Sách Tiếng Anh công nghệ ô tô và chế tạo máy: Phần 2

Phần 2 cuốn sách trình bày các nội dung: Troubleshooting leaks, squeaks, smells, and strange sensations, what to do if your car drops dead or wont start, keeping your car clean and beautiful, getting rid of dings, dents, and other hard knocks, the ten most important preventive maintenance sensations,... Mời các bạn tham khảo.

you can pull it o ff the plug The shiny thing sticking out of

the e n g in e block is the term inal o f the spark plug Figure

12-10, later in this chapter, shows you all the parts of a spark plug, including the term inal

2 U se a nice soft rag or a sm all paint brush to clean around the area w here the spark plug enters the block - or you can blow the dirt aw ay w ith a soda straw

D oing so keeps loose jun k from falling down the hole into the cylin der w hen the plug is rem oved

3 Find your spark plug socket (the big one with the rubber lin ing) and place it dow n over the spark plug; exert some pressure w hile turning it slightly to be sure that it's all the way down

Like everyth in g else in auto repair, d on ’t be afraid to use som e strength But do it in an even, controlled manner If you bang or je rk th ings, you can dam age them , but you’ll never get anyw here i f you tippy-toe around

4 Pick up your ratchet handle and stick the square end into the square hole in the spark-plug socket

I f you can w ork m ore com fortably by adding a couple of extensions betw een the handle and the socket so that you can m ove the handle freely from side to side without hit­ting anything, go ahead You add them in the same way you added the sock et to the handle (If you have trouble with gpttinp the plug loose, see the “ D ealing with difficult plugs” section, w h ich follow s, for encouragem ent.)

The little knob on the back o f the ratchet handle makes the ratchet turn the socket eith er clockw ise or counter­clockw ise) You can tell w h ich way the handle will turn the plug by listen in g to the clicks that the handle m akes when you m ove it in one d irection I f it clicks w hen you move it

to the right, it w ill turn the socket coun terclockw ise when you m ove it, silen tly, to the left I f the clicks are audible on

the leftward swing, it will move the socket clockwise on the rightw ard swing Every screw, nut, bolt, and so on that you encounter should loosen counterclockwise and tighten clockw ise I f your ratchet clicks in the wrong direction, just m ove that little knob to reverse the direction Figure 12-9 shows you the proper way to use a socket wrench, and the sidebar “Breaking loose old plugs and m isconceptions” tells you how to handle difficult plugs.

5 Loosen the spark plug by turning it counterclockwise W hen

the ratchet turns freely, finish the job by rem oving the ratchet handle and turning the socket by hand until the plug is free from the engine

After you’ve rem oved the spark plug from the engine, re­move the plug from the socket But don’t go on to the next plug until you’ve read the plug (see the section “Reading your spark plugs” and Table 12-1) and gapped and replaced

it, follow ing the instructions later in this chapter

Dealing with difficult plugs

W ith all the stuff crammed under the hoods o f vehicles, it can

be hard to get at some spark plugs and, even when you can reach

I f you find that one or m ore plugs are blocked by an air con dition er or som e other part, try using various ratchet handle

extensions to get around the problem T here are universal ex­

tension s that allow the ratchet handle to be held at odd angles;

T-bar h an dles for better leverage; and offset han dles for hard-

to-reach places (See C hapter 2 for exam ples.)

On som e veh icles, you can ’t get at the plugs until you re­

m ove other parts that are in the way On som e transverse en­gines, you have to rem ove the top engine m ount bolts by the radiator so that you can tilt the engine forw ard to replace the rear spark plugs And on other engines, it m ay be easier to get

to som e spark plugs from underneath or through the wheel well area

On som e sm all cars equipped w ith option al b ig engines, you have to h oist the entire engine out o f the car to reach at least one plug I f you have one o f these beasts, I bet that when you finally get that plug out, you’ll find that it’s n ever been replaced during all the profession al tune-ups you’ve paid for And you’ve paid even m ore because that one funky plug probably not only increased your fuel consum ption but also added to air pollution Both you and your car should be glad to get rid o f it!

I f you absolutely cannot reach the offending plug, you can alw ays drive to your service station and hum bly ask them to change ju st that one plug T hey w on ’t like it, but it is a last resort I f you get to that point, you’ll probably be glad to pay to have it done But do try very hard first I f you ca n ’t get to the plug in the ordin ary way, go under, over, around, or through

gaps in the thing that’s blocking it Or get som eone to help you move w h at’s in the way (but be sure that you can get it back in place correctly) Use your im agination; it’s the only hard part of the job And you w on’t have to do it again for a long time.

