- SL
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- Abbreviation for Special ledge
- An API designation of gasoline engine oil for 2001-04 passenger cars, sports utility vehicles, vans and light trucks Oils meeting API SL requirements have been tested according to the American Chemistry Council (ACC) Product Approval Code of Practice and may use the API Base Oil Interchange and Viscosity Grade Engine Testing Guidelines. It replaces API Service Category SJ and was replaced, in turn, by the latest SM oils.
API SL Category
- Slack
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- The amount of free play in a chain or belt too much slack could cause the chain/belt to slip and jump the sprockets; too little slack (the chain seems tight) causes excessive wear on the final drive system.
- Brake actuator stroke prior to effective application of force.
See
- Slack adjuster
- An adjustable member that transmits brake application force and permits compensation for lining wear.
- Slagging
- Formation of hard deposits on boiler tubes and/or piston crowns, usually due to the presence of sodium, vanadium, and sulfur.
- Slant engine
- This is an in-line engine in which the Cylinder block has been tilted from a vertical plane. Also called Inclined engine
- Slapper
- A colloquial term for a Bumping blade
- SLA suspension
- Abbreviation for Short arm/long arm suspension
- Slatted grille
- An aerodynamic radiator grille developed by Ford in 1976. The horizontal aerofoil grille elements are shaped like aircraft wings to allow the cooling air to flow towards the radiator at low speeds, whereas excess airflow is directed upwards across the front of the car at higher speeds to produce an effect similar to that of a spoiler
- Slave con rod
- A connecting rod of two-stroke dual piston engines which is articulated on the master con rod, not directly on the crankpin. See
- Slave cylinder
- A small cylinder containing a piston which, under hydraulic pressure from a master cylinder, operates the brake shoes or pads in hydraulic brakes or the working part in any other hydraulically operated system (such as a clutch slave cylinder). See
- Sledge hammer
- A large, heavy hammer usually with a long handle. The head is double sided so that either end can be used to strike an object
- Sleeper
- A sleeping compartment mounted behind a truck cab, sometimes attached to the cab or even designed to be an integral part of it.
- Sleeve
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- A tube fitted externally over two cylindrical parts in order to join them.
- A cylindrical insert.
- Sleeve bearing (SLV)
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- Any bearing of tubular or sleeve-like construction
- A bearing that resembles a short length of bronze tubing with grooves to direct oil flow. Good for low noise level.
- Sleeve nut
- A long nut with right or left threads for connecting two rods to make an adjustable member. See
- Sleeve valve
- Consists of metal sleeves located between the piston and cylinder wall. When moved up and down, holes in the sleeves coincide with inlet and exhaust parts to provide passage for the gases at the right time.
- Slick
- A very wide tire, without a tread pattern, designed to provide a maximum amount of traction. It is used for racing on dry surfaces.
- Slide carburetor
- A type of carburetor often used in motorcycle engines, in which a slide valve modifies the venturi of the carburetor
- Slide hammer
- A tool with a long round shaft on which a hammer weight slides; the force produced by quickly moving the weight towards the end of the shaft is used for loosening or pulling off tight parts; often used in combination with pullers.
Slide Hammer Dent Puller
- Slide-in camper
- A structure which fits into a truck bed for camping purposes. It usually has beds and possibly cooking and washing facilities. Also called a Truck camper or just camper.
Slide-in camper
- Slider
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- (CVT) A device which senses the position of the half of a primary pulley that slides.
- The lower (moving) tube on a bicycle suspension fork which is attached to the front hub.
- A mechanism that allows a tandem axle suspension to be moved back and forth at the rear of a semitrailer, for the purpose of adjusting the distribution of weight between the axles and fifth wheel.
- Sliding caliper
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- Similar to a floating caliper, but instead of riding on guide pins and bushings, the caliper slides on machined ways and is retained by keys or spring plates.
- Single piston calipers which use pins or rails to obtain a self-centering action. The caliper slides on these pins or rails to center over the disc when the brakes are applied.
- Sliding-caliper disc brake
- A disc brake design with a sliding caliper. In one type, the caliper floats on the caliper frame grooves. The major components are caliper (a casting with one cylinder and piston), caliper frame (casting) which is bolted to the suspension. In another type, the caliper floats on caliper locating pins. A third type, is the floating-frame disc brake. Sometimes subtle design differences are used to differentiate between sliding caliper disc brakes and floating caliper disc brakes, but usually these terms are treated synonymously.
- Sliding contacts
- An ignition assembly developed by Lucas, that causes the moving contact to slide vertically across the face of the fixed contact when the spark is advanced
- Sliding Fifth Wheel
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- A Fifth wheel mounted to a mechanism that allows it to be moved back and forth for the purpose of adjusting the distribution of weight on the tractor's axles. Also provides the capability to vary vehicle combination lengths.
