Haynes Nissan/Datsun Pick-Ups and Pathfinder Automotive Repair Manual 1563921987, 9781563921988

Citation preview

72030

(771)

NISSAN/DATSUN PICK-UP & PATHFINDER Pick-ups (1980 thru 1996) Pathfinder (1987 thru 1995) All

2WD and 4WD

models with a gasoline engine

Automotive Repair

iVIanual

o^J^^JLOg

'"'^9^5^

^^Cp'^^^

Digitized by the Internet Archive in

2010

http://www.archive.org/details/nissanpickupsautOOpaul

Nissan Pick-ups Automotive Repair

Manual by Rik Paul, Ken Freund and John HHaynes Member

of the Guild of Motoring Writers

Models covered: Nissan/Datsun pick-ups 1980 through 1996 Pathfinder 1987 through 1995 Does not Include

dlesel engine Information

^^^"^ Haynes Publishing Group Sparkford Nr Yeovil Somerset BA22 7JJ England

Haynes North America, 861 Lawrence Drive Newbury Park California

91320

USA

Inc

MEMBER

Acknowledgements We are grateful for the fielp and cooperation of tfie Nissan Motor Company, Ltd. for

assistance

witfi

technical information, certain illustrations

vehicle photos. Nissan also supplied the vehicle

shown on the

© Haynes North America, Inc.

989,

1

988,

1

1

991

,

1

and

rear cover.

993,

1994, 1996 With permission from J H Haynes &

A book

in

Printed

the

in

Co

Ltd

Haynes Automotive Repair Manual Series

the

USA

reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, recording or by any information storage or retrieval system, without permission in writing from the copyright

All rights

holder.

ISBN1 56392 198 Library of

7

Congress Catalog Card Number 96-76645

is made to ensure that the information in this correct, no liability can be accepted by the authors or pubin, or omislishers for loss, damage or injury caused by any errors sions from, the information given.

While every attempt

manual

is

Contents Introductory pages About this manual 0-5

Introduction to the Datsun/Nlssan pick-ups and Pathfinder ^fc W^

counterclockwise to loosen

to loosen oil

drain plug locations (left — four-cylinder engines)

V6

engine;

right

13.3

These tools are required when changing the engine oil and filter

Drain pan - It should be fairly shallow wide in order to prevent spills

Rubber gloves - When removing filter it is

inevitable that

(the gloves will

you

will

in

depth, but

and on your hands

the drain plug

get

oil

prevent burns)

Breaker bar - Sometimes the

oil

drain plug

is

pretty

and a long breaker bar is needed to loosen it Socket - To be used with the breaker bar or a ratchet tight

(must be the correct size to fit the drain plug) wrench - This is a metal band-type wrench, which requires clearance around the filter to be effective Filter wrench - This type fits on the bottom of the filter and can be turned with a ratchet or breaker bar (different size wrenches are available for different types of filters) Filter

'^

.

Be sure

to clean the drain plug to

metal particles clinging to

it!

remove any

1

Chapter

1

1-21

Tune-up and routine maintenance

1 Allow the old oil to drain into the pan. It may be necessary to move the pan as the oil flow slows to a trickle. After all the oil has drained, wipe off the drain plug with a clean 1 1 rag. Small metal particles may cling to the plug and would immediately contaminate the new oil (see illustration). 1 2 Clean the area around the drain plug opening and reinstall the plug. Tighten the plug securely with the wrench. If a torque wrench is available, use it to tighten the plug. 13 Move the drain pan into position under the oil filter. 1 4 Use the filter wrench to loosen the oil filter (see illustration). Chain or metal band filter wrenches may distort the filter canister, but it doesn't matter since the filter will be discarded anyway. Completely unscrew the old filter. Be careful; it's full of oil. Empty 1 5 the oil inside the filter into the drain pan. 1 6 Compare the old filter with the new one to make sure they're the

LOOSEN

same

type. 1 7 Use a clean rag to remove all oil, dirt and sludge from the area where the oil filter mounts to the engine. Check the old filter to make sure the rubber gasket isn't stuck to the engine. If the gasket is stuck to the engine, remove it.

13.14

locations (left - V6 engine; four-cylinder engines)

Oil filter

right

—

light coat of clean oil to the rubber gasket on the new oil (see illustration). 1 9 Attach the new filter to the engine, following the tightening directions printed on the filter canister or packing box. Most filter manufac1

8 Apply a

filter

turers

recommend

of overtightening

against using a

and damage

filter

wrench due

to the possibility

to the seal.

