A fuel blend of 85% methanol and 15% gasoline.
An abbreviation for milliampere.
The relative ease with which materials can be shaped by cutting, drilling, or other chip-forming processes.
A car, usually a late-model car.
A device capable of doing work.
MacPherson Strut
A type of front suspension having a shock absorber mounted directly below the coil spring.
MacPherson Strut Rear Suspension
An independent, rear-suspension system having a shock-absorber strut assembly on each side, two parallel control arms, a tie rod, a strut rod, a forged spindle, a jounce bumper, and a bracket assembly.
MacPherson Strut Suspension
A front-end, independent suspension system in which the combined strut, steering knuckle, and spindle unit, supported by the coil spring at the top, is connected from the steering knuckle to an upper-strut mount.
An abbreviation for Mobile Air Conditioning Society.
An abbreviation for magneto.
An acronym for magnesium.
A term used for a lightweight wheel, such as one made of aluminum or magnesium.
Mag Wheels
A magnesium wheel.
A term used to describe any chromed, aluminum offset, or wide-rim wheel of spoked design.
A dry, nondestructive magnetic test to check for cracks or flaws in iron or steel parts.
A trade term for a wet, magnetic, and ultraviolet nondestructive test to check for cracks or flaws in iron or steel parts.
An element, Mg, that is the lightest in weight of all structural metals.
Magnetic Clutch
A coupling device used to turn the compressor on and off electrically.
Magnetic Field
The area of influence of a permanent- or electro-magnet that exists between its north and south poles.
Magnetic Filter
A magnet or magnet assembly located in a fluid system to attract and retain ferrous metal, nickel, and cobalt particles which may be present. Composite particles in which a ferro-magnetic material is entrained may also be present.
Magnetic Lines of Force
The invisible magnetic lines set up between the north and south pole of a magnet.
Magnetic Particle Test
A non-destructive test using a magnet and magnetic particles, such as iron filings, to check iron or steel parts for cracks.
Magnetic Pick Up
The system of an electronic ignition that triggers the amplifier to generate voltage to fire the plugs.
Magnetic Pickup Coil
A small coil of wire wound on an iron core in an electronic ignition system that is magnetically affected as the reluctor teeth pass by.
Magnetic Pole
The point at which the magnetic lines of force enter or leave a magnet.
Magnetic Switch
A switch energized electrically with a coil of wire serving as an electromagnet, such as in a relay.
Magnetic Timing
A procedure for checking or adjusting an engine's ignition timing by inserting a magnetic probe into a receptacle near the crankshaft harmonic balancer or flywheel.
The natural or electrical ability to attract a ferrous metal.
An electrical device requiring no outside power source, that generates and delivers current to fire the spark plugs.
The main bearing.
The feature event.
Main Bearings
The bearings that locate and support the crankshaft in an engine block.
Main Cap
The structural device that holds the crankshaft in place in an engine block.
Main Hoop
A rollbar placed just behind the driver's seat in a race car.
Main Jets
The nozzle in a carburetor that provides fuel during part- or full-throttle operation.
Main Journals
The journals that fit into the engine block to support the crankshaft.
Main Leaf
Usually the top leaf on multiple-leaf springs that provides the main vehicle support and contains the spring-mounting eyes.
Main-Body Structural Components
The assembly made up of the dash panel, underbody, roof, body panels, doors, and deck lid to form the passenger and luggage compartments.
Mainline Pressure
The pump-developed, hydraulic-regulated pressure that operates apply devices, such as bands, and is the source of all other pressures in an automatic transmission.
A term used for main bearings and main cap.
Maintenance Awareness Program (MAP)
A coalition of automobile repair shops, suppliers, car companies, and associations dedicated to building trust between the aftermarket and its customers.
Maintenance Manual
A manufacturer's or independent publication containing comprehensive maintenance information for a certain vehicle.
Maintenance Specifications
A listing of interval oil and lube grades, service points, and capacities for periodic and routine preventative maintenance service.
