire or a compact space-saver tire, generally for emergency service, but available for use when needed.
Spark Advance
The moving ahead of the ignition spark in relation to the piston position.
Spark Advance Curve
The rate at which ignition timing advances as plotted on a graph; the line rises from some initial amount of advance and levels off at the maximum advance.
Spark Decel Valve
A vacuum valve, located in the line between the distributor and carburetor, to advance the spark during deceleration, to reduce emissions.
Spark Delay Valve (SDV)
A vacuum valve acting like a restrictor, used in the vacuum line between the distributor and carburetor, to delay vacuum-timing advance under certain driving conditions to reduce NOX (oxides of nitrogen) emissions.
Spark Duration
The time a spark is established across the gap of a spark plug.
Spark Ignition (SI)
An engine-operating system where the air/fuel mixture is ignited by an electrical spark.
Spark Knock
A term used for detonation or ping.
Spark Line
The line on an oscilloscope that indicates the voltage required to fire the spark plug and the number of degrees the distributor turns while the spark exists.
Spark Plug
An ignition component threaded into the cylinder head that contains two electrodes extending into the cylinder that form a gap across which high-voltage electricity arcs to ignite the compressed air-fuel mixture.
Spark Plug Fouling
An accumulation of deposits on the lower, exposed end of the spark plug that act as an electrical conductor, thereby creating a path for electricity to leak to ground rather than jump across the electrode gap.
Spark Plug Heat Range
The temperature limits hot, normal, or cold, within which a spark plug is designed to operate. It is determined by varying the length of the exposed lower section of the plug ceramic insulator.
Spark Plug Well
The recess in a cylinder head for a spark plug.
Spark Plug Wire
A special high-voltage wire from the distributor cap to the spark plug.
Spark Plug, Resistor Type
A spark plug having an electrode resistance of 5,000 to 10,000 ohms to increase electrode life and suppress radio interference.
Spark Test
A quick check of the ignition system made by carefully placing a metal end of one of the spark plug wires close to the engine while cranking the engine to see if there is a spark gap and to determine its intensity.
The metal particles expelled during fusion welding that do not form a part of the weld.
Spatter Paint
The technique of applying two separate colors of paint simultaneously to provide a speckled finish.
Spec Car
A term used for specification car.
One car in a group of identical specification cars that form their own racing category with a focus on driving skills.
A high-performance, individually built car, such as a prototype.
Specialty Equipment Market Association (SEMA)
A trade association for the automotive aftermarket industry.
Specialty Repair Shop
A term used for specialty service shop.
Specialty Service Shop
A repair shop that specializes in certain vehicle components, such as engine rebuilding, brake repair, radiator repair, and so on. Also known as specialty shop.
Specialty Shop
A term that may be used for specialty service shop.
Specialty Tire
Any of several types of tires such as, all-season tire, puncture-sealing tire, snow-and-mud tire, or studded tire.
Specification Car
One car in a group of identical cars that form their own racing category with a focus on driving skills. Also known as spec car.
Technical data, numbers, clearances, and measurements used to diagnose and adjust automobile components supplied by the manufacturer.
A term used for specifications.
A rate-of-motion measured in miles per hour or kilometers per hour.
Speed Adjustment
A term used for idle-speed adjustment.
Speed Flare Up
An operating condition where the engine speeds up without an increase in vehicle speed.
Speed Rating
A tire rating that indicates the maximum safe vehicle speed that a tire will withstand.
Speed Ratio
A comparison of the difference in speed between two moving parts such as impeller speed and turbine speed.
Speed Sensor
An electrical device that can sense the rotational speed of a shaft or member and transmit this information to another device, such as a readout.
Speed Shift
To upshift a manual transmission without releasing the accelerator.
The art of upshifting a manual transmission without using the clutch.
A short, oval dirt track.
An instrument, usually dash mounted, used to measure the speed of a vehicle.
An open, two-passenger roadster.
A large oval-track racing facility.
An abbreviation for sequential-port fuel injection.
Spherical Joint
A term used for ball joint.
A set of gears in the differential that allow the rear wheels to rotate at different speeds as the vehicle is cornering.
