- CR
- Acronym for Compression ratio
- CRABS
- Acronym for Cement Recycled Asphalt Base Stabilization -- A resurfacing process that involves grinding the existing roadway surface down to the gravel base, then adding a strengthening agent, such as cement, to the old asphalt. The mixture is then compacted and used as the base for a new layer of asphalt. The section is then overlaid with a new layer of pavement.
- Crack
-
- To open something just a little.
- A fracture in something which does not split it open. A Hairline crack is a very narrow fracture which is often barely visible with the naked eye.
- Crackage
- Joint in a structure which permits movement of a gas or vapor through it, even under a small pressure difference.
- Cracked
- A petroleum product produced by a secondary refining process such as thermal cracking or vis-breaking processes which yield very low quality residue.
- Cracker
- A non-American colloquial term for something that is very enjoyable, e.g., "My car's a cracker."
Also see
- Cracking
-
- The action of opening a valve slightly and then closing the valve immediately.
- Forming of cracks for instance in the sidewalls of a tire because of the hardening of the rubber or in paintwork because of weathering.
- CRADA
- Acronym for Cooperative Research and Development Agreement
- Crank
-
- An arm set at right angles to a shaft or axle, used for converting reciprocal (to-and-fro) motion into circular motion.
- The action of trying to start a vehicle engine or an electrical motor by means of a crank handle or by an electrical starter.
- Crankarm
-
- A part on a bicycle, where one end is attached to the Bottom bracket axle and the other holds a pedal, whose forward rotation provides the leverage needed to power the Bicycle.
- An arm set at right angles to a shaft or axle, used for converting reciprocal (to-and-fro) motion into circular motion.
- Crankarm bolt
- The bolt that holds a Crankarm on the end of the axle in a Cotterless crankset
- Crankarm fixing bolt
- The bolt that holds a Crankarm on the end of the axle in a Cotterless crankset of a Bicycle.
- Crankcase
- The lower part of the engine that surrounds the Crankshaft. It contains the Crankshaft, Piston Cylinders, Connecting rods and other moving parts of the engine. As well, in non-air-cooled engines, it has a number of internal passages for the Coolant and oil transfer. In air-cooled engines, it has internal passages for oil transfer; but usually it has fins on the exterior to dissipate the heat. The Crankcase is not to be confused with the pan which is a thin steel Cover that is bolted to the bottom of the Crankcase.
- Crankcase breather
- A vent which allows fumes and blow-by gases to escape. It reduces condensation. This breather is usually connected to the air intake of the carburetor so that the fumes can be burned in the combustion chamber
- Crankcase compression
- The primary compression in a two-stroke engine located below the pistons and enables a more fresh charge to be fed into the cylinder. Also called crankcase pre-compression.
- Crankcase depression regulator
- (CDR) a device which aids in the control of crankcase gases by maintaining a specific amount of vacuum in the crankcase
- Crankcase dilution
- An accumulation of unburned Gasoline in the Crankcase, an excessively rich fuel mixture or poor Combustion will allow a certain amount of Gasoline to pass down between the Pistons and Cylinder walls and dilute the engine oil.
- Crankcase half
- One side of a crankcase usually split down the middle. Usually found in motorcycle engine.
- Crankcase scavenging
- A system in a two-stroke engine where the fresh charge is induced into the cylinder by way of the crankcase and the transfer ports
- Crankcase ventilation
- Circulation of air through the crankcase of a running engine to remove water, blow-by, and other gases in order to prevent oil dilution and contamination, sludge formation, and pressure build-up.
- Crank cotter
-
A tapered pin or wedge which is inserted into holes in two parts to secure them. Older bicycles used a cotter to secure the crank arm to the crank spindle. Also called just cotter
Cotter
Also see
- Cranking
- The act of engaging the Starter by
turning the key in the Ignition
switch which makes the engine turn over. In the old days, a
hand Crank was used to do this, thus
the term cranking.
Also see
- Cranking on the throttle
- The action of moving a twist grip so that more fuel enters the engine and thus increases the speed of the vehicle.