20 Remove

all tools, rags, etc. from under the vehicle, being careful not to spill the oil in the drain pan, then lower the vehicle. 21 Move to the engine compartment and locate the oil filler cap. 22 If an oil can spout is used, push the spout into the top of the oil can and pour the fresh oil through the filler opening. A funnel may also be used. 23 Pour three or four quarts of fresh oil into the engine. Wait a few minutes to allow the oil to drain into the pan, then check the level on the oil dipstick (see Section 4 if necessary). If the oil level is above the L mark, start the engine and allow the new oil to circulate. 24 Run the engine for only about a minute and then shut it off. Immediately look under the vehicle and check for leaks at the oil pan drain plug and around the oil filter. If either one is leaking, tighten it a little

more. 25 With the new oil circulated and the filter now completely full, recheck the level on the dipstick and add more oil as necessary. 26 During the first few trips after an oil change, make it a point to check frequently for leaks and correct oil level. 27 The old oil drained from the engine cannot be reused in its present state and should be disposed of. Oil reclamation centers, auto repair shops and gas stations will normally accept the oil, which can be refined and used again. After the oil has cooled it can be poured into a container (capped plastic jugs or bottles, milk cartons, etc.) for transport

13.18

Lubricate the oil filter gasket with clean engine before installing the filter on the engine

oil

to a disposal site.

14

Valve clearance adjustment (four-cylinder engines only)

1 Although the valves can be adjusted with the engine cold, it's better them with the engine hot. If they're adjusted cold they should be rechecked once the engine has warmed up and readjusted if neces-

to adjust

sary to conform to the hot engine specifications. Start the engine and allow it to reach normal operating temperature, 2 then turn the engine off. Remove the rocker arm cover as described in Chapter 2. 3

1980 models Refer to illustrations 14.5. 14.9 and 14.1

4

Rotate the crankshaft until the number one (front) camshaft lobe points straight up. This can be done with a ratchet and socket on the crankshaft pulley bolt at the front of the engine — turn the crankshaft clockwise. Removing the spark plugs makes this easier. Another method is to use the ignition key to operate the starter in short bursts. If this is done, the ignition coil wire should be disconnected from the distributor cap and grounded on the engine to prevent the engine from starting.

The valve clearance is measured by inserting the specified size gauge between the heel of the cam lobe and the rocker arm (see You should feel a slight amount of drag when the feeler gauge is moved back and forth. If the gap is too large or too small, loosen the rocker pivot locknut 6 5

feeler

Feeler

gauge

14.5

On 1980 models, measure

inserting a feeler

the valve clearance by of the cam lobe

gauge between the heel and the rocker arm

illustration).

and turn the rocker pivot to obtain the correct gap. Once the gap has been set, hold the rocker pivot in position with 7 one wrench and retighten the locknut with another. 8 Recheck the valve clearance. Sometimes it'll change slightly when the pivot locknut

is

tightened.

If

so, readjust

it

until it's correct.

1

1-22

Chapter

1

Tune-up and routine maintenance

With the camshaft in this position the number 1,3,5, and 7 valves 9 can be adjusted using the procedure just described (see illustration). 10 Rotate the camshaft until the number one cam lobe is pointing straight down. In this position the number 2, 4, 6 and 8 valves can be adjusted in the same manner. 1 After all valves have been adjusted, check the torque on the rocker pivot locknuts (see illustration). A special adapter, available from import auto parts stores, is required for this check. After all valves have been adjusted, reinstall the rocker arm cover. 1 2

1981 and 1982 models Refer

to illustrations

14.14 and 14.18

3 Rotate the crankshaft until the number one (front) camshaft lobe points straight down. This can be done with a ratchet and socket on the crankshaft bolt at the front of the engine. Turn the crankshaft clockwise. Removing the spark plugs makes this easier. Another method is to use the ignition key to operate the starter in short bursts. If this is done, the ignition coil wire should be disconnected from the distributor cap and grounded on the engine to prevent the engine from 1

starting.

14 The valve clearance

is

measured by

T)

(3)

inserting the specified size

(5)

feeler

gauge between the end

(see illustration).

of the valve

You should

stem and the adjusting screw

feel a slight

amount

of drag

when

If

the locknut is tightened. If so, readjust it until it's correct. 1 8 With the camshaft in this position, the number 1,4,6 and 7 valves can be adjusted using the procedure just described (see illustration). 19 Rotate the camshaft until the number one cam lobe is pointing straight up. In this position the number 2, 3, 5 and 8 valves can be adjusted in the same manner. 20 After all valves have been adjusted, reinstall the rocker arm cover. 1

983 and

later

models

Refer to illustration 14.22

Run the engine until normal operating temperature is reached. Remove the rocker amn cover from the engine as described in Chapter 2. 22 Position the number one piston at top dead center (TDC) on the

21

®

Front

Front

Correct tightening of the rocker arm pivot locknut 14.11 on 1980 models requires a special adaptor (available through dealer parts departments and import auto parts stores)

®

With the number one cam lobe pointing UP, the valves in the upper illustration (1, 3, 5 and 7) can be adjusted, while the valves in the lower illustration (2, 4, 6 and 8) can be adjusted when the number one cam (1980 models only) lobe is pointing 14.9

®

Front

DOWN

Front

When the number one cam lobe is pointing DOWN, the valves shown in the top illustration (1, 4, 6 and 7) can be adjusted: the valves shown in the lower illustration (2, 3, 5 and 8) can be adjusted when the number one cam lobe is pointing UP (1981 and 1982 models)

