Site Glossary of Terms

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Amskeptic
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Site Glossary of Terms

Post by Amskeptic » Thu Jan 12, 2012 12:03 pm

********** Shop **********

Front - whatever is closer to the front bumper is to the front

Left - driver's side U.S. and in reference to the vehicle only

CW - clockwise (righty tighty)

CCW - counter-clockwise (lefty loosey)

Anti-Seize - a metal-enhanced paste to protect threads, good for exhaust fasteners

Lithium or Molybdenum Disulfide grease - general purpose & body or severe duty like CV joints & wheel bearings

Socket - allows you to loosen/tighten nuts or bolts from directly above

Ratchet - allows you to loosen or tighten nuts and bolts without lifting off

Extension - allows you to reach into recesses with your socket/ratchet

Breaker Bar - a specially designed socket driver to loosen/tighten tough nuts or bolts

Cheater - a leverage enhancing addition to the end of your breaker bar

Regular Screwdriver - flat blade >most common error is too small for the screw

Phillips Screwdriver - cross pattern bit capable of greater torque > most common error is too big or too small for the screw

Allen/12-pt/Torx - bit variations evolving towards greater strength

Fasteners - bolts nuts, studs, screws, items that hold assemblies together

Bolt - a male threaded rod with a hex head that accepts wrenches or sockets

Stud - a headless male threaded rod

Screw - a male threaded rod with a slotted head that can accept above screwdrivers

Nut - a female threaded hex that clamps items with studs or bolts

Tinnerman Nut - a female threaded clip that can accept a screw or bolt

Helicoil - thread repair method that serves as a "spiral shim" between threads

TimeSert - a more robust and expensive strategy to repairing stripped threads-recommended

EZ-Out - a repair tool for removing broken bolts or studs

Tap - cleans and cuts damaged female threads

Die - cleans and cuts damaged male threads

Thread Pitch, Size, Grade - from coarse to fine, from 4 to 46mm, and here's a link for grade:
http://www.americanfastener.com/technic ... _steel.asp

Flat, Spring, Lock Washer - assists in load distribution, give, and clamping

Driveline - those parts responsible for moving the car down the road

Drivetrain - transmission, differential axles

Double Clutching - a method of pre-synchronizing engine speed to the next gear you are about to select which reduces wear in the transmission and clutch

Clutch Disc - a friction device that takes up engine torque and transmits it to the transmission

Pressure Plate - a spring-loaded clutch disk clamping device that that allows you to engage/disengage engine from transmission

Release Bearing - a ball bearing that allows your stationary clutch actuator to push the rapidly spinning pressure plate fingers

Cross-Fork - a cable actuated pivoting release bearing pusher

Bowden Tube - a flexible cable guide tube from the chassis to the transaxle that helps dampens out clutch chatter

Wingnut - the clutch pedal freeplay adjuster at the end of the threaded clutch cable

Clutch Chatter - a damaging bounce between the pressure plate and the clutch disk during engagement

Clutch Slip - when pressure plate cannot adequately clamp the clutch disk to the engine > most usually due to extreme wear or contamination

Clutch Sticking - when pressure plate does not release the clutch disk from the engine > very damaging to transmission

Synchronizers - little brass rings that force the transmission gear you select to match the speed of the shaft it's riding on before engagement can take place

Shift Fork - a sliding selector that directs gear engagement in the transmission

Detent - a spring-loaded pin that holds selector in precise position

Hockey Stick - end of shift rod in transmission that selects which fork you want via selector assembly that prevents more than one fork from being engaged at one time

Nose Cone - removeable front of transmission where hockey stick and selector reside

Shift Rod - horizontal rod that transmits your instructions to shift

Shift Lever - vertical rod with the gear shift knob at the top that informs shift rod

Stop Plate - an adjustable floor plate that prevents inadvertent engagement of reverse

Shift Coupler - a noise and vibration absorber as well as a flexible joint between shift rod and transaxle

Shift Rod Bushings - support sleeves at front middle and rear of shift rod traverse

CV Joint - allow independent driveshafts to move up and down while transmitting power by use of precise balls in carefully engineered grooves

Torsion Bar - cross-wise (transverse) spring steel bars that twist axially with input from arms attached to the wheel assemblies > excellent springing choice

Tire vs Wheel - a tire is a removeable rubber-based assembly, a wheel is metal

Bowden Tube (preheater) - used only on 1968-70 1600 upright engines, allowed thermostat to direct warm air into the air cleaner only until engine was warmed up

********** Suspension **********
Toe - wheels are not exactly parallel, toe-in is if they want to roll towards each other, toe-out if away from each other. Front axle prefers toe-in, rear prefers toe-out

