DICTIONARY OF AUTOMOTIVE TERMS - "Cr"

CR :

Acronym for "compression ratio."

Crab :

The action of a vehicle where the rear wheels are offset from the track of the front wheels.

Crab-tracked :

A situation where the front wheels are wider apart than the rear.

Crack :

1. To open something just a little.
2. 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.

Also See:
circumferential crack
groove cracks
incipient crack

Crackage :

Joint in a structure which permits movement of a gas or vapor through it, even under a small pressure difference.

Cracker :

A non-American colloquial term for something that is very enjoyable, e.g., "My car's a cracker."
Also See:
nut cracker

Cracking :

1. The action of opening a valve slightly and then closing the valve immediately.
2. Forming of cracks for instance in the sidewalls of a tire because of the hardening of the rubber or in paintwork because of weathering.

Also See:
heat cracking
radial cracking
stress corrosion cracking
stress cracking
weather cracking

Cracking a valve :

Opening a valve a small amount.

Cracking groove :

A split in the grooves of the tread caused by excessive strain.

Cracking tread :

A split in the grooves of the tread caused by excessive strain.

Cradle frame :

A motorcycle frame with two tubes passing under the engine.
Also See:
open cradle frame

Crane :

A lifting device used to remove or lift a motor or transmission

Crank :

1. An arm set at right angles to a shaft or axle, used for converting reciprocal (to-and-fro) motion into circular motion.
   Also See:
   cottered crank
   cotterless crank
   flat crank
   hand crank
2. 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 :

1. 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.
2. 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.

Crank bolt :

A bolt that run through the end of the crankarm and into the bottom bracket spindle.

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.
Also See:
positive crankcase ventilation system
positive crankcase ventilation

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 emissions :

Pollutants allowed to escape into the atmosphere from the crankcase

Crankcase half :

One side of a crankcase usually split down the middle. Usually found in motorcycle engine.

Crankcase pre-compression :

See:
crankcase compression

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.
Also See:
closed crankcase ventilation
positive crankcase ventilation
positive crankcase ventilation system

Crankcase ventilation system :

See:
positive crankcase ventilation system

Cranked :

Something which has an elbow or right-angle shape.

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:
cold cranking ability

Cranking ability :

See:
cold cranking ability

Cranking amps :

See:
cold cranking amps

Cranking circuit :

See:
starting system.

Cranking motor :

See:
starter.

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.

Cranking speed :

The speed at which the starter turns the engine.

Crank kit :

A reground or reconditioned crankshaft and new main and connecting rod bearings

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:
splayed crankpins

Crank pulley holder :

A tool which secures the crank in place while other adjustments are being made.

Crankset :

A group of components on a bicycle that includes the bottom bracket removable parts, two crankarms, and one or more chainrings.
Also See:
cotterless crankset

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.
Also See:
assembled crankshaft
balanced crankshaft
built-up crankshaft
offset crankshaft
stroked crankshaft

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 :

1. The journals running in the main bearings as opposed to those for the big-end bearings.
2. Part of shaft which contacts the bearing on the large end of the piston rod.

Crankshaft position sensor :

A sensor ring with lobes which sends information concerning the precise position of the crankshaft so that accurate ignition timing can be achieved.

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 runout :

A term used to describe how much a crankshaft is bent

Crankshaft seal :

Leakproof joint between crankshaft and compressor body.

Crankshaft sprocket :

A chain-sprocket mounted on the nose of the crankshaft which drives the camshaft by means of a timing chain

Crank throw :

1. The part of the crankshaft that the connecting rod fastens to. See crankpin.
2. The distance between the crankpin and the axis of rotation or centerline of the crankshaft, which is equal to half the stroke

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.

Crash :

A vehicle collision with another vehicle or a stationary object.
Also See:
car crash
frontal crash
head-on crash
oblique crash test

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 box :

An informal term for a non-synchromesh transmission. Short term for "crash gearbox."

Crash gearbox :

An informal term for a non-synchromesh transmission.

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:
oblique crash test

Crash test dummy :

A specially designed manikin which records the effects in the event of a crash

Crate :

1. A framework of wooden boards for protecting something during transport.
2. A vehicle which appears to be unreliable and ready to fall apart.

Crater :

A depression in the face of a weld, usually at the termination of an arc weld

Cratering :

The formation of holes in the paint coat due to surface contaminants.