14.18 14.14 on 1981 and 1982 models, valve clearance is adjusted by inserting a feeler gauge between the adjusting screw and valve stem and tuming the screw

the

gauge is moved back and forth. 1 5 the gap is too large or too small, loosen the locknut and turn the adjusting screw to obtain the correct gap. 1 6 Once the gap has been set, hold the screw in position with a screwdriver and retighten the locknut. 1 7 Recheck the valve clearance. Sometimes it'll change slightly when feeler

Chapter

1

1-23

Tune-up and routine maintenance

compression stroke (see Chapter 2). The valve clearances for valves 2, 4 and 6 can now be checked (see illustration). 1 23 Insert a 0.01 2-inch (0.30 mm) feeler gauge between the valve stem and the adjusting screw. If the feeler gauge fits between the stem and screw with a slight amount of drag, the clearance is correct. 24 If adjustment is required, loosen the adjusting screw locknut and carefully loosen or tighten the adjusting screw until you feel a slight drag on the feeler gauge as it's withdrawn from between the valve stem and screw. 25 Hold the adjusting screw and tighten the locknut securely. Recheck the clearance to make sure it didn't change. 26 Turn the crankshaft one complete revolution (360°) clockwise so the number four piston is at TDC on the compression stroke. Verify this by checking where the distributor rotor is pointing. Adjust the number 3, 5, 7 and 8 valves (see illustration 14.22). ,

27

Install

the rocker arm cover.

14.22

On 1983 and

later

models use

this

diagram to

locate the valves

15.3a

15.1

The upper suspension

balljoints usually installed in the grease fitting holes

have plugs

Materials required for chassis and body lubrication

Engine oil — Light engine oil in a can lile removed with a chemical cleaner Follow the

of the

rust

9

procedureoutlined

in

the manufacturer's instructions.

If

the radiator is sev-

Common

spark plug conditions NORMAL Symptoms:

Brown to grayish-tan color and slight electrode wear. Correct heat range for engine and operating conditions. Recommendation: When new spark plugs are installed, replace with plugs of the same heat range.

TOO HOT

WORN Symptoms:

Rounded electrodes with a small amount of deposits on the firing end. Normal color. Causes hard starting in weather and poor

damp fuel

Recommendation:

or

cold

economy. Plugs have

been left in the engine too long. Replace with new plugs of the

same

heat range. Follow the recschedule.

ommended maintenance

Dry sooty deposits indicate a rich mixture or weak ignition. Causes misfiring, hard starting hesitation.

Recommendation: Make

sure the plug has the correct heat range.

Check

a clogged air filter or the fuel system or engine management system. Also check for ignition system problems. for

problem

in

ASH DEPOSITS Symptoms:

Light brown deposits encrusted on the side or center electrodes or both. Derived from oil and/or fuel additives. Excessive amounts may mask the spark, causing misfiring and hesitation

during acceleration.

Recommendation:

Blistered, white insu-

lator, eroded electrode and absence of deposits. Results in

shortened plug correct

plug

advanced

heat

If

OIL DEPOSITS oil

Oily coating

control. Oil

is

caused leaking

past worn valve guides or piston hngs into the combustion chamber. Causes hard starting, misfiring and hesitation.

Symptoms:

Melted electrodes.

Insulators are white, but may be dirty due to misfiring or flying

debris

in

the combustion chamber.

Can lead to engine damage. Recommendation: Check for the correct

plug

heat

Correct the mechanical condition with necesinstall

range,

over-

advanced

ignition timing, lean fuel mixture, insufficient engine cooling and lack of lubrication.

HIGH SPEED GLAZING Symptoms: ish,

Insulator has yellow-

glazed appearance. Indicates

combustion chamber temperatures have risen suddenly during hard acceleration. Normal deposits that

melt to form a conductive coating. misfiring at high speeds.

Recommendation:

new

Install

new

plugs. Consider using a colder plug if

driving habits warrant.

DETONATION Insulators

may be

cracked or chipped. Improper gap setting techniques can also result in

a fractured insulator

to piston

tip.

Can

lead

damage.

Recommendation: Make

sure the

anti-knock values meet engine requirements. Use care when setfuel

ting the

Recommendation: sary repairs and

over-

intake manifold vacuum leaks, sticking valves and insufficient engine cooling.

mixture,

Symptoms:

by poor

for the

range,

ignition timing, lean fuel

Causes

excessive deposits accumulate over a short time or low mileage, install new valve guide seals to prevent seepage of oil into the combustion chambers. Also try changing gasoline brands.

Symptoms:

life.

Recommendation: Check

PREIGNITION

CARBON DEPOSITS Symptoms:

and

Symptoms:

gaps on new plugs. Avoid

lugging the engine.

plugs.

MECHANICAL DAMAGE Symptoms: May be caused by

GAP BRIDGING Symptoms: Combustion

deposits electrodes.

between the Heavy deposits accumulate and bridge the electrode gap. The plug ceases to fire, resulting in a dead lodge

cylinder.

Recommendation:

Locate the and remove the deposits from between the electrodes. faulty plug

a

foreign object in the combustion chamber or the piston striking an incorrect reach (too long) plug.

Causes a dead result in piston

cylinder

and could

damage.

