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SESSIONS.....WATCH OUT FOR DETAILS Official Driving School for The Civil Protection Department. Cell: 79693511 |
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rectifier: A device used to change AC (alternating current) into DC (direct current). Some small motorcycles use a single diode for this purpose (half-wave rectifiers), the overwhelming majority use four diodes connected in a bridge which yields full-wave rectification. Also see diode. red line: [1] Top recommended engine rpm. If a tachometer is used, it will have a mark (red line) indicating maximum rpm. Some tachometers mark the red line with a colored sector. Others have two lines: the lower one marking the maximum allowable sustained engine rpm, the higher line indicating the absolute maximum rpm. [2] (RL) Tires with a red concentric line which were marketed in the late '60s and early 70s. reducer: The solvent that is used to thin enamel. reducing flame: An oxygen-fuel gas flame with a slight excess of fuel gas. reduction of area: Difference in cross sectional area of a specimen after fracture, as compared to original cross sectional area. reed valve: A one-way valve used in a . It is made of a flat strip of metal that lies on the floor of the crankcase over a hole connected to the carburetor. As the piston moves up, the vacuum developed in the crankcase lifts the reed valve off the hole. The vacuum causes the fuel-air mixture to flow from the carburetor into the crankcase. Then, as the piston starts to move down, pressure increases in the crankcase pushing the reed valve down, closing the hole and sealing the crankcase. reefer : A refrigeration unit which is mounted on a large truck to cool the contents in the trailer. reel: A revolving, often cylindrical device for winding up or letting out cord, wire, or strap. See inertia reel. refit: closure of a plant for the purpose of plant conversion or retooling. reformulated gasoline: Fuel with less volatility and reduced levels especially of toxic hydrocarbons. reformulated gasolines: Fuels with less volatility and reduced levels of especially toxic hydrocarbons. refrigerant: The liquid used in refrigeration systems to remove heat from the evaporator coils and carry it to the condenser. It absorbs and gives up heat as it changes from a liquid to a gas to a liquid. Freon-12 was a common automotive refrigerant, but it has been replaced by C134. refrigerant-12: The name applied to refrigerant generally used in automotive air conditioning systems and refrigerators. Also called freon-12. registration: motor vehicle ownership that is filed with the province/state. regrooveable tire: See special mileage tire. regrooving: The act of cutting new tread grooves into the crown of the tire after the original tread is worn down. A practice which is legally forbidden in many places. regulator, voltage: See voltage regulator. regulator: A device to reduce and control pressure in gas or liquid. reinforcement: Any material, usually rubber and fabric, vulcanized to the tire to return strength to the cord body upon an injury. reinforcement of weld: Excess metal on the face of a weld. relay: An electro-magnetically operated switch used to make and break the flow of current in a circuit. As low amperage current is passed through one circuit of the relay, it switches a greater current through another line. For example, when installing auxiliary lights with a heavy draw, the stock light switch may not be able to take the current. Thus a relay is installed so that when the light switch is turned on, low current is sent to the relay. The relay closes the circuit of heavy wiring directly from the battery to the lights. Also called "cutout" and "circuit breaker." relay valve: See ABS Relay Valve. release finger: See clutch semi-centrifugal release fingers. release fingers: See clutch semi-centrifugal release fingers. relief valve: See pressure relief valve. relieve: To remove, by grinding, the small lip of metal between the valve seat area and the cylinder and removing any other metal deemed necessary to improve the flow of fuel mixture into the cylinders. Porting is generally done at the same time. remanufacturing: The process of taking a used part and returning it to original equipment (OE) specifications through disassembly and cleaning of the core, testing, and remachining or replacement of worn components. remote Keyless Entry: A system where the door locks can be opened or locked by a switching device located several meters away. remote mirror: An outside mirror that is adjusted by a toggle device inside the passenger compartment. Older styles relied on a cable that transferred physical movement from the toggle to the mirror. On newer vehicles, the mirror is controlled by electrical controls. remover: A chemical or compound used to clear away unwanted material. See bug and tar remover. Renault: The 45 HP models of 1925-1948 with required application are classic cars. Reo: The 1931-33 Royale 8-31, Royale 8-35, Royale 8-52, and Royale Custom 8 and 1934 N1, N2, and 8-52 are classic cars. repair gum: See cushion gum. replacement market: all products and services used in the repair and maintenance of vehicles. repro: Abbreviation for "reproduction." reproduction: Parts or complete vehicles that have been manufactured to closely follow or exceed original specifications, materials, and performance. Also called "repro" or "repros." These parts often are so perfect that not even a concours judge can tell that they are not NOS or OEM. research & development: R&D expenditures (product and process development). resin: [1] A secretion from trees used in varnishes, printing