To skid out of control by 180 degrees or more.
Spin on Filter
An oil filter having a threaded attachment for the ease and speed of replacement.
A shaft or stub axle upon which the wheel hub and bearing rides.
A shaft which carries either cutting tools or work that is being machined.
A term used for knock-off hub.
Spinning Balancer
A balancer that rotates the tire and wheel to determine the amount and location of any unbalanced condition.
Spiral Bevel Gears
A differential ring gear with helical gear teeth.
Spiral Spring
Springs formed from flat strip of wire wound in the form of a spiral, loaded by torque about an axis, normal to the plane of the spiral.
Spiral-Grooved Shock Absorber
An arrangement that is used to reduce the mixture of air with the fluid as it passes through the valves by breaking up the air bubbles and, at the same time, reducing lag.
Splash Lubrication
A non-pressurized system of lubrication, same as splash-feed oil system.
Splash Shield
A stamped sheet-metal deflector plate located behind the disc-brake rotor providing component protection from dirt and water and improving the flow of air over the rotor.
Splash-Feed Oil System
A type of engine lubrication system in which oil is splashed onto the engine parts to be lubricated.
Splined Discs
Multiple-disc clutch components splined internally to the side gears or over a special hub on single-pack types.
Splined Yoke
A consideration to allow the driveshaft length to increase and decrease to accommodate the movement of the rear axle.
The internal or external longitudinal grooves in a gear or shaft that mesh when assembled, causing the gear to turn with the shaft, but allow lateral movement.
Split Brake System
A service-brake system having two or more separate fluid, electrical, mechanical, or other circuits. If one circuit fails, full or partial brake actuating capability is retained.
Split Crankcase
An oil pan split horizontally, in the same plane as the crankshaft, into two or more pieces to simplify service.
Split Guide Ring
Part of a torque converter assembly designed to reduce fluid turbulence and improve efficiency.
Split Pin
A round, split-spring steel tubular roll pin used for locking purposes, such as a gear to a shaft.
Split Sump
A term used for split crankcase.
Split Torque Converter
A design having a simple planetary gear set to divide engine torque between mechanical and hydraulic operation.
Split Valve Guide
A two-piece valve guide used in some older flathead engines with mushroom valves.
An aerodynamic device that spoils the airflow over the vehicle.
A device attached below the front bumper to reduce drag by deflecting air away from the vehicle.
A device mounted on the rear deck to provide a downward force.
The wire-like bracing between the hub and rim of a wire wheel.
Wire wheels.
Spongy Brake Pedal
A condition where the brake pedal is not solid when depressed, but bounces softly. This is caused by air in the hydraulic lines, distortion or stretching of the connecting parts, or swelling of the hydraulic hoses.
Spongy Pedal
A term used for spongy brake pedal.
Spontaneous Combustion
The process by which a material ignites and burns by itself.
To psych, distract, or unnerve a competitor at the start of a race.
A final drive without any differential action.
A term used for locked rear end.
Spool Valve
A rod used to control oil flow in an automatic transmission.
Sport Utility Vehicle (SUV)
A very popular truck-like vehicle with a box-like open or enclosed body, generally having a short wheel base, a manual four- or five-speed transmission, and four-wheel drive.
Sports Car
A two-seated vehicle with a manual transmission built for performance rather than passenger comfort.
A vehicle built to incorporate the appearance, performance, and handling of a race car, but retain the qualities and requirements for regular road use.
Sports Car Club of America (SCCA)
A major road-racing sanctioning body.
Sports Sedan (SS)
A pony car under USAC stock car rules.
Sports Vehicle
A multipurpose vehicle for road and off-road service, generally appealing to the outdoor enthusiast, available in two-wheel drive, four-wheel drive, or all-wheel drive having a pickup-truck body design with standard cab or extended cab area. Van designs are considered sport vehicles, but for family use.
Sporty Car
A compact two-door, four-passenger sports-styled coupe or convertible having a long hood and a short deck.
Spot On
A critical measurement.
Absolutely correct or accurate.
Spot Putty
A body filler for slight dents and scratches.
Spot Repair
A small repair such as a scratch or dent.
