| Sail
panel |
Another
term for C-pillar. See C-pillar. |
|
|
| Saloon |
A
British term for sedan. See Sedan. |
|
|
| Sandblast
|
A
method of cleaning parts by spraying with a high-pressure stream
of sand particles. Mined and filtered silica sand which contains
sharp edges is typically used. The sand is typically loaded into
a sandblaster, or placed in a sandblast cabinet where the sand is
then forced through a ceramic nozzle by compressed air. Very effective
at removing rust and paint -- used widely by restorers and autobody
technicians. |
|
|
| Scavenge
pump |
The
pump which returns oil to the oil sump in a dry sump lubrication
system. |
|
|
| Scavenging |
A
method of creating a better "breathing" engine by drawing
exhaust gasses out of a cylinder using the momentum of flowing exhaust
gasses in an exhaust pipe. By tuning the exhaust system, the pulsing
waves of exhaust in the exhaust pipe can be used to help "draw"
the exhaust out of a cylinder. |
|
|
| Scoop |
See
Hood Scoop. |
|
|
| Scope |
Short
for Oscilloscope. See Oscilloscope. |
|
|
| Score |
A
scratch, ridge, or groove in a machined surface such as inside an
engine's cylinder, or on a bearing surface. |
|
|
| SCR |
Short
for Silicon-Controlled Rectifier. |
|
|
| Scrub |
See
Tire Scrub. |
|
|
| Scrub
radius |
See
Steering effort. |
|
|
| Scuffing |
Undesirable
rough marks on a piston and/or cylinder wall caused by lack of lubrication
between the two. |
|
|
| Scuff
plate |
A
metal or plastic cover that is screwed to the bottom of a door jamb
and protects the paint from becoming scuffed (and unsightly) from
passengers shoes while getting in and out of a vehicle. |
|
|
| Scuttle |
Another
term for Cowl. See Cowl. |
|
|
| Sealed
beam |
A
sealed headlight unit, typically made of quartz glass, and contains
a filament and inert gas inside. The whole unit must be replaced
if it becomes damaged or burns out. The square and round light bulbs
used on older automobiles. |
|
|
| Seam
sealer |
A
rubberized caulk-like product used widely around automobiles to
seal sheetmetal body seams during the manufacturing process to prevent
future rust and corrosion of body panels and the floorpan. Used
to seal seams at the inside edges of doors, separate panels on pickup
truck beds and on floorpans. After many years of exposure the seam
sealer can crack or peel away allowing moisture to enter critical
seam. Leads to rust on door bottoms and other critical seams. Autobody
shops usually apply new seam sealer to seams after installing new
panels or making panel repairs. Also see Body replacement &
repair panels and Sheetmetal. |
|
|
| Seat |
A
machined surface which another part rests against. Typically applied
to valve seat -- a machined portion of the cylinder head where
a valve rests. Also see: Valve
A
padded and upholstered chair or bench in the passenger compartment
which passengers ride on. Seats come in a variety of styles such
as bench (split back, 50/50 split, 60/40 split, 70/30 split, built
in head rests, etc.); bucket seats (low back, high back, head
& shoulder support, integral head rest and captains chairs)
and rear seats (folding back, 50/50 split, buckets, captains chairs
and those with built in headrest).
Reclining
bucket seats allow the passenger to recline the seatback. Some
allow the passenger to recline nearly horizontally.
Split
bench seats usually include a padded armrest between the seats
and may also have reclining seatbacks. A 60/40 split bench is
split with 60% of the seat for passenger use, 40% for the driver.
It allows the drivers and passengers to adjust their seats independently
yet still carry three persons in the front seat.
|
|
|
| Seat
back |
The
upright portion of a seat which supports an occupant's back and
shoulders. Also see Backrest. |
|
|
| Seatback
angle |
The
angle (from vertical) of a seat backrest. Measured in degrees. Most
bucket seats allow drivers and passengers to adjust the seatback
angle. |
|
|
| Seat
belt |
A
device used to restrain occupants in the event of an accident. Most
seat belts are of the 3-point design which consists of a lap belt
and shoulder strap that connects to three point on the chassis.