ink, and plastic as a binder. [2] A synthetic product with some of the same physical properties as the plant secretion. [3] A liquid plastic used in body work. resistance: [1] An opposing force. [2] A measure of a conductor's ability to retard the flow of electricity. Also see air resistance. resistance welding: Welding metals using the resistance of the metals to the flow of electricity, as the source of heat. resistor: A device placed in a circuit to lower the voltage. It will also decrease the flow of current. Also see ballast resistor. resistor spark plug: A spark plug containing a resistor designed to shorten both the capacitive and inductive phases of the spark. This will suppress radio interference and lengthen electrode life. Using a non-resistor spark plug may also damage a CDI box. resleeve: See re-sleeve. re-sleeve: This is a term used of the piston cylinders. The old cylinder inserts are completely removed and new inserts or sleeves are pressed in. This action is done when the cylinder cannot be rebored. Also see cylinder sleeve. resonator: A small muffler-like device that is placed into the exhaust system near the end of the tail pipe. It is used to provide additional silencing of the exhaust. restoration: The act of working on a vehicle with such care as to bring it back to its original condition (including original parts, paint, chroming processes, etc.) rather than merely rebuilding or repairing one. restraint: A device used to halt the movement of something. See head restraint. retard: [1] To set the ignition timing so that a spark occurs later or less degrees before TDC. It involves adjusting the camshaft, distributor spark, or valve operation. In this way, the spark plugs fire or the valves open later in the cycle. Also see spark retard. The opposite of advance. [2] The device for doing this action. retainer: A device which holds something in place. See valve keeper. retread: [1] A means of extending the life of a tire that has worn its original tread, yet still has a sound carcass. The casing is prepared by buffing off tread rubber and vulcanizing new tread rubber stock in its place. [2] A casing to which tread rubber has been affixed to extend the useable life of the tire after the original tread has been worn out. retreading: See retread. ReVere: The 1925-1948 models are classic cars. reverse brake shoe: See trailing brake shoe. reversed polarity: (Electrode positive-anode) referring to DC and causing electrons to flow from the base metal to the electrode. reverse-Elliot type axle: A solid bar front axle on which the steering knuckles span or straddle the axle ends. reverse flush: Cleaning the cooling system by pumping a powerful cleaning agent through the system in a direction opposite to that of normal flow. reverse idler gear: A gear used in the transmission to produce a reverse rotation of the transmission output shaft. reversion: Excessive heating of a cured rubber compound leading to deterioration of its physical properties. revolutions per kilometer: (RPK) A measurement of the number of times a tire turns in one kilometer of travel. revolutions per mile: (RPM) A measurement of the number of times a tire turns in one mile of travel. revolutions per minute: (RPM) The speed the engine crankshaft is turning. Also see RPM. RH: Acronym for "right hand," as in RH drive. For all vehicles, left and right are from the perspective of sitting in the driver's seat. RHD: Acronym for "right-hand drive." rib: The continuous raised portions of rubber that run circumferentially (straight or in a zigzag pattern) making up the tread on the tire. Also the term applies to various raised surfaces circling the sidewall, i.e., guide rib. ricardo principle: An arrangement in which a portion of the combustion chamber came in very close contact with the piston head. The other portion, off to one side, contained more space. As the piston neared TDC on the compression stroke, the fuel mixture was squeezed tightly between the piston and head thus causing the mixture to squirt outward into the larger area in a very turbulent manner. This produced a superior mixture and allowed compression ratios to be raised without detonation. rich air-fuel mixture: A mixture of air and fuel in which there is less air and more fuel. See air-fuel ratio. rich mixture: A mixture of air and fuel in which there is less air and more fuel. See air-fuel ratio. ride height: A measurement between the ground and some fixed reference point on a car's body. The exact location of the fixed point varies among manufacturers. This dimension can be used to measure the amount of suspension deflection or the height of the body from the ground. ride steer: A generally undesirable condition in which a wheel steers slightly as its suspension compresses or extends. Also called "bump steer." ridge: An edge or ledge or lip which protrudes beyond the normal face of an object. See piston ring ridge and burr. riding the clutch: A situation where the driver rests his foot on the clutch pedal while the vehicle is being driven. This action can cause undue wear on the clutch plates because they may be rubbing against each other ever so slightly. right: When referring to the side of a unit, the right side is always from the perspective of operation. In other words, when sitting in the driver's seat or when riding a bicycle or when pushing a mower, the right side is the operator's right hand side. In other words the left or right side is determined by facing the rear of the unit. right hand thread: See right-hand thread. right-hand thread: The common direction (clockwise) which is used to secure a nut to a bolt. Also see left-hand thread.