Spot Weld
A weld made between or upon overlapping members in which bonding may start and occur on the mating surfaces or may proceed from the outer surface of one member.
A one-way clutch used in an automatic transmission.
Sprag Clutch
A device containing numerous oblong parts, called sprags, that operate by tilting between an inner and outer race to lock up when the outer race is turned in one direction and to slip when it is turned in the opposite direction.
A one-way clutch having cam-profiled locking elements that engage cylindrical outer and inner races.
The atomization of a liquid into a fine mist.
Spread Bore Carburetor
A four-barrel carburetor having small primary and large secondary barrels.
Spread Tandem Suspension
A two-axle assembly in which the axles are spaced to allow maximum axle loads under existing regulations, usually more than 55 inches (140 cm).
Small steel coils that are used to close the intake and exhaust valves when the cam lobes release pressure on the valve stem.
A steel or composite elastic leaf- or coil-like device that compresses as it absorbs energy and returns to its original position when it releases that energy.
Spring Back
The tendency of a material to return to its original shape or near its original shape after being bent.
Spring Bind
A term used for coil bind.
Spring Break Chamber
A device used with brake-foundation assemblies as a fail safe unit that automatically applies the truck's service brakes in the event of an air loss.
A device used as a parking brake and is used with cam and wedge-type foundation brakes.
Spring Break Valve
A device that limits the hold-off pressure to the spring-brake chambers via a relay valve or quick release valve.
A device that provides a modulated spring-brake application to the front axle proportional to the service braking pressure whenever a loss of pressure occurs.
Spring Chair
A term used for axle seat.
Spring Energized
A one-way roller clutch that has the rollers held in contact with the cam and race by individual springs, or by means of a spring-actuated cage.
Spring Eye
The main spring-leaf end that is formed in an O-shape for placement of the rubber spring-mounting bushings.
Spring Hanger
The vehicle-frame bracket for the eye at the front of the rear leaf spring.
Spring Leaf
A long, flat section of spring steel making up all or part of a leaf spring.
Spring Leaf Insert
Small, replaceable composition pads placed between the spring leaves near the ends to aid in slippage between the leaves while they are flexing.
Spring Load
A measure, in pounds or kilograms, of how much weight a spring can support, generally at the installed height.
Spring Oscillation
Continued compression and rebound motion of a spring, after the wheel has encountered a bump or hole on the road surface, which diminishes gradually, depending on the condition of the shock.
Spring Pin
A small piece of metal rolled in a pin-like manner that is used to dowel small parts that may occasionally have to be disassembled and reassembled.
Spring Rate
The relationship of spring deflection to load applied, such as the amount of weight, in pounds per inch or newtons per millimeter, required to deflect the rear spring.
Spring Retainer
The element which locates and provides reaction for the spring in a one-way roller clutch.
Spring Sag
The loss of spring load due to overloading and/or metal fatigue.
Spring Seat
The recess in a chassis where a coil spring is mounted.
Spring Shackle
A small, swing-arm attachment at the rear of the leaf spring to allow the spring to flex.
Spring Torque Windup
A term used for a Hotchkiss drive.
Spring Walk
The tendency of a valve spring to bounce around in its seat at high-engine speed.
Spring Windup
The slight S-shape assumed by the leaf spring during extreme acceleration and braking that may be controlled by traction bars on high-performance vehicles.
Springy Thingy
A dragster that has a light, flexible structure to allow for maximum weight transfer.
Sprint Car
A single-seat, front-engine car designed for short oval tracks.
Sprint Race
A short race of a few laps on an oval track.
A sheet-like disk with teeth around its outer perimeter that mesh with a belt or chain.
Sprocket Pitch
The dimension between the centers where the rollers would be bedded against the bottoms of adjacent tooth spaces.
Sprocket-Pitch Diameter
The pitch diameter of a sprocket used in a synchronous belt drive that coincides with the belt pitch line and is always greater than the sprocket outside diameter.
Sprung Weight
The mass of the vehicle that is supported by the springs, including the body, engine, and transmission.
Spun Bearing
Any bearing on the crankshaft that has seized on the journal and turned in the housing bore.