- Crankpin
- The bearing surface on a Crank of the
Crankshaft to which the
Connecting rod is attached. Also called the
Journal or Crank throw.
Also see
- Crank pulley holder
-
A tool which secures the crankshaft in place while other adjustments are being made.
Crank Pulley Holder
- Crank sensor
- A device which picks up signals to locate the position of the No. 1 cylinder and sends the information to the ECU in order to determine engine speed.
- Crankset
-
A group of Components on a Bicycle that includes the Bottom bracket removable parts, two Crankarms, and one or more Chainrings.
Crankset
Also see
- Crankshaft
-
A main rotating shaft running the length of the engine. The crankshaft is supported by Main bearings. Portions of the shaft are offset to form throws to which the Connecting rods are attached. As the Pistons move up and down, the Connecting rods move the crankshaft around. The turning motion of the crankshaft is transmitted to the Transmission and eventually to the driving wheels.
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CrankshaftAlso see
- Crankshaft angle sensor
- A device which picks up signals to locate the position of the No. 1 cylinder and sends the information to the ECU in order to determine engine speed.
- Crankshaft balancer
- A circular device in the front end of the crankshaft, designed to dampen some of the impulses from the combustion events in the cylinders. Also called Harmonic balancer
- Crankshaft counter-balance
- A series of weights attached to or Forged integrally with the Crankshaft so placed as to offset the Reciprocating weight of each Piston and rod assembly
- Crankshaft counterbalance
- Series of weights attached to or forged integrally with crankshaft and placed to offset reciprocating weight of each piston and rod assembly
- Crankshaft gear
- A gear mounted on the front of the Crankshaft. It is used to drive the Camshaft gear.
- Crankshaft journal
-
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Crankshaft journal- The journals running in the main bearings as opposed to those for the big-end bearings.
- Part of shaft which contacts the bearing on the large end of the piston rod.
- Crankshaft position sensor
-
(CP or CKP) A sensor ring with lobes which sends information concerning the precise position of the crankshaft so that accurate ignition timing can be achieved.
Crankshaft Position Sensor
- Crankshaft pulley
- A wheel attached to the front end of the Crankshaft which is connected by Fan belts to the fan, the Alternator, and other devices so that the rotating Crankshaft can drive these other parts as well. The crankshaft pulley usually has Timing marks located on it, and these are necessary for checking and adjusting Timing with a Timing light. Also called a harmonic balance wheel.
- Crankshaft sensor
- A device which picks up signals to locate the position of the No. 1 cylinder and sends the information to the ECU in order to determine engine speed.
- Crankshaft sprocket
- A chain-sprocket mounted on the nose of the crankshaft which drives the camshaft by means of a timing chain
- Crank throw
-
- The part of the crankshaft to which the connecting rod fastens.
- The distance between the crankpin and the axis of rotation or centerline of the crankshaft, which is equal to half the stroke
Also see
- Crank web
-
One of the pair of arms which carry the big-end journal. The webs join the crankpins and the main journals, and also serve as balance weights for smooth engine running.
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Crankshaft Web
- Crash barrier
- A longitudinal railing usually found on the edge of the road especially around a curve to help prevent vehicles from leaving the road.
- Crash recorder
- An electronic device which measures and records a number of characteristics of a vehicle for 60 seconds before a crash the speed, direction, braking, etc. so that the cause of a crash can be determined.
- Crash sensor
- A sensor which deploys an air bag when a crash is determined -- usually because of excessive deceleration
- Crash test
- A controlled test of a vehicle in which it is propelled into a wall or another vehicle at a
given speed in order to determine the effect on its structure and the effectiveness of its safety
devices.
Also see
- Crate
-
- A framework of wooden boards for protecting something during transport.
- A vehicle which appears to be unreliable and ready to fall apart.
- Crate Motor
-
- A brand new, never fired engine or electric motor.
- A remanufactured engine or electric motor.
- Crawler
-
- An off-road vehicle utilizing track propulsion instead of wheels.
