Introduction to Motor Vehicle Craft: Student’s Book

129 Pages·1984·26.081 MB·English

by  J Hirst, J Whipp (auth.), R Brooks (eds.)

Macmillan Motor Vehicle Craft Studies Series
Introduction to Motor Vehicle
Craft
Student's Book
Editor R Brooks
Senior Lecturer in Motor Vehicle Subjects
Bolton Institute of Higher Education
Authors J Hirst
Lecturer in Motor Vehicle Subjects
Burnley College of Arts and Technology
J Whipp
Senior Lecturer in Motor Vehicle Subjects
North Manchester College
M
MACMILLAN
© R. Brooks, J. Hirst, J. Whipp 1981, 1984
All rights reserved. No reproduction, copy or transmission
of this publication may be made without written permission.
No paragraph of this publication may be reproduced, copied
or transmitted save with written permission or in accordance
with the provisions of the Copyright Act 1956 (as amended),
or under the terms of any licence permitting limited copying
issued by the Copyright Licensing Agency, 33- 4 Alfred Place,
London WC1E 7DP.
Any person who does any unauthorised act in relation to
this publication may be liable to criminal prosecution and
civil claims for damages.
First published 1981
Reprinted 1981, 1984, 1988 (twice)
Published by
MACMILLAN EDUCATION LTD
Houndmills, Basingstoke, Hampshire RG21 2XS
and London
Companies and representatives
throughout the world
ISBN978-0-333-36186-3 ISBN978-1-349-06976-7(eBook)
DOI 10.1007/978-1-349-06976-7
PREFACE
It iswidely recognised that oneof the prime aimsof almost everyyoung
personisto own amotor-car, in sodoing to achievethe mobility andfree
dom associated with it. This providesapowerful incentive to learnabout
motorvehicles,in fact often with far greaterapplication than may beshown
for more academicsubjects. It wasasadirect result of thesevery natural
aspirations that this book wascompiled.
The young peoplefor whom the book isprimarily intended arelikely to
bein their final yearat school or taking part in atraining programme prior
to starting work. Importantly, it isintended to beof interest andvalueto
everyonewho uses it and not merely asacareerintroduction. However,any
budding automobile engineeriscertain to find it of especial benefit.
Arranged in workbook style on large(A4) pages, the student isableto
complete the information presentedandconclude the various investigations
in note and sketch form. Sufficient guidanceisgiventhroughout sothat the
student isableto produce good-quality resultswithout the needfor either
laborious note-taking or extensivesketching. This addsvalueand personality
to the book and finally producesauseful work of reference.
Whilst it isclearly impossible to cover everyaspectof the complex field
of automotive work, the items selected form asound basisfor further study.
The production team consistsof practising teacherswith a substantial series
of popular motorvehicle books to their credit andextensiveexperiencein
the teaching of motorvehicle subjects.
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To help teachersreducepreparation time, acompleted 'answerbook' (or
Lecturer's Guide) isavailable.This hasbeencarefully produced sothat
transparenciescaneasilybemadefrom each page.This facility enables
teachers,if they wish, to display completed drawingsandtext with the
minimum of effort, thus enabling more time to bedevoted to 'proper'
teaching and student-basedinvestigations. Much thought hasalsobeengiven
to conducting the work outlined in the books with only aminimum outlay
of specialised equipment.
The authors andeditor alwayswelcome constructive comments from users
of this book. Do not hesitateto contact usvia the publishers.
R. Brooks
(Editor)
Ford Sierra Ghia 2.3 litre
Austin mini Metro 1.3 HLS
Ford retained the conventional in-line engine and rear-wheel drive
With its transversely mounted engine driving the front wheels the for their highly successful Sierra. Its slightly unusual body styling
mini Metro is typical of modern space-saving design. makes it highly aerodynamic.