- A fifth-wheel assembly capable of being moved forward or backward on the tractor to adjust the load distribution on the tractor and the overall length of the rig.
- Sliding fit
- Parts that are assembled so that there is clearance between them so that one part can slide in or on the other. Also called clearance fit
- Sliding gear
- A transmission gear that is Splined to the shaft. It may be moved back and forth for shifting purposes.
- Sliding-mesh gearbox
- An obsolete type of transmission or gearbox in which the gears on the layshaft are fixed to the shaft rigidly, whereas the gears on the main shaft can slide on it by means of splines but are otherwise in permanent rotational mesh with the shaft.
- Sliding-pillar suspension
- A once popular front suspension layout (e.g., in Lancia and Morgan cars), in which a carrier-mounted stub axle slides up and down a vertical pillar with enclosed coil springs providing the suspension; less sophisticated versions were used in several pre-war cycle cars
- Sliding side window
- A window style of classic roadsters, consisting of aluminum frames with tracks for two sliding window panels made of clear Plexiglas, and with draft seals; on some cars, also furnished with flaps. See
- Sliding Tandem
- A mechanism that allows a tandem axle suspension to be moved back and forth at the rear of a semitrailer, for the purpose of adjusting the distribution of weight between the axles and fifth wheel. Also called a slider.
- Sliding-vane pump
- A positive displacement pump in which an eccentric rotor revolves in an eccentric or circular case. The pumping element consists of multiple blades which slide in slots in the rotor and divide the crescent-shaped fluid space into variable volumes. Some sources state that in the sliding-vane type, vanes do come into contact with the casing, whereas in vane-type pumps a clearance of about 0.004 inches is maintained between vanes and casing. See
- Sliding weight
- A functional part of a Slide hammer that provides the inertia required for the pulling force
- Sling psychrometer
- Measuring device with wet and dry bulb thermometers. Moved rapidly in air, it measures relative humidity.
- Slinky bus
- A colloquial term for an articulated bus
- Slip
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- The relative motion between driving and driven parts.
- The difference between the speed of the rotating magnetic field (which is always synchronous) and the rotor in a non-synchronous induction electric motor. Slip is expressed as a percentage of synchronous speed and generally increases with an increase in load
- Slip angle
- The difference in the actual path taken by a vehicle making a turn and the path it would have taken if it had followed exactly as the wheels were pointed. The slip angle is the result of the tire carcass's flexibility and is the angular difference between the direction the wheel is traveling and the direction of the tread. If the slip angles of the rear tires are greater than the slip angles of the front tires, the vehicle is said to be oversteering.
- Slip-in bearing
- A liner, made to extremely accurate measurements which can be used for replacement purposes without additional fitting
- Slip joint
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- A Joint that will transfer driving torque from one shaft to another while allowing longitudinal movement between the two shafts. A variable length connection that permits the driveshaft or axle shaft to change its length as the shaft moves up and down. The British term is sliding joint.
- A connection in an exhaust pipe where one pipe slips into another.
- Slip-on
- Any device which slides on to the main component, e.g., a slip on muffler slides onto the existing exhaust pipe
- Slipper piston
- A piston with the lower edge cut away so that the Piston skirt is short on the two sides not used as thrust surfaces. Such a design lightens the piston making it easier to accelerate and decelerate, wastes less power, and is easier on the bearings. Cutting away the skirt also allows the Connecting rod to be made shorter but leaves enough room between the Counterweights and the pistons so the overall height of the engine can be reduced.
- Slip ring
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- One of several conductive metal rings attached to the rotor shaft in an alternator that periodically changes the direction of current flow.
- A conductor band, mounted on an armature and insulated from it. A conductor strip slides on the band as the armature rotates. The function of the slip ring system is essentially the same as a commutator and brushes. Slip rings are also used to transmit current from the armature in a generator application
- Slip-ring end bracket
- A cover housing the bearing at the slip-ring end of an alternator. At the other end is the Drive end bracket
- Slip stream
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- A stream of air behind a moving vehicle.
- A racing technique in which one vehicle tucks in closely behind another (catches a tow). The total aerodynamic drag acting on the two vehicles is actually less than the drag that acts on each vehicle when they are separated by greater lengths; this allows both vehicles to gain straightaway speed. The lead vehicle cuts into the air acting as a wind break for the following vehicle, and the closeness of the second vehicle reduces the turbulence normally generated at the rear of the first vehicle. Also called Drafting.
- Slip the clutch
- To operate the clutch so that it partially disengages, as when keeping up the revs when driving off; causes wear on the clutch. See
- Slip Washer
- A washer with an opening large enough to slip the washer over a bolt, and under the bold head. Also called a C washer.
- Slip yoke
- A component at the front of the first U-joint which accommodates changes in drive shaft length as the rear axle assembly moves up and down with the rear suspension. Internal splines on the U-joint yoke slide in and out on the external splines of the transmission output shaft. This splined coupling also allows the drive shaft to be removed from the vehicle when the rear U-joint is disconnected. The drive shaft may fall to the ground and be ruined if either U-joint breaks while the vehicle is in motion.