- A British term for a slow-moving vehicle
- Crawling
-
- A colloquial term for traveling very slowly, usually at a time when there is a traffic jam.
- An electric motor that runs up to one-seventh of full speed.
- Crazing
- Many fine Cracks in the paint surface, resembling crow's feet. It is similar to checking, but more sever, where fine lines or cracks appear in the paint
- Creep
-
- The tendency of a vehicle with automatic transmission to edge forward when idling when the transmission is in Drive and the brake is not engaged. Also called idling drag.
- When a crankshaft has slightly excessive runout (is slightly bent), it can sometimes be corrected by laying the crank in its saddles, installing the center main bearing cap (with its bearing insert) and leaving it for a day or two. Sometimes the crank will creep or bend enough to put it within the specified runout range
- The change of an adhesive or sealer under constant pressure or load, following its first slip from its original position (elastic deformation). Creep at room temperature is sometimes called cold flow
- Creepage
- The slow spreading of rust under the paint which usually first appears as a blister and then flaking
- Creeper
-
A platform on four small Caster wheels that allows you to move around easily while lying on your back under your vehicle.
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Creeper
- Creep strength
- A measure of the resistance of fasteners to stress under elevated temperatures. At higher temperatures, a fastener can change in dimension under the same load, and that is called creep. Creep can cause the loosening of fasteners as temperature increases.
- Crescent® wrench
-
An adjustable wrench with smooth jaws. Used to fit a variety of sizes of nuts and bolt heads
Crescent Wrench
- Crest
-
- The highest point of a screw thread. The opposite is called a root
- That surface of the thread which joins the flanks of the thread and is farthest from the cylinder or cone from which the thread projects.
Also see
- Crest Clearance
- As in a thread assembly, the distance, measured perpendicular to the axis, between the crest of a thread and the root of its mating thread.
- Crest Truncation of Thread
- The distance, measured perpendicular to the axis, between the sharp root and the cylinder or cone which bounds the root.
- Crevice corrosion
- Rust or corrosion that develops on an object where there is a joint or sharp bend and is caused by a lack of oxygen in formation or by moisture.
- Crew Cab
-
A pickup truck with a large passenger compartment with four full-size doors which lead to two full rows of seating. The doors are mounted so that they swing open the same way as most four-door car doors do. Toyota calls it a Double Cab, Dodge calls it a Quad Cab, Ford calls it a SuperCrew.
Crew Cab
- Crimping
- The creation of corrugations in two thin metal parts as they are pressed tightly together in order to join them. This is often the method used to attach fittings to the end of an electrical wire -- thus avoiding the necessity of soldering
- Crimping pliers
-
A tool which looks like pliers with serrated jaws which are used to attach fittings to the end of an electrical wire.
Crimping Pliers
- Crimping tool
- A tool which looks like pliers with serrated jaws which are used to attach fittings to the end of an electrical wire.
- Crisper
- Drawer or compartment in refrigerator designed to provide high humidity along with low temperature to keep vegetables-especially leafy vegetables-cold and crisp.
- Criteria pollutant
- A pollutant determined to be hazardous to human health and regulated under EPA's National Ambient Air Quality Standards. The 1970 amendments to the Clean Air Act require EPA to describe the health and welfare impacts of a pollutant as the criteria for inclusion in the regulatory regime.
- Critical pressure
- Compressed condition of refrigerant which gives liquid and gas the same properties.
- Crocodile clip
- British term for Alligator clip
- Crosley
- A vehicle brand of which the 1950-52 Hotshot/SS models are milestone cars.
- Crossbar
-
- Any transverse bar, especially a tie rod across the chassis.
- The top tube of a bicycle or motorcycle frame.
- A short bar used to assist a combination wrench in providing extra torque. The British term is Tommy bar
- Cross-bolt
- A system of securing the main bearing caps with four bolts per cap by which two bolts support the bearing cap from below, in the conventional manner, and two other bolts enter the bearing from the side, passing through the sides of the engine block. The cross-bolts are visible from the outside of the engine. This system of securing the main bearing caps ensures good side-to-side, as well as up-and-down rigidity
- Cross charged
- Sealed container of two fluids which together create a desired pressure-temperature curve.