Recommendation:

Repair the

mechanical damage. Remove the object from the engine install the correct reach

foreign

and/or plug.

2 3 4 5 6

1

1-40

Chapter

1

Tune-up and routine maintenance

The PCV valve screws into the intake manifold (arrow) (1982 model shown)

44.1

Tools required for changing spark plugs

45.2 erely corroded,

damaged or leaking, should be removed (Chapter 3) and it

Spark plug socket -

1

taken

a radiator repair shop.

to

Remove the overflow hose from the coolant recovery reservoir.

1

the reservoir and flush Reinstall

11

and

it

and

block drain plug.

Slowly add

1

the radiator

Close the

new

air

valve

in

Add coolant to the

reservoir up to the lower mark.

the upper radiator hose (V6 engine only).

cap off and run the engine in a well-ventilated area until the thermostat opens (coolant will begin flowing through the radiator and the upper radiator hose will become hot). Turn the engine off and let cool. Add more coolant mixture to bring 1 the level back up to the lip on the radiator filler neck. 1 Squeeze the upper radiator hose to expel air, then add more coolant mixture necessary. Replace the radiator cap. 1 Start the engine, allow to reach normal operating temperature and check for leaks.

Leave the

1

Torque wrench - Although not mandatory, using

Ratchet - Standard hand tool to fit the spark plug socket Extension - Depending on model and accessories, you may need special extensions and universal joints to reach one or

coolant (a 50/50 mixture of water and antifreeze) to

until it's full.

if

it

way

this tool is

ensure the plugs are tightened properly

to

more of the plugs Spark plug gap gauge - This gauge for checking the gap comes in a variety of styles. Make sure the gap for your

5

radiator

it

have special padding inside

3 4

the best

tighten the

will

2

with clean water, then reconnect the hose.

tighten the radiator drain plug. Install

This

spark plugs porcelain insulator

to protect the

Drain

engine

is

included.

on the new plugs (see

illustration).

A

special plug wire removal tool

available for separating the wire boots from the spark plugs, but solutely necessary.

A

it

isn't

torque wrench should be used to tighten the

is

ab-

new

plugs.

The best approach when replacing the spark plugs is to purchase the new ones in advance, adjust them to the proper gap and replace them one

3

at

a time.

When buying the new spark plugs, be sure to obtain the correct

plug type for your particular engine. This information can be found on the

PCV

44

Refer

Emission Control Information label located under the hood and in the factory owner's manual. If differences exist between the plug specified on the emissions label and in the owner's manual, assume the emissions label is

valve check and replacement

to illustration 44.

all models the PCV valve threads into the intake manifold and is connected by a rubber hose and metal tube to the crankcase (see illustra-

On

1

tion)

2

When

rect

one

3 4

Remove

purchasing a replacement your vehicle.

PCV

valve,

make

sure

it's

the cor-

correct.

4

Allow the engine to cool completely before attempting to remove any While you're waiting for the engine to cool, check the new

of the plugs.

plugs for defects and adjust the gaps.

5

The gap is checked by

the electrodes at the the

air

cleaner.

Loosen the clamp securing the hose to the

PCV valve and disconnect

the hose from the valve.

5

Unscrew the valve from the

6

Compare

new one

to

the plug (see illustration).

same as the one specified on the Emissions The wire should just slide between the elecamount of drag. the gap is incorrect, use the adjuster on the gauge body to bend the curved side electrode slightly until the proper gap is obtained (see illustration). the side electrode is not exactly over the center electrode, bend with the adjuster until is. Check for

the electrodes should be the

Control Information label.

trodes with a slight

intake manifold.

the old valve with the

tip of

make

sure they're the

same. Screw the new valve into the manifold and connect the hose to it. 7 More information on the PCV system can be found in Chapter 6. 8

gauge between The gap between

inserting the proper thickness

for

If

If

it

it

cracks

in

the porcelain insulator

(if

any are found, the plug shouldn't be

used).

With the engine cool, remove the spark plug wire from one spark plug. on the boot at the end of the wire $ don't pull on the wire. A plug wire removal tool should be used if available (see Illustration). 6

45

Pull only

Spark plug replacement

7 compressed air is available, use to blow any dirt or foreign material away from the spark plug hole. A common bicycle pump will also work. The If

Refer

to illustrations 45.2, 45.5a, 45.5b.