If you’re lucky enough to own a car without air conditioning, power steering, power brakes, and so on, chances are much greater that all your plugs will be easy to get at Think it over next time you’re tem pted to buy a vehicle with all the “extras.” Those “extras” tend to block the things you want to work on, and they often go wrong them selves Some, like air con dition ­ing if you live in a hot climate, are worth it Others, like power brakes on a small car, are not

Reading your spark plugs

You can actually read your spark plugs for valuable “clues”

about how your engine is operating To read your spark plugs, follow these steps:

1 When the first spark plug is out o f the engine, rem ove the plug from the spark plug socket and take a look at it.Compare the deposits on the plug to the conditions shown

in Table 12-1 Figure 12-10 can help you to identify the various parts o f a plug m entioned in the table

2 Check the plug’s shell, insulator, and gaskets for signs of cracking or chipping

3 Look at the plug’s firin g end (the end o f your plug that was

inside the cylinder)

The hook at the top is the side electrode (refer to Figure 12-10) The bump right under its tip is called the cen ter

electrode The spark comes up the center o f the plug and jum ps the gap betw een these two electrodes This gap must

be a particular distance across for your engine to run e ffi­ciently

Table 12-1 What Your Old Spark Plugs Tell You about Your Car

T e rm in a l

Figure 12-10:

The anatom y

Figure 12-11 shows why you should never use a flat feeler gauge for this purpose The reading will be inaccurate

The gauge wire probably has a lot o f room to wiggle around

in This m ay be because your old plug has worn down its cen ter electrode, causing a gap that is too large If the gauge goes in and out with a lot o f room on either side, the gap is too large If the gauge can ’t fit between the center and side electrodes, the gap is too sm all, which means that the spark plug is not burning the fuel/air mixture efficiently

5 Look at the little center electrode bump again and use Table 12-1 to judge its condition

Is it nice and cylindrical, like the cen ter electrodes on your new spark plugs? Has the e le ctrod e’s flat top worn down to

a rounded lump? Or has it w orn down on only one side?

C hances are it’s pretty w orn because it’s old When the cen ter electrode wears down, the gap becom es too large

W hen you do your tune-ups yourself, you’ll probably check your plugs m ore often and replace them before they get too worn to operate efficiently

6 Clean the plug Then either gap it or replace it with a new one, follow ing the instructions in the next two sections

To clean a plug, gently scrub the gunk and goo away with

E ither replace all the plugs w ith new ones or clean and reinstall all the old ones D on’t m ix plugs in varying states of wear If you do, your engine w on ’t operate efficien tly I f you find

that a few o f your old plugs aren’t too worn and are in fairly good shape, but you need to replace the others, clean and regap the salvageable plugs and store them in your trunk com part­ment tool kit for em ergencies.

Som etim es you can cure a problem - such as carbon-fouled plugs - by going to a hotter- or cooler-burning plug You can identify these by the plug number The higher the number, the hotter the plug Never go more than one step hotter or cooler at

a time

If your plugs indicate that som ething is seriously wrong with the way your engine is running, ask a professional m e­chanic for an opinion If you’re told that it requires extensive or expensive work, get a second opinion at another service facility without telling the technicians that you went to the first place This is a good policy to follow whenever major repair work is suggested We w isely get second opinions when doctors tell us

we need major surgery; why not give your vehicle the same thorough attention before incurring a m ajor expense?

Gapping your spark plugs

As I m entioned in the preceding section, the space, or gap, between the center and side electrodes needs to be a particular distance across; otherw ise, your plugs don’t fire efficiently A d ­

justing the distance betw een the two electrodes is called g a p ­ ping your spark plugs.

Gap new as well as old spark plugs, even if the package says that the new plugs are “pre-gapped.” To avoid problem s, work on only one plug at a time, in cylinder sequence order.The follow ing steps explain how to gap your spark plugs:

1 If you're regapping a used plug, make sure that it's clean

If you’ re using a new plug, it should be clean and looking, with the tip o f the side electrode centered overthe center electrode

new-There should be no cracks or bubbles in the porcelain insu­lator, and the threads should be unbroken

3 Adjust the gap as necessary.

I f the wire didn’t go through, the gap is too narrow Hook the part o f the feeler gauge that is used for bending elec­

trodes under the side electrode and tug very gen tly to widen

the gap

I f the wire goes through too easily, without touching the electrodes, the gap is w ide P ress the side electrode against

a clean, m a r-p roof surface, very gen tly, until it’s slightly

bent down tow ard the cen ter electrode

4 Run the gauge through the gap again

5 R epeat Steps 3 and 4 until the gap is ju s t right.

You want the gauge w ire to go through fairly easily, just catchin g the electrodes as it passes The w ire should just

“h an g” in the gap but go through with a little guidance

I f you keep gettin g the gap too narrow or too w ide, don't feel bad E veryone I know goes through the “too large-too small-too

large” bit a couple o f times for each plug, especially the perfec­tionists.