Spur Gear
A transmission or differential gear having teeth cut straight across its face, parallel to the rotational axis.
A light, two-person, horse-drawn carriage.
A light, two-person sports roadster.
Square Engine
An engine in which the bore and stroke dimensions are the same.
Squash Area
A term used for quench area.
The tendency of the rear end of a vehicle to press down on its springs during hard acceleration.
A high-pitched noise of short duration.
A continuous high-pitched noise.
A flexible rubber block used to apply glazing putty and light coats of body filler.
A metal-backed rubber blade having a handle used to clean windshields.
A driver that cannot handle a vehicle very well.
Poor handling.
Squirt Hole
A hole in the side of a connecting rod in an OHV engine which squirts oil toward the camshaft.
A hole in the pin end of a connecting rod to squirt oil to the underside of a piston for cooling.
Squirt Racing
A term used for drag racing.
The action where some compressed air/fuel mixture is pushed out of a decreasing space between the piston and cylinder head of the combustion chambers in some engines.
An abbreviation for street roadster.
An abbreviation for Street Rod Equipment Association, now known as Street Rod Market Association.
An abbreviation for Street Rod Market Association.
An abbreviation for single rear wheel.
An abbreviation for stainless steel.
An abbreviation for Super Stock, Sports Sedan, and Showroom Stock.
An abbreviation for the Suspension Specialists Association.
An abbreviation for the Service Station Dealers of America.
Stabilize Bar Link
A device that connects the lower control arm to the stabilizer bar.
A device that uses the torsional resistance of a steel bar to reduce the roll of a vehicle and prevent too great a difference in the spring action at the two front wheels.
Stabilizer Bar
A long, spring-steel bar attached to the cross member and interconnects the lower control arm that twists like a torsion bar during turns to transmit cornering forces from one side of the vehicle to the other to help equalize wheel loads and prevent excessive leaning.
Stabilizing Ball Joint
A term for non-load-carrying ball joint.
Stacked Pattern
A term used for raster pattern.
A term used for velocity stacks.
To place a competition vehicle in a proper starting position.
Staged Turbos
Turbochargers in series, one feeding the other.
Staggered Timing Camshaft
A camshaft ground so as to provide a longer duration for the cylinders farthest away from the main intake tract to equalize the amount of fuel mixture reaching all of the cylinders.
Staging Area
The area between the pits and starting line in drag racing where the cars are lined up.
Steam Holes
Passages designed to permit the flow of steam in an engine cooling system in hot spot areas where steam is expected to collect.
Steam Rollers
Huge drag-racing slicks.
Steel Shim Gasket
The same as a corrugated metal gasket.
Wheels made of a ferrous material.
Steering Arm
An arm that is attached to the steering knuckle that turns the knuckle and wheel for steering.
Steering Axis
The vertical line through the centerline of the upper and lower pivot- or ball-joints on a steered wheel.
Steering Axis Inclination
The angle of a line through the center of the upper strut mount and lower ball joint in relation to the true vertical centerline of the tire, viewed from the front of the vehicle.
Steering Brake
A braking system that provides separate control for the left and right rear wheels as an aid in steering around curves and/or correcting a pull to either side in some off-road vehicles.
Steering Column
Tubing through which the steering shaft mounts and rotates, providing a surface for the mounting of the hazard switch, turn signal switch, ignition switch, and transmission selector or shifter.
Steering Column Shift
An arrangement where the transmission shifter is mounted on the steering column.
Steering Drift
The tendency of the steering to gradually drift to either side when the vehicle is driven straight ahead on a smooth, level road surface, generally caused by improper caster or camber or an under-inflated tire. Also known as steering pull.
Steering Gear
The assembly that converts motion from the steering column to the pitman arm.
Steering Geometry
The relationship of the steering linkage and the wheels to the road affected by caster, camber, scrub radius, steering offset, toe in, and toe out.
Steering Kickback
The shock felt in the steering wheel as the front wheels encounter obstructions in the road.
Steering Knuckle
The part around which each front wheel pivots as it is steered.