45.6 and 45. 10

Replace the spark plugs with new ones at the intervals recommended in 1980 fourmodel four-cylinder engines require eight plugs (two per cylinder). V6 engines, obviously, have six plugs. In most cases, the tools necessary for spark plug replacement include 2 a spark plug socket which fits onto a ratchet (spark plug sockets are padded inside to prevent damage to the porcelain insulators on the new plugs), various extensions and a gap gauge to check and adjust the gaps 1

in

the Routine maintenance schedule. Four plugs are used

cylinder engines, while later

it

idea here

is to eliminate the possibility of debns falling into the cylinder as is removed. Place the spark plug socket over the plug and remove from the en8 gine by turning it in a counterclockwise direction. Compare the spark plug to those shown in the accompanying photos 9

the spark plug

it

an indication of the general running condition of the engine. Thread one of the new plugs into the hole until you can no longer turn

to get 1

with your fingers, then tighten

it

with a torque

wrench

(if

it

available) or the

1 2 3

Chapter

1

Tune-up and routine maintenance

1

-41

^ ^

45.5a

Spark plug manufacturers

recommend using a wire type gauge when checking the gap - the wire does if

not slide between the electrodes with a slight drag, adjustment is required

45.5b To change the gap, bend the side electrode only, as indicated by the arrows, and be very careful not to crack or chip the porcelain insulator surrounding the center electrode

45.6

When removing

the spark plug on the boot and twist it back-and-forth

wires, pull only

A length of 3/16-inch ID rubber hose will save time and prevent damaged threads when installing the spark plugs

45.10

47.2 ratchet. It might be a good idea to slip a short length of rubber hose over the end of the plug to use as a tool to thread into place (see illustration). The hose will grip the plug well enough to turn it, but will start to slip if the plug begins to cross-thread in the hole - this will prevent damaged threads and

On

later

models, the distributor cap by two screws (arrows)

is

held

in

place

it

the

accompanying

1

repair costs.

Before pushing the spark plug wire onto the end of the plug, inspect

following the procedures outlined

in

it

Section 46.

Attach the plug wire to the new spark plug, again using a twisting moon the boot until it's seated on the spark plug. 1 Repeat the procedure for the remaining spark plugs, replacing them one at a time to prevent mixing up the spark plug wires. 1

tion

areas, cracks and other damage. Don't bend the wire excessively or the conductor inside might break. Disconnect the wire from the distributor cap. Again, pull only on the 6 rubber boot. Check for corrosion and a tight fit in the same manner as the spark plug end. Reattach the wire to the distributor cap.

Check the remaining spark plug wires one at a time, making sure they 7 are securely fastened at the distributor and the spark plug when the check is complete. 8 cific

If new spark plug wires are required, purchase a new set for your speengine model. Wire sets are available pre-cut. with the rubber boots

Remove and replace the wires one at a time to avoid mix-ups in the firing order. The wire routing is extremely important, so be sure to note exactly how each wire is situated before removing it. already installed.

46

1

vals

2

Spark plug wire check and replacement

The spark plug wires should be checked at the recommended interand whenever new spark plugs are installed in the engine. The wires should be inspected one at a time to prevent mixing up the

which is essential for proper engine operation. 3 Disconnect the plug wire from one spark plug. To do this, grab the rubber boot, twist slightly and pull the wire free. Do not pull on the wire itself, only on the rubber boot (see illustration 45.6). 4 Check inside the boot for corrosion, which will look like a white crusty powder. Push the wire and boot back onto the end of the spark plug. It should be a tight fit on the plug. If it isn't, remove the wire and use a pair of pliers to carefully crimp the metal connector inside the boot until it fits securely on the end of the spark plug. 5 Using a clean rag, wipe the entire length of the wire to remove any built-up dirt and grease. Once the wire is clean, check for holes, burned

47

Distributor

cap and rotor check and replacement

order,

Refer to illustrations 47.2. 47.4. 47.5 and 47.8 Note :\t's common practice to install anew distributor cap and rotor whenever

new spark plug

wires are installed.

Although the breakerless distributor used on these vehicles requires much less maintenance than a conventional distributor, periodic inspections should be performed at the intervals specified in the routine maintenance schedule and whenever any work is performed on the distributor 1

2

Disconnect the ignition coil wire(s) from the coil(s), then unsnap the clips or loosen the screws that hold the cap to the distributor body

spnng

(see illustration) Detach the distributor cap and wires.

1

-42

1

Chapter

1

Tune-up and routine maintenance

INSUFFICIENT SPRING TENSION

CORBODED

The ignition rotor should be checked for wear and corrosion as indicated here (if in doubt about its condition, buy a new one)

47.4

47.5

Later

- don't

model

distributor rotors are retained by a bolt (arrow)

try to pry off the rotor until the bolt

has been loosened!

Place the cap, with the spark plug and coil wires still attached, out of Use a length of wire or rope to secure it. if necessary.

3

the way.

now

visible on the end of the distributor shaft. Check it and carbon tracks. Make sure the center terminal spring tension is adequate (not all models) and look for corrosion and wear on the rotor tip (see illustration). If in doubt about its condition, replace

The

4

rotor is

carefully for cracks

it

new one.

with a

5

If

replacement

is

required, detach the rotor from the shaft

new one. On 1 980 models, the rotor can later

simply be pulled

off

and

install

the shaft.

a

On

models, the rotor is retained on the shaft by a single screw (see illus-

tration).

Check the wire connections at the IC unit (on 1 980 models this is the on the outside of the distributor body with a wiring connector attached on 1 981 and later models, it's inside the disthbutor. with two or three wires leading to it) Make sure they're clean and tight. Also check the wires to make sure they aren't cracked or broken. 7 While the distributor cap is off, check the air gap as deschbed in Chap6

unit

to

it;

.

ter 5.