Seat belt use significantly reduces occupant injury caused by collisions. |
|
|
| Seat
cushion |
The
lower, horizontal portion of a car seat. Supports the occupant's
thighs and buttocks. |
|
|
| Secondary
brake shoe |
The
rear or "trailing" brake shoe used in a drum brake system.
Due to servo action that occurs when brakes are applied, the primary
shoe causes the secondary shoe to apply itself even tighter against
the drum. See Primary Shoe for more information on servo action. |
|
|
| Section
height |
The
distance from the rim seat to the tire's tread surface of an inflated
tire. Measured anywhere but the tire's bulge. High performance tires
typically have a low section height. Also can be determined by multiplying
the section width by the tire's aspect ratio. See Section Width
and Aspect Ratio. |
|
|
| Section
width |
An
inflated tire's width in millimeters from sidewall-to-sidewall,
not measured at the bulge. Includes any ribs or raised lettering. |
|
|
| Sector
gear |
A
partially circular gear inside a recirculating ball-and-nut steering
box. The gear is typically machined onto the top of the sector shaft
(output shaft) and meshes with gear teeth on the outside of the
ball-and-nut assembly. As steering moment causes the ball-and-nut
assembly move up and down the steering shaft, the sector gear, and
thus the output shaft, are rotated. |
|
|
| Sedan |
An
automobile that typically contains four doors (but can have anywhere
from two to five), a closed roof design, typically notchback and
usually seats between four to six passengers. Used primarily for
family transport. The name originates from a type of handcart used
to transport fish in the small town of Sedan, France which was later
applied to the sedan chair which was a single-seat enclosed chair
carried on poles by two men. |
|
|
| Seize |
The
binding of two materials together, usually caused by excessive heat
or poor lubrication. In an engine, pistons can become seized to
cylinder walls, or bearings can become seized to crankshaft journals.
The result is a ruined engine. |
|
|
| Self-energizing
brakes |
See
Primary brake shoe. |
|
|
| Self-leveling
suspension |
A
suspension system that automatically compensates for added weight
in a vehicle. Typical system consists of a compact air compressor
and air shocks or an air bladder and sensors at the rear wheels
or each wheel. When the sensors indicate a low ride height, the
air compressor pumps air into the shocks. The vehicle rises until
it reaches the proper ride height. Also called Automatic leveling. |
|
|
| Semiconductor |
A
material used in integrated circuit chips and other electrical components.
|
|
|
| Semi-elliptic
spring |
A
curved leaf spring which is roughly half an ellipse. |
|
|
| Semi-floating
axle |
An
axle housing design used in most light-trucks, SUV's and full-sized
rear wheel drive cars where the drive axles support the vehicle's
weight as well as providing torque to drive the wheels. In contrast,
a full floating axle design uses two bearings (one on each side)
for each wheel hub to support vehicle weight and the axle supports
no weight. A semi-floating axle uses one bearing on each axle. The
disadvantages of a semi-floating axle design are: heavy loads are
hard on the bearings, if an axle breaks, the wheel may fall off,
and, the entire wheel must be removed in order to change the axle. |
|
|
| Semi-monocoque |
The
use of a tube-frame chassis along with body panels which give the
chassis strength and rigidity. |
|
|
| Semi-trailing
arm |
A
simple, yet popular independent rear suspension design which uses
one control arm per side. A stout lower control arm is mounted at
about a 45 degree angle to each wheel. It allows good suspension
moment and maintains proper steering geometry through most of its
travel. |
|
|
| Sending
unit |
A
sensing device that measures temperature or pressure and sends the
signal to the gauges. Can be mechanical, electromechanical, electric
or electronic. An example is an oil pressure sending unit which
screws into the side of an engine. It reads oil pressure and sends
an electric signal to the gauges or warning light. |
|
|
| Sensor
plate |
A
plate used in a continuous flow injection system which measures
airflow into the engine's intake. |
|
|
| Sensor
unit |
See
Sending unit. |
|
|
| Sequential
fuel injection |
See
fuel injection |
|
|
| Series |
Class
or width of tire. See Aspect ratio.
|
|
|
| Serpentine
belt |
A
single, flat, grooved belt that drives engine accessories such as
a power steering pump, alternator, and air-conditioning compressor.