rigid axle: A simple non-independent suspension, consisting of a rigid transverse member with wheel hubs solidly bolted to it. The axle can be attached to the body by leaf springs, or by a combination of suspension arms and links. Riley: The 1925-1948 models with required application are classic cars. The 1945-55 2.5 (RMA, RME) models are milestone cars. rim: [1] On a bicycle, the metal or wooden hoop of a wheel that holds the tire and tube and the outer ends of the spokes. [2] On a truck, the metal assembly consisting of a base and either a side ring or a side and lock ring combination, which are removable from one side for tire mounting. The opposite side has a fixed flange to retain the tire. Note: Passenger and tubeless rims do not have removable side and lock rings. Also see drop center rim and safety rim. rim brake: Any type of brake that slows or stops a wheel by pressing its pads against the sides of the wheel rim. rim drivers: Riveted or welded metal blocks or extrusions on both sides of the valve slot to prevent valve damage due to rim slippage on cast spokes. rim offset: A measurement in inches from the center of the rim (between the flanges) to the tip of the 28° gutter bevel. rim pull: Actual amount of effort in pounds available at the point of contact of tire and road surface. rim taper: The slope of the rim. See advanced rim taper, semi-drop center rim taper, drop center rim taper, flatbase rim taper, and intermediate rim taper. ring: A circular piece or band of metal. See balk ring, chainring, chrome ring, compression ring, flywheel ring gear, lockring, oil control ring, oil ring, o-ring, piston ring, piston ring, chrome, piston ring, compression, piston ring end gap, piston ring expander, piston ring groove, piston ring job, piston ring, pinned, piston ring ridge, piston ring side clearance, ring and pinion, ringbolt, ring gear, slip ring, and snap ring.
ringbolt: An iron bolt having a ring through an eye at one end, through which a rope can be passed and tied. ring, chrome: See piston ring, chrome. ring, compression: See piston ring, compression. ring end gap: See piston ring end gap. ring expander: See piston ring expander. ring gap: See piston ring end gap.
ring groove: See piston ring groove. ring job: See piston ring job. ring, pinned: See piston ring, pinned. ring ridge: See piston ring ridge. rings: See piston ring. ring side clearance: See piston ring side clearance. rising rate suspension: See rising-rate suspension. rising-rate suspension: A suspension system where the spring rate increases when the wheels move further into jounce. This action can be accomplished by configuring the geometric shape of the suspension, by using springs which change tension as they are compressed, or by using two or more springs with rubber stops. The purpose of a rising-rate suspension is to maintain consistent ride and handling characteristics under a variety of situations: loaded or unloaded, straight roads or curves, and smooth roads or bumpy. riser: See heat riser. rivet: A metal pin used to hold two objects together. One end of the pin has a head and the other end must be set or peened over to create another head. RL: Refers to red line tires which were marketed in the late '60s and early 70s. RMA: Acronym for "Rubber Manufactures Association" road feel: The feeling imparted to the steering wheel by the wheels of a vehicle in motion. This feeling can be very important in sensing and predetermining vehicle steering response. road hazard: Injury to a tire sustained in normal operation, excluding collision or vandalism and that is not reparable by accepted standards. roadholding: The ability of a vehicle to grip the pavement. Technically described as "lateral acceleration," because cornering is actually a continuous deviation from a straight path. Measured in g's. road load horsepower: The amount of power at the driving wheels needed to move a vehicle down the road at a steady speed. This power varies according to the vehicle's speed, aerodynamic drag, mechanical friction, and the tires' rolling resistance. Road-load horsepower is distinct from engine power because the output of the engine is sapped by various mechanical losses between the engine's output at its flywheel and the driving wheels. roadster: (Rdstr) An open-type body with one cross seat and a luggage compartment in the rear deck. The weatherproof fabric top may be folded, and side curtains may be removed. The windshield usually may be folded down. Also see sport roadster. Roamer: The 1925 8-88, 6-54e, 4-75; 1926 4-75e and 8-88; 1927; 1928; 1929 8-88; 1929 8-125; and 1930 8:125 models are classic cars. Robertson screw: A screw with a recessed square hole. It is more commonly found in Canada than the US, especially in woodworking situations. It is easier to install and remove than a Phillips screw and does not strip the head as easily. There are four basic sizes (measured across the flats): 1.6 mm, 2.0 mm, 2.6 mm, and 3.0 mm. Rochet-Schneider: The 1925-1948 models with required application are classic cars. rocker arm: A curved lever that pivots in the middle. One end is attached to the top of the valve stem. In overhead-valve engines the other end is attached to