8

Check the distributor cap for carbon tracks, cracks and other damage.

Closely examine the terminals on the inside of the cap for excessive corro-

and damage (see illustration). Slight deposits are normal. Again, if doubt about the condition of the cap. replace it with a new one. When replacing the cap, simply transfer the spark plug and coil wires, one at a time, from the old cap to the new cap. Be very careful not to mix up sion in

9

CARBON TRACK

the wires! 1

Reattach the cap

to the distributor,

tion the spring clips to hold

it

in

then tighten the screws or reposi-

place.

Shown here are some of the common defects to look for when inspecting the distributor cap (if in doubt about its condition, install a new one)

47.8

48

Ignition timing

Refer

check and adjustment

to illustrations 48.

1.

48.2. 48.4

and 48.

1

Note: Ignition timing on 1 990 and later models is controlled electronically by the E. C. U. and cannot be altered by the home mechanic. Additional information can be found in Chapter 6. 1 The proper ignition timing setting for your VECI label located on the underside of the hood.

is printed on the can also be found in the Specifications section at the beginning of this Chapter. If there are any discrepancies between the figures, the VECI label should be considered correct. Some special tools will be required for this procedure (see

vehicle It

illustration)

2

On four-cylinder engines, locate the timing plate on the front of the en-

The mark is Top Dead Center (TDC). To locate which mark the notch in the pulley must line up with for the timing to be correct, count back from the mark the number of gine, near the crankshaft pulley (see illustration)

degrees BTDC (Before Top Dead Center) noted in the Specifications. Normally each mark on the timing plate equals 5 degrees, so if your vehicle Specifications call for 6-degrees BTDC, you should make a mark with white paint or chalk at the 5 mark on the timing plate. 3 Locate the timing notch in the pulley and mark with a dab of paint or chalk so it'll be visible under the strobe light. To locate the notch may be necessary to have an assistant temporarily turn the ignition off and on in short bursts to turn the crankshaft. Warning: Stay clear of all moving engine components the engine is turned in this manner! 4 On the V6 engine, the timing mark scale is on the vibration damper and the timing indicator (pointer) is stationary, attached to the engine (see illustration). Highlight the pointer and the appropriate mark on the vibration damper with chalk or white paint (refer to the Emissions Control Inforit

it

if

mation

label).

1

Chapter

1

1-43

Tune-up and routine maintenance

48.2 When setting the ignition timing, the crankshaft pulley notch (marked with white paint) should align with the specified notch or point on the timing plate (four-cylinder engines)

On some models,

as noted

must disconnect the Tools needed to check and adjust the ignition timing

48.1

Vacuum plugs - Vacuum hoses

1

2

most cases, have to be disconnected and plugged. Molded plugs in vanous shapes and sizes are available for this. Inductive pick-up timing light - Flashes a bright concentrated beam of light when the number one spark plug fires. Connect the leads according to the instructions supplied with the

3

Distributor

will, in

light.

reach and turn with

conventional wrenches or sockets. this

the hold-down

A

special wrench like

must be used.

VECI label, you vacuum advance hose and plug

the Specifications or on the

off,

it.

connect the pick-up lead of the timing

inductive-type pick up. Don't pierce the wire or attempt to insert a wire be-

tween the boot and plug wire. Connect the timing

light

power leads accord-

ing to the manufacturer's instructions.

Make sure

components, then then allow

it

all

moving engine

Race the engine two

or three times,

the wiring for the timing start the

to idle for

engine.

light is

clear of

a minute.

Point the flashing timing light at the timing marks, again being careful

9

not to come in contact with moving parts. The marks you highlighted should appear stationary. If the marks are in alignment, the timing is corIf the marks aren't aligned, turn off the engine. On 1 980 models, loosen the distributor mounting bolt until the distribcan be rotated. On later models, loosen the adjusting bolts (indicated by the long slots they're mated with) which are separate from the distributor mounting bolts. 1 Start the engine and slowly rotate the distributor either left or right until the timing marks are aligned (see illustration).

rect.

Connect a tachometer according to the manufacturer's instructions and make sure the idle speed is correct. Adjust if necessary as described 5

it

in

6

Section 37.

Allow the engine to reach normal operating temperature. Be sure the if equipped, is off. On 1 980 models, disconnect the hose

air conditioner,

from the

48.4

air injection

On

pipe assembly and securely plug the pipe opening.

the V6 engine, the timing marks are on the vibration a pointer is attached to the engine

damper and

light

number one spark plug wire. On four-cylinder engines, it's the front one. On V6 engines it's the first spark plug on the right side as viewed from the dhver's seat. Use either a jumper lead between the wire and plug or an to the

8

wrench - On some models,

bolt for the distributor is difficult to

7

in

distributor

With the ignition switch

10

utor

48.11

by turning the distributor as needed

Ignition timing is adjusted slightly

3 6

1

-44

12

Shut

bolts, 1

still

off

Chapter

Tune-up and routine maintenance

the engine and tighten the distributor mounting/adjusting

move

being careful not to

1

7

To keep -pinging"

a minimum, yet

still allow you to operate the veuse gasoline of the same octane at all brands and octane levels can decrease performance

at

hicle at the specified timing setting,

the distributor.