Camber - wheels are not exactly vertical, if they lean in at the top camber is negative, if they lean out at the top camber is positive

*Caster- the centerline of the wheels is slightly behind the centerline of the steering axis at the ball joints > this helps car roll and return to straight

*Steering Axis Inclination - helps dial in dynamic response and centering action > a steering axis that is inside of the tire footprint will tell driver of braking loads by jerking wheel towards side of greatest traction (positive scrub radius), negative scrub radius will actually try to help car self-correct in uneven braking traction events

*Ackerman Effect - front wheels describe two different size circles in corner, angle of steering arms will make inside wheel turn sharper to hold the smaller inner circle > if outside is 20*, inside needs to be 23*
*non-adjustable parameters

Ball Joints - allow steering and suspension movement between the supporting arms and the steering knuckle/wheel assembly > early VW used horizontal link pins at arms and vertical king pins for steering axis ... we like our ball joints

Tie Rods - transmit your intentions from the steering box or relay lever to the wheels using baby ball joints at the ends for flexibility

Drag Link - sort of like a "main tie rod" from steering box to relay lever on buses, it has baby ball joints too

Pitman Arm- is the stout push/pull lever coming out of the steering box

Relay Lever (swing lever) - in buses, transfers the fore/aft push/pull of the drag link to side-to-side action of the tie rods and wheels

Four Wheel Alignment - the superior method of getting all of your wheels cooperating with each other as to where they all want to go

Spring Plate - the thin wide plate arms that go from the rear wheel assemblies to the torsion bars which spring the car, they also transfer all acceleration and braking forces

Diagonal Arm - introduced with the half-shaft rear axles, they transfer cornering forces to the rear torsion tubes > older VWs swing axles used to transfer cornering forces directly to the side plates of the transaxle

Spring Plate Bushings - allow the torsion bar/spring plates to pivot in nice quiet isolating rubber
Torsion Bar Splines - allow you to adjust the ride height of the car by indexing the torsion bar to the spring plate
Sag - a typical result of torsion bar settling > it usually takes only once to re-adjust suspension back to factory height

Play - a description of what happens when closely fitted parts no longer do

Zerk Fitting - a spring-loaded ball in a nipple that allows the introduction of grease into suspension components without it subsequently leaking out

*********** Electrical **********
Voltage Regulator - an electromagnetic or solid state device that controls output voltage of charging system and cuts it out of the circuit when ignition is off

Voltage Stabilizer - found at fuel gauges it is a "voltage choke" to keep voltage below expected lowest point to prevent errant readings

Series Resistors - same sort of deal, these are ceramic resistors that drop fuel injector voltages below lowest expected system voltage so they will perform accurately at all times

Generator - earlier charging device used by VW through '71, it plucks the (+) electrical flow from wires rotated inside of magnets

Alternator - later charging device that uses both sides (+)(-) of the waves created by rotating a magnet through a field of wires > thus almost doubling output

Ground Path (battery, transaxle, spade terminal) - the equally important but often neglected side of all electrical circuits found in cars > every circuit has to find its way back to the battery through the metal of the car

Spade Terminal (push-on) - the typical quick-disconnect for VWs that needs to be treated with caution and kept clean

Screw Terminal - found in critical areas like generators and voltage regulators and starter-to-battery cables, cleanliness is critical

Wire Gauge - it is not really a gauge, it is an idiotically arcane unit of measure going from small 22-24 to big 10 and even 8 ...

Fuse - a method of shutting down (opening) an electrical circuit that has been shorted (positive to ground) using amperage-induced heat to melt a sliver of soft wire > VWs generally use 8 or 16 amp

Breaker - shuts down a damaged circuit like a fuse, but can be reset or automatically reset depending on design

Fusible Link - a hardwired fuse for big amperage electrical devices, it requires involved replacement to help you remember to fix the problem first

********** Engine **********

Turns Over (cranks) - engine spins with starter motor but doesn't fire

Catches - sporatic combustion events and kicking but not running

Backfire - combustion that blasts out the tailpipe, loud sometimes smoke

Pop - combustion that comes up the carb, muted by air filter if on, scary pow if air filter is off ... good idea to keep cranking to suck any flame back into the engine

Ping - can be a subtle rattle sound, but it is very damaging detonation under full load due to overheat or advanced timing

Rattle - can be a dumb loose bracket or tin, or internal part failure, like loosening valve clearances

Knock - dumb loose large part hitting, or dangerous internal large part loosening up, like connecting rod bearing failure or worn main bearings

