Dictionary of Automotive Terms Abbreviations

DICTIONARY OF AUTOMOTIVE TERMS - "Si"

SI

Acronym for spark ignition
Acronym for SI Units (Système international d'unités)

Siamesed: Arrangement of ports when intake or exhaust valves are in pairs which allows two-into-one passages to be cast into the cylinder head. For example, with the usual valve arrangement in a four-cylinder engine the head can be designed so only two ports connect to the intake manifold and only three to the exhaust manifold. Also, when the engine cylinders are connected solidly together (as in the Vega block) instead of being totally surrounded by water jackets, the cylinders are said to be siamesed.

SIC: Acronym for Standard Industrial Classification on "http://strategis.ic.gc.ca/SSGF/am00655f.html". Industry class that represents a level of organization of production by type of specialization. Currently the 1980 Standard Industrial Classification is in effect identifying each industry at the 4 digit level. The term has been replaced by NAICS

SID: Acronym for side impact dummy

Siddeley: See
Armstrong-Siddeley.

Side: See
differential side gear
discharge side
exhaust side
federal side impact standard
heavy side pattern
high side
low side
outlet side
piston ring side clearance
rear side window
ring side clearance
suction side

Side aperture panel: See
aperture panel

Side bumper panels: Large plastic body side moldings attached to the lower body sides which protect the body against road debris, road salt corrosion, and mechanical impact. Sometimes called Sacco panels because they were introduced by Bruno Sacco, the chief designer at Mercedes-Benz

Sidecar

An addition to a motorcycle which is added to its side. It has an outboard wheel and is designed to carry a passenger or luggage.
Small carriages attached to the side of a motorcycle to provide extra carrying capacity.

Side clearance: See
piston ring side clearance
ring side clearance

Side curtain: The early name for side windows which were made of celluloid in a rigid frame supported by the sides of the body and the doors; some had a hinged flap through which the driver could extend his hand for signalling purposes. On classic roadsters, the entire assembly of sliding windows and flaps; wedge-type side curtains permit the side curtain brackets to be wedged into the door plates without bolts; regular spring-type side curtains are mounted to the doors by means of wing nuts or bolts. The curtains can be stored behind the rear seat squab or in a pocket at the back of the front seats

Side cutters: A tool like a pair of pliers except the end opposite the handles have sharp edges used to cut wire, etc. The British term is end cutters or end cutting pliers

Sidedraft carburetor: A carburetor in which the air passes through the carburetor into the intake manifold in a horizontal plane. Contrasts with a downdraft carburetor.

Sidedraught carburetor: British spelling for sidedraft carburetor

Side electrode: The ground electrode at the side of the threaded part of a spark plug shell

Side flasher: A small amber or red signal light located in the side of the front or rear fenders

Side gear: See
differential side gear

Side-hung float: Float design has a pivot axis that is perpendicular to the vehicle axles. It has slightly better float control and fuel handling during acceleration and braking than its center-pivoted counterpart

Side impact: See
federal side impact standard

Side impact air bag: Fabric bags installed in the doors of some cars that inflate rapidly during a side impact collision. Inflation occurs at speeds of 12 miles per hour or higher, preventing passengers from hitting their heads against the windows or pillars of the car.

Side impact bar: A longitudinal reinforcing beam in a car door, designed to withstand side impact. Also called side impact intrusion beam

Side impact dummy: (SID) A dummy developed to investigate the effects of side impact crashes

Side impact intrusion beam: A metal beam in the door or along the side of the passenger compartment that adds additional protection in the case of an accident. It reinforces the side of the car.

Side impact standard: See
federal side impact standard

Sidelamp: See
sidelight

Side-lift jack: See
tower jack

Sidelight: A low-intensity white lamp usually located on the side of front fender ahead of the front wheel. It is usually illumined in a steady glow when the signal lights are activated.

Sidelight pod: A design feature of older cars that had their side or parking lights incorporated into a separate sheet metal molding on top or at the side of the front fenders

Side marker lamp: A low-intensity lamp mounted on the side of a vehicle to indicate its presence when seen from the side

Side marker light: A low-intensity lamp mounted on the side of a vehicle to indicate its presence when seen from the side

Side member: A box-section member inboard of the outer sill that often runs from the front to the rear of the car and provides reinforcement of both sides of the floorpan

Side molding: See
body side molding

Side panel

A quarter panel between the B-pillar and the rear.
An aperture panel.
A vertical panel on the inside of a body shell, e.g., the panel joining the lock pillar to the rear wheel housing.