Steering Linkage
The assembly of tie rods, idler arms, and links that transfer steering motion from the steering gear box to the steering spindles with the rods, pivoting joints, and supporting parts that transfer steering motion from the pitman arm to both knuckle arms.
Steering Lock
A locking device on the steering column that prevents steering wheel rotation and/or selector lever motion unless unlocked using an ignition key.
Steering Offset
A term used for scrub radius.
Steering Pull
The tendency of the steering to gradually pull to the right or left when the vehicle is driven straight ahead on a smooth, level road surface, generally caused by improper caster or camber or an underinflated tire. Also known as steering drift.
Steering Ratio
The ratio of the worm to the sector.
The ratio of the rack to the pinion.
Steering Sector
A term used for sector gear.
Steering Shaft
A shaft that extends from the steering wheel toward the gearbox through the steering column.
Steering Spindle
A term used for spindle.
Steering System
The mechanism that permits the driver to change vehicle direction by turning a wheel inside the vehicle.
Steering Terminology
Terms that apply to steering, such as bump steer, memory steer, steering pull, steering wander, and torque steer.
Steering Wander
The tendency of the steering to pull to the right or left when the vehicle is driven straight ahead on a smooth road surface that may be caused by improper caster adjustment.
Steering Wheel
The wheel, located at the top of the steering shaft, which the driver uses to steer the vehicle.
Steering Wheel Centering
The procedure of turning both tie-rod couplings equally in the proper direction to correctly position the steering-wheel spokes, and placing the steering gears on their high (center) position.
Steering-and-Ignition Lock
A device that locks the ignition open and, at the same time, locks the steering wheel in position so it cannot be turned.
A tradename for a very hard alloy made from cobalt (Co), chromium (Cr), and tungsten (W) used for valve-seat inserts.
Stem-Type Service Valve
A service valve requiring a special wrench be affixed to a stem for opening and closing.
A condition where the valve radius section has corroded to the extent that it has a smaller diameter than the stem.
The raised portion of a chassis providing added clearance over the axle.
A term used for stepped flywheel.
A raised portion on one part so another part can be joined to it.
Step Ratio
A transmission with steps or gear ratios, such as four steps for a four-speed transmission.
Step Side
The tradename of a popular pickup truck by Chevrolet.
Stepless Transmission
A transmission without gears that goes from low gear to overdrive without meshing gears.
Stepped Flywheel
A flywheel having a ledge to which a pressure plate is attached.
Stepped Resistor
A resistor having two or more fixed-resistance values.
A resistor assembly having a switch that is wired in series to increase/decrease the circuit resistance thereby controlling an electrical motor speed.
A medical-type listening device used to detect and isolate noises within an engine while it is running.
A camshaft.
A term used for stick shift.
Stick Shift
A manual transmission.
A measure of the dynamic elongation of a belt under tension.
A slightly conical pipe used as an exhaust resonator to which individual headers feed, such as at the top of a high-performance Volkswagen Beetle engine.
Stirling Engine
A type of internal-combustion engine where the piston is moved by changes in pressure of the alternately heated and cooled working gas.
A factory-manufactured vehicle having standard design, parts, and color.
Stock Car
A regular production vehicle.
A production vehicle modified to NASCAR standards for racing.
Stoichiometric Ratio
The ideal air to fuel ratio of 14.7:1, in terms of mass, to achieve the most complete combustion possible in an internal-combustion engine.
Excited or enthused.
Stop Solenoid
A term used for idle-stop solenoid.
Stoplight Switch
An electrical device used to illuminate the stoplights when the brakes are applied.
Lights at the rear of a vehicle that are illuminated when the driver applies the brakes to slow or stop the vehicle. Also known as brake lights.
Stopping Distance
The distance required to stop a vehicle based on speed, reaction time, and road conditions.
Storage Battery
A device that stores electrical energy in chemical form and produces that electrical energy when required.
To perform very well.
Originally, a 1929 Chevrolet; now any Chevrolet vehicle or engine.
A brand name for a popular oil or fuel additive.
An abbreviation for standard temperature and pressure.
Moving or continuing in one direction without turning.
Not curved or bent.
A straight stretch in a closed race course.
Straight Cut Gear
A term used for spur gear.