Tick - most usually a benign loose valve/hydraulic lifter

Thump - out-of-round tires dragging out-of-round brake drums/rotors, loose or damaged shock bushings

Whine - electrical interference through radio, bad alternator/generator bearing, bad transmission bearing, fresh generator commutator (benign)

Whistle - benign air flow sound through FI throttle body, vacuum leak, fresh air leak through seals or ventilation

Whir - cam gear mesh, distributor bushings, generator/alternator brushes, foreign object rubbing v-belt

Surge - a noticeable change in power output while accelerating

Miss - either intermittent or steady negative pulse most usually indicating a loss of spark or dead cylinder

Hesitate - a full engine intermittent loss of power

Lean - insufficient fuel at the combustion chambers > low power and hesitation, gets worse as engine warms up

Rich - too much fuel at combustion chambers causes stumbling and low power but can run really well when cold

Overrun - any time the car is pushing the engine, as in engine braking

Accelerate - when engine or car is increasing in rpm or speed

Decelerate - when engine or car is losing rpm or speed

Light throttle - just off idle operation or slow rate of acceleration

WOT (Wide-Open Throttle) - pedal-to-the-metal full acceleration where engine vacuum is at its lowest

Clearance - the space required for parts to function through expansion and contraction based changes of dimension, usually measured in thousandths of an inch

Play(end-play) - the space required for parts to function through expansion or contraction or load

Slop - unintended clearances or play due to wear
Preload - the intentional running of parts under contact load, like steering gear or differential ring and pinion

Seize - the unintended bonding of two parts that wish they didn't > most usually under heat and friction

Grenade - colloquial term describing the destruction of a complex assembly like an engine or transaxle where destroyed parts destroy other parts > necessitates a rebuild or replacement of engine

Valve Drop - a catastrophic release of a valve from its retainer where it falls into the piston > necessitates a rebuild

Seat recession - the movement or erosion of the hard steel ring that seals valves in the cylinder heads > necessitates a rebuild

Smokes - the burning of oil either through the engine or on hot surfaces

Drips - usually oil sometimes gas or brake fluid or gear oil > always investigate

Flooding - the uncontrolled dumping of gasoline into the carburetor or the rich stall of an engine due to too much fuel delivery

Starvation - inadequate fuel (or oil supply > a dangerous condition)

TDC (Top Dead Center) - piston at the very top of the cylinder, an important reference point for timing the spark or setting parts to be synchronized with each other

BTDC (Before Top Dead Center) - the movement of the crankshaft in degrees before the piston arrives at the top of the cylinder

ATDC (After Top Dead Center) - the movement of the crankshaft in degrees after the piston goes down the cylinder
Combustion Chamber- the specially shaped portion of the cylinder heads where the valves and spark plug reside and combustion is enhanced

Thrust Bearing - any surface that has to resist axial movement of a rotating part

Bearing Saddle - the structure under main bearings that supports and absorbs combustion and rotational forces

Bearing Inserts - replaceable surfaces that ride against rotating parts

Bearing over/undersize - optional size replacement bearings that are matched to reconditioned machined under or over-sized rotating parts

********** Fuel Delivery **********

Manifold Sensor - the measuring device that informs D-Jetronic fuel injection how much fuel to deliver to the engine based on vacuum below the throttle plate

Air Flow Meter (AFM) - the measuring device that informs L-Jetronic fuel injection how much fuel to deliver based on air flow above the throttle plate

Auxiliary Air Regulator (AAR) - the fuel injection component that insures correct idle speed when the engine is cold

Decel Valve - the fuel injection component that reduces hydrocarbon emissions during deceleration

Evaporative Emission Control (EEC) - the capture of fuel tank vapors

Double Relay - the component that powers/isolates the fuel injection system from the vehicle electrical system when the ignition is on/off, and that controls the fuel pump

Temperature Sensor II (cylinder head) - informs fuel injection computer of engine temperature to moderate fuel mixture

Temperature Sensor I (air intake) - informs the fuel injection computer of the temperature of incoming air

Bypass (throttle/mixture) - an adjustable gate to allow air to bypass either the throttle plate or the airflow meter flap to moderate either the idle speed or the fuel mixture

Vapor Lock - the vaporization of gasoline in a fuel line under high temperatures > cannot be pumped through a typical diaphragm fuel pump nor can it be delivered properly in fuel injection systems

Percolation - the expansion of fuel in a hot fuel line > can cause ...
... Flooding - too much pressure that allows fuel to drip into a carbureted engine, or, in a fuel injected engine with a leaky injector, preventing it from starting

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