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

302
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.

Use 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 away w ith a soda straw.
D oing so keeps loose junk from falling down the hole into
the cylinder w hen the plug is rem oved.

3.

Find your spark plug socket (the big one with the rubber
lining) 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 everything else in auto repair, don’t be afraid to use
som e strength. But do it in an even, controlled manner. If
you bang or je rk things, you can dam age them , but you’ll
never get anyw here if 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 move the handle freely from side to side without hit­

ting anything, go ahead. You add them in the same way
you added the socket to the handle. (If you have trouble
with gpttinp the plug loose, see the “ D ealing with difficult
plugs” section, w hich follow s, for encouragem ent.)
The little knob on the back o f the ratchet handle makes
the ratchet turn the socket either clockw ise or counter­
clockw ise) You can tell w hich way the handle will turn the
plug by listening to the clicks that the handle m akes when
you m ove it in one direction. If it clicks w hen you move it
to the right, it will turn the socket counterclockw ise when
you m ove it, silen tly, to the left. If the clicks are audible on


303
the leftward swing, it will move the socket clockwise on
the rightward swing. Every screw, nut, bolt, and so on that
you encounter should loosen counterclockwise and tighten
clockwise. If your ratchet clicks in the wrong direction,
just move 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. When
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, re­

move 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


304
them easily, they may be difficult to remove. This section provides
tips on extracting your spark plugs with a minimum o f hassle.
A lm ost every vehicle has at least one plug that’s a miser­
able th in g to reach.
If you have one, save it for last. Then you can work on it
with the satisfaction o f know ing that, when you get the darn
thing finished, you will have finished the job.
If you find that one or more plugs are blocked by an air
conditioner or som e other part, try using various ratchet handle
extensions to get around the problem . There are universal ex­
tensions that allow the ratchet handle to be held at odd angles;
T-bar handles for better leverage; and offset handles for hardto-reach places. (See C hapter 2 for exam ples.)
On som e vehicles, you can’t get at the plugs until you re­
move other parts that are in the way. On som e transverse en­
gines, 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 with optional big engines, you
have to hoist 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 never been replaced
during all the professional 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
always drive to your service station and hum bly ask them to
change just that one plug. T hey w on’t like it, but it is a last
resort. If 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 ordinary way, go under, over, around, or through


305
gaps in the thing that’s blocking it. Or get someone to help you
move w hat’s in the way (but be sure that you can get it back in
place correctly). Use your imagination; it’s the only hard part of
the job. And you won’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 tempted 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 condition­
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 firing 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 between these two electrodes. This gap must
be a particular distance across for your engine to run effi­
ciently.


What Your Old Spark Plugs Tell You about Your Car

Table 12-1
Condition
N o rm a l p lu g

Clues

Probable Causes

Remedies

B r o w n o r g r a y is h - ta n

E v e ry th in g 's fin e .

J u s t c le a n a n d re g a p th e p lu g .

B la c k , d ry , f lu f f y s o o t o n

O v e rly r ic h f u e l/ a ir m ix tu r e ;

S w it c h to " h o t t e r " p lu g s .

in s u la to r tip a n d e le c tr o d e s

m a lfu n c tio n in g c h o k e ; d ir t y a ir

(T h e h ig h e r th e p lu g

filte r ; o r ju s t to o m u c h d r iv in g a t

n u m b e r, th e h o tte r th e p lu g .)

d e p o s it o n s id e e le c tr o d e
C a rb o n -fo u le d p lu g

lo w s p e e d s , o r s ta n d in g a n d

O tl-fo u le d p lu g

B u r n t p lu g

W e t, b la c k , o ily d e p o s its

O il m a y b e le a k in g in to c y lin -

C le a n a n d re g a p th e p lu g

o n in s u la to r tip a n d e le c tr o d e s

d e r s p a s t w o r n p is to n s o r p o o r ly

o r r e p la c e it, b u t fin d o u t

a d ju s te d o r w o r n v a lv e s .

w h e r e th e le a k is c o m in g fro m .
R e p la c e th e p lu g .

B lis te r s o n in s u la to r tip ,

E n g in e o v e r h e a tin g ; g a p to o

m e lte d e le c tr o d e s ,

w id e ; w r o n g o r lo o s e p lu g s ;

b u r n t s tu ff

o v e r ly le a n f u e l/ a ir m ix tu r e ;
in c o r r e c t tim in g .

W o r n p lu g

S e v e re ly e r o d e d o r
w o r n e le c tr o d e s

P lu g h a s b e e n in th e r e to o lo n g

R e p la c e th e p lu g .

306

id lin g fo r a lo n g tim e .


307

T e rm in a l

In s u la to r

R e s is to r
- S p r in g
S h e ll

- C e n te r
seal
G asket

Figure 12-10:

.C e n te r

The

e le c tr o d e

anatom y
of a spark
plug.

4.

-T h re a d s

^Gap
In s u la to r
tip

- S ide
e le c tr o d e

Take your wire or taper feeler gauge and locate the proper
wire (if your spark-plug gap specifications say .035, look
for this number near one o f the wires on the gauge). Then
slip that gauge wire between the two electrodes on your
old plug.
Figure 12-11 shows why you should never use a flat feeler
gauge for this purpose. The reading will be inaccurate.