Straight Eight
An inline, eight-cylinder engine.
Straight Flexible Hose
A term used for flexible hose.
Straight Four
An inline, four-cylinder engine.
Straight in Damage
Damage caused by one vehicle hitting another vehicle directly or straight on.
Damage caused by hitting the wall nose first in closed-course racing.
Straight Six
An in-line, six-cylinder engine.
A straight stretch in a closed race course such as the front and back straightaway at Indy.
A metal bar used to check the engine block deck and cylinder head for warpage.
A condition where all elements of a surface or an axis are in a straight line.
Stranded Wire
A conductor made up of several small wires twisted together.
To layer or to have in layers.
Stratified Charge
A type of combustion having a small amount of rich air/fuel mixture near the spark plug with a leaner mixture throughout the remainder of the combustion chamber.
Stratified-Charge Engine
An engine in which each cylinder has two combustion chambers connected by a small passage; the smaller prechamber contains the spark plug and receives a rich mixture while the main chamber receives a lean mixture which is ignited by a flame front from the prechamber.
An upper portion of the atmosphere that extends 10 to 30 miles (16 to 48 km) above the surface of the Earth.
Stratospheric Ozone Layer
A layer extending from 6 to 15 miles (9.7 to 24.1 km) above Earth's surface, protecting the Earth from ultraviolet (UV) rays from the sun.
A specific class vehicle with a fully enclosed body, including the wheels, for dry-lakes racing.
A racing car with an aerodynamically enclosed body.
The shaping of a vehicle body so as to minimize air resistance.
Street Legal
A vehicle which is driven legally on a public street or highway.
Street Machine
A custom-built vehicle or hot rod built for street use.
Street Racing
Racing done on public streets. It is usually illegal.
Street Roadster (SR)
A hot rod with roadster body work built for street use.
A specific category of drag racer having pre-1937 roadster body work.
Street Rod
A hot rod built for street use based on a pre-1949 car or light truck.
Street Rod Equipment Association (SREA)
An association now known as Street Rod Market Association.
Street Rod Market Association (SRMA)
A street rod division of SEMA.
The left-hand side of a vehicle.
Stress Relieve
An engine block that has been relieved of the stress caused by casting and machining.
Stress Riser
An area of a part that is most likely to crack due to mishandling and/or misuse.
A luxury sedan that has been lengthened and made into a limousine.
Stringer Bead
A type of weld bead made without appreciable weaving motion.
Thin paint or decal stripes added to the paint work.
A vehicle, sometimes stolen, from which parts have been removed for resale.
The lowest price vehicle in the line.
A chemical used to remove paint.
Short term for stroboscope.
An instrument used in the study of the rapid revolutions or vibrations of a body by rendering it visible at frequent intervals with a flash of light.
The distance traveled by the piston from top dead center (TDC) to bottom dead center (BDC).
To increase the stroke in an engine.
To drive carefully or treat gently.
An engine that has been stroked.
A camshaft used to stroke an engine.
Stroker Kit
A special crankshaft and connecting rod kit used to increase the displacement of an engine by lengthening the stroke of the pistons.
Components connected from the top of the steering knuckle to the upper strut mount that maintain the knuckle position and act as shock absorbers to control spring action in a vehicle's suspension system. This is used on most front wheel drive cars and some rear wheel drive cars.
Strut Actuator
An electronically controlled actuator that controls strut firmness in a computer-controlled suspension system.
Strut Adjusting Knob
In an adjustable strut, an eight-position adjusting knob which can vary the strut orifice opening, generally accessible without having to raise the vehicle.
Strut Cartridge
A self-contained unit with a pressure tube and a piston rod assembly, factory sealed and calibrated.
Strut Rod
A heavy steel rod in the suspension system located ahead or behind a lower control arm. A strut attached between car framework and lower control arm outer end on many vehicles to determine fore-and-aft position of the outer arm.
Strut Suspension, MacPherson
See MacPherson strut.
Stub Axle
The short shaft upon which the wheel hub and bearings ride.
Stub Frame
A term used for sub frame.
A round, bolt-like metal fastener with threads on both ends.