Maintenance-Free Battery
A sealed battery having no practical provision for the addition of water to the cells, since periodic maintenance is unnecessary.
Major Diameter
The largest in diameter of a cylinder.
The largest in the diameter of a bolt, its threads.
Major Overhaul
An engine overhaul just short of a rebuild, where all worn or damaged parts are rebuilt or replaced.
Major Tune-Up
A conventional, ignition-engine maintenance procedure that may include points, capacitor, cap, rotor, plugs, plug wires, valve adjustment, and a carburetor overhaul.
To close a switch.
A distinctive name given to a group of cars by a manufacturer, such as Riviera, by Buick.
Make and Break
The term used when a switch is closed or opened.
A pair of contact points, one stationary, and the other operated by a cam that makes the brake, such as in a conventional distributor.
To construct something then tear it down.
Make the Show
To qualify for a race.
A term universally applied to any part which fits into another part, such as the shaft on which a pulley or gear hub fits.
Male and Female
Terms that apply to inner and outer members which fit together, such as a bolt and nut.
An improper or incorrect operaton of a device or system.
The ability of a metal to be formed through hammering or bending.
An element (Mn), used in alloys of iron, steel, aluminum, and copper, often confused with magnesium (Mg).
Manganese Bronze
An alloy of copper, zinc, and up to 3.0% manganese used for toothed wheels and gears.
Manganese Steel
A steel alloy with 12–14% manganese; used for drill bits.
A device used to hold two or more gauges with fluid passages and flow provisions; used for testing and servicing purposes.
A conduit-like device used to channel the air/fuel mixture into an engine.
A conduit-like device used to duct the exhaust gas out of an engine.
Manifold Absolute Pressure (MAP)
The pressure in an intake manifold relative to atmospheric pressure.
Manifold Absolute-Ppressure Sensor
A variable resistor used as a sensor to signal an engine-control computer relative to the vacuum conditions in the intake manifold.
Manifold Air Temperature
The temperature of the intake stream in the intake manifold, as increased by a heat riser or an Early Fuel-Evaporation system, and/or converted to an engine-control computer input by a sensor.
Manifold Gauge Set
A set of gauges used to service an air-conditioning system.
A set of gauges used to measure vacuum or pressure in an engine's intake or exhaust system.
Manifold Heat Control
A flapper-type valve in the exhaust manifold that diverts heat to the intake manifold.
Manifold Pressure
A positive pressure in the intake manifold measured in pounds per square inch or bars.
Manifold Vacuum
The negative pressure in an engine's intake manifold produced by the engine's pumping action and measured in inches of mercury.
Manomometer (u-tube)
A u-shaped tube with a graduated scale used for measuring the pressure of gases or vapors.
Manual Bleeding
A two-technician technique for bleeding brakes; one pumps the brakes as the other opens and closes the bleeder screws when required.
Manual Control Valve
A spool valve, located in the valve body, that determines fluid flow from the valve body to various hydraulic circuits controlled by the vehicle driver through the selector lever.
Manual Low
The position of the units in an automatic transmission when the driver selects the Low or first-gear position of the quadrant.
Manual Operation
The act of operating the power steering system in the event of an engine system failure; increased effort is required. 2.The ability to override or cancel any automatic or semi-automatic function.
Manual Selection
The vehicle operator's ability to:
Move the gear selector lever by hand, such as with a manual transmission.
Select any condition or function using a keypad, switch, or lever.
Manual Slide Release
The release mechanism for a sliding fifth wheel, which is operated by hand.
Manual Transmission
A manually shifted gearing device in the power train that allows variation on the relationship between engine speed and road speed.
A person, firm, or corporation engaged in the mass production or assembly of vehicles or any other product.
Manufacturer's Code
An alpha-numerical code to identify a product.
A lettered marking code on tire sidewalls indicating tire manufacturer, plant, tire size, type of construction, and date of manufacture.