After you’re done gapping your spark plug, it’s time to in­sert it in the engine The next section has the details

Installing a spark plug

To insert a spark plug into the engine, follow these steps:

1 Clean the spark plug hole in the cylinder block with a clean, lint-free cloth

Wipe away from the hole; don’t shove any dirt into it

2 Lightly coat the threads o f the spark plug with anti-seize compound, being careful not to get any on the center or side electrodes

3 Carefully begin threading the spark plug into the engine

by hand, turning it clockwise.

This is called “seating the plug.” You have to do it by hand,

or you run the risk o f starting the plug crooked and ruining the threads on the plug or threads in the engine

If you have trouble holding onto the plug, you can buy a spark plug starter and fit it over the plug, or you can use

an old spark plug wire boot or a piece o f vacuum hose to make your own

4 After you engage the plug by hand, turn it at least two full turns before utilizing the spark plug socket and ratchet

5 Slip the spark plug socket over the spark plug, attach the ratchet handle, and continue turning the plug clockwise until you m eet resistance

Don’t overtighten the plug (you can crack the porcelain); just get it in nice and tight with no wiggle The plug should stick a little when you try to loosen it, but you should be able to loosen it again without straining yourself Tighten and loosen the first plug once or twice to get the proper feel o f the thing

I f you have a torque w rench, you can look in th e manual for the proper settin g and use it after you seat the plug by hand Then try to loosen the plug by hand T his gives you the proper feel for how tight it should be M ost do-it- you rselfers tend to replace plugs without torque wrenches because torque w ren ch es are difficult to w ork with in the

sm all space betw een the block and the oth er parts of the vehicle

6 In spect the entire length o f the spark plug wire before attach ing its boot to the plug If the wire is cracked, brittle,

or frayed or is saturated with oil, replace it

7 B efore you attach the boot to the spark plug, apply some silicone lubricant to the inside o f the boot; then push the boot over the exposed term inal o f the new plug and press

it firm ly into place

You’ve just cleaned, gapped, and installed your first spark plug D on’t you feel terrific? N ow you have on ly three, five,

or seven m ore to do, depen din g on your en gine

8 R epeat the steps to rem ove, read, gap, and install each spark plug

It’s at tim es like these that ow ners o f 4 -cy lin d er cars have the edge on th ose w ho drive those big, expen sive 8-cylin- der m onsters

W hen you’re done, start your engine to p rove to yourself that everyth in g still w orks T hen wash your hands with hand cleaner I f you’ve had a hard tim e with a h ard-to-reach plug, get some rest before taking on additional work N ext tim e, the job should be a breeze

4 Servicing your Distributor

M ost cars built after 1975 have electronic ign ition systems that require no regular servicin g Some have no distributors at all All testin g and serv icin g o f these system s should be left to

trained professionals because they are easily damaged if hooked

up im properly, and they employ high voltage that can also dam ­age you

If your car has an electronic ignition system, the only work you can do is to replace the distributor cap and rotor if they become dam aged However, even if you have a distributorless system, don ’t forget to read and change your spark plugs and check that your cables and connections haven’t becom e corroded

or detached I’d do so at least twice a year, or w henever your vehicle stops running sm oothly or your fuel consum ption sud­denly increases

If you aren’t sure w hether your vehicle has one o f the older non-electronic distributors that must be manually serviced, note that older distributors have one thin wire on the side, whereas the electronic ones have two wires or more If you’re still not certain, check your ow ner’s manual or service manual, or call the service departm ent at a dealership that represents your car’s manufacturer

If you have a distributor that does need servicing, check the items in the section called “W hat You Need to Do the W ork in This C hapter,” paying special attention to the parts and tools preceded by the © sym bol

Get to the scene of the action

The distributor gets voltage from the ignition coil and dis­tributes it to each spark plug in turn To accom plish this, the distributor contains a set o f points, a rotor, and a condenser Servicing your distributor involves cleaning and checking these parts and replacing them if necessary O f course, to get to the scene o f the action, you have to remove some stuff that’s in the way But d on ’t panic: The follow ing sections take you step by step through the entire process