the push rod. In some overhead-cam engines the other end is attached directly to the camshaft lobe. As the camshaft rotates, the rocker arms pivot causing the valves to open and close. Also see ball joint rocker arm and high lift rocker arms. rocker arm cover: A metal lid located on top of the cylinder head on vehicles that have valves that are activated by an overhead cam or by rocker arms. See valve cover. rocker arm shaft: The shaft upon which the rocker arms are mounted. rocker panel: That section of the vehicle body between the front and rear fenders and beneath the doors. Rockwell hardness: A measurement of the degree of hardness of a given substance. rod: [1] A modified car. Also see street rod. [2] To drive a vehicle hard. [3] A connecting rod. See connecting rod, boxed rod, and throwing a rod. [4] To clean out a radiator by passing a rod through the lines. See rodding the radiator. [5] A thin bar. See boxed rod, metering rod, panhard rod, push rod, radius rods, tie rod, TV rod, and arc welding. rod bearing: See big-end bearing. rodding the radiator: The top and sometimes, the bottom tank of the radiator is removed. The core is then cleaned by passing a cleaning rod down through the tubes. This is done when radiators are quite clogged with rust, scale, and various mineral deposits. Rohr: The 1925-1948 models are classic cars. roll: The motion of a vehicle in which the springs on one side of the vehicle compress while the springs on the other side extend. If the roll is extensive, the vehicle will fall on its side. Also less accurately called "sway" or "lean," it occurs in corners because the car's center of gravity is almost always higher than the axis about which it rotates. Also see anti-roll bar, rollbar, roll cage, roll center, roll steer, roll stiffness. roll cage: A protective structure which surrounds the driver in the event of a rollover or crash. It includes a rollbar and other bars welded to the rollbar. The roll cage also adds chassis strength and stiffness which makes for better handling characteristics. roll center: A term which is used to describe the point around which the body of the vehicle rolls when it corners. If the movement of the vehicle is controlled only by linkages, the roll center can be discovered by the geometry of the suspension. roll-off: See tire roll-off. roll pin: See spiral wrapped pin. roll resistance: See roll stiffness. roll steer: A characteristic of handling which gives a slight improvement to steering as the suspension moves in body roll. Sometimes a bad roll steer occurs when the suspension is poorly designed. roll stiffness: The turning moment or torque that the suspension makes when the body rolls and the suspension tries to pull the body back to its normal upright position. It is usually measured in lb-ft/degree of roll. When the springs are stiffer or when the perpendicular distance from the springs to the roll center is greater then the roll stiffness increases. As a result, the vehicle corners flatter. Also called roll resistance. rollbar: A heavy steel bar or tubular steel that goes from one side of the frame, up and around in back of the driver in a hoop, and back down to the other side of the frame. It is used to protect the driver in the event his vehicle rolls over. roller: [1] A device for replacing sliding friction with rolling friction. [2] While ball bearings use a series of balls in a cage, roller bearings use a series of small cylinders. Also see worm and roller. roller bearing: A bearing using a series of straight, cupped, or tapered rollers engaging an inner and outer ring or race. Also see tapered roller bearing. rollercam brake: See rollercam brakes. rollercam brakes: mountain bike brakes that are attached to the frame posts and use a cam and pulley system to modify pressure on the rims. roller clutch: A clutch, using a series of rollers placed in ramps, that will provide drive power in one direction but will slip or freewheel in the other direction. roller lifter: See roller tappets. roller lifters: See roller tappets. roller tappet: See roller tappets. roller tappets: valve lifters that have a roller placed on the end contacting the camshaft. This is done to reduce friction between the lobe and lifter. They are generally used when special camshafts and high tension valve springs have been installed. Also called "roller lifters." rollers: A stationary training device that consists of a boxlike frame and three rotating cylinders (one for a bike's front wheel and two for its rear wheel) on which the bicycle is balanced and ridden. rolling radius: The distance from the center of the tire's ground contact patch to the center of the wheel rim. rolling resistance: As the wheels begin to turn, there are forces which resist its motion such as low tire pressure, rough road surface, increased tire temperature, tire composition, and increased vehicle weight. rolling start: !!! Definition under construction !!!. Rolls-Royce: The 1925-1948 models are classic cars. All the 1947-67 models are milestone cars. roll steer: A steering effect induced by load transference from side to side. The axles may move out of their normal parallel relationship due to spring deflection. Romeo: