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    GLOSSARY TERMS

    N

    N
    The neutral position of an automatic transmission.
    The chemical symbol for nitrogen.
    N-Heptane
    A hydrocarbon with an octane number of 0.
    NAAA
    An abbreviation for National Auto Auction Association.
    NACA duct
    A bottle-shaped, low-drag air intake design.
    NACAT
    An abbreviation for National American Council of Automotive Teachers, Inc.
    NADA
    An abbreviation for National Automobile Dealers Association.
    Nail it
    To apply full throttle.
    NARSA
    An abbreviation for National Automotive Radiator Service Association.
    NASA Duct
    A frequent but incorrect reference for NACA duct.
    NASCAR
    An acronym for National Association for Stock Car Auto Racing.
    Nasty car
    A NASCAR stocker.
    NATEF
    An abbreviation for National Automotive Technicians Education Foundation.
    National American Council of Automotive Teachers, Inc. (NACAT)
    An association of secondary and post secondary automotive technology instructors.
    National Association for Stock Car Auto Racing (NASCAR)
    The major sanctioning authority for stock car racing.
    National Auto Auction Association (NAAA)
    A trade association of auto auction owners.
    National Automobile Dealers Association (NADA)
    A trade association representing franchised new car and truck dealers.
    National Automotive Radiator Service Association (NARSA)
    A trade association that represents operators of automotive radiator and air conditioning repair shops and cooling system service businesses as well as manufacturers and suppliers for the trade.
    National Automotive Technicians Education Foundation (NATEF)
    A non-profit organization administered by ASE that sets standards for training programs in Vocational-Technical schools.
    National Highway Traffic Safety Administration (NHTSA)
    An agency of the Department of Transportation responsible for establishing and enforcing highway safety regulations.
    National Hot Rod Association (NHRA)
    The major authority for drag racing events.
    National Institute for Automotive Service Excellence
    A non-profit corporation founded in 1972 to promote and encourage high standards of automotive service and repair through voluntary testing.
    National Institute for Occupational Safety and Health
    A branch of the Federal Government, through the Occupational Safety and Health Administration, that is responsible for overseeing and enforcing occupational safety and health issues.
    National Institute for Standards and Technology (NIST)
    A national organization that helps to set standards and technology for mobile air-conditioning systems.
    National Lubricating Grease Institute
    A trade association of manufacturers and distributors of grease.
    National Street Rod Association (NSRA)
    A sanctioning body for street rods.
    National Tire Dealers and Retreaders Association, Inc. (NTRDA)
    A trade association of tire dealers and tire retreaders.
    National Tractor Pullers Association (NTPA)
    A sanctioning body for tractor-pull events.
    National Vehicle Leasing Association (NVLA)
    A trade association of vehicle leasers, dealers, and funders.
    National Wheel and Rim Association (NWRA)
    A trade association for the distributors of vehicular wheels, rims, and brake drums.
    Natural gas
    A gas occurring naturally in the earth, such as methane, ethane, butane, and propane.
    Naturally aspirated
    An engine that uses atmospheric pressure to force the air into the cylinders.
    NC
    An abbreviation for normally closed, usually expressed nc. Sometimes used to indicate no connection.
    NDRA
    An abbreviation for the Nostalgia Drag Racing Association.
    NDT
    An abbreviation for non-destructive test.
    Near side
    The side of a vehicle closest to the curb.
    Necking
    A narrowing area of the exhaust pipe due to a buildup of exhaust by-products.
    Necking knob
    A knob attached to the steering wheel that permits rapid one-hand steering.
    Needle and seat
    A metering assembly to admit fuel into the carburetor.
    Needle bearing
    A bearing that contains needle-like rollers.
    Needle valve
    The small, tapered male part of a needle and seat.
    Negative
    One of the two poles of a magnet.
    One of the two poles of a battery, representing ground.
    Negative Back-pressure EGR valve
    An exhaust-gas-recirculation valve having a normally closed bleed hole which opens when back pressure drops, reducing vacuum above the Diaphragm and cutting the recirculation flow.
    Negative Camber
    The inward vertical tilt of the wheels on a vehicle.