Manufacturer's Service Manual
A book containing service information and technical data that is provided by the vehicle manufacturer.
Manufacturers of Emission Controls Association (MECA)
A trade association of the manufacturers of emission-control systems and components.
The science of planning, designing, managing, and scheduling people, goods, material, equipment, and machinery to produce a useable and sellable product.
An acronym for Maintenance Awareness Program.
An acronym for manifold absolute pressure.
MAP Sensor
A device used to measure MAP.
Small pieces of dirt, rubber, or other debris on the outer edges of a race track, outside the racing line.
The spring assembly in the clutch-drive plate that absorbs the energy when the clutch lever is released.
The material between the face and head of an intake or exhaust valve.
One of a series of cars usually identified by a Roman numeral.
A term often mistakenly used for marque.
The identifying marks on an assembly or component.
A French term meaning make, as in make of car.
The installation of a vehicle's power train in its chassis on an assembly line.
An abbreviation for mass airflow sensor.
To cover up, as in prior to painting.
The modifying of intake ports with dams to redirect the air flow.
Masking Area
A preparation stage in a paint shop in which the parts that are not to be painted are covered with paper and held in place with masking tape.
The measure of the quantity of matter that is contained in a given quantity of solid, liquid, or gas.
Mass Airflow Sensor (MAS)
A device found at the inlet of the intake manifold of an electronic fuel-injection system which supplies the computer with input as to the volume of air entering the manifold, using the temperature differential between a heated platinum wire or a plastic film and the passing air, to generate a signal of varying voltage.
Mass Production
The manufacture of a product in large quantities.
Master Cylinder
A brake-system component having an integral reservoir filled with hydraulic brake fluid where pressure is developed when the driver depresses the brake pedal causing a linkage to move a piston.
Master Kit (MK)
An engine kit that contains crankshaft and camshaft bearings, lifters, oil pump, pistons, rings, gasket set, and core plugs.
Master Leaf
A term used for main leaf, as in a spring.
Mat Fabric
A fiberglass fabric with an irregular strand pattern.
Match Bash
Two out of three, or three out of five drag racing events.
Match Race
The same as match bash.
Material Expanders
Fillers that are used in the place of active material in a battery; the primary difference between a 3- and 5-year battery.
Material Safety Data Sheet (MSDS)
A sheet required of the product manufacturer by OSHA, containing specific information about hazardous materials to be displayed in any workplace where such materials are used.
A large, cartridge-type fuse having a higher current-capacity use because they are less likely to cause an underhood fire when overloaded.
An abbreviation for microprocessor control unit.
An abbreviation for Mechanics' Education Association.
A top performing driver.
A car tough to beat in a race.
Mean Effective Pressure (MEP)
The average pressure developed within an engine cylinder during a four-stroke cycle.
Mean Motor Scooter
A top-performing car in drag racing.
Mean Rating
A more accurate rating than absolute rating or nominal rating.
The act of determining the size, capacity, or quantity of an object.
The structural metal often found in an engine block.
Big tires.
Drag racing slicks.
An abbreviation for Manufacturers of Emission Controls Association.
Mechanical Efficiency
The percentage of input power as related to the output power in a mechanical transfer.
Mechanical Fuel Pump
A device which draws fuel from the gas tank and delivers it to the carburetor by use of a mechanically operated Diaphragm.
Mechanical Properties
The characteristics of a material that are displayed when a force is applied to the material; usually relating to the elastic or inelastic response of the material.
Mechanical Seal
A seal that is formed with direct metal-to-metal contact.
Mechanical Valve Lifters
An adjustable valve lifter that provides direct cam-to-push-rod contact.
Mechanics' Education Association (MEA)
An association that offers upgrade educational courses to independent shops.
Medium Riser
Standard-height cylinder heads offered for the Ford 427 cid engine in the 1960s.
A term often used for competition, such as in drag meet.
The point where two or more pieces are joined together.
An abbreviation for methyl ethyl ketone.