Takes the place of several belts and is threaded around, over and
under pulleys. Compared to traditional "V" belts, serpentine
belts are quieter, operate with less vibration, last longer and
grip pulleys better. |
|
|
| Service
manual |
A
book which explains how to service a particular vehicle. Usually
covers, general maintenance, engine and transmission rebuilding,
brake and electrical repairs and troubleshooting problems. Aftermarket
service manuals are cheaper and do a good job covering general
problems, but factory service manuals produced by the manufacturer
are typically much more comprehensive, have more illustrations
and provide more data and information about all aspects of servicing
a particular model.
|
|
|
| Servo
action |
A
twisting force that occurs in rear drum brakes which causes amplification
of brake forces. When brakes are actuated, both brake shoes are
pushed outward against the brake drum; the friction of the shoes
against the spinning drum creates a twisting motion on the shoes.
The twisting force causes the shoes to become "cocked"
inside the drum which forces the shoes against the drum with even
greater pressure. The primary shoe, sometimes called the leading
shoe (front shoe) essentially pushes the trailing shoe (rear shoe)
harder against the drum. Also see Primary brake shoe. |
|
|
| Setscrew |
A
small screw often mounted at the base of a gear or pulley that when
tightened secures the gear/pulley to a shaft. |
|
|
| Shackles |
Swinging
metal supports that secure one end of a leaf spring to the chassis.
Shackles swing to accommodate the changing length of the leaf
spring caused buy the springs arch flattening due to bumps or
surface irregularities.
Extended
shackles are longer shackles which compensate for worn or sagging
springs. Also can be used to lift the rear end of a vehicle for
a more aggressive stance or to clear larger rear tires.
|
|
|
| Shackle
reverse kit |
A
popular suspension conversion performed on front end of solid axle
leafsprung sport utility vehicles such as Jeep Wranglers to improve
ride and handling and increase off-road prowess. The process involves
moving the movable shackles from the front of the spring to the
rear, and installing aftermarket brackets to support the front of
the springs. |
|
|
| Shaker
hood scoop. |
See
Hood scoop. |
|
|
| Shaved
tire |
A
tire whose tread has been purposely removed to a certain level.
Performed on race tires for improved traction. Tires are often shaved
to 3/32nd of an inch. |
|
|
| Sheetmetal |
Steel
sheet used to make body panels, floor pans, structural braces
and other parts of an automobile. During manufacture, door parts,
fenders, roofs, floorpans and other components are formed by inserting
flat sheets of steel into dies which are pressed together in heavy
metal presses. Many parts are made of multiple welded pieces of
stamped steel. A door, for example is a combination of several
pieces welded together.
Sheetmetal
thickness is measured by gauge, such as 16 gauge, 18 gauge
and so on. The lower the number of gauge thickness, the thicker
the metal. Outer body panels on most modern vehicles are commonly
made from 20 or 22 gauge sheet metal. Although thinner the16 and
18 steel used to make panel on vintage and classic cars, newer
sheet metal contains a higher carbon content (for strength) and
helps reduce weight for greater economy. Also see Dies and Gauge.
|
|
|
| Shift
boot |
A
decorative piece of molded, flexible rubber or sewn leather covering
that installs around the base of a floor shifter and the transmission
tunnel or floor console and prevents engine and road noise from
entering the vehicle through the shifter hole. Also see Transmission
tunnel. |
|
|
| Shift
fork |
A
Y-shaped devices used in manual transmissions that moves gears and
synchronizer rings back and fourth when changing gears. |
|
|
| Shift
interlock |
A
system used on many modern vehicles which prevents shifting the
transmission into gear unless the brake pedal is pressed. Prevents
a running vehicle from being inadvertently shifted into gear by
pets or small children. An electrically operated solenoid near the
shift linkage (usually under the dash or center console) locks the
shift lever into "Park". When the brake pedal is pressed,
the solenoid opens and allows the lever to be moved. |
|
|
| Shift
lever |
The
lever that is used to change transmission gears. Can protrude through
the floor of the passenger compartment or be mounted on the steering
column and connect to the transmission with linkages. In a few models,
a lever isn't used at all, rather, an electromechanical system using
pushbuttons and solenoids/electric motors is used to change transmission
gears. Also called Gear shifter. |
|
|
| Shift
linkage |
Rods,
levers and/or cables that convert shift lever motion into movement
of gears inside a transmission. |
|
|
| Shift-on-the-fly |
A
four-wheel-drive system which allows a driver to conveniently
switch between two-wheel-drive and four-wheel-drive at road speeds.