- Cross coat
- Paint spraying technique in which consecutive coats are sprayed at right angles to one another
- Cross-country bike
- A mountain bicycle suited to racing on varied terrain; features include wide-range gearing with super lows, sometimes with short Travel (3 inches or less) dual-suspension, great brakes, and a light performance-oriented frame
- Cross-draught carburetor
- A Sidedraft carburetor
- Cross flow
- A flow of gas or fluid going across another flow at an angle essentially perpendicular to one another.
- Crossflow cylinder head
- A cylinder head design (especially in an OHC engine) with the inlet manifold on one side and the exhaust manifold on the other side of the head, so that inlet and exhaust valves are arranged on opposite sides of the combustion chamber, giving a wider engine but better gas flow.
- Crossflow head
- A cylinder head with the intake valves) on one side of the combustion chamber and the
exhaust valve(s) on the other. Also called T-head
- Crossflow radiator
- A radiator in which the water flows sideways instead of vertically, and which is therefore wider than it is high, permitting a lower hood line
- Cross-hatch
- The desired checkerboard design of the inner surface of cylinder after it is Honed.
- Cross-hatch coat
- Checkerboard application of paint to be sure of a continuous paint film. One medium coat is usually followed by a second medium Coat in a perpendicular direction.
- Cross-head screw
- A screw with a slot which looks like an X or + into which the tip of the blade of a Phillips or Reed and Prince screwdriver can be inserted
- Cross-jetting
- Rejetting the carburetor jets from left-to-right to compensate for a left-to right variation in performance. These tests are usually conducted using an engine dynamometer
- Cross member
- A brace or strut which provides structural stability for the sides of a frame -- often in the shape of an X.
- Crossover
- A widely used term to indicate a smaller two-box configuration SUV based on a car
chassis rather than a truck chassis. E.g., Ford Flex
See
- Crossover gearing
- A Bicycle Gearing system whose shift sequence involves moving from the lowest to the midrange of gears on the smaller Chainring, then crossing over to the larger Chainring for the remainder of the gears.
- Cross-ply tire
- Tire in which the sidewall reinforcement plies run diagonally from the bead towards the tread - each
layer of textile at a different angle to its adjacent layer. Generally superseded by radial-ply tires
whose thinner, more flexible sidewalls and braced tread yield better grip and lower rolling resistance.
Because of thicker, multi-ply sidewalls, not so prone to sidewall damage as radials and can have low-cost
applications when operating continuously on rock. However, reduced pressures in soft going can, due to the
thick sidewalls, cause overheating and possibly delamination of the tire.
See
- Cross scavenging
- Scavenging in a two-stroke engine with flow across the cylinder assisted by a wedge-shaped piston crown
- Cross-shaft
-
- Any transverse shaft.
- The outgoing shaft of the steering gearbox, to which the pitman arm is connected. The British term is rocker shaft
- Cross shaft
- The shaft in the steering Gearbox that engages the Steering shaft worm, the cross shaft is Splined to the Pitman arm.
- Cross-spoke wheel
- Modern design of alloy wheel which imitates the appearance of the classical wire wheel
- Cross-threaded
- The characteristic of a bolt or nut in which the bolt is inserted at an angle so that the original threads are damaged
- Cross three
- A spoking pattern in which a Spoke passes over two and under a third spoke before being attached to the rim.
- Crotch rocket
- A term some people use to refer to Sportbike.
- Crowbar
- A iron bar tool with a crook at one end with a forking device for removing nails, etc. The other end has a wedge shape.
- Crowded engine compartment
- An engine compartment or bay in which all the available space around the engine is occupied by other objects (alternator, pumps, air intake system, battery, wiper motor, heater motor, windshield washer motor, starter, radiator, air conditioner, hoses, pipes, wiring, electronic boxes, etc.)