To destroy or damage by overheating.
Melt Down
A description among drivers of what happens to pistons when they seize in an engine due to preignition or too lean a mixture.
Melting Capacity
A term used for ice-melting capacity.
Melting Point
The temperature at which a solid becomes a liquid.
Melting Range
The temperature range between solidus and liquidus.
Melting Time
The time required for an overcurrent to sever a fuse element.
The time required for a solid to become a liquid.
An abbreviation of Motor and Equipment Manufacturers Association.
An essential part of a machine or an assembly.
A person that belongs to a club or a group.
Memory Chip
A semiconductor device that stores information in the form of electrical charges.
Memory Seat
A power-seat feature which allows the driver to program different seat positions that can be recalled at the push of a button.
Memory Steer
An occurrence when steering does not return to the straight-ahead position after a turn, and attempts to continue in the original turn direction caused by a binding condition in the steering column or in the steering-shaft universal joints.
The top of a column of liquid in a tube.
An abbreviation for mean effective pressure.
An element (Hg).
A term used to designate a vacuum on the English scale, such as inches of mercury or in-Hg.
The engaging or mating of the teeth of two gears.
Metal Conditioner
A chemical used to remove light rust from a metal before surfacing or painting.
Metal Filament
The electrical conductor that glows when heated, as in an incandescent lamp.
Metal Inert Gas (MIG)
A gas used to shield a weld to prevent oxidation.
Metal Inert Gas Welding (MIG welding)
A welding method using an inert gas shield.
Metal Matrix Composite (MMC)
A mixture of metal and ceramic that is light weight and resistant to high temperature; used as an insulator.
Metal Pickling
A condition where metal is exposed to acid or is electroplated, causing it to become brittle.
Metallic Bond
The principal bond that holds metals together.
Metallic Brake Lining
Brake linings made of metal particles that have been bonded or sintered together.
Metallic Friction Material
A sintered friction material formulated with metallic or metallic-ceramic materials.
Metallic Paint
A paint that contains very small metallic particles causing the paint to seem to sparkle.
Metalworking Area
The area in an auto-body repair shop where a vehicle body is repaired.
The metal fabrication area of a service facility engaged in such activities as installing truck beds.
A term used for dynameter.
A metric unit for linear measure.
To regulate the flow of a liquid or gas.
An instrument, such as a voltmeter or ammeter.
Metering Device
Any device that meters or regulates the flow of a liquid or vapor.
Metering Rods
The tapered rods that regulate the flow of gasoline in a carburetor.
Metering Slit
A small, narrow opening used to meter fuel output in a fuel injector.
Metering Valve
A valve in a carburetor to deliver a precise amount of fuel or air.
A valve in the brake system that delays brake action to front-disc brakes until after application of the rear-drum brakes.
An odorless, colorless natural gas.
A form of alcohol used as a fuel for Indy cars and some drag-race classes: 85% methanol/15% gasoline.
Methyl Alcohol
A form of alcohol used as a fuel in Indy cars and some drag-race classes.
Methyl Ethyl Ketone (MEK)
A highly flammable fluid used for cleaning.
Methyl Tertiary Butyl Ether (MTBE)
An oxygenated compound used to raise the octane rating of gasoline.
Metri-Pack Connector
A connector similar to the weather-pack connector, but without the seal on the cover half.
Metric System
A measuring system used by most of the free world, except the United States which uses the English system. The United States is slowly moving to the metric system.
An insulating material used to separate the commutator bars of a generator or starter motor.
Mickey Thompson Entertainment Group (MTEG)
An organization to promote stadium races for off-road vehicles.
A tiny silicon chip with thousands of electronic components and circuit patterns etched onto its surface.
Microetch Test
A test in which the specimen is prepared with a polished finish, etched, and examined under high magnification.
A machine process to finish a surface of a part to reduce friction.
A metric unit of linear measure equal to one-millionth of a meter.