Equipment usually consists of automatic locking front wheel hubs,
a vacuum servo or solenoid near the transfer case, and a dash-mounted
switch rather than a floor lever. When the driver wishes to engage
or disengage the four-wheel-drive, a push of the switch automatically
locks the front wheels and causes the solenoid or vacuum servo
at the transfer case to move transfer case gears which applies
engine torque to the front wheels (as well as rear wheels). However,
switching into low-range usually still requires the vehicle to
come to a complete stop.
Older
part-time four-wheel-drive systems required a driver to stop the
vehicle, get out and manually turn a dial on the front wheel hubs
before shifting into four-wheel-drive. Not very convenient on
a wet, muddy day. However, on older trucks, once the front hubs
were "locked" or engaged, the driver could shift a lever
inside the cab between two and four-wheel-drive at highway speeds.
But when the transfer case was in the two-wheel-drive mode, the
locked front wheels would turn all front gears and front driveshaft
until the driver manually unlocked them.
One
disadvantage to many shift-on-the-fly systems is a lag period
that occurs from the time the switch is pushed until four-wheel-drive
is engaged/disengaged. It can range from several seconds to minutes.
For
more info, see Four-wheel-drive and Locking hubs.
|
|
|
| Shim |
Thin
strips of metal often used as spacers between parts. |
|
|
| Shimmy |
Rapid
side-to-side movement of a car's front wheels, usually creates a
vibration at the steering wheel. Typically caused by worn suspension
parts (tie rod ends), improper alignment, or unbalanced tires. Leads
to premature tire wear. |
|
|
| Shock(s)
|
Short
for Shock absorber(s) See below. |
|
|
| Shock
absorber |
A
friction device that dampens spring oscillations. Shock absorbers
don't actually absorb road shock or bumps -- springs do. Shock
absorbers dampen spring oscillations and prevent what would otherwise
be continued bouncing after bumps are encountered. Shocks convert
energy from springs into heat which is dissipated to the air.
Nearly
all automobiles use tubular-shaped hydraulic shocks. Most shock
absorbers are filled with pressurized inert gas (typically nitrogen)
and hydraulic oil, and contain a piston with a valve or orifice
through which the oil must flow. As bumps are encountered, the
car's suspension compresses and rebounds which causes the piston
to move up and down in a cylinder. Resistance is created by the
resistance of oil-flow through a small orifice in the piston.
Pressurized gas in the shock body prevents the oil from foaming
under bumpy road conditions which reduces a shock's effectiveness.
Adjustable hydraulic shock absorbers found on many luxury and
sports cars typically use a computer or switch-operated solenoid
to turn a plate that contains different orifice sizes which varies
oil-flow and thus alters a shocks resistance to movement.
|
|
|
| Shoe |
See
Brake shoe. |
|
|
| Short |
See
short circuit. |
|
|
| Short
block |
An
engine block that contains all of it's internal components, for
example, pistons, rods, crankshaft, bearings, (timing chain and
camshaft if a V engine) and sometimes an oil pump, but does not
include any bolt-on parts like the heads, manifolds, fuel system
or oil pan/valve covers. Rebuilt engines are typically sold either
in short block or long block form which allows the purchaser to
determine state of completeness. |
|
|
| Short
circuit |
A
defective electrical circuit where the current in a wire or device
takes an alternate (typically shorter) path to ground. Usually the
result of melted, burned or broken wire(s) or damaged electrical
part. Usually referred to as just short. |
|
|
| Short-long
arms |
See
unequal-length A-arms. |
|
|
| Shot
peen |
A
process of adding strength to the surface of metal parts by blasting
the surface with tiny metal balls. Shot peening reduces the tendency
of surface cracks developing. |
|
|
| Shrink
fit |
Fitting
two parts by heating one part (and sometimes cooling the other)
to the point where it expands enough to fit over the other part.
