| Gasket |
A
thin, soft material used to create a seal between two metal surfaces.
A head gasket is sandwiched between the cylinder head and the engine
block. It produces a good seal keeping combustion gasses and pressure
inside the combustion chamber while keeping coolant out. Gaskets
are also used on other major engine components to prevent oil from
leaking out of the motor. The term gasket can also be applied to
the rubber door seals used to keep wind noise out of the passenger
compartment.
Engine
gaskets are often made from cork, asbestos, specially treated cardboard,
soft copper and silicone rubber.
|
|
|
| Gasoline |
The
liquid fuel derived from oil used to power most engines. |
|
|
| Gas-pressure
shock absorber |
A
shock absorber that uses pressurized inert gas (typically nitrogen)
rather than air to fill the space not occupied by the shocks working
fluid (oil). The pressurized gas prevents the oil from foaming under
bumpy road conditions which reduces the shock's effectiveness, thereby
producing a shock that is more consistent than conventional air-filled
shocks. Also see Shock absorber. |
|
|
| Gas-pressurized
struts |
See
Strut. |
| |
|
| Gas
tank |
See
Fuel tank. |
|
|
| Gas
tank sealer |
A
fuel-resistant, thick liquid product which can be be used to seal
the inside of a gas tank. Used by auto restorers to seal a repaired
fuel tank, or in instances where a replacement fuel tank is unavailable.
Usually requires special preparation on the inside of the tank. |
|
|
| Gauge |
A
graduated device, either digital or analog (needle), mounted in
an instrument cluster to display speed, fuel level and important
information such as coolant temperature, oil pressure and voltage.
Also
a measurement of sheetmetal thickness.
|
|
|
| Gauge
cluster |
A
collection of gauges mounted in the dashboard in front of the driver.
|
|
|
| Gear |
A
round part with teeth cut into its outer edge that mesh with the teeth
of other gears to transmit power from one to another. Used in transmissions
and differentials. By using gears of different size, speed and power
can be increased. |
|
|
| Gearbox |
Another
term for transmission. A sturdy device usually constructed of heavy
cast iron or thick aluminum that is bolted to the engine. Inside the
gearbox is a system of gears which multiplies engine torque for delivery
to the wheels. In reality the gearbox doesn't bolt directly to the
engine. A bell housing, which covers the clutch and flywheel, bolts
to the engine. The gearbox bolts to the flywheel. In some applications
the gearbox and bell housing are cast as one unit. |
|
|
| Gear
lever |
Another
term for gear shifter. The rod that leads to the transmission that
the driver uses to change gears. |
|
|
| Gear
ratio |
The
number of revolutions a driving gear makes relative to the number
of revolutions that a driven gear makes. For example, imagine one
gear is turning another gear. If the main drive gear turns 4 revolutions
to each revolution of the driven gear the gear ratio is 4:1. Gear
ratios are used in automotive differentials and transmissions. By
altering gear ratios, torque, power and speed can be increased or
decreased. A driver changes gear ratios in the transmission when he/she
shifts into a different gear. |
|
|
| Gearset |
Two
or more gears used to transmit power. Also, in many applications gears
are matched together or wear together and are generally replaced in
pairs or sets to ensure even wear. |
|
|
| Gearshift |
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 connected to the transmission with linkages. In some rare
applications, a lever isn't used at all, rather, an electromechanical
system using pushbuttons and solenoids/electric motors is used to
change transmission gears. |
|
|
| Generator |
A
device mounted to an engine that produces electricity which is used
to maintain a "charged" battery, perform ignition, and operate
power accessories. Strictly speaking, a generator produces direct
current (DC). Generators were a commonly used in automobiles until
manufacturers switched over to more efficient alternators, which produce
alternating current (AC) around 1965. |
|
|
| Glass-pack
muffler |
A
through-muffler that uses no baffles but has a perforated main pipe
which is surrounded with fiberglass insulation to dampen engine noise.
Does not muffle engine noise as well as a baffled muffler but produces
a deep throaty sound desired many street rodders and off-roaders.
Although most glass packs are low-restrictions mufflers, glass packs
which have inner protruding fingers often restrict airflow more than
a standard muffler. Also called Cherry bomb mufflers. |
|
|
| Glaze |
A
smooth polished surface. In the automotive world it can mean several
things. Cylinder walls can become glazed by the friction of piston
rings which is undesirable because it can reduce a piston's ability
to seal to the cylinder wall. Brake rotors and brake pads can become
smooth and glazed which reduces friction and therefore stopping
power.
Glaze
can also apply to a wax or rubbing compound which can be used to
remove oxidized paint and restore the smoothness and luster of a
car's finish.
|
|
|
| Global
positioning system (GPS) |
A
system using satellites to help navigate. Originally developed by
the U.S. Department of Defense using several orbiting satellites which
can determine precise location anywhere using a system of triangulation.