    Negative Offset
    A wheel rim that has been placed inward from the center of its mounting flange.
    Negative Pole
    The negative terminal on a battery. Also known as negative post.
    Negative Post
    Same as negative pole.
    Negative Terminal
    The side of a battery or electrical device nearest ground potential, often identified by a minus (−) sign.
    Neoclassic
    The modern design of a car to resemble a classic of the late 1920s and early 1930s.
    Neoprene
    A type of synthetic rubber that is resistant to heat, light, oil, and oxidation.
    Nerf
    To bump or shove another car in an oval-track race.
    Nerf Bars
    Small, tubular bumpers at the front and rear of an oval-track race car.
    Net Horsepower
    The maximum engine horsepower as measured on a dynamometer.
    Net Torque
    The maximum engine torque as measured on a dyno.
    Net Valve lift
    The lift, less the running clearance, of a valve.
    Neutral
    The position of an automatic transmission when the engine is disengaged from the drive train.
    A condition of a planetary gear set when all members, gears, and planet carriers, are free to rotate.
    Neutral Flame
    An oxyfuel gas flame that has neither oxidizing nor reducing characteristics.
    Neutral Safety Switch
    An electrical switch used on vehicles equipped with automatic transmissions to open the starter control circuit when the transmission shift selector is in any position except PARK or NEUTRAL. Also known as neutral start switch.
    Neutral Start switch
    A term used for neutral safety switch.
    Neutral Wire
    A grounded conductor in a three-wire electrical system that does not carry current unless the system is unbalanced.
    Neutron
    A particle in the nucleus of an atom.
    New Old Stock (NOS)
    Old shelf-worn parts that have not been used.
    Newton's Laws of Gravity
    Every mass in the universe exerts an attractive influence on every other mass.
    For two objects, the force of gravitation acting between them is directly proportional to the product of their masses, and inversely proportional to the square of the distance between their centers of mass.
    Newton's Laws of Motion
    There are three laws:
    A body in motion remains in motion, and a body at rest remains at rest, unless some outside force acts on it.
    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.
    For every action, there is an equal and opposite reaction.
    NG
    An abbreviation for no good.
    NHRA
    An abbreviation for the National Hot Rod Association.
    NHTSA
    An abbreviation for the National Highway Traffic Safety Administration.
    Nickel
    An element, Ni, used in alloys and electroplating.
    Nikasil
    A trade name of a popular coating applied to the walls of cylinder sleeves to reduce friction and promote sealing at high temperatures.
    Nitride
    A compound containing electronegative nitrogen and an electropositive element or metal.
    Nitrile Seal
    Seal made by mixing butadiene and acrylonitrile.
    Nitro
    A short term used for nitromethane.
    Nitrogen
    A colorless, odorless, tasteless gas that makes up 78% of the atmosphere and is part of all living tissues.
    Nitrogen Oxide
    Any chemical compound of nitrogen and oxygen (NOX) as a by-product of combustion that forms smog in the presence of sunlight.
    Nitromethane
    A highly combustible liquid that is the main ingredient in drag-racing fuels.
    Nitrous
    A term used for nitrous oxide.
    Nitrous Oxide
    A non-flammable, non-explosive gas (N2O) used as an oxidizing agent with gasoline or methanol to increase the rate and efficiency of combustion thereby increasing the horsepower.
    Nitrous Oxide Systems (NOS)
    A popular manufacturer of nitrous oxide injection systems.
    NO
    An acronym for normally open, usually given as no.
    No-Load Test
    A starting-motor test to determine the rpm and current draw of a starter motor. A mechanical tachometer is placed on the drive end of the armature shaft and the motor is then connected to a proper power source. An ammeter, attached to the power means, determines current required.
    No-tilt Convertible Fifth
    A fifth wheel with fore/aft articulation that can be locked out to produce a rigid top plate for applications that have either rigid and/or articulating upper couplers.
    Noble Metals
    A rare and expensive group of metals that resist corrosion such as gold (Au), iridium (Ir), platinum (Pt), palladium (Pd), ruthenium (Ru), and rhodium (Rh), some of which may be found in catalytic converters.