Figure 12-11:
W hy you
can't use a
fla t fe e le r
gauge on
an old
spark plug.


308
The gauge wire probably has a lot o f room to wiggle around
in. This may be because your old plug has worn down its
center 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 center electrodes on your
new spark plugs? Has the electrod e’s flat top worn down to
a rounded lump? Or has it worn down on only one side?
C hances are it’s pretty w orn because it’s old. When the
center 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
a wire brush.
Keep in m ind that although you don’t need to clean new
spark plugs, you do need to gap them . Some plugs are sold
“ pregapped,” but I’d check them w ith a feeler gauge any­
way.

7.

R epeat the entire process for each additional plug, work­
ing on only one at a time.
A good w ay to keep track o f w h ich plug belongs in which
cylin der is to use an egg carton as a container and put the
plugs into the carton’s d epressions in numerical order as
you rem ove them from the engine.

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


309
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 part­
ment 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 e­
chanic 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 wisely get second opinions when doctors tell us
we need major surgery; why not give your vehicle the same
thorough attention before incurring a major 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 between 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 newlooking, with the tip o f the side electrode centered over
the center electrode.
There should be no cracks or bubbles in the porcelain insu­
lator, and the threads should be unbroken.


310
2.

Take your feeler gauge, select the proper wire, and run it
betw een the electrodes (see Figure 12-12).
If the wire doesn’t go through or if it goes through too
easily, without touching the electrodes, you need to adjust
the distance betw een the electrodes.

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 wide. Press the side electrode against
a clean, m a r-proof surface, very gently, until it’s slightly
bent down toward 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
catching the electrodes as it passes. The wire should just
“hang” in the gap but go through with a little guidance.

I f you keep getting the gap too narrow or too wide, don't feel
bad. Everyone I know goes through the “too large-too small-too


311
large” bit a couple o f times for each plug, especially the perfec­
tionists.
After you’re done gapping your spark plug, it’s time to in­
sert 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.


312
I f you have a torque w rench, you can look in the manual for
the proper setting 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-ityourselfers tend to replace plugs without torque wrenches
because torque w renches are difficult to w ork with in the
sm all space betw een the block and the oth er parts of the
vehicle.
6.

Inspect the entire length o f the spark plug wire before
attaching 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? Now you have only three, five,
or seven m ore to do, depending on your engine.

8.

Repeat the steps to rem ove, read, gap, and install each
spark plug.
It’s at tim es like these that owners o f 4 -cylin d er cars have
the edge on those w ho drive those big, expensive 8-cylinder m onsters.

W hen you’re done, start your engine to prove to yourself
that everything still w orks. Then wash your hands with hand
cleaner. If you’ve had a hard tim e with a hard-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 ignition systems
that require no regular servicing. Some have no distributors at
all. All testing and servicin g o f these system s should be left to


313
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 damaged. 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 become corroded
or detached. I’d do so at least twice a year, or w henever your
vehicle stops running sm oothly or your fuel consumption sud­
denly increases.
If you aren’t sure whether 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 © symbol.

Get to the scene of the action
The distributor gets voltage from the ignition coil and dis­
tributes 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 don’t panic: The following sections take you step by
step through the entire process.


314

Although you can jum p to any o f the follow in g sections to
get specific inform 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 what each part looks like and does.
Then return here and work 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 .
If you go step by step, you can do everything you need to in
the m ost efficien t order, thereby increasing the chances of your
vehicle starting the first tim e you try it after the work is dene.
R em ove y o u r d istribu tor cap
The distributor cap is the first thing 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 description o f the distributor - where it is, what it does,
and w hat it contains.

2.

Use a long-handled 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 oving 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 hey should be
sim ilar, although som e parts may be made o f plastic in­
stead o f m etal. If 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.)


315

Figure 12-13:
R em oving a
d is trib u to r
ca p w ith
s c re w
clam p s.

Figure 12-14:
R em oving a
d is trib u to r
cap w ith
clip s.

P o in t se t h o ld -d o w n s c re w
Lead w ire s
P o in ts co n ta c ts .

P rim a ry te rm in a l

Points
C o n d e nse r

Figure 12-15:
The a na tom y

Coil w ire

of a non­

te rm in a l

e le c tro n ic
d istrib u to r.

V a cu um a d va n ce


316
If, w hen you look inside your distributor cap, you do not find
the parts in the illustrations in the follow ing section s, you prob­
ably have an electronic ignition system and can consider your­
se lf pretty lucky. As I m entioned earlier, you don’t have to deal
with adjusting or replacing traditional points and condensers.
All 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 sys­
tem s, and adjustm ents usually require expen sive tools and spe­
cialized expertise com pared to conventional 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 em o v e the rotor
S ittin g on top o f everything else inside 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 shows different
kinds o f rotors).

Figure 12-16:
V arious
typ e s of
rotors.


317
To rem ove your rotor, follow these steps:
1.

Before you remove your rotor, move it on its shaft.
Does it move easily? If not, you really need this tune-up
badly!