Slip yoke
- Slope
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- The percentage of full hydraulic system pressure supplied to the rear brakes by the proportioning valve. Expressed as the ratio of rear pressure to front pressure.
- Degree of deviation of a surface from the horizontal, measured as a numerical ratio, as a percent, or in degrees. Expressed as a ratio, the first number is the horizontal distance (run) and the second number is the vertical distance (rise), as 2:1. A 2:1 slope is a 50 percent slope. Expressed in degrees, the slope is the angle from the horizontal plane, with a 90 degree slope being vertical (maximum) and a 45 degree slope being a 1:1 slope.
See
- Sloper
- A colloquial term for an Inclined engine
- Slot
- A narrow channel or aperture, especially the groove in the head of a screw which receives the tip of the blade of a screwdriver.
- Slotted Head
- The head, of a bolt or screw, which has one or more slots across the top to fit a screw driver.
- Slotted Nut
- A hexagon nut having opposed slots at the end opposite to the bearing face which are perpendicular to the axis, designed for insertion of a cotter to secure the nut in place when used with a drilled fastener.
- Slotted Pin
- A pin that has a slot, either a square or round bottom, into which an external clip or key is affixed in a locking position.
- Slow charging
- The charging of a battery by using a charging current which corresponds to 10% of the battery capacity. See
- Slow down indicator
- An indicator light on the instrument panel that warns the driver to slow down in the event of excessive catalytic converter temperature. A protective warning circuit causes the indicator to flash if the catalytic converter becomes overheated. If the temperature increases beyond a certain second level, the lamp will glow continuously
- Slow leak
- A tire which loses its air pressure over a period of time. It is usually caused by a small puncture, a leaking tire valve, or a tire that is not properly seated on the rim.
- Slow passer
- A vehicle off in the distance behind you in your lane that is driving faster than you. When he pulls out to overtake you, he drives at your speed for several minutes before picking up speed again to finish the passing action.
- Sludge
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- A thick, black, mushy, greasy deposit found throughout the interior of the engine. Caused from a mixture of dust, oil, gasoline, water, and Blowby being whipped together by the moving parts. Some engines oils have Detergent to break down sludge. A composition of Oxidized Petroleum products along with an emulsion of oil and water, forming a pasty substance that clogs oil lines and passages and interferes with engine lubrication. Sludge is formed in engines with neglected oil changes.
- Deposits in fuel tanks and caused by the presence of wax, sand, scale, asphaltenes, tars, water, etc. The sludge formed in a #6 fuel oil storage tank is mostly composed of heavy hydrocarbons. Alken Even-Flo® 905 eliminates this type of sludge by breaking the sludge into small particles and re-suspending them in the fuel for more efficient combustion. The sludge formed in diesel storage tanks is a combination of water with fungus and bacteria, which grow on the unevenly mixed water/fuel interface. Adding Alken Even-Flo® 910 and 910S to stored fuel promotes a clean separation of water and fuel, reducing the substrate upon which bacteria and fungus can grow. Since the bacteria and fungus bind to the separated water, they can be removed by draining the water from the storage tank. If draining the storage tank is impossible, EF 905 and 910E will emulsify the water into tiny droplets and break the sludge into such small particles that they will no longer clog filters and will efficiently burn.
- A dense, slushy, liquid-to-semifluid product that accumulates as an end result of an industrial or technological process designed to purify a substance. Industrial sludges are produced from the processing of energy-related raw materials, chemical products, water, mined ores, sewerage, and other natural and man-made products. Sludges can also form from natural processes, such as the run off produced by rainfall, and accumulate on the bottom of bogs, streams, lakes, and tidelands.
See
- Slug
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- Unit of mass equal to the weight (in US units) of object divided by 32.2 (acceleration due to the force of gravity).
- Detached mass of liquid or oil which causes an impact or hammer in a circulating system.
- Slurry seal
- A thin mix of liquid asphalt and fine aggregate is placed on the street as a preventive maintenance measure to fill in ruts, cracks, and breaks. A thin layer of about 3/8' to 1/2' thick is applied by a special truck-mounted paving system. When the slurry seal is applied it may be brown, but gradually dries to black. You can drive on it after it solidifies in 4 to 6 hours. The work must be done during warm, dry weather.
- Slush box
- A derogatory colloquial term for an automatic transmission used by those who prefer a manual transmission.
- Slushbox
- A derogatory colloquial term for an automatic transmission used by those who prefer a manual transmission.
- Slush molding
- A thermoplastic casting in which a liquid resin is poured into a hot, hollow mold where a viscous skin forms; excess slush is drained off, the mold is cooled, and the molded product is stripped out.
- SLV
- Abbreviation for Sleeve bearing