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Contents
Glossary of technical abbreviations and terms
vi
Chassis layout and vehicle body 1
Spark-ignition engines: principles and construction 7
Cooling 18
Lubrication 27
Petrol fuel system 34
Transmission: clutch 42
Transmission: gearbox 48
Transmission: propellor shafts and drive shafts 53
Transmission: final drive 56
Suspension 59
Wheels and tyres 66
Brakes 73
Steering 80
Engine electrical system 84
Vehicle electrical systems 94
Electricity 106
Health and safety 112
v
Glossary of technical
abbreviations and terms
Aswithany specialisedsubject, motorvehicletechnology HT Hightension alternatingcurrent,and ismore efficientat lowengine
hasitsown 'language'.This glossaryhasbeencompiled to i.f.s. Independent frontsuspension speedsthan adynamo.
helpyou understand someofthe more commonly used i.r.s. Independent rearsuspension ammeter Instrumentthatmeasuresthe amountofelectric
terms. k/h Kilometres perhour currentpassingto andfrom the car'sbattery. Itisoften
LT Lowtension marked with a+and- forchargingor discharging.
m.p.g. Milespergallon automaticchoke Devicein the carburettorwhich controls
COMMON ABBREVIATIONS mph Milesperhour the choke flap according to the enginetemperature,to pro
o.h.c. Overheadcamshaft videarich mixturefor starting andanincreasingly weak
Sincepublic interest in motorvehiclesissowidespread,
o.h.v. Overheadvalve mixtureasthe enginewarmsup.
quitealotofthe abbreviationsarenotsopreciseor stan
psi Poundspersquareinch automatictransmission Gearbox thataltersthe gearratio
dardisedasthoseusedin the strictly technical sense.
rpm Revolutions perminute automatically tosuitcar speed and load. It also eliminatesthe
However,thefollowingwill often beencountered in suchas
(rev/min) needfor manualclutch andgearlever.
manufacturer'sbrochures, manualsand ingeneralconversa
SW Switch axle Transverse beamwhich carriesthe wheelsandsup
tion.
t.d.e, Topdeadcentre ports the body viasprings.
A (amp) Ampere UNC Unified Course(thread) ball joint Method ofjoiningtwocomponents endto end
AC Alternatingcurrent UNF Unified Fine (thread) sothattheycanpivotin anydirection relative to each
AF American Fine (thread) other.
Ah Ampere hour additives Chemicalsaddedto oil andpetrol to givethem beamaxle Rigid transverseaxlecarryingwheelswith no
(amphr] specialproperties. independentsuspension.
b.d.c. Bottomdeadcentre air-cooled engine Enginecooled only by air which is bearing Deviceforsupportingarotatingshaft or moving
bhp Brakehorsepower blown overfinned cylinder surfaces,usually by afan. componentwith the minimum offriction andwear.
BSF British Standard Fine (thread) air filter Usually found on topofthe carburettor. Itfilters bevelgears Conical-shapedgearswhich permittransmis
SSW British Standard Whitworth (thread) the air before itentersthe engine. sionthrough 90°1asin the final drive.
cc Cubic centimetre air vent Small hole in the top ofafluid reservoir, float bigend Largerendofthe connecting rod mounted onthe
c.b. Contactbreaker chamber or tank toallowatmospheric pressuretoact on crankpin ofthe crankshaft.
d.c. Directcurrent fluid. big-endbearing Material betweenthe connecting rod big
DoT DepartmentofTransport alignment Usually describesadjustmentoffrontwheels, endandthe crankpin.
emf Electromotiveforce alsothe setting ofheadlampbeams. bore Diameter ofany hole, butespeciallyusedto describe
hp Horsepower alternator Engine-drivenelectricgeneratorwhich produces internal diameterofacylinder.
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bottomdeadcentre Lowest pointof the piston'stravel in fuel pump. motionofthepistontothe rotary motion of the crankshaft.
the cylinder,at the bottom of itsstroke. capacity Usually expressed incubiccentimetres,the capa constant-mesh gears Describesgears on the gearboxwhich
brake back plate Describes the plate of adrum-brake city of an engine isthe volumeswept by allthe pistons in are always meshed together.
assembly which isfixed and which carriesthe brake shoes. the engine over the length of theirtravel. constant-velocityjoint Atype of universal jointwhich
brakedrums The drumsare fixed to the road wheels and carburettor Adevice to meterthe amountsof fuel and givesasmooth drive on front-wheel drive cars even when
rotatewiththem.Shoes inside the drumsare pressed against air drawn intoan engine,and mix them together. steeringon full lock.