The basic electronic arithmetic, logic, and control computer elements required for processing. Widely used as the control devices for microcomputers; very useful and extremely important to the automotive industry.
Microprocessor Control Unit (MCU)
A device referred to as an electronic control unit or ECM.
The black box that controls various electrical and mechanical functions of a vehicle.
A chassis layout whereby the engine is behind the driver, but in front of the rear wheels.
A small, oval-track racing car.
The position of a stem-type service valve where all fluid passages are interconnected.
An incorrect term used for midpositioned.
An acronym for metal inert gas.
MIG Welding
A term used for metal inert gas welding.
Short for millimeter.
Mild Steel
A steel alloy with a low carbon content.
Miles Per Gallon (mpg)
The distance, in miles, a vehicle will travel per gallon of fuel.
Miles Per Hour (mph)
An indication of distance/time traveled.
Military Standard (MS)
A system of grading the quality of fasteners and other items.
An engine.
Milliampere (ma)
A metric unit of electrical measure.
Millimeter (mm)
A metric unit of linear measure.
Mini Stock
A category for four-cylinder, sub-compact vehicles on an oval track.
Minimum Forward Reduction
Simple planetary-gear-set combination with the ring gear as input, the planetary carrier output, and the sun gear held.
Minimum Thickness
The lower limit of the thickness required after metal has been removed from an item such as a brake disc, to retain its integrity.
Minispare Tire
A compact spare tire.
Minor Diameter
The smallest diameter of a cylinder.
The smallest diameter of a bolt thread.
Minor Overhaul
An engine-repair procedure that includes a valve job, replacing the piston rings, the rod bearings, and the gasket set.
Minor Tune Up
An engine-maintenance procedure performed on distributor ignition vehicles that includes only the replacement of parts found to be defective.
Capable of being mixed in all proportions.
An intermittent or continuous failure to ignite the air/fuel mixture in one or more cylinders.
A brief engine hesitation such as a misfire.
Missing Teeth
A condition found in a synchronous belt drive that may be caused by under-tensioning, misalignment, or excessive shock loads.
Teeth broken off a gear.
Mitsubishi Jet Valve
A tiny third valve that admits nothing but air to churn up the air/fuel charge and promote lean running and a complete burn.
To blend or combine.
To use parts, such as tires, of two or more sizes or types.
Mixing Chamber
That part of an apparatus in which a fuel gas, and oxygen or air are mixed.
Mixture Adjustment
To adjust the portions of a mixture, such as air and fuel.
An abbreviation for master kit.
An engine parts kit that contains all of the parts found in an MK plus the timing gears.
An abbreviation for metal matrix composite.
Mobile Air Conditioning Society (MACS)
A nonprofit organization founded in 1981 for the dissemination and distribution of comprehensive technical information, training, and communications to its members consisting of automotive air-conditioning shops, installers, distributors, suppliers, and manufacturers in the United States and Canada.
A term generally used to describe a particular set of operating characteristics.
Model Year
The year of vehicle manufacture, as designated by the manufacturer; not consistent with the calendar year.
Modesty Panel
The panel below the bumpers that conceals the chassis components. Also known as modesty skirt.
Modesty Skirt
Same as modesty panel.
To alter or change from the original.
A vehicle that has been reworked for high-performance operation.
Modified MacPherson Strut
A type of MacPherson strut suspension that uses shock struts with coil springs mounted between the lower arms and spring pockets in the cross member, to absorb minor road vibrations by the chassis rather than fed back to the driver through the steering system.
Modified Strut
A strut suspension where the coil spring is not part of the assembly and is independently located between the lower control arm and the frame.
Modular Wheel
A wheel made of different sections that are bolted or riveted together.
Modulated Vacuum
A vacuum signal regulated to a particular level.
A device that varies the frequency amplitude and phase of electromagnetic waves.
A device that regulates hydraulic line pressure in a transmission to meet varying load conditions.
A semi-conductor control for an electronic-ignition system.