Restart the engine and recheck the timing to in

1

make sure the marks are

times. Switching fuel

and economy, and possibly damage the engine.

alignment.

Disconnect the timing light. 15 Race the engine two or three times, then allow it to run at idle. Recheck the idle speed with the tachometer. If it has changed from the correct 14

setting readjust 1

Drive the vehide and listen for "pinging" noises. They'll be noticeable

when the engine is

hot and under load (climbing a hill, accelerating from a you hear engine pinging, the ignition timing is too far advanced (Before Top Dead Center) Reconnect the timing light and turn the distributor to move the mark 1 -degrees or 2-degrees in the retard direction (counterclockwise). Road test the vehicle again to check for proper operation. stop).

49

Oxygen sensor replacement

it.

If

.

1

The oxygen (exhaust gas) sensor, used on

all

1

984 and

later

models,

should be replaced at the specified intervals. The sensor is threaded into the exhaust manifold and can be

2

identi-

by the wires attached to it. Replacement consists of disconnecting the wire harness and unthreading the sensor from the manifold. Tighten the new sensor to the specified torque, then reconnect the wire harness. fied

Chapter 2 Part

A

Four-cylinder engines

Contents Camshaft, bearings and rocker arms - inspection Camshaft - removal and installation Crankshaft pulley - removal and installation Cylinder compression check Cylinder head - installation

- removal and replacement Engine mounts - replacement Engine oil and filter change Engine overhaul - general information Engine - removal and installation Exhaust manifold - removal and installation Flywheel/driveplate - removal and installation Front cover - removal and installation Front crankshaft oil seal - replacement General information Intake manifold - removal and installation Oil pan - removal and installation

Cylinder head

Drivebelt check, adjustment

9

Oil

8

Oil

16 15 See Chapter 8 23 Repair operations possible with the engine in the vehicle 2 Rocker arm assembly (1980 models) - removal

17 14 13

and installation 5 Rocker arm cover - removal and installation 4 Spark plug replacement See Chapter 1 Timing chain and sprockets - removal and installation 20 Top Dead Center (TDC) for number one piston - locating 3 Valve rocker assembly (1981 and later models) -disassembly and reassembly 7 Valve rocker assembly (1981 and later models) - removal and installation 6 Valves servicing See Chapter 2C Valve springs and seals - replacement in vehicle 10 Water pump - removal and installation See Chapter 3

1

24 See Chapter 1 See Chapter 2C See Chapter 2C 12

22 19 18 1

11

21

Specifications

All

engines

Cylinder

numbers

(front-to-rear)

Firing order

1-2-3-4 1

-3-4-2

Displacement

L20B (1980) Z20 (1984 and 1985) Z22 (1981 through 1983) Z24 (1984 and 1985) Z24i (1986 on)

KA24E Valve clearances

installation

Pilot bushing - replacement Rear crankshaft oil seal - replacement

See Chapter 2C

See Chapter

pump - inspection pump - removal and

1952 cc 1952 cc 2187 cc 2389 cc 2389 cc 2389 cc See Chapter

1

.

Chapter 2 Part A

2A-2

Four-cylinder engines

L20B engine (1980) Camshaft Journal diameter

Bearing

clearance

oil

in

(47.949 to 47.962

in

(48.000 to 48.016

.

in

(0.038 to 0.067

.8877

to

1

1

.

.

limit

0.002

in

End play Lobe height

0.008

in (0.2

Runout

mm) mm) mm)

.8883

.8898 to 1 .8904 0.001 5 to 0.0026

1

Bearing inner diameter

Intake

1

Exhaust

1

mm) mm)

(0.05

.5866 to .5866 to

1

.5886

in

(40.30 to 40.35

1

.5886

in

(40.30 to 40.35

mm) mm)

pump

Oil

tip clearance Standard

Rotor

Less than 0.0047 in (0.12 0.0079 in (0.20 mm)

Limit

Outer rotor-to-body clearance Standard

mm)

mm)

0.0059 to 0.0083 in (0.15 to 0.21 0.0197 in (0.5 mm) Less than 0.0024 in (0.06 mm) Less than 0.0012 in (0.03 mm)

Limit

Rotor end clearance Body-to-straightedge clearance

Torque specifications

Ft-lbs

Cylinder head bolts

51 to 61

Cylinder head-to-front cover bolts

3 to 6

INTAKE

I

I

Front cover-to-block bolts

mm mm

6 8

3 to 7 7 to 12

Chain guide and tensioner

bolts

.