Although you can jum p to any o f the follow in g sections to get specific in form ation, I recom m end that you read Chapter 6 before goin g any further It will help you find your distributor and fam iliarize you with w hat each part looks like and does Then return here and w ork your way through the rest of the

sections in succession , using the ® and T sym bols to identify

work that you can do on your particular system

I f you go step by step, you can do everything you need to in the m ost e fficie n t order, thereby increasing the chan ces of your vehicle startin g the first tim e you try it after the w ork is dene

R em ove y o u r d istrib u tor cap

The distribu tor cap is the first th in g to go To remove it, follow these steps:

1 Find your distributor

If you’re still not sure where to find it, C hapter 6 provides

a descrip tion o f the distributor - where it is, w hat it does, and w hat it contains

2 Use a lon g-h an d led screw driver to loosen the distributor cap

M ost caps are held in place by either screw s (see Figure 12-13) or clips (see Figure 12-14)

3 Now that your distributor cap is free, rem ove it without rem ovin g any o f the w ires that are attached to the cap Place it to one side and take a look inside your distributor (see Figure 12-15)

Does the stu ff in there look like the replacem ent parts you bought? L ook at the structure o f the rotor (and the points and con d en ser, w hen you get to them ) T h ey should be sim ilar, although som e parts m ay be m ade o f plastic in­stead o f m etal I f they look different, you’ve got the wrong parts Go back to the auto parts store and start over (You may not collect $200, but at least you w on ’t go to ja il.)

If, w hen you look inside your distributor cap, you do not find the parts in the illustrations in the follow in g section s, you prob­ably have an electron ic ignition system and can consider your­

s e lf pretty lucky As I m entioned earlier, you d on ’t have to deal

w ith adjusting or replacing traditional poin ts and condensers

A ll you have to do is check and change your spark plugs now and then and check for a defective distributor cap or rotor if your en gin e starts running roughly or stops running completely.Because there are m any types o f electron ic ignition sys­tem s, and adjustm ents usually require expen sive tools and spe­cialized expertise com pared to conven tion al ignitions, I strongly advise you to rely on a good autom otive e‘ technician if neither the cap nor the rotor appears dam aged

R e m o v e the rotor

S ittin g on top o f everyth in g else in side the distributor is the rotor R otors vary in size from sm all plastic gizmos that sim ply lift o ff the distributor shaft, to big round plastic plates that have two screws to rem ove (Figure 12-16 show s different kinds o f rotors)

Figure 12-16:

V arious

ty p e s of rotors.

To rem ove your rotor, follow these steps:

1 Before you rem ove your rotor, move it on its shaft

Does it move easily? I f not, you really need this tune-up badly!

2 Remove the rotor from the shaft

To rem ove a small rotor, just lift it straight up o ff the distributor shaft (see Figure 12-17) To remove a large ro­tor, you need to unscrew the two screws and lift the rotor

o ff the distributor shaft (see Figure 12-18)

Figure 12-17:

Removing a small rotor.

Figure 12-18:

You release

this type of

rotor by rem oving the screw s.

it, because you tend to forget how it’s situated, and some­tim es you have to m ake a choice D on’t be afraid to draw pictures if you aren ’t sure you’ll rem em ber how something fit together.

4 Look at the m etal contacts that conduct current to the spark plug term inals

I f the rotor contacts are corroded, broken, or cracked, you really need a new one! In any case, plan to use the new one after you’re through w ork in g on the rest o f the distributor

5 Set the old rotor aside

U nder the rotor on som e veh icles, you may find something

called the c en trifu g a l advan ce (see Figure 12-19) Its

function is rather com plicated, it has nothing to do with this m inor tune-up, and it hardly ever breaks Just leave it

w h ere it is and forget it

Figure 12-19:

A

ce n trifu g a l

advance.

R em ove the static shield

On som e vehicles, you may find a static shield, shown in

Figure 12-20, which you have to remove before you can change your points and condenser The static shield’s purpose is to prevent radio interference Som etim es the working o f the elec­trical system in your car produces strange noises on the car radio This gizm o prevents that

The static shield isn ’t hard to rem ove, but when you finish working on your distributor, be careful to put the shield back exactly the way it was I f you can’t get it back properly, don’t worry - your car will run perfectly without it, so just put the pieces in a paper bag and drive to your friendly service station They’ll put it back for you (although you may have to take a little kidding)

Remove and replace the condenser

U nder the rotor (and possibly the static shield) are the points and condenser Before you rem ove the condenser, look at the two little wires, one leading to the points and the other to the

o f the distributor, w h ich is called the breaker plate If they touch the breaker plate, they short out and the car doesn’t start.Now follow these steps:

1 Take a closer look at how the w ires connect

Are the little clips at the ends o f the w ires touching each other? Or are th ey separated w ith som ething? Does the screw that holds them in place touch them ? Or is there som ething in b etw een ? Figures 12-21, 12-22, 12-23, and 12-24 show how to disconn ect several types o f primary term inal arrangem ents

can rem ove

them.

the prim ary

term inal nut

Even i f you think that you can rem em ber exactly how the

w ires are connected, draw a picture o f them before you

rem ove them !