Also See
cowl side panel
scuttle side panel

Side pattern: See
heavy side pattern

Side pipe: An exhaust pipe running along the side of the car. Compare lakers or lakes pipes

Sidepull brake: A bicycle brake where the cable attachment is on one side rather than in the middle

Side radiator guard: A molded cover panel fitted to the sides of the radiator to protect it from water splashes

Side rail: See
side member

Side ring: A demountable metal flange to hold the tire on the rim base. It can be self contained, locking into the gutter, or may be held in place by a lock ring, depending on the type.

Side rod: See
tie rod

Side scoop: An air intake for the engine and/or for cooling on mid-engine or rear-engine cars; typically found on sports cars such as the Ferrari range

Side shaft: See
axle shaft

Side shake: See
end play

Side shift: Damage to the frame when the vehicle has been hit from the side

Side skirt: An extra body panel fitted over the sills (for cosmetic reasons only)

Side step: A step plate below the doors to facilitate entry into the relatively high cabin of a commercial vehicle

Side styling: See
straight-through side styling

Sideswipe

Body damage caused by a car hitting an obstacle at an acute angle, causing the panels to be dented over a relatively large area.
To scrape along the side of a car.

Side valve: Valves positioned at the side of cylinder

Side-valve engine: (SV) An engine with the valves to the side of the cylinders

Sidewall: That portion of a tire between the tread and bead. See tire sidewall.; [2] The vertical part of the box section of a side member

Side window: See
rear side window
sliding side window

SI engine: A spark ignition engine or gasoline engine internal combustion engine of the reciprocating type in which an air/fuel mixture is compressed and then ignited by an electric spark. It is unlike a diesel engine

Sight glass: A viewing glass or window set in the refrigerant pipe of a car's air-conditioning system, usually in the top of the receiver-drier, which allows a visual check of the refrigerant passing from the receiver to the evaporator. The fluid should be clear and free from foam; A glass window in the liquid line, the top of the receiver-drier, or a test manifold, for checking refrigerant flow.; Glass tube or glass window in refrigerating mechanism. It shows amount of refrigerant or oil in system and indicates presence of gas bubbles in liquid line.

Sighting point gauge: A device incorporating a sighting pin, used to measure car bodies for misalignment

Sigma welding: See
gas metal- arc welding

Signal

To indicate a change in direction (turning, stopping, etc.).
An indicator.

Also See
reversing warning signal
right hand turn signal

Signal amplifier: Any device, such as the booster venturi, that amplifies a vacuum signal

Signal indicator: See
turn signal indicator

Signal light: The small lights which blink on either side of the front of the vehicle and either side of the rear of the vehicle. Some early cars (like the Austin and Flying Standard) had small illuminated arms that flipped out from the B-post instead. The purpose of signal lights is to warn other drivers of a change in direction when turning a corner or changing lanes. Also called "direction indicator." In Japan they are called "winkers."

Signal light warning light: A light on the instrument panel which flashes when the signal lights are operating. Usually this light is in the shape of a green arrow. On some cars, like Cadillac, a secondary light is mounted in a pod on the upper edge of each front fender and in a pod inside the cab above the backlight (i.e., back window). Also called "direction indicator warning light."

SIG RTN: Acronym for Signal Return (sensor ground)

SIL: Acronym for shift indicator light

Silencer

A muffler.
A device in an air-conditioning system designed to minimize pumping sounds from the compressor.

Also See
air silencer
front silencer
straight-through silencer

Silencer shaft: See
balance shaft

Silencer-tailpipe tool

A chisel-type tool with several cutting edges to cut muffler sleeves without damaging tailpipes.
An L-shaped tool whose short end is driven between the silencer and tailpipe to break the bond

Silent chain

A quiet timing chain with V-shaped teeth
A type of chain with teeth formed on its links to engage with the teeth in the sprockets. Silent chains drives are not truly silent. The links in a silent chain drive, however, engage with the sprocket teeth with little impact or sliding, and as a result a silent chain produces less vibrations and noise than other chains. The amount of noise generated by a silent chain drive depends of many factors including sprocket size, speed, lubrication, load, and drive support. A link belt silent chain includes removable links joined by rivets or interlocking tabs. These chains offer the advantage of installation without dismantling drive components, reducing inventory, and increasing temperature ranges. Also called inverted-tooth chain