Modulus of Elasticity
The point at which a material has been bent too far to snap back into shape.
Humidity, dampness, wetness, or small droplets of water.
Moisture Ejector
A valve mounted to the bottom or side of the supply and service reservoirs that collects water and expels it every time the air pressure fluctuates.
A hollow form into which molten metal is poured to form a part.
A fungus.
To form or shape an object.
To rejoin body panels using a filler material to conceal the seam.
Molded Connector
A male or female electrical connector usually having one to four wires that are molded into a one-piece component.
Molded Curved-Radiator Hose
A term used for preformed radiator hose.
Molded Hose
A section of hose permanently formed to fit a particular application.
Molecular Sieve
A drying agent.
The smallest particle a substance can be divided and still remain that substance.
Short for molybdenum.
Moly Lube
A lubricant popular for coating engine parts during rebuilding to avoid an initial dry start up.
Moly Ring
A piston ring with a molybdenum coating.
An element (Mo) used in some steel alloys to add hardness and strength.
Molybdenum Disulfate
A combination of molybdenum (Mo) and sulfur (S) sometimes added to oil and grease to improve their lubricating qualities.
Moment of Inertia
The tendency of a body to resist angular or rotational acceleration, such as a vehicle resisting a cornering effort.
An abbreviation for motor octane number.
An alloy of nickel (Ni) and copper (Cu).
Money Grabber
A driver who enters and starts a stock car race but leaves after a minimum number of laps, collecting appearance money but not racing seriously.
Money Pit
A vehicle that is expensive to restore and/or maintain.
An electronic sensor, such as the lambda sensor.
Monkey Motion
The excessive movement of a mechanical device, such as an improperly adjusted carburetor linkage.
The chemical term for refrigerant-22 (HCFC-12).
A unitized, autobody-frame structure with stressed-sheet-metal body panels.
Eye protection that may be worn over glasses.
Monoleaf Spring
A spring that is made up of a single steel leaf.
A device or structure made as a single unit.
Monolithic Catalytic Converter
A catalytic converter which has its catalytic materials coating a ceramic honeycomb, as distinguished from the pellet-bed converter.
Monolithic Timing
The use of an electronic timing device to make precise adjustments in engine timing when the engine is running.
Monster Truck
A truck, usually a pick-up, having huge, oversized wheels and tires with a heavy duty power train to drive them.
Montreal Protocol
An agreement signed by representatives of the participating countries to reduce CFC and HCFC emissions into the atmosphere by restricting and regulating the manufacture and sale of such products.
Moon Disc
A smooth hub cap that completely covers the wheel.
A device that converts electrical energy into mechanical energy, such as a fan motor.
Motor and Equipment Manufacturers Association (MEMA)
An association of manufacturers of automotive aftermarket parts, original equipment parts, tools, chemicals, and other products.
Motor Home
A self-contained vehicle built on a bus or truck chassis containing a driver's compartment and complete living facilities.
Motor Mounts
Supports made of hard rubber for the engine and transmission to be secured to the vehicle's frame.
Motor Mouth
An overly talkative person.
Motor Octane Number (MON)
A term used for octane number.
Motor Oil
A lubricant expressly formulated for use in an engine.
Motor Town
Detroit, Michigan.
Motor Vehicle
A machine, usually on rubber tires, that is propelled by means other than muscle power, and which does not operate on rails.
Motor Vehicle Manufacturers Association (MVMA)
A trade association of the major automobile and truck manufacturers in the United States.
The name of a Detroit-based record company.
Short for motor town or Detroit.
A Bosch electronic fuel-injection and ignition-management system.
Mount and Drive
Pulleys, mounting plates, belts, and fittings necessary to mount a compressor and clutch or any other engine-driven assembly on an engine.
Mountain Motor
A big block V–8, usually Chevrolet or Ford, enlarged to 500 cid or more; often to as much as 600 to 800 cid.