Once cooled, the fit is extremely tight. |
|
|
| Shroud |
See
Fan shroud. |
|
|
| Siamesed |
Joined
or paired components or section of components. A way of pairing
components where two go into one. For example, arranging intake
or exhaust ports so that the ports from two cylinders come together
next to each other, or as one. Intake and exhaust manifolds that
have their ports arranged in pairs can also be termed siamesed |
|
|
| Side
curtain |
A
detachable (but non rollable) window used on some British open top
coupes to provide some protection from wind and rain. Typically
consists of a metal frame and window with a cloth portion. |
|
|
| Side-draft
carburetor |
A
horizontally positioned carburetor. The air/fuel mix is drawn into
the engine horizontally. Most engine have a vertically mounted carburetor,
but many race engines and some production vehicles such as the Volkswagen
Beetle use side-draft carburetors. |
|
|
| Side
force |
Lateral
force on a turning vehicle that attempts to push it away from the
turn. If side force becomes greater than the tire's cornering force,
the the vehicle can begin to slide. The vehicle has reached it cornering
limit. See Centrifugal force. |
|
|
| Side
marker lamps |
Lamps
mounted to the fenders and rear quarter panels of vehicles that
illuminate when the lights are turned on which increase vehicle
visibility to other drivers, particularly from the side. |
|
|
| Side
pipes |
Exhaust
pipes which run next to or beneath the vehicle's rocker panels (just
below the doors) and expel exhaust to the sides of the car near
the rear tires. Was factory equipment on several muscle and sports
cars of the 1960's such as the Corvette and AC Cobra. Typically
coupled with exhaust header pipes as part of a high-performance,
low-restriction exhaust system. Became a popular aftermarket exhaust
treatment for 1970's muscle cars and vans. Side pipes are typically
much louder than a regular exhaust system but make their own style
statement. Also see Exhaust system, Exhaust headers and Exhaust
Stacks. |
|
|
| Sidepod |
The
body portion of a formula or Indy-style race car which protrudes
on both sides of the cockpit and extends between the front and rear
wheels. Usually contains air ducts for cooling. Special routing
or airflow over the pods known as Sidepod Airflow is used to create
downforce which aids traction and cornering. |
|
|
| Side
rail |
The
main, longitudinal members of an automotive frame. |
|
|
| Side
valve |
See
Flathead. |
|
|
| Sidewall |
The
vertical portion of a tire between the rim and the tread. Consists
of several casing plies and a thin layer of rubber which enables
it to be flexible. Each time the tire rotates the sidewall flexes. |
|
|
| Sidewall
height |
See
Section height. |
|
|
| Sidewinder |
A
term for a vehicle with a transversely mounted engine. Also referred
to as east-west location. |
|
|
| Silencer |
Another
term for an exhaust muffler. See Muffler. |
|
|
| Silicon-controlled
rectifier (SCR) |
An
electronic component which converts an alternator's current from
AC (alternating current) to DC (direct current). |
|
|
| Silicon-impregnated
aluminum |
A
type of material used to make lightweight engine blocks. Silicon
is mixed with aluminum during the casting process. Afterwards, a
chemical is applied to the cylinders which etches away a thin layer
of aluminum leaving behind a durable surface which the piston rings
ride on. The process eliminates the need for iron cylinder liners. |
|
|
| Sill |
The
horizontal surface of a chassis beneath the door, next to the seats
cushions. Typically covered with a metal or plastic Sill plate (also
called Scuff plates) which prevents scuffing passengers' shoes from
scuffing the painted surface when entering or leaving an automobile. |
|
|
| Simulated
wire wheels |
Full
wheel covers with wire spokes and a center caps that when installed
mimic a wire wheel. Used widely on automobiles produced from the
late 1970's to early 90's. Many featured a locking system to prevent
theft. |
|
|
| Simulated
wood grain |
A
paint treatment or plastic overlay used on interior plastics to
mimic the color and look of wood paneling which was once widely
used in automobiles. Commonly found on the dashboard, instrument
panel fascia, center console and door panels. |
|
|
| Single
Overhead Cam (SOHC) |
An
engine that contains a single camshaft in each cylinder to operate
intake and exhaust valves for that head. |
|
|
| Single-point
injection |
See
Fuel injection and Continuous fuel injection. |
|
|
| Single-seater
|
A
term applied to single-seat type of race car such as used for Indy,
Formula, Cart or Grand Prix racing. |
|
|
| Sintered
metal |
Metal
which has been heated to just below it's melting point, then pressed
into dies or molds. |
|
|
| Sixty-special
seat |
The
name of a 60/40 seat system used on some Cadillacs. |
|
|
| Supplemental
Inflatable Restraint (SIR) |
See
Supplemental Restraint System (SRS) and Airbag. |
|
|
| Skit
pad |
A
flat paved area with a circle of a known diameter painted on it's
surface. Used in handling tests to determine lateral acceleration.