2 W h en you have a picture o f h o w th ey are attached,

d isco n n ect the w ires.

Put the screw s or other parts that cam e o ff on a clean surface so that you’ll know w here th ey are when you need them later

3 Push the co n d e n se r (that little c y lin d er in there)

th ro u g h the rin g that h olds it, and th en put it near the screw s that you re m o ved in Step 2.

Som e con d en sers are attached to the clips that hold them, and you have to rem ove them , clip and all Figures 12-25, 12-26, and 12-27 show a few o f the m ost com m on setups

Figure 12-27:

Some condensers

4 U se a clean, lint-free rag to w ipe around the breaker plate

w here the condenser was restin g Then take the new con­denser and slide it in w h ere the old one was

I f th ere’s a new clip in the tune-up kit but you were able

to slide your old con d en ser out w ithout rem oving the old clip, forget the new clip as lon g as the old one seems to

be in good condition and d oesn ’t w iggle around

C ongratulations! You just rep laced your condenser On to the points!

Remove and replace the points

The points on your veh icle m ay look a bit different from the ones in Figure 12-28, but they w ork the same way Here's a rundow n o f som e basic types o f poin ts that you m ay encounter:

♦ Som e points are m ade in a sin gle unit; others consist of

tw o halves that fit togeth er Som e C hrysler products have dual sets o f points, but these are no m ore difficult to install

or change

♦ Som e foreign cars have little springs that com e out sepa­rately from the points I f you have points like these, be

sure to hold your free hand over the distributor when you loosen the points, or it will spring out and get lost.

♦ Some points have two screws that fit into slots in the points

- these can be loosened, and the points will slide out O th­ers have a screw to hold the points down and another screw

to adjust them

Before you rem ove your old set o f points, com pare them to

the new set o f points you just bought If they don’t look exactly alike, return them for the proper kind

Once you know w hich kind o f points you have, do the follow ­ing:

1 Take your screw driver and open up the points in your dis­tributor so that you can see between them

Are the contacts rough where they m eet? This is usually the result o f norm al wear and tear If they’re badly burned

or pitted, the points should be replaced

If the points are relatively new, excessive wear can be a sign that som ething is im properly adjusted or m alfunc­tioning E xcessively worn points or burned points usually

result from either poor adjustment when they were installed (this m eans that they w ere incorrectly gapped) or a bad condenser, or the accidental introduction o f oil or cam lu­bricant betw een the point contacts

Because used points are im possible to read accurately with

a feeler gauge (F igure 12-29 show s you w hy), you won’t be able to tell if this is a case o f poor adjustm ent But if your olds points look badly burned or worn, be sure to check your new points after about 1,000 m iles o f driving, and if these look bad, too, ask your m echanic for an opinion

F igu re 12-29:

W h y y o u

c a n 't g e t an

a c c u ra te gap re a d in g

3 Put your old points aside, and use the clean rag that you used to clean around under the condenser to wipe the rest

o f the breaker plate (the floor o f your distributor)

Before installing the new points, you need to do another little job

Lubricate your distributor

Lubricating your distributor is som ething that seem s incon­sequential but is really very im portant because it can increase the life o f your points In the package with your new points, there may be a little capsule o f cam lubricant I f there isn ’t any, you can buy a tube o f it very cheaply Then follow these steps:

1 Take a little bit o f cam lubricant on your index finger and wipe it around the sides o f the cam wheel (see Figure 12-31).Use the lubricant very sparingly You don’t want lumps, just a nice greasy finish on the cam wheel only I f you don’t lubricate this wheel, your points could burn out very quickly

If you use too much, the stuff flies around inside the dis­tributor when the wheel spins and fouls things up or causes your points to burn Because your points open and close

very fast (at around 12,000 tim es a m inute when you drive

a V -8 engine at 60 m ph), you can see w hy the lubricant is necessary and w hy it tends to fly aiou nd if you’re too gen­erous You w ant ju st enough to make your cam wheel lobes slide easily past the points

burn the points.