Mounting Grommet
The replaceable rubber bushings used at both ends of the shocks for mounting to reduce the transfer of sounds and jarring motions between the shocks and their mounting points on the vehicle.
A reinforced eyelet through which a fastener is attached.
Mounting Position
The position at which a device is mounted, such as horizontal or vertical.
A computer input device for moving a cursor or data around on the display screen.
Mouse Milk
An additive for oil or fuel.
Mouse Motor
A Chevrolet small-block V-8.
Moving Vehicle Resistance
A measure of the air resistance of an auto body design.
An abbreviation for miles per gallon.
An abbreviation for miles per hour.
An abbreviation for military standard.
An abbreviation for Material Safety Data Sheet.
An abbreviation for methyl tertiary butyl ether.
An abbreviation for Mickey Thompson Entertainment Group.
Mud and Snow Tire
An all-season tire.
A term used for snow-and-mud tire.
Mud Bogging
Racing an off-road vehicle through a 100–200 foot (30–61 meter) mud hole.
Mud Flap
A flap hanging down behind a tire to prevent the tire from throwing debris against the lower panel of the vehicle or into the path of a following vehicle.
Mud Plug
A cap installed in the center of a wheel to keep out mud and other debris.
A hollow, tubular device used in the lines of some air conditioners to minimize the compressor noise or surges transmitted to the inside of the car.
A device in the exhaust system used to reduce noise.
Muffler Bearing
A non-existent part.
Muffler Clamp
A clamp that secures the muffler, or pipe, to the bracket or hanger.
Muffler Hanger
A hanger that is used to secure the muffler.
A yard tractor not suitable for over-the-road service.
A road race car used for practice or testing.
Multi-Fuel Vehicle
A vehicle having a modified engine that runs on more than one fuel, such as LPG and gasoline.
Multi-Leaved Spring
A flat suspension spring having more than one leaf.
Multi-Point Fuel Injection
A type of fuel-injection system that has a separate fuel injector for each of the engine's cylinders to deliver better performance and lower emissions than throttle-body injection (TBI) systems.
Multi-Point Injection
A term used for multi-port fuel injection.
Multi-Purpose Vehicle
A term used for sports vehicle.
Multi-Valve Head
A cylinder-head design having more than one exhaust and/or intake valve per cylinder.
Multi-Viscosity Oil
An oil having a low viscosity when cold and a high viscosity when hot.
Multiple Disc
A clutch with several driving and driven discs.
Multiple Pass
A term that applies to a recovery/recycle unit that removes refrigerant from an air-conditioning system and circulates it through the recovery/recycle unit to remove contaminants before it is pumped into the recovery cylinder.
Multiple-Disc Clutch
A clutch having a large drum-shaped housing that can be a separate casting or a part of the transmission housing.
Multiple-Leaf Spring
Leaf springs having a series of flat, steel leaves of varying lengths clamped together with a center bolt extending through them to maintain their position.
Multiple-Strand Chain
An assembly made up of two or more rows of roller links joined into a single structure by pins extending transversely through all rows.
Multiple-Viscosity Oil
An engine oil that has a low viscosity when cold and a high viscosity when hot.
Multiple-Wire Hard-Shell Connector
A connector, usually having a removable, hard-plastic shell, that holds the connecting terminals of separate wires.
A popular four-speed manual transmission built by General Motors in Muncie, Indiana.
An early, dry-lake site in the Mojave Desert, now known as Rogers dry lake; it is a space shuttle landing site at Edwards Air Force Base.
Muscle Car
A high-performance car with a big-block engine in a light-weight chassis on heavy-duty suspension with a two-door body.
Mushroom Lifter
A valve lifter having a foot diameter larger than the body diameter.
Mushroomed Valve Stem
A valve stem that is worn so much that its end has spread and metal is hanging over the valve guide.
Mutual Induction
A condition whereby a voltage is generated in a secondary coil due to the application of voltage in an adjacent primary coil, such as the coil used in a conventional ignition system.
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