Crawler :

A British term for a slow-moving vehicle

Crawler gear :

A British term for a very low gear used especially in off-road application

Crawler lane :

A British term for a truck lane for slow moving trucks, especially going up a hill.

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

Cream :

1. To hit another vehicle.
2. A soft paste.
   Also See:
   barrier cream

Crease :

A wrinkle or ridge in metal as a result of design or accident damage.

Creep :

1. 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."
2. 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
3. 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.
Also See:
mechanic's creeper

Crescent :

The part between the inner and outer gears of an internal gear pump

Crescent wrench :

An adjustable wrench with smooth jaws.

Cressida :

A model of automobile manufactured by Toyota
Click image for books on Cressida

Crest :

The highest point of a screw thread. The opposite is called a "root."
Also See:
thread crest

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.

Crimper tool :

See:
wire stripper/crimper tool

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 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.

Critical pressure :

Compressed condition of refrigerant which gives liquid and gas the same properties.

Critical speed :

The top speed of an engine or shaft at which unwanted vibration begins.

Critical temperature :

Temperature at which vapor and liquid have same properties.

Critical vibration :

Vibration which is noticeable and harmful to structure.

Crocodile clip :

British term for alligator clip

Crosley :

A vehicle brand of which the 1950-52 Hotshot/SS models are milestone cars.

Crossbar :

1. Any transverse bar, especially a tie rod across the chassis.
2. The top tube of a bicycle or motorcycle frame.
3. 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 border shopping :

See:
Canadian cross border shopping

Cross bracing :

Strengthening ribs or other members which connect two sides of a frame

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-country vehicle :

An off road vehicle

Cross-draught carburetor :

A sidedraft carburetor

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 :

See:
cross-hatch.

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-head screwdriver :

A Phillips or Reed and Prince screwdriver where the tip forms an X or +

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".
Also See:
axle crossmember
rear axle crossmember
rubber-isolated crossmember

Crossover :

See:
heat crossover.

Crossover cable:

See stirrup cable

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 :

See:
conventional cross ply

Cross-ply tire :

See:
bias ply tire

Cross-point screwdriver :

A Phillips or Reed and Prince screwdriver where the tip forms an X or +

Cross scavenging :

Scavenging in a two-stroke engine with flow across the cylinder assisted by a wedge-shaped piston crown

Cross section :

A view of an object when cut transversely at right angles across its center.
Also See:
section width

Cross-shaft :

1. Any transverse shaft.
2. The outgoing shaft of the steering gearbox, to which the pitman arm is connected. The British term is "rocker shaft"

Cross-shaft lug wrench :

See:
lug wrench.

Cross-shaft lug wrench :

See:
lug wrench.

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.

Crosswind :

Wind blowing at the side of a vehicle

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 :

1. The top part of the head of a piston.
   
2. The outward curvature of an apparently flat sheet metal panel.
3. The tread area of a tire.
4. The curve or convex surface of a properly finished weld.
5. A model of automobile manufactured by Toyota
   Click image for books on Toyota Crown
   

Also See:
fork crown
high crown spoon
low crown panel
pent crown piston
piston crown
valve crown

Crown panel :

See:
high crown panel
low crown panel

Crown piston :

See:
pent crown piston

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 spoon :

See:
high crown spoon

Crown Victoria :

A model of automobile manufactured by Ford
Click image for books on 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

Crown width :

The distance of a tire tread shoulder to shoulder measured along the buffed contour.

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 :

Unrefined petroleum as it comes out of the ground. It forms the basis of gasoline, engine oil, diesel oil, kerosene, etc.

Cruise :

To drive at a constant speed, often at highway speed.

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.

Cruiser:

1. Any motorcycle designed to be ridden long distances.
2. Motorcycle riders who ride long distances.

Also see beach cruiser

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

Cruising circuit :

The main carburetor metering system

Cruising speed :

Constant speed at which a vehicle can be driven on the highway

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

Crusher :

A machine which crushes scrapped cars into small blocks.

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.

CRX :

A model of automobile manufactured by Honda
Click image for books on Honda CRX

Cryogenic fluid :

Substance which exists as a liquid or gas at ultra-low temperatures (-250°F or lower).

Cryogenics :

1. The study of physical phenomena at a temperature below -50°F (46°C)
2. Refrigeration which deals with producing temperatures of 250°F below zero and lower.

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