them,so thatthefriction slows and eventuallystopsthe clutch A partof thetransmission which enablesthe driver contact breaker Aswitch inthe coil ignition system which
wheels. to move thevehicle away smoothlyfrom rest;disconnects constantly breaksand remakesthe low-voltagecurrent,so
brakefluid The hydraulicfluid used inthe brakingsystem engine from gearbox duringgear changing, and givestem causing thecurrent inthe coil to collapse and provide high
inordertotransferenergyfrom the pressingof the brake porary neutral. voltage current. It isoperated mechanically, usually by a
pedal tothe operation of the discs or drums. clutch drag Inefficiency of clutch disengagementusually cam mounted on thedistributorspindle. Also referred to as
brakeshoe Metalsegmentally-shaped componentswith caused by faulty adjustmentor mechanical wear. 'points'.
friction material on the outerface of the curve. Used inside clutch driven plate A metal disc mounted on theshaft control box Part of the electrical system with threefunc
the drum of adrum brake,they are forced apartto brake leading tothegearbox. It hasfriction linings on itsface tionstogether inasealed box;automaticcut-out,voltage
the wheel. which transmitdrive from theflywheel. regulatorand currentcontrol.
breather An openingor ventused to relieve internal pres clutch lining Friction material bonded or riveted to either crankpins Bearingsurfacesof the crankshaftwhich carry
sure or toallow air to enteraspace, e.g.gearboxes have side of theclutch driven plate. the big-end bearings of the connecting rods.
breathers. clutch pressure plate Heavy metal disc which forces the cylinder block Iron or aluminium alloy cast block housing
brushes Pads made of carbon thattransfer the current clutch driven plateagainsttheflywheel. the cylindersand theirwater-cooling passages,or fins for
from the rotatingarmature of an alternator or the rotating clutchslip Usedto describethe effectof thefailure of the air-cooled engines. On water-cooled engines it isusually one
commutatorof adynamo. pressure platetogrip the driven plate properly. Usually piece with thecrankcase.
bush Asleeve, usually of metal, rubber or plastic,which is caused by oil contamination or excessive wear. cylinder head Cast iron or aluminium piece which fits on
fitted intoa bore and acts asa bearing. coil Twowindingsof copperwire housed togetherand thecylinder block and which containsthe combustion
butterfly,or butterflyvalve Usedtodescribe the throttle providingthe high voltage currentnecessaryfor causinga chambers and the valvegear, aswell asthe continuation of
valveinthe main air ventof the carburettor,which isadisc sparkatthespark-pluggap. It does this by collapsingthe water passagesor finning.
of metal thatcan be rotated tocontrol the air flow and so magneticfield created by low-voltage currentflowing cylinder-head gasket Thin layer, sometimesof metal with
thespeed of the engine. through the outer (shorter) winding and so inducing high asbestos,usedtopreventleakage of gasbetween the cylinder
by-passfilter Atype of oilfilter inthe engine's lubricating voltage from the inner (longer) winding. block and cylinderhead. It also stopswaterfrom thewater
systemwhich receives some of the oilfrom the pumpand coil ignition Describes an ignitionsystem which employsa passagesgetting intothe cylinders.
filters it before it ispumpedtothe engine. coil to induce highvoltage. cylinderliners Usually cast-iron sleeveswhich fit inside the
cam Arounded wedge, usually on ashaft,which will push compression-ignitionengine An engine inwhich combus cylinder block wherethe pistondoes notrun directly inthe
and release anothercomponentastheshaftrotates, e.g.the tion isachieved by the heatgenerated by compressed air, block itself, although they can be used toreplace worn
engine camshaftwhich opensand closes the valves. such asadiesel engine. Inthis,acharge of atomised fuel is cylinderwalls. Dry liners are surrounded by the metal of
cam follower Any componentthattransmitsthe motion injected into the hotcompressed air inthe combustion the block,whereaswet liners are exposed directlytothe
of the cam tothe nextcomponentin line, likea push-rod chamber,so effecting ignition. coolant.