Stud-Mounted Rocker Arms
Individually mounted rocker arms with the use of a stud and ball.
Studded Tires
Tire that provide improved traction on ice, but are prohibited by law in many states because their use resulted in road-surface damage.
A supercharger.
The tendency of an engine to falter and catch resulting in a hesitation.
A momentary abrupt deceleration during acceleration.
Sub Frame
A partial front or rear chassis frame often used in unibody design to support engine or suspension assemblies.
Sub-EGR Control Valve
A vacuum valve used on Chrysler/Mitsubishi 2.6 liter engines that is operated mechanically by means of the throttle linkage, so it varies the signal to the exhaust-gas recirculation valve according to the position of the accelerator pedal.
A self-contained group of parts or electrical components that are a part of the whole overall assembly.
A section of liquid line used to ensure that only liquid refrigerant is delivered to the metering device; may be a part of the condenser or may be placed in the drip pan of the evaporator.
The cooling of a liquid below its condensing temperature.
Submerged Arc Welding (SAW)
A process where a weld is made by feeding a bare wire into a blanket of grandular fusible flux.
The supporting structure in a catalytic converter where the catalyst is applied.
A large truck-based station wagon marketed by Chevrolet and GMC.
Suction Accumulator
A term used for accumulator.
Suction Accumulator/Drier
A term used for accumulator.
Suction Line
The line connecting the evaporator outlet to the compressor inlet.
A low-pressure line in a system usually used as a return line.
Suction Manifold
The point where vapor enters a compressor.
Suction Pressure
Compressor inlet pressure.
Suction Service Valve
A term used for low-side service valve.
Suction Side
That portion of a system that is under low pressure.
Suction Throttling Valve
A back-pressure regulated device that prevents freeze-up of the evaporator core.
Suction-Line Regulator
A device used to regulate the pressure in the suction line.
Suicide Doors
Vehicle doors that are hinged at the rear and open from the front.
Suicide Front Axle
A special spring and front axle design for early Fords.
Suicide Front End
A term used for suicide front axle.
Sulfated Battery
A battery condition where sulfate has built up on the plates to the extent that it can no longer be charged.
The lead sulfate that builds up on a battery as a result of battery action that produces electric current.
Sulfur Oxides
Small amounts of acids (SOX) that forms as a result of a reaction between the hot exhaust gas and the catalytic converter catalyst.
Sulfuric Acid
An electrolyte used in batteries.
The bottom part of some compressors that contains oil for lubrication of the moving parts of the compressor.
The reservoir for oil at the bottom of an engine.
Sun Gear
Central gear the planet gears mesh with and revolve around.
Heat intensity and/or light intensity produced by the sun.
Sunload Sensor
A sensor placed on the dashboard to determine the amount of sun coming into the vehicle; a device that senses heat and/or light intensity.
A term for supercharger.
Super Car
A term used for the early muscle car.
An ultra-powerful, expensive, limited-edition vehicle such as a Ferrari.
Super Stock (SS)
An American factory-production vehicle that meets NHRA drag rules and performance ratings.
Super Tape
Duct tape.
Super-Duty Parts
High-performance heavy-duty parts.
Super-Stock Eliminator
Any vehicle running under the NHRA index/handicap system.
A compressor which pumps air into the engine's induction system at a pressure much higher than atmospheric pressure.
The heat intensity added to a gas after the complete evaporation of a liquid.
Superheat Switch
An electrical switch activated by an abnormal temperature-pressure condition, such as a superheated vapor, used for system protection.
Superheated Vapor
Vapor at a temperature higher than its boiling point for a given pressure.
A high-banked, paved track at least 1 mile (1.6 kilometers) long.
Supplemental Brake System
An additional brake system used to assist the service-brake system in retarding a vehicle.
Supporting Career
A career path that is related to auto mechanics, such as careers in claims adjusting, vocational teaching, auto-body repair, frame and alignment repair, and specialty repair shops.
A limited-slip differential by Chrysler.
Surface Finish
The roughness or smoothness of a surface.
Surface Ignition
The ignition of the air/fuel mixture in a combustion chamber by heated metal or carbon deposits.