2 Look at the top o f the distributor shaft, where the rotor was sitting I f th e re ’s a wick inside it, place a few drops of light engine oil on the wick in the shaft, as shown in Fig­ure 12-32

I f you don ’t have the proper kind o f oil, forget it this time and pick som e up in tim e for the next tune-up

Figure 12-32:

If a w ick is

p resent lubricate the distributor shaft with

just a fe w

drops of oil.

Install the new points

A fter the distributor is properly lubricated (see the preced­ing section), you’re ready to install your new points Follow these sim ple steps:

1 Pick up the new points and gently rub the two contact tips together

Points usually com e from the factory with some kind of coating on them, and this coating can keep the spark from going across the gap Gently rubbing the tips together re­

m oves this coating Don’t use cloth, paper, or a file to re­move this coating - the lint or tiny filings will foul the points A little rub is all they need

2 Install the new points where the old ones were (see F ig­ures 12-33 and 12-34), but don’t tighten down the screws that hold them in place until you have adjusted the gap Som etim es it’s easier to connect the lead wires that come from the points and the condenser before you replace the points in the distributor

3 Be sure that the clips on both wires touch each other.but

do not touch any other metal T hey’re designed to go back

to back so they fit snugly into the clip on the prim ary term inal Refer to Figures 12-21 through 12-24 to see the different types o f configurations and the way to reassem ble yours

If you don’t see your configuration in these illustrations - and you neglected to make a drawing o f the way yours was

- use your im agination If you get it wrong, your car sim ply

w on't start until you get it right N othing else will happen,

so don ’t worry Just fit the wire clips together and put them in the clip so that they’re not touching anything metal (this includes the side o f the clip, if it’s made o f metal, and the distributor base) As I said earlier, this can be done eith er before or after you get the points in place, w h ich ­ever is easier

A d ju st yo u r points

N ow it’s tim e to adjust your point gap (also called “gapping your p oin ts”) B efore you can adjust the point gap, the little rubbing block that protrudes from the side o f the points nearest

the cam w heel m ust rest on the h ig h est point o f one o f the cam lobes T his forces the points open to th eir w idest gap - and

th at’s the gap you’re going to adjust:

1 If the rubbing block isn’t resting on the point of the cam lobe, use your ignition key to “bump” your starter until the cam wheel turns to the correct position (see Figures 12-35 and 12-36)

Figure 12-33:

Some points have a knob that fits into

a locating hole on the floor of the distributor

Figure 12-34:

Other points fit over a locating post on the floor of the distributor.

If you have difficulty doing this, run a chalk m ark down the side o f the distributor and onto the base, or whatever it’s sitting on (This line will help you later to get it back the way it was.) Then turn to the section called “Adjust your tim ing,” later in this chapter, to see how to locate the distributor hold-down clamp Loosen it and turn the dis­tributor until the rubbing block is resting on the point o f the cam lobe and the points are wide open:

2 Look at your specifications for the proper point gap; then take your flat feeler gauge and select the correct blade

3 Slide the blade o f the feeler gauge between the points and note how narrow or wide the opening is

Is the gap too small to let the blade in? If you left it like that, your car would be hard - or im possible - to start, and your points would get burnt and pitted Is the gap so wide that the gauge doesn’t touch both surfaces as it goes in and out? This results in a weak spark and poor engine perfor­mance at high speeds So if your gap is either too wide or too small, it needs adjusting

There are three basic kinds o f point-adjusting set-ups Some

cars have an adjusting screw (in addition to the screw or screws that hold the points in place) Other cars have an adjusting slot Still others have a little window in the distributor cap that

allows you to adjust the points without rem oving the distributor cap Look at Figures 12-37, 12-38, and 12-39 to determ ine which one your vehicle has and then follow the appropriate set o f steps:

If you have an adjusting screw, see Figure 12-37 and follow

these steps:

1 Loosen the screw or screws that hold the points in place

2 Turn the off-center adjusting screw

3 Place the correct feeler gauge blade between the point con ­tacts

The contacts should still be at th eir widest gap If they aren’t, follow Step 1 at the begin nin g o f the “Adjust the poin ts” section to turn the distributor until they are

4 Turn the adjusting screw (see Figure 12-37) until the feeler gauge blade can slip in and out betw een the contacts, just touching them as it slides

There should be a minuscule grab as the blade goes through, but it should go through easily I f you aren’t sure, try the next th ick er and th inn er blades I f the gap is correct, nei­ther should w ork properly

5 W hen you get the gap ju st right, tighten the screws that hold your points in place (n ot the adjusting screw) and recheck w ith the gap with the gauge