See Lateral acceleration. |
|
|
| Skirt |
The
sides of a piston at right angles to the piston pin bushing that
hang down and make contact with the cylinder's surface. The piston
skirt absorbs the lateral thrust which is a result of the connecting
rod angle.
On
a vehicle's body, an skirt is a rubber or fiberglass body part
that hangs low to the ground on the sides or rear of a vehicle
to direct air over and around the body for aerodynamic purposes.
See Air dam.
|
|
|
| Slalom |
A
handling test where cones are spaced in a straight line, and the
driver must drive around the cones as quickly as possible. Used
by engineers and magazine tests to compare maneuverability between
vehicles. I slalom competitions, drivers typically race against
the clock, not each other. Touching or knocking over cones usually
results in a time penalty where time is added to a driver's overall
time. |
|
|
| Slap |
Another
term for Piston slap. See Piston slap. |
|
|
| Slave
cylinder |
A
piston and cylinder assembly that is operated solely by hydraulic
pressure from a master cylinder. In an automobile, the term slave
cylinder typically refers to the lower part of a hydraulic clutch
system which mounts on or near the transmission and engages/disengages
the clutch. It is operated by hydraulic pressure created by the
clutch master cylinder. |
|
|
| Sleeve |
A
cylindrical metal insert that fits into a cylinder bore that the
piston rides in. Used widely in aluminum blocks to provide durability;
and also in large commercial diesel motors because they can be removed
from an engine for servicing or replacing. Also see Liners. |
|
|
| Slick |
Tires:
A wide tire with no tread; used for racing on dry pavement.
Also;
A layer of spilled oil on a paved surface.
|
|
|
| Sliding
caliper |
See
Floating caliper |
|
|
| Sliding-gear
transmission |
See
Constant mesh gearbox. |
|
|
| Sliding
rear window |
A
multi-paned rear window assembly found in the rear of many pickup
trucks where the center window panes can be slid apart for purposes
of increasing ventilation in the cab. |
|
|
| Slip
angle |
A
handling term. The angle between the direction a wheel is traveling
and the direction the tread is heading. Usually a result of the
tire's sidewall flexing. However, can help determine oversteer and
understeer characteristics. If the slip angles of the rear tires
are greater than those of the front tires when cornering, the car
will tend to oversteer. Greater slip angles at the front wheels
will lead a car to understeer. If the front/rear wheels have equal
slip angles, steering will be neutral. |
|
|
| Slip
joint |
A
type of connection that allows a driveshaft to increase or decrease
in length. On rear-wheel-drive and four-wheel-drive vehicles (front
driveshaft) the driveshafts are positioned at an angle. When the
suspension becomes compressed or during rebound, the driveshaft
needs to become shorter or longer, respectively. A spilled shaft
and yoke are usually used to accomplish this. |
|
|
| Slipper
skirt piston |
A
piston with a shortened or cut off piston skirt. A technique used
when building race engines. The piston's weight is reduced and shorter
connecting rods can be used which helps produce a quick accelerating
engine. |
|
|
| Slipstream |
An
aerodynamic term. The low-pressure area behind a vehicle at high
speeds. Racers take advantage of another vehicle's slip stream which
allows them to substantially reduce their aerodynamic drag and thus
conserve fuel. See Drafting. |
|
|
| Sludge |
A
thick gooey mixture of oxidized petroleum products, contaminants,
oil and water that can occur in engines and clog oil passages and
reduce engine oiling capabilities. |
|
|
| Slush
box |
A
colloquial term for an automatic transmission. |
|
|
| Smog |
Hazy
pollution which occurs over many industrialized urban areas. The
term is a combination of the words smoke and fog. Smog consists