Silica: A common mineral (silicon dioxide) found as sand, quartz, etc., used in the manufacture of glass, ceramics and abrasives

Silica gel

A form of silica capable of absorbing large quantities of water, used to keep electronic apparatus, etc., dry
A highly absorbent drying agent, usually located in the accumulator or receiver-drier, used to remove moisture from refrigerant.
Absorbent chemical compound used as a drier. When heated, moisture is released and compound may be reused.

Silica sand: A form of silica used for sherardizing or mechanical plating

Silicon

A non-metallic chemical element occurring in several forms (principally sand and rock), used in the manufacture of glass and steel (as well as transistors etc.)
A semiconductor material made from silica, purified for photovoltaic applications.

Silicon carbide: A material of excellent abrasion and corrosion resistance used in bearings and mechanical seals

Silicon-controlled rectifier: (SCR) Electronic semiconductor which contains silicon. Controls current by timing pulses.

Silicone: A silicon compound with a high resistance to heat, water, and chemicals, and with good insulating and lubricating properties; used in oils, polishes, sealants, etc.

Silicone adhesives: Adhesive compounds of this base have remarkable stability through a wide temperature range. Chief limitations in present use are their high temperature cure, sensitivity to fuels, and relatively high cost. Outstanding high temperature (above 149°C) and low temperature (-73°C) performance have been reported. Highly resistant to oxidation, to ozone, and to corona radiations. Very good dielectric properties.

Silicone brake fluid: A brake fluid which does not absorb water

Silicone-rubber sealant: A semi-liquid sealant which keeps out oil and water but not gasoline. Also called RTV sealant

Silicon glove: See
barrier cream

Silicon steel: An alloy of silicon and chromium with steel, often used for exhaust valves

Sill

A longitudinal box-section member of the body shell at floor level, located below the doors.
A box-section crossmember just below the lower edge of the trunklid (when closed).

Also See
door sill
inner sill
outer sill

Sill cover: A non-structural part covering the sill on its entire length; used on certain designs with separate chassis but also on unitary designs

Sill end piece: A small panel at the front and rear end of the sill that closes off the hollow sill section towards the front and rear wheel arches. Compare closing panel

Sill membrane: A horizontal stiffening panel between the outer sill and the side member box section; it is ribbed or drilled for extra rigidity

Sillment seal: A gas-tight seal between center electrode of a spark plug and insulator and between insulator and shell

Sill panel: See
under sill panel

Sill stiffener: See
sill membrane

Sill structure: The overall design of the sills including outer sills, side member, or inner sill and sill membrane

Silver brazing: Brazing process in which brazing alloy contains some silver as part of joining alloy.

Silver-plating: The electrolytic deposition of silver

Silver solder: Similar to brazing except that a special silver solder metal is used. It is used primarily on bicycle tubing.

SIMA: Acronym for Special Import Measures Act.

Simple circuit: The simplest circuit includes an electrical power source, a load, and some wire to connect them

Simple tappet: See
flat tappet

Simplex chain: A chain with only one row of rollers.

Also See
duplex chain
triplex chain

Simpson gear set: It consists of two simple planetary gear sets with a common sun gear and internal gears of different diameter; the planet carrier of one set is fixed to the internal gear of the other set

Simpson planetary gear set: It consists of two simple planetary gear sets with a common sun gear and internal gears of different diameter; the planet carrier of one set is fixed to the internal gear of the other set

Sine wave, AC current: Wave form of single frequency alternating current; wave whose displacement is sine of angle proportional to time or distance.

Single

A small, lightweight motorcycles. What the bike lacks in overall power, it gains in its lightweight, small size that makes it easy to ride even if it has a large engine displacement.
Any single cylinder engine vehicle (especially, a motorcycle)

Single-acting: Having a piston or pistons of a reciprocating engine or pump that are pressurized on only one side

Single-anchor self-energizing brake: A type of servo brake where both shoes pivot about one fixed point

Single barrel: See
single-barrel carburetor.

Single-barrel: See
single-barrel carburetor.

Single barrel carburetor: See
single-barrel carburetor.