2.

Remove the rotor from the shaft.
To remove a small rotor, just lift it straight up o ff the

distributor shaft (see Figure 12-17). To remove a large ro­
tor, you need to unscrew the two screws and lift the rotor
off the distributor shaft (see Figure 12-18).

Figure 12-17:
Removing a
small rotor.

Figure 12-18:
You release
this type of
rotor by
removing
the screw s.


318
3.

Take a close look at the old rotor to see how it fits onto the
shaft so that you can put the new one in properly later on.
A ll rotors go on in only one way: They either have a squarepin-insquare-hole/round-pin-in-round-hole arrangement, or
th ey’re notched or shaped so that they fit on the shaft
pointing in only one direction. Still, it’s a good habit to
take a long look at anyth in g you rem ove before you remove
it, because you tend to forget how it’s situated, and some­
tim 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 orkin g on the rest o f the distributor.

5.

Set the old rotor aside.
U nder the rotor on som e vehicles, you may find something
called the cen trifu ga l advance (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 here it is and forget it.

Figure 12-19:
A
cen trifu ga l
advance.


319
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. Sometimes the working o f the elec­
trical 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. If 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 remove the condenser, look at the
two little wires, one leading to the points and the other to the


320
condenser, that jo in together - usually with som e sort o f little
screw and w asher arrangem ent (refer to Figure 12-13).
Take a good look at how the wires (som etim es called leads)
fit together in the gadget that holds them (called the primary
term inal). The m ain purpose o f the prim ary term inal is to pre­
vent the clips at the ends o f these wires from touching the floor
o f the distributor, w hich 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 wires connect.
Are the little clips at the ends o f the wires touching each

other? Or are they separated with som ething? Does the
screw that holds them in place touch them ? Or is there
som ething in betw een? Figures 12-21, 12-22, 12-23, and
12-24 show how to disconnect several types o f primary
term inal arrangem ents.

Figure 12-21:
On some
distribu to rs,
the w ire s
m ust be
loosened
from the
prim ary te r ­
minal, as
shown,
before you
can remove
them.


321

Figure 12-22:
On another
type of dis­
tributor, you
m ust use a
special tool
to remove

the prim ary
term inal nut
and release
the contact
spring and
lead wires.

Figure 12-23:
On other dis­
tribu to rs, the
nut on the
prim ary te r­
m inal must
be loosened
to release
the co n ta ct
spring and
lead w ire s


322

Figure 12-24:
Still an othe r
d is trib u to r
has its w ire s
attach ed as
show n. You
rem ove
the se by

loosening
the nut at
the prim ary
term in al.

Even if you think that you can rem em ber exactly how the
wires are connected, draw a picture o f them before you
rem ove them !
2.

W h en you have a picture o f h ow th ey are attached,
d iscon n ect the w ires.
Put the screw s or other parts that came o ff on a clean
surface so that you’ll know w here they are when you need
them later.

3.

Push the con d e n se r (that little cylin d er in there)
th rou gh the ring that holds it, and then put it near
the screw s that you rem oved 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.


323

Figure 12-25:
This type of

condenser
has one
s cre w to
remove and
tw o locating
bumps to
help you
position the
new one
securely.

Figure 12-26:
Other con­
densers
have a
'lo c a tin g
hole in the
mounting
bracket.


324
Figure 12-27:
Some
condensers
are c o n ­
nected to
the prim ary
te rm in a l by
a copper

strap tha t
m ust be
released
before they
can be
rem oved.

4.

Use a clean, lint-free rag to w ipe around the breaker plate
w here the condenser was restin g. Then take the new con­
denser and slide it in w here 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 denser 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.

Congratulations! You just replaced your condenser. On to
the points!

Remove and replace the points
The points on your vehicle m ay look a bit different from the
ones in Figure 12-28, but they w ork the same way. Here's a
rundown o f som e basic types o f points that you may encounter:
♦

Som e points are made in a sin gle unit; others consist of
two halves that fit together. 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 sepa­
rately from the points. If you have points like these, be


325
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. Oth­
ers have a screw to hold the points down and another screw
to adjust them.

Before you rem ove your old set o f points, compare 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 dis­
tributor so that you can see between them.
Are the contacts rough where they meet? 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 alfunc­
tioning. E xcessively worn points or burned points usually


326
result from either poor adjustment when they were installed
(this means that they were incorrectly gapped) or a bad
condenser, or the accidental introduction o f oil or cam lu­
bricant betw een the point contacts.
Because used points are im possible to read accurately with
a feeler gauge (Figure 12-29 shows you why), 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.

Actual point opening .025

F igu re 12-29:
W h y yo u
c a n 't g e t an
a c c u ra te
gap re a d in g
on old

-.020 Feeler gauge

p o in ts.

2.

R em ove the old points by rem oving the screw or screws
that hold them in place (see Figure 12-30).
I f you have slotted points, sim ply loosen the screw and
slide the points out.
This is a good tim e to use a screw holder. It holds the screw
until you release it, so you don’t have to cram your fingers
into the distributor to hold onto the screw.