    Nodular Cast Iron
    Cast iron used to make engine blocks that is treated, while molten, with an alloy that causes the formation of graphite in very small lumps.
    Nomex
    A popular trade name for a fabric that is used in race drivers' apparel.
    Nominal Rating
    The lowest rating of a system or device.
    Nominal Size
    A designation used for general identification, such as the inside diameter of a tube.
    Non-Destructive Test (NDT)
    A method of testing without causing damage.
    Non-Live Axle
    A non-driven truck axle that is held off the road when the vehicle is empty and put on the road when a load is being carried, used extensively in eastern states with high per-axle weight laws.
    Non-Load Bearing Ball Joint
    A term used for non-load-carrying ball joint.
    Non-load-Carrying Ball Joint
    A ball joint designed with a preload which provides damping action that maintains suspension component location but does not support the chassis weight. Also known as stabilizing ball joint.
    Non-miscible
    Not capable of being mixed in any proportion.
    Non-Servo
    A type of drum brake in which the brake shoes work independently of each other.
    Non-slip Differential
    A differential that is designed so that when one wheel slips, the major portion of the driving power is transferred to the non-slipping wheel.
    Nonconductor
    A material that does not conduct electricity.
    A material that is resistant to the conduction of heat.
    Noncorrosive Flux
    A soldering paste, usually composed of resin-based materials, that does not chemically attack the base metal.
    Nonfriction Modified
    An automatic transmission fluid without friction modification agents.
    Nonmetallic Leaf Spring
    A term used for fiber-composite spring or fiber-composite leaf spring.
    Nonparallel Drive Shaft
    A drive shaft with working angles of equal length; the companion flanges and/or yokes are not parallel.
    Nonpolarized Gladhand
    A gladhand that can be connected to either the service- or the emergency-gladhand.
    Nonsynchronized Mode
    A mode of operation on a throttle body, fuel-injection system in which the injector is pulsed every 12.6 milliseconds, independent of a distributor reference pulse.
    Normal Evacuation
    An evacuation to remove air and moisture from a system with only one pump down.
    Normal Wear Pattern
    The wear pattern of a part or assembly that is normal or expected.
    Normally Aspirated
    An engine that is not equipped with a forced means of inducing air.
    Normally Closed (nc)
    A term referring to a device, such as an electrical switch, that is closed in its normal position.
    Normally Open
    A term referring to a device, such as an electrical switch, that is open in its normal position.
    North-South
    Placing an engine longitudinally in a vehicle, as in most front-engined, rear-drive vehicles.
    NOS
    An abbreviation for Nitrous Oxide Systems.
    An abbreviation for new old stock.
    Nose
    Front end of a vehicle.
    The uppermost part of a camshaft lobe.
    The front of a semi-trailer.
    Nose Over
    An engine or other component that is starting to self-destruct.
    Nose Plug
    A threaded, tapered plug used to repair cracks in the diesel engine cylinder head around the injector holes.
    Nostalgia Drag Racing Association (NDRA)
    An organization staging drag races for older cars.
    NOX
    Oxides of nitrogen, not to be confused with nitrous oxide (N2O).
    NOX control system
    A device or system used to reduce the oxides of nitrogen (NOX) produced by an engine.
    Nozzle
    The orifice or jet through which fuel passes when it is discharged into a carburetor.
    NSRA
    An abbreviation for the National Street Rod Association.
    NTP
    An abbreviation for normal temperature and pressure.
    NTPA
    An abbreviation for National Tractor Pullers Association.
    NTRDA
    An abbreviation for National Tire Dealers and Retreaders Association, Inc.
    Number Failure Code
    A term used for failure code.
    Number of Cylinders
    The total number of cylinders (1, 2, 4, 6, or 8) contained in an engine.
    Numeric Tire Rating
    An alpha-numeric group molded into the tire sidewall indicating tire application, aspect ratio, and rim size.
    Nut
    A fastener having internal threads used on a bolt to secure two or more pieces together.
    NVLA
    An abbreviation for National Vehicle Leasing Association.
    NWRA
    An abbreviation for National Wheel and Rim Association.
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