GPS receivers are available in handheld versions and on many new mobile
telephones as well as part of a computerized navigation system in
some automobiles. Generally have an accuracy of about 50 feet but
can be used anywhere in the world. |
|
|
| Glove
box |
A
storage compartment typically located on the passenger side of the
dash that can be used to store maps, driving records, cassette tapes/CDs
and, you guessed it - gloves. |
|
|
| Glow
plugs |
An
electrical device used in diesel motors that looks similar to a spark
plug but contains a heating element on the end that facilitates starting
a cold diesel engine. Called "glow" plugs because when turned
on the heating elements glow red-hot. One glow plug is used for each
cylinder. Once the engine has started, the glow plugs are turned off. |
|
|
| Governor |
A
mechanical limiting device. Used on many vehicles, particularly sports
cars to limit speed and protect against over-revving the engine which
might cause damage. |
|
|
| GPS |
An
acronym for Global Positioning System (above) |
|
|
| Grab
bar/handle |
A
rubber bar or strap on the dash or above the passengers head that
allows passengers to steady themselves. |
|
|
| Grand
Touring (GT) |
American
version of Grand Tourismo applied to the name of some American muscle
cars. |
|
|
| Grand
Tourismo (GT) |
Italian
for Grand Touring. The term is often applied to vehicles with a coup
body style. |
|
|
| Grand
Tourismo Omologato (GTO) |
A
Italian term that defines Grand Touring cars, or race cars, that
are produced in enough volume to qualify for a race class. Comes
from the British term 'Homologated' which is applied to race cars
that are built in road-going form in enough quantity to qualify
it as a "production" car, as is required by certain racing
classifications.
Also,
GTO is the name of a popular muscle car produced by General Motors
(Pontiac division) in the 60's & 70's.
|
|
|
| Graphic
equalizer |
An
electronic device used on some car stereo systems that allows a listener
to fine-tune different audio frequencies using individual controls
for different frequencies, typically by way of sliding controls. |
|
|
| Greenhouse |
The
upper area of a vehicle that is glassed in (roof, roof pillars windows,
etc.). The greenhouse area usually begins from the base of the windshield
on up. |
|
|
| Grille |
A
vented stylish panel that attaches to the front of a vehicle though
which air passes through to cool the radiator. Grille's on vintage
automobiles were often made of many chrome plated or painted rods
and appeared somewhat like a traditional cooking grille. Modern grilles
are typically slotted plastic or fiberglass panels painted to match
vehicle color. |
|
|
| Grille
screen |
A
wire or nylon mesh screen usually with a thin frame which can be placed
in front of the vehicle's grille to prevent bugs and debris from clogging
the radiator. |
|
|
| Grille
surround |
A
structure, often made of painted plastic or anodized aluminum that
mounts on the front some vehicles to which the grille mounts. It effectively
surrounds the grille. |
|
|
| Grip |
A
tire's traction to the road. |
|
|
| Gross
horsepower |
The
maximum power output of an engine measured on an engine dynamometer
under ideal conditions. Usually the motor is outfitted with a modified
intake and high-flow exhaust and minus any power-robbing accessories
(e.g.. power steering, alternator, air-conditioning). |
|
|
| Gross
torque |
See
Gross horsepower (above) |
|
|
| Ground |
The
negative terminal of a battery which is connected to the vehicle chassis
and frame making the frame of the car also a ground. By grounding
the car's frame, a single power wire is all that is required to power
accessories. Current is fed to an accessory the one wire and the frame
itself serves as the return wire of the circuit. |
|
|
| Ground
clearance |
The
height of the lowest part of the vehicle measured on level ground.
It's the tallest road hazard a vehicle can drive over with out major
damage. On trucks and sport utility vehicles, the lowest point is
typically the center of the rear differential. |
|
|
| Ground
effect |
The
use of air dams and panels underneath race cars and high performance
productions cars to increase traction. Air dams can either create
a partial vacuum underneath the vehicle which "pulls" the
vehicle to the road at high speeds resulting in increased traction
and cornering speeds, or direct air over the top of the vehicle (prevent
air from going underneath) which reduces the airplane wing affect
that leads to lifting (reduced traction) at high speeds. |
|
|
| GT |
See
Grand Tourismo and Grand Touring (above). |
|
|
| GTO |
See
Grand Tourismo Omologato (above). |
|
|
| Guide |
Shortened
term used for Valve guide. See Valve guide. |
|
|
| Gullwing |
A
door opening design where the vehicle's doors are hinged at the roof
and open upward. When both doors are open the car and doors appear
like a seagull with spread wings. Famous cars that sported gullwing
doors include the Mercedes-Benz 300SL and the DeLorean DMC-12. |