- Crown
-
-
The top part of the head of a piston.
Piston Crown
- The outward curvature of an apparently flat sheet metal panel.
- The tread area of a tire.
- The curve or convex surface of a properly finished weld.
- A convex road surface that allows runoff to drain to either side of the road prism.
-
A model of automobile manufactured by Toyota
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Toyota Crown
-
- Crown radius
- The measurement of the curvature of a tire tread between the shoulders of the tire. Expressed as a percentage, it indicates the relative flatness of the tire tread area.
- Crown Victoria
-
A model of automobile manufactured by Ford
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Ford Crown Victoria
- Crown wheel
- The larger of two gears in a bevel gear drive with teeth around its periphery facing sideways
- Crown wheel and pinion
- A pair of gears in the final drive of a vehicle, always found in the back axle of a rear-wheel drive layout where the pinion is on the end of the propeller shaft driving the crown wheel mounted on the differential at right angles to it, and also in front-wheel drives where the engine is not transversely mounted
- CRT
- Acronym for Cathode ray
tube
- Cruciform frame
- A frame with an X-shaped bracing either as a chassis frame, or in a monocoque as strengthening for the floor
- Crude oil
- A mixture of hydrocarbons that exists in liquid phase in natural
underground reservoirs and remains liquid at atmospheric pressure
after passing through surface separating facilities. Depending upon
the characteristics of the crude stream, it may also include:
- Small amounts of hydrocarbons that exist in gaseous phase in natural underground reservoirs but are liquid at atmospheric pressure after being recovered from oil well (casinghead) gas in lease separators and are subsequently commingled with the crude stream without being separately measured. Lease condensate recovered as a liquid from natural gas wells in lease or field separation facilities and later mixed into the crude stream is also included
- Small amounts of nonhydrocarbons produced with the oil, such as sulfur and various metals
- Drip gases, and liquid hydrocarbons produced from tar sands, oil sands, gilsonite, and oil shale
Also see
- Cruise control
- A feature that keeps your vehicle moving at a set Speed.
Old cruise controls were mere Throttle control units which
kept the engine speed the same.
When the vehicle approached a hill, the vehicle slowed down noticeable going up and speeded
up going down. Later models used Vacuum controls to
push or pull on the Accelerator rod. Newer models use
electronic controls to accomplish this task. It can be turned off by hitting the off
Button or touching the
Brake pedal. The resume switch allows you to return to the
pre-set speed after brake disengagement. The Coast switch
slows the speed down and the accelerate switch increases it.
Also see
- Cruiser
-
- Any motorcycle designed to be ridden long distances.
- Motorcycle riders who ride long distances.
Also see
- Cruiser bag
- A leather bag which is mounted on the top surface of the fuel tank or possibly other parts of a motorcycle. Although it can be filled with anything for a trip, usually it contains items that you want to access quickly (e.g., camera, road map).
- Cruiser stern
- A spoon-shaped stern used on most merchant ships designed to give maximum immersed length
- Crumple zone
- An area of a vehicle that is designed to compress during an accident to absorb the energy from the impact.
- Crush
- A slight distortion of the bearing shell that holds it in place as the engine operates
Also see
- Crush height
- The precision insert bearing must fit the bottom end of the connecting rod in order to transfer friction heat to the connecting rod. The insert will protrude a small amount above the rod bore parting surface. This distance is called the crush height. When the rod halves are drawn together, the inserts touch before the halves, thus forcing the inserts tightly into place.
- Crush washer
- A disc with a hole in the center. It is placed around the threads of a bolt and secured with a nut or screwed into a hole. When the head of the bolt is forced against it, the washer is squashed. Crush washers are used on some spark plugs to provide a better seal when installed.
- Cryogenic fluid
- Substance which exists as a liquid or gas at ultra-low temperatures (-157°C or lower).
- Cryogenics
-
- The study of physical phenomena at a temperature below -46°C
- Refrigeration which deals with producing temperatures of -157°C and lower.