of smoke, moisture, and compounds which result from combustion from
power plants, automotive engines, forest fires and garbage. Sunlight
then reacts with the airborne chemicals and combustion byproducts
and forms other dangerous and noxious compounds. The result is a
thick haze or fog which pose health risks. |
|
|
| Snap
ring |
A
ring-shaped clip made of spring steel and fit into thin grooves;
used to retain bearings, gears and other cylindrical parts onto
shafts and in cylinder bores. Two common types of snap rings are
internal snap rings and external snap rings. Internal snap rings
retain parts in a cylindrical bore; external snap rings usually
retain gears, pulleys or other parts onto shafts. |
|
|
| Snorkel |
An
extended air breather tube which is routed higher or outside the
vehicle in a higher location in order to allow air to be drawn into
the engine from a higher location -- usually near the roof. The
higher location may provide the engine with air with less dust in
it or allow the vehicle to ford deep streams without letting water
into the air intake (which would cause a damaging condition caused
hydrolock). Found on serious off-road vehicles and safari rigs such
as Land Cruisers and Land Rovers and also a common customization
technique. Also see Naturally aspirated and Hydrolock. |
|
|
| Snow
plow |
A
removable device which can be mounted on the front of a vehicle,
predominately pickup trucks, for snow removal. A special frame is
bolted to the truck frame which enables the plow to be hooked up
or removed. Raising and lowering of the plow as well as angling
the blade left/right is controlled by hydraulic rams which operate
off an electrically driven 12V hydraulic pump and driver-operated
controls. |
|
|
| Snow
tires |
Tires
specially designed for winter use. Generally have wider spaces between
the tread blocks, deeper tread, and made of softer compound which
grip better in snow. Metal studs can be inserted in many snow tires
where local laws allow for improved traction. |
|
|
| Snubber |
Another
term for Bump stop. A rubber bumper that limits suspension movement
and prevents metal suspension parts from violently crashing into
each other which could cause damage. |
|
|
| Society
of Automotive Engineers (SAE) |
An
organization which consists of engineers from different engineering
fields. The organization publishes papers, designs and sets measurement
standards for the automobile industry but have spread their influence
to other related industries. Their full title is "SAE International,
The Engineering Society for Advanced Mobility Land, Sea, Air and
Space." |
|
|
| Sodium-cooled
valve |
An
exhaust valve that uses sodium inside it's valve stem to achieve
low valve temperatures. The valve stem is hollow and filled with
sodium. When the valve reaches 280 degrees F. the sodium melts and
splashes up and down inside the stem which carries heat from the
valve head to the stem which is cooler. The heat from the stem is
absorbed into the cooler valve guide and thus the cylinder head.
The result is a cool-running valve less prone to damage under severe
operating conditions. |
|
|
| Soft
top |
A
term for the fold-down top of a convertible. Can also be applied
to a convertible vehicle.
Many
small sport utility vehicles such as Jeeps and Suzuki Samurai's
also use removable canvas or vinyl soft tops.
|
|
|
| SOHC |
See
Single overhead cam. |
|
|
| Solenoid |
An
electromagnetic device that moves a plunger when current is applied
to it's coils. Used in automobiles to operate automatic door and
trunk locks, and some engine, transmission and driveline controls. |
|
|
| Solid
axle |
See
Axle. |
|
|
| Solid
state ignition |
An
electronic engine system used in all modern vehicles made up of
electronic components such as resistors, diodes, transistors and
IC chips rather than relying on mechanical parts like ignition points
and rotors. |