Surface Loading
The transfer of pressure as one part acts on another.
The application by welding, brazing, or thermal spraying of a layer of material onto a surface to obtain desired properties or dimensions.
A condition where the engine speed increases and decreases slightly with no throttle action.
Surge Bleeding
A brake-bleeding technique designed to dislodge air from wheel cylinders by creating turbulence in the wheel cylinder.
Surge Tank
The reservoir of a cooling system where coolant condenses before being returned to the radiator.
The ability of a fluid to suspend heavier dirt particles rather than letting them fall to the bottom.
The system that supports the weight of the vehicle and provides for a comfortable and safe ride for the driver and passengers.
Suspension Arm
An arm pivoted on the frame at one end and on the steering-knuckle support on the other end.
Suspension Specialists Association (SSA)
A trade association of heavy-duty service facilities and suppliers.
Suspension System
Components that support the total vehicle, including front and rear suspensions, springs, shock absorbers, torsion bars, axles, MacPherson strut system, and connecting linkages.
An abbreviation for sports utility vehicle.
A trade name for duPont's new generation of ozone-friendly refrigerants. R-134a is a SUVA refrigerant recommended for automotive use.
Swaged End
A tube or pipe having an inside diameter that has been stretched to accept the outside diameter of another tube or pipe that is the same size.
To reduce or taper.
To replace one component with another.
To trade components or vehicles.
Swap Ends
To spin a vehicle a full 180 degrees.
Swash Plate
An angular plate attached to the bottom of the four pistons on a Stirling engine. As the pistons move downward, the swash plate is turned.
A mechanical system that is used for pumping, having an angled plate attached to a center shaft, and pistons that are attached to the plate along the axis of the shaft. As the shaft rotates, the pistons move in and out of a cylinder, producing suction and pressure.
Swash-Plate Compressor
A compressor in which the pistons are driven by an offset (swash) plate affixed to the main shaft, such as the six-cylinder air-conditioning compressor.
Sway Bar
A bar on the suspension system that connects the two sides together. It is designed so that during cornering, forces on one wheel are shared by the other.
Sway-Bar Link
A connector from the lower control arm to the sway bar.
A term used for purge.
Swing Attachment
A leaf-spring shackle.
Swing Axle
A drive system used with independent rear suspension systems.
Swing Pedals
Pedals that are suspended from beneath the dash, such as clutch, brake, and accelerator.
A cylinder-head design that causes the air/fuel mixture to enter the combustion chamber at a high rate of speed, increasing its atomization.
An electrical device that controls the on and off of a sub-system or system.
Swivel Foot
A valve-adjusting screw having a ball that swivels when it contacts the valve stem.
Corresponding in size, form, and relative position on opposite sides of a line, plane, point, or axis.
Symmetrical Camshaft Lobes
Camshaft lobes having identical opening and closing ramps.
Symmetrical Rear-Leaf Spring
A term used for rear-leaf spring.
The trade name for an all-wheel drive system by Volkswagen.
A type of manual transmission where the synchronizer is used to bring a selected gear up or down to the speed of the main shaft.
Synchromesh Transmission
A transmission having a synchronizer.
To cause two or more events to operate at the same time and/or the same speed.
A device used in a manual transmission to bring a selected gear up or down to the speed of the main shaft.
Synchronous Belt
A belt having cogs or teeth that mesh in mating cogs or teeth of a pulley.
A term for synthetic fuel.
Synthetic Fuel
A fuel made by liquefying coal or by extracting oil from shale or tar sands.
Synthetic Oil
A type of engine lubricant consisting of highly polymerized chemicals.
A non-mineral based lubricant for use in automotive air conditioners.
System Overcharge
A term used for an overcharged system.
System Pressure
The average pressure in a system, such as the fuel-injection system.
System Protection Valves
A device that is used to protect the brake system against accidental loss of air pressure, buildup of extreme pressure, or backflow and reverse air flow in a truck braking system.
System-Dependent Recovery System
Refrigerant recovery system that relies on system components, such as the compressor, to remove the refrigerant from the system.® ©2001- 2020  AutoZone, Inc. All Rights Reserved.