or valvestem. compression ratio The ratio of the volumeof mixture damper Adevice used tocontrol the movementof the
camberangle The angle by which wheels deviatefrom 90° above the piston at the bottom of itstravel compared to piston inavariable-jetcarburettor,by dampingtheaction
to the road, lookingfrom thefront. Positive camber means thevolumeabove it at thetop.The higher the ratio,the smoothingoutthe response to thethrottle. Alsoaterm
thatthewheelsarefurther apartat thetop;negative camber more the poweroutputof the engine. Averaged-sized car used todescribeashock-absorber inasuspension system.
means they are further apartat the bottom. engines-will haveacompression ratio of 8.5:1 to 9.5:1. decarbonising A process for removingthecarbondeposits
camshaft The shaftwhich isrotated by the engine and connectingrod The forged steel componentthatjoinsthe thatcan build up on piston crowns, valveends and inside
actuatesthevalvegear. It may also drive thedistributorand piston to the crankshaft,transferringthe up-and-down thecombustion chamber.
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detergentoil Speciallyformulated engine oil that has an thefinal drive to the road wheels. Another namefor half feeler gauges Asetof hardened metal stripsof varying
additiveto hold sludge-formingmaterial insuspension, pre shafts. thickness used to measureclearances incomponents,e.g.
venting itfrom settling,and so keeping the engine interior droparm Lever mounted on the steering box which is thegap inaspark plug.
clean. operated by thesteeringwheel pinion and which inturn flnaldrlve The last phase of thetransmission system. On a
differential Asetofgears (usually ina housing bolted to controlsthetrack-rod linkage. rear-wheel drive car thiswould be the crown wheel and
thecrown wheel) which enablesthe driven wheelsto rotate drum brakes Amethodofbrakinginwhichdrumsattached pinion.
at differentspeeds (aswhen cornering) butstill receive to thewheelsare slowed by internal convexshoes lined firing order The order inwhich the cylindersof an engine
equal torque. with friction material,forced outwards by hydraulic pres reach the 'firlng'or 'power'stroke.
directcurrent Electriccurrentwhich onlyflows inone sure from the brake pedal assembly. fluid reservoir This usually refers to acontainerwhich
direction,such asthat produced by a battery or dynamo. dual-braking Twoseparate hydraulic brakingsystems stores hydraulicfluid for the brake or clutch systems. (May
disc brakes A brakingsystem which works by heavy metal workingside by side to provide adequate braking ifone also describesuch asacontainerstoringwindscreen-washer
discs being pinched by friction pads mounted incalipers circuitshouldfail. Thesecan eitherduplicate thewhole fluid.)
thatsurroundthe disc. Thedisc isattached to the road brakingsystem, or one front and one rear brake,diagonally flywheel Heavy metal disc bolted to the engine crankshaft.
wheel and rotateswith it. opposed. It smoothsoutthe individual burstsof energyfrom the
distilled water Purified water used for topping up the dustexcluder See 'gaiter'. cylinders;forms aconvenientmounting pointfor the
battery. dynamicbalance The balance of any rotating part,such as clutch;and has thestarter ringgear around its outeredge.
distributorcap Hard plastic mouldingwith connections thewheelsor crankshaft,while the component isrevolving. four-stroke cycle (Ottocycle) The basic sequence of
whichacceptthe high-voltage currentfrom the coil,and earth Theconnection from any electrical component operationsof the internal combustion engine.
subsequently pass it to each spark-plug lead by way of the whichattachesto thechassis or bodyto effectacompleted i.e. Induction
rotor arm. circuit. Compression
distributordrive shaft Theshaftthat rotatesthe rotorarm east-west mounting Alsoknownastransverse,thisdescribes Power
and thecams which operatethe contact breaker. Driven by an engine mounted across the car instead of the more usual Exhaust
the enginecamshaft, it isgeared to rotate at half engine mounting inwhich theengine isin line with the car. Also known somewhat picturesquelyas: 'suck', 'squeeze',
speed. electrolyte Asolution of distilled waterand sulphuricacid 'bang', 'blow'.