Single-barrel carburetor: A carburetor with one throttle opening or barrel from the carburetor to the intake manifold.

Also See
carburetor
double-barrel carburetor
and four-barrel carburetor

Single bead: A tire built with only one wire bundle in the bead.

Single-bed 3-way catalytic converter: A converter for the control of HC, CO, and NOx emissions, consisting of one three-way catalyst; in combination with an oxygen sensor, this type of converter yields the lowest emission values

Single-bed oxidizing converter: A converter with one catalyst bed for HC and CO control

Single brake system: A brake system using only one hydraulic circuit for all wheels.

Single cell test: A test of the fuel cell performance based on one unit cell. The test is typically a laboratoryscale test in which several variables can be adjusted in order to obtain data over a wide range of conditions, such as temperature, current density, fuel and oxidant flow rates, etc. The outcome of a single cell test may be a polarization curve, a voltage stability plot, or other data related to fuel cell performance.

Single-circuit braking system: An old form of hydraulic braking system in which a single circuit serves all four brakes. Not to be confused with single-line braking system

Single-circuit line: A transmission line with one electric circuit. For three-phase supply, a single circuit requires at least three conductors, one per phase.

Single coat: A coat of paint, with each stroke overlapping the previous stroke by 50%. Also see double coat

Single-coil twin ignition: In the early days of straight eight engines, a distributor with two sets of contact points, firing alternately

Single-connector system: An electrical circuit, where only one wire comes from the voltage source to the load. To complete the circuit, the electricity uses the metal body of the vehicle

Single crystal silicon

(Czochralsky) An extremely pure form of crystalline silicon produced by dipping a single crystal seed into a pool of molten silicon under high vacuum conditions and slowly withdrawing a solidifying single crystal boule (rod) of silicon. The boule is sawed into thin silicon wafers and fabricated into single-crystal photovoltaic cells.
Silicon cells with a well-ordered crystalline structure consisting of one crystal (usually obtained by means of the Czochralsky growth technique and involving ingot slicing), composing a module. Ribbon silicon is excluded.

Single-cut file: A file with teeth in only one direction and used for filing soft material

Single-cylinder engine: An engine with just one cylinder such as used on some motorcycles and utility engines (e.g., lawn mower engine, water pump, portable generator, etc.)

Single-decker bus: A bus with one storey or deck. See double-decker bus

Single-grade oil: Oil suitable for use within a narrow temperature range; outside this range, its flow characteristics will not allow adequate lubrication. Also called "straight-weight oil." Compare multigrade oil

Single leading brake shoe: The use of a single hydraulic plunger and a common pivot point which expands two shoes against the drum with equal pressure whether braking from forward or reverse direction. The leading brake shoe is usually called the "Primary Shoe" and trailing shoe is called the "Secondary Shoe." Also see double leading brake shoe.

Single-leaf spring: A suspension spring which has just one flexible beam

Single-line braking system: A braking system in which a single line is used to connect towing vehicle and trailer. It is not to be confused with single-circuit braking system

Single master cylinder: A master cylinder with only one pressure chamber, used in single brake systems.

Single overhead cam: (SOHC) The camshaft is located between the valves and is driven by a chain or belt from the crankshaft; the valves are normally opened by short rocker arms. See overhead cam.

Single-overhead cam: (SOHC) An engine with a single overhead camshaft to operate both intake and exhaust valves. See overhead cam.

Single overhead camshaft: (SOHC) The camshaft is located between the valves and is driven by a chain or belt from the crankshaft; the valves are normally opened by short rocker arms. See overhead cam.

Single-overhead camshaft: (SOHC) An engine with a single overhead camshaft to operate both intake and exhaust valves. See overhead cam.

Single phase electrical: A circuit energized by a single alternating electromotive force.

Single-phase motor: Electric motor which operates on single-phase alternating current.

Single-piece rim: A one-piece rim

Single-piece wheel: A one-piece wheel

Single-piston caliper: A disc brake caliper that has one hydraulic cylinder and piston, unlike calipers with two or four pistons.