6 I f you’ve m oved the distributor, put it back where it was, with the chalk m arks lin ed up

I f you have an adjusting slot, see Figure 12-38 and followthese steps:

1 Loosen the lock in g screw or screw s that hold the points inplace

2 M ake sure that the points are at their widest gap

I f they aren’t, follow Step 1 at the beginning o f the “Adjust the poin ts” section to move the distributor until they are Then insert the tip o f your screwdriver into the adjusting slot and, by m oving it one way or the other, open the gap

so that the correct feeler gauge blade can slip in

3 Insert the correct feeler gauge blade and, using your screw ­driver in the adjusting slot, adjust the contacts to allow the blade to slide in and out between the contacts, just touching them as it slides

The blade should just touch both contacts as it moves, but

it should move easily, with just a little bit o f grab as it goes

by If you aren’t sure, try the next thicker and thinner feeler gauge blades If the gap is correct, neither should work properly

4 Tighten the screws that hold the points in place and then recheck the gap with the gauge

5 If you m oved the distributor, put it back the way it was, with the chalk m arks lined up

If you have an external adjustm ent window, see Figure 12-

39 and follow these steps:

1 R eassem ble your distributor and put the distributor cap back on

You can find instructions for doing so in the next section under “R eplace the static shield” and “R eplace the rotor."Your points p robably w on’t need adjusting because they com e p reset from the factory They should need adjusting only i f your car w on ’t start

I f your car w on ’t start, first make sure that you’ve hooked the w ires from the points and the con denser together so that th ey d on ’t touch any m etal parts except each other (See Step 3 o f the section called “Install new points” for details.)

I f your poin ts do need adjusting, follow the rest of these steps

2 U se a h ex w ren ch (an A llen w rench shaped to fit into hex­agonal h oles) to turn the adjusting nut behind the sliding

w indow in the distributor cap, as show n Figure 12-39

I f a little hex w rench cam e w ith the points, use it If not, you’ll have to get your own

3 Start your car and leave the engine running with the emer­gency brake on and the car in either Park or Neutral Turn the nut clock w ise until the engine starts to falter Then turn the screw h a lf a turn coun terclockw ise, remove the

w rench, and close the w indow

Get it all together again

Once you’ve replaced the condenser, replaced and adjusted your points, and put those pesky little lead wires safely back in their clip, it’s just a m atter o f putting everything back the way

it was before you started servicing the distributor Relax; you’re

in the hom e stretch The next sections will see you safely to the winner’s circle

R eplace the static shield

If you have a static shield, put it back now, before you re­place the rotor For details, refer to “Remove the static shield” and Figure 12-20 in the earlier section called “G etting to the scene o f the action.”

R eplace the rotor

Now it’s time to install the new rotor you purchased

Be sure to put the new rotor back exactly the way the old one went (the previous section called “Remove the rotor” may refresh your m emory) All rotors fit properly one way only, and it’s easy to check the position o f yours Once it’s back on the shaft, just turn the rotor to see whether it settles back into place easily I f you ran turn it in more than one direction, you haven’t replaced it properly

Check the d istributor cap

Take the time to clean and check your distributor cap th or­oughly I f it’s defective, replace it:

1 Pick up the distributor cap (don’t let any wires come off) and take a look inside it Wipe the inside clean with a lint-free rag

Do you see any cracks in the cap when you hold it up and shine a light through it? If you do, you can buy another cap very cheaply Follow the instructions in the sidebar called

“R eplacing a distributor cap is easy.”

2 Look at the inside o f your cap where the w ires enter it Push gently on each wire where it enters its “tow er,” and

m ake sure that it’s in tightly

A re the insides o f the tow ers clean? Each little metal thing you see inside the cap is an electrode that transfers elec­tricity to the rotor; you don’t want these electrodes to be too fouled to conduct the electricity

3 I f the electrodes look dirty, scrape them with a small screw­driver to rem ove the carbon

I f the electrodes are burnt or very dirty, you may need to replace your w ires I f you feel that you can do the job accu­rately, con n ectin g each wire to the proper tow er on the cap and the proper spark plug, one at a tim e, fine I f not, you’re probably better o ff having som eone w ith m ore experience replace the w ires for you

4 W hen you’re satisfied that all is w ell, replace your dis­tributor cap

Figures 12-40 and 12-41 show you the two steps necessary

to replace different types o f caps

5 Start your engine to see whether you’ve got everything right

I f your car starts right up, great! Y ou’re ready to move on

to the section called, “C hecking and adjusting your work.”