distributor rotorarm Resin-based plasticwith a brass strip inthe battery. free travel (free play) The amountof 'play'orfree move
inlaid alongthetop. It rotates underneath the distributor electronic ignition Asystem of ignition inwhich an elec ment insuch asacontrol leveror foot pedal before it
cap and passes high-voltage currentfromthe high-voltage tronic unit triggers pulses of high-tension electrical energy begins to takeeffect.
inputconnectionfrom thecoil to the connectors leading tothesparkplugs,soreplacingthecontactbreakerassembly. friction pads Segmentsof friction material inadisc brake
to thespark plugs. More efficientthan the mechanical method,especially in thatare pressed on to thedisc to effect braking.
dog clutch Aswith all types of clutch,these are a means high performance engines. front-wheel drive Atransmission system inwhich the
of transferringdrive. Projectionsaround the edge of one ethyleneglycol Achemical which preventswaterfrom enginedrives thefront wheels of the car.
half of the clutch slide intocorresponding indentationson freezingatthe usual temperature,and isthus used inmost fuel pumps (petrol pump) A pumpwhich drawsfuel from
the other. Usually found ingearboxes. antifreezecompounds. It ismixed with corrosion-inhibiting the tank and delivers it to the engine.
drag coefficients A measure of the resistance to air of a chemicalsso that it will notattack the metal of the coolant full-flowfilter Atype of oil filter through which allthe
moving object,such asacar body. system. engine oil must pass before it reaches the engine bearings.
drag-link The rod between the droparm of asteeringbox exhaustgases The gasesgiven off by the combustion of fuse Athin piece of wire of known electrical-carrying
and the linkage which controlsthe track-rod. petrol and air. They includecarbon monoxide, carbon capacity which isincorporated inacircuit inorder to
drain-plug Ascrew-in plug found atthe bottom of a com dioxide, oxidesof nitrogen, unburnt hydrocarbonsand protect it. Itshould be the first partof the circuitto break
ponentfor drainingfluid. Typically found inthe sump, watervapour. inthe eventof an overload.
gearbox,final drive or radiator. exhaust manifold Cast-iron pipework of variouscon gaiter (dustexcluder) Asynthetic rubber flexible shroud
drive-shafts Especially used where theshaftsare not figurationswhich isbolted to the engineand which takes or cover used to keep outdustand grit from such asa
enclosed intheaxle casing. They transmitthe drive from away the exhaustgasesforced outof thecylinders. steering ball joint.
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gap This usually refersto such asthe distance between the ingoutalong a shaft protrudingfrom a housing,e.g. acrank- the low speedatwhich the engine runswhen thevehicle is
contactbreaker points, or between thespark-plugelec- shaftwhere it passesthrough its crankcase. Usually made of not moving andtheaccelerator isnotdepressed.
trodes. syntheticrubber. small end Thesmallerend of the connecting rod which is
gasket Athin sheetof material such ascopper,cork, overall gear ratio Numberof engine revolutions per single connected tothe piston by thegudgeon pin (piston pin).
rubber or paperwhich issandwiched between twoclose- revolution of thedriving wheels. (Gearbox ratio Xfinal solenoid Atightlywound coil of wire with acentral,
fitting componentssoasto prevent leakage of any kind. drive ratlo.) moveable iron core.When current ispassed through the
gearbox Can be applied toalmostany housing (or box) points See 'contactbreaker'and 'spark plug'. winding,the magneticfield produced causesthe core to be
containinggears. Usually it refersto the transmission gears piston Formsa moveablegasand oil-tightseal inthe pulled intothewinding. The moving corecan close large
which are controlled by the driver in accordancewith con- engine cylinder. Ittransmits,viathe gudgeon (or piston) area contacts(asinastartersolenoid).
ditionsof load,speed and gradient. It then also providesa pin, theforce of the expandinggasestothesmall end of spark plug The component providingthe insulated spark
means of reverse and a permanent position of neutral. the connecting rod. Most pistonsare made of aluminium. gap within thecombustion chamber. It has a metal body,
gear ratio Relative speedsat which twogears revolve. Ifthe Pistonsof differentdesign are used inhydraulic braking which screws intothe enginecylinderhead,and a central
inputgear rotatestwiceasfast asthe outputone,the gear systems. electrode insulated by ceramicmaterial,which carriesthe
ratio is2:1. pressurecap Thisisusually the radiatorfiller-cap. Italso high-tension currentto the gap. Thegap between the spark
generator (dynamo) Adevice which converts mechanical maintainsthe liquid inthe coolingsystem under pressure plug's two electrodes isusually inthe region of 0.025 in.