Single-pivot steering: A steering system in which a beam axle is pivoted at its mid-point; rare except on horse-drawn vehicles and trailers. Also see double-pivot steering

Single-plate clutch: A normal type of clutch, with one driven plate; usually dry (i.e., without oil). Also see multi-plate clutch

Single point injection: (SPI) A gasoline fuel-injection system which sprays fuel under pressure into the intake air at one place, usually the throttle body on the inlet manifold. It is less complicated than a multi-point injection system but achieves better carburation than a carburetor. Also see multi-point injection

Single-pole, double-throw switch: (SPDT) Electric switch with one blade and two contact points.

Single-pole, single-throw switch: (SPST) Electric switch with one blade and one contact point.

Single rate spring: A spring with a constant spring rate. For example, if a 100-pound force deflects the spring by one inch, an additional 100 pounds will deflect it one more inch, and so on until the spring either bottoms or fails. The opposite of progressive rate spring.

Single roller chain: See
simplex chain

Single-Source Leasing: A service in which companies can lease both drivers and trucks from the same source, rather than having to procure them from different companies.

Single-spark ignition coil: In a distributorless ignition system with an odd number of cylinders, each cylinder requires its own ignition coil; distributor logic on the low-voltage side performs the voltage distribution to each coil. Also see multi-spark ignition coil

Single-stage compressor: Compressor having only one compressive step between inlet and outlet.

Single-throw switch single-pole: (SPST) Electric switch with one blade and one contact point.

Singletrack: A trail just wide enough for one person or bicycle

Single-tube shock absorber: A common type of shock absorber with the working cylinder and reservoir contained in one tube.

Also See
double-tube shock absorber
gas shock absorber

Single-wheel suspension: See
independent suspension

Single wire circuit: An electrical system in which the hot line is in a wire, but the ground line uses the frame.

Single wire system: Lighting circuit which uses car frame for return ground line

Sink: See
heat sink

Sink in: A tendency of a hardened filler to settle excessively, making the feather edges of the filled area stand out on the painted surface

Sinter

To manufacture parts from powdered metals by heating or pressure or both.
The fine powdered metal itself

Sintered bronze: Tiny particles of bronze pressed tightly together so that they form a solid piece. The piece is highly porous and is often used for filtering purposes.

Sintered metal brake pad: A type of brake pad made of sinter and is designed to reduce noise and increase performance and life.

Sintering: The process of fusing a metal-powder mixture together under high heat and pressure.

SIP: Acronym for State Implementation Plan

Sipe: Fine lines or grooves cut into the tread of tires. They allow the tire to flex and give better traction on wet surfaces. They may also reduce tire noise.

SIPS: Acronym for Side Impact Protections System

SIR

Acronym for Supplementary Inflatable Restraint
Acronym for Supplemental Inflatable Restraint

SIS: Acronym for Solenoid Idle Stop

Sissy bar: A chrome rail which projects up from the back of a motorcycle saddle.

Sister ships: Ships built on the same design.

SIT: Acronym for Spontaneous Ignition Temperature. The temperature at which an oil ignites of its own accord in the presence of air or oxygen under standard conditions.

Site: See
nucleation site

Sitting position: See
upright sitting position

SI units: System of coherent metric units (Système International d'Unités) proposed for international acceptance in 1960.

SI unit system: (le système international d'unités) Metric system of measurement adopted by most technical industries throughout the world.

Six: See
flat six
straight six
V-six

Six banger: Six cylinder engine.

Six-cylinder engine: An engine with six cylinders; may be in-line (a straight six) or in a V-layout (a V-6)

Six-light sedan: An old designation of a four-door body style that features another small quarter window behind the rear side doors, resulting in three side windows per side or six windows overall

Six-pack: Refers to a special triple two-barrel induction system used on some Chrysler V8 engine in the late 1960s and early 1970s. However, other special heavy-duty parts were used in engine that came from the factory equipped with this induction system, so "six-pack" is frequently used as an adjective to describe other engine components used on these engines. E.g., six-pack connecting rods

Six-speed: See
hurst six-speed shifter

Six-speed shifter: See
hurst six-speed shifter

Six-speed transmission: A manual transmission with six forward gears. See Hurst six-speed shifter.

Sixteen: See
V-sixteen

Sixteen valve engine: (16V) A four-cylinder engine with four valves to each cylinder. This system permits more air-fuel into the cylinder and exhaust out of the cylinder.

Size: See
die size
engine size
metric size
rim size

Size designation: See
tire size designation

Size marking: The first part of a tire marking molded on the sidewall, giving the tire's width in millimeters

Size markings: See
tire size markings