I f the car w on’t start, don ’t panic; the instructions in the next section will soon set things right

Figure 12-40:

Som e distributor

ca p s have either a locating lug that fits into

a slot in the cap spring hanger

(left), or a groove or slot in the cap that fits over a boss

on the distributor housing

Ir ig h tI

Restart your car

If your car doesn’t start (this isn’t unusual), the answer to one o f these troubleshooting questions will solve your problem:

♦ Is your vehicle still in Park or Neutral? It w on’t start in any other gear

♦ Is your distributor cap on correctly? I f it isn’t, put it on properly If it is, rem ove it so that you can look inside and answ er the other questions in this list

♦ Are the lead w ires from the condenser and the points cor­rectly replaced and tightened down? (Refer to Figure 12-13.) I f th ey’re touching anything metal except each other, the spark is grounding out instead o f passing through the points while th ey’re closed

♦ A re your points properly gapped? C heck them again with the proper feeler gauge blade Som etim es they move back together when you tighten them dow n after adjusting them.Run a bit o f very clean, lint-free cloth between them - maybe som ething got in there and is preven tin g the spark from goin g across Do the points close com pletely? They must open and close to work

♦ Did you accidentally d iscon n ect any oth er wires while you

w ere w orking? Reattach them

A fter you correct the problem , put your distributor cap back again and start the engine It should start this time Don’t panic

if you still have trouble alm ost everyone does the first time But you ran the engine after you chan ged the spark plugs, so if there is a problem , it has to be in the distributor, right?

I f you still can’t get the car started, rem ove the new con­

d en ser and put the old one back in M aybe the new one is defec­tive T his could also be true o f the points or rotor If you keep tryin g and still have no luck, the w orst that can happen is that your frien dly m echanic w ill have to get you out o f the hole So how bad can it be?

Check your distributor With a dwell meter

A fter you start your car follow in g a tune-up, it’s time to

ch eck the dwel I assum ing that you bought or borrow ed a dwell

m eter (You’ll also w ant to ch eck your v eh icle’s tim ing, follow­

in g the instructions at the end o f this ch apter.)

The difference betw een the cost o f doin g this tune-up once

y o u rse lf and paying to have it done for you is probably more than the cost o f a dw ell m eter plus a tim in g light

A dw ell m eter (see “W hat You N eed to Do the W ork in This

C h a p ter” for a description o f this and other tools) is a handy gadget for determ in ing w h eth er your points are properly gapped and w h eth er your distributor is operatin g properly

A dwell m eter checks the distance that your distributor shaft rotates when your points are closed - which is the same as saying that it measures how long the points stay closed (or

“dwell togeth er” ) This distance is called the cam angle, and,

like all angles, it’s measured in degrees

H ooking up a dw ell m eter

The first thing you have to do when you check the dwell is

tb hook up the dwell m eter to the distributor The follow ing shows how to hook up two o f the most popular types o f dwell meters

To hook up a dwell m eter with two clips (see Figure 12-42):

1 W ith the engine shut off, find the little wire on the side o f the coil that connects at its other end to the distributor and hook the red clip to the clamp that holds that wire in place

2 H ook the black clip to “ground.”

“G round” can be anything on the vehicle that’s made o f

m etal, through which electricity can pass back to the bat­

tery In this case, ground can be any part o f the metal

fram e o f the car, but the best ground is an unpainted pipe

or bolt bolted directly to the engine (N ot too near the carburetor, please! You d on ’t w ant a stray spark setting off the fuel in the carburetor.)

To hook up a dwell m eter w ith th ree clips (see Figure 12-43):

1 C on n ect the red clip to the p o sitiv e term inal o f the battery.

2 Connect the black clip to the negative terminal o f the battery.

3 C on n ect the green clip to th e clam p that holds the little

w ire on the side o f the coil that conn ects at its other end to the distributor

Som e Ford cars have an insulated slip-on term inal on the wire lead in g from the distribu tor to the ignition coil If you have a Ford w ith this con figu ration , lift the slip-on terminal and slide the Ford adapter clip in place (see Figure 12-44); then push the term in al down A ttach the Green clip to the adapter clip, as show n in Figure 12-44

D on’t allow the Ford adapter clip to touch any other m etal­lic part o f the coil case or the engine.

3 Start the engine and let it idle, with the em ergency brake

on and the gearshift in Park or Neutral

4 Look at the line on the dwell m eter that has the same number o f cylin ders as your vehicle has, and see where the needle is pointing Is the needle pointing to the correct figure listed under “Dwell" on your specifications sheet? It can be plus or minus 2 degrees For exam ple, if your spec sheet show s a dwell o f 38 degrees, a dwell anywhere be­