See Alfa Romeo. RON: Acronym for "Research Octane Number" see octane number. roof pillars: !!! Definition under construction !!!. rosette weld: See plug weld rotary engine: An internal combustion engine which is not of a reciprocating (piston) engine design. There is no true crankshaft, although the power-take-off shaft is sometimes called the crankshaft. It is stationary or fixed in that it simply spins in place. The central rotor turns in one direction only and yet produces the required intake, compression, firing and exhaust strokes. Because it uses rotary motion instead of reciprocating motion, the rotary engine has better balance and less vibration than piston engines. Two common rotary engines are the gas turbine and the Wankel. rotary flow: The movement of the oil as it is carried around by the pump and turbine in a torque converter. The rotary motion is not caused by the oil passing through the pump, to turbine, to stator, etc., as is the case with vortex flow. Rotary flow is at right angles to the center line of the converter whereas vortex flow is parallel (more or less depending on the ratio between the speeds of the pump and turbine). rotate tires: See tire rotation. rotation: See tire rotation. rotator: See valve rotator. Rotax: A trademark name of a manufacturer of two-stroke engines used in Ski-Doo snowmobiles and Sea-Doo watercraft. rotor: [1] A small rotating cap-like unit at the end of the distributor shaft. It is located on the breaker cam inside the cap. It connects between the center electrode and the various outer spark plug terminals as it turns, thus distributing the high voltage from the ignition coil secondary winding to the proper spark plug. [2] A rotating armature inside a stator. As the rotor turns within the stator, electricity is produced to power the electrical components. [3] A trichoidal device in a rotary engine. rotovalve: See Thompson rotovalve. roughing stone: A coarse stone used for quick removal of material during honing. roundel: See BMW roundel. RPK: Acronym for "revolutions per kilometer" in measuring the number of times a tire turns in one kilometer of travel. RPM: [1] Acronym for "revolutions per minute." A tachometer measures engine revolutions in terms of rpm. Also see engine speed and red line. [2] Acronym for "revolutions per mile" in measuring the number of times a tire turns in one mile of travel. RS: [1] Acronym for "Rally Sport"; a term used to identify some Chevrolet Camaro models. [2] Acronym for "rumble seat." RTV: Acronym for "Room Temperature Vulcanizing" sealant. rubber: [1] All the rubber seals, mats, and pads that cushion and protect vehicle windows, trim, handles, bumper sections, carpets, etc. [2] The tires. See also peel rubber. [3] An elastic substance used in tires. Also see butyl, natural rubber, and synthetic rubber. rubber-isolated crossmember: A laterally aligned structural member that is attached to the body or the frame via vibration-absorbing rubber isolators. By bolting suspension or driveline components to such crossmembers, automotive engineers can reduce the transmission of noise and/or ride harshness to the body. rubbing block: A little block located on the movable point that contacts the distributor cam wheel and causes the points to open. A spring causes the points to close. rubbing compound: A polish that contains abrasives harsh enough to remove layers of "dead" paint. Useful in radical restoration procedures, rubbing compounds should not be used on new cars or those with delicate finishes. rumble: [1] A noise found in high-compression engines and associated with bending vibration of the crankshaft. It is caused by abnormally high rates of pressure rise near top dead center. [2] A vibration caused by loose components. Also see rumble seat. rumble seat: (RS) An open-air seat at the back of some older automobiles. Called a "dickey" in Britain. runabout: An open sporting-type vehicle, lightweight, with two seats and with simple bodywork. run flat: Damage sustained by a tire due to driving with insufficient air pressure or while flat. Some types of tires will allow you to run the tire with no air pressure for a short period of time. run in: See break-in. run-in: See break-in. running board: A long flat footboard on either side of a vehicle which acts as a step for passengers. They were particular common on vehicles before 1940. running fit: See running-fit. running-fit: A fit in which sufficient clearance has been provided to enable the parts to turn freely and to receive lubrication. running gear: The system of the engine, transmission, drive shaft, differential, and wheels. run on: Condition when the engine continues to run, even when the key is turned off. See dieseling. runout: The amount a gear or wheel moves in and out away from its true center as it is rotated. If runout is excessive the gear or wheel can be seen to wobble as it rotates. Also see vacuum runout point. rustproofing: A process in which metal (such as iron and steel) is sealed from moisture and oxygen so that it will not corrode. Ruxton: The 1925-1948 models are classic cars. RWL: Acronym for "raised white letter," as in rwl tires. |
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