energy into electrical energy. One of its primefunctions is and so raises the temperatureat which it boils. (twenty-five 'thou') or 0.6 mm and this iswhere the high
to chargethe battery. An alternator performsthesame propellorshaft (prop-shaft) The tubularshaftwhich ina tensioncurrentfrom the ignition coil mustjumpacross,
function. front-engined, rear-drive vehicle transmitstorquefrom the creatinga sparkand ignitingthefuel/air mixture.
glass-reinforced plastic (glass-fibre) Often known simply as gearbox to the rear axle. It isusually fitted with two starter motor Asmall, but powerful,electricmotor used
GRP,this isa laminated material used inthe manufacture universal jointsand a sliding joint. to startthe engine.When activated, it engages asmall
and repair of some car bodies. radiator Thedevice used for loweringthetemperature of pinion gear with atoothed ring on the engineflywheel.
independentsuspension Each wheel has its ownspringand the coolantwhich hasabsorbed heatfrom the engine. starter ring (ring gear) The toothed ringfitted tothe outer
linkage with car body,allowing it to move without influ- rocker cover Adeeply-domed cover (or lid) which encloses edge of theflywheel with which the pinion of thestarter
encinganotherwheel. Most cars have independentfront the valvemechanism on topof an overhead valveengine. motorengages.
suspension butfewer have it all round. seal See 'oil seal'. 'Seal' issometimes used instead of the stubaxle Ashortfixed shafton which the non-driven hub
inlet manifold Pipework(oftenaluminium)which conducts word 'gasket'. of acar wheel revolves on bearings.
petrol/air mixturefrom the carburettorto the engine. servo (brake) Aform of auxiliary power used toassist the synchromesh Acomponentwhich causestwogears to
jets Generally carburettorcomponentswith small-diameter driverwhen applying the brakes. In mostcars theauxiliary revolveatthe same speed beforetheyare meshed together,
holes drilled inthem. They are used to control the amount power isprovided viavacuum existing inthe inlet manifold. inorderto preventclashing.The effect isachieved by using
of fuel thatcan pass through them. shockabsorber Damperto control body movement in aconeclutch to synchronisethespeed of rotation of one
Windscreen washersalso havejets tocontrol fluid flow. relation tothe suspension, preventingcontinuous bouncing gear with the other.
king pin A hardened steel pin aboutwhich a front wheel on thesprings. tappet Acolloquial term for afollower which bears on the
pivots. On most modern cars it has been replaced by two ball silencer The partof an exhaustsystem designed to reduce enginecamshaft.Itisusually ashort,bucket-shapedcylinder,
jointswhich givethesame steeringeffect butalso allow for exhaust noise. It has a larger volumethan the exhaust pipe theflat end of which bears againstthecam.The open ends
movementof the independentfront suspension. and contains baffle platesand sound-deadening materials holdsa push-rod or avalvestem (ifan overhead camshaft
leaf spring A long, fairly narrowspringconsistingof one, which reduce resonance. Afaulty system,allowingcarbon system isfitted).
or more,flat blades (or leaves). Common on commercial monoxidefumes intothe car,can be lethal. thermostat Atemperature-sensitivevalve placed inthe
vehicles and the rear suspension of manycars. slavecylinder Acylinderatthe end of the hydraulic brake coolingsystem between the top of the engineand the
manifold See 'inlet'and 'exhaust'manifold. or clutch system which convertsthe hydraulic pressure radiator. Thethermostat isclosed when the engine iscold,
master cylinder The main pressure pumpof a hydraulic back into mechanical effort,and operatesthe brakesor allowingthe coolant inthe enginetowarm up quickly. As
brake (or clutch) system. clutch. an operatingtemperatureof about85° isreached, it opens
oil seal Acomponentused to preventoil (or grease) leak- slow running Also called either 'tick-over'or 'idling', it is to allowthe passageof coolantthrough the radiator.
ix