87

Manifold bolts/nuts

9 to 12 87 to 116

Camshaft sprocket bolt Camshaft thrust plate bolts Rocker arm cover bolts Oil strainer

pump mounting

Oil

pan mounting

to

116

[exhaust

I

4.3 to 7.2

7 to 12 7 to 12 8 to 11

mounting bolts

Oil

MiO o o o

4.3 to 7.2

Crankshaft pulley bolt

bolts

4.3 to 7.2

bolts

Flywheel driveplate-to-crankshaft bolts

101 to 116

Spark plug wiring

NAPS-Z engine

for the Z24i four-cylinder

(1981 on)

Camshaft .2967 to

Journal diameter

1

End

0.008

play

Cam Cam

lobe

wear

1

limit

Camshaft runout (one-half TIR

Beanng

inside diameter

Bearing

oil

Oil

in

48 0.0098

lobe height

@ center journal)

0.008

1

.2974

(0.2

68

1

in

(0.25

in

.51

(0.2

in

(32.935 to 32.955

mm)

in

(38.477 to 38.527

mm)

mm)

to

mm) mm) mm) mm)

2992

to

1

3002

in

(33.000 to 33.025

0.0018

to

0.0035

in

(0.045 to 0.090

1

clearance

.51

pump

tip clearance Standard

Rotor

Less than 0.0047 in (0.12 0.0079 in (0.20 mm)

Limit

Outer rotor-to-body clearance Standard Limit

Rotor end clearance Body-to-straightedge clearance

0.0059 to 0.0083 in (0.1 5 to 0.21 0.0197 in (0.50 mm) Less than 0.0024 in (0.06 mm) Less than 0.0012 in (0.03 mm)

Torque specifications

Ft-lbs

Camshaft sprocket bolt Chain guide and tensioner

87to 116 1210 16

Crankshaft pulley bolt

bolts

4.5 to 7

87

to

116 12 to 16

Cylinder head bolts

Z22 engine 1981 and 1982 1983

mm)

51 to 58

58

to

65

mm)

engine

1

Chapter 2 Part A

2A-3

Four-cylinder engines

Torque specifications (continued)

Ft-lbs

Cylinder head bolts

Z20 and Z24 engines Step 1 Step 2 Step 3 Step 4

®

22 58 Loosen 22 58

Step 5 Exhaust manifold bolts/nuts

all

bolts

12 to 15

Flywheel/driveplate-to-crankshaft bolts

101 to 116

Rocker arm cover

0.7 to 2.2

bolts

8

/©•' \QQ,

O r^~

Front cover-to-block bolts

6

®

(D (D

Z>

mm mm

3 to 7 7 to 12 12 to 15

Intake manifold bolts/nut Oil

pan mounting

Oil

pump mounting

bolts

3.5 to 5

8

bolts

Valve rocker assembly mounting bolts

KA24E engine

4-cylinder engines except Z-series

All

to 11

11 to

Cylinder location and

18

w

distributor rotation

(1990 on)

Camshaft Journal diameter

1 .2967 to 1 .2974 in (32.935 to 32.955 0.008 in (0.2 mm) 1 .7653 to 1 .7728 in (44.839 to 45.029 0.0098 in (0.25 mm) 0.0008 in (0.02 mm)

End play

Cam Cam

lobe height

lobe wear limit Camshaft runout (one-half TIR

@

center journal)

Bearing inside diameter

1

Bearing

0.0018

Oil

oil

clearance

.2992 to to

1 .3002 0.0035

mm)

mm) mm)

33.025

in

(33.000

in

(0.045 to 0.090

to

mm)

pump

tip clearance Standard

Rotor

Less than 0.0047 in (0.12 0.0079 in (0.20 mm)

Limit

Outer rotor-to-body clearance Standard

mm)

0.0059 to 0.0083 in (0.15 to 0.21 0.01 97 in (0.50 mm) Less than 0.0024 in (0.06 mm) Less than 0.0012 in (0.03 mm)

Limit

Rotor end clearance Body-to-straightedge clearance

Torque specifications

Ft-lbs

Camshaft sprocket bolt Chain guide and tensioner

87

mm)

116

to

5.1 to 9.0

bolts

87

Crankshaft pulley bolt

116

to

Cylinder head bolts

Step

22 58 Loosen all 22 54 to 61

1

Step 2 Step 3 Step 4 Step 5 Exhaust manifold bolts/nuts

bolts completely

12 to 15

105 to 112 69 to 76

Flywheel-to-crankshaft bolts Driveplate-to-crankshaft bolts Intake manifold bolts/nuts

12 to 15

Oil

pan mounting bolts pump mounting bolts Rocker arm cover bolts Valve rocker assembly mounting

3.5 to 5.0

Oil

8 to

1

2.9 to 5.8

27

bolts

to

30

The following 1

General information

engine

is

If

the engine has

and mounted on a stand, many Chapter 2 will not apply.

vehicle

This

Pan

of

Chapter 2

the four-cylinder engines. installation

Pan C

is

All

devoted

to in-vehicle repair

procedures

for

information concerning engine removal and

and engine block and cylinder head overhaul can be found Chapter

of this

in

of

based on the assumption that the been removed from the

repair procedures are

installed in the vehicle.

The

Specifications included

in this

of the

steps outlined

in this

Part

Part of Chapter 2 apply only to the

procedurescontained in this Part. Part C of Chapter 2 contains the Specifications necessary for cylinder head and engine block rebuilding.

2A-4

Chapter 2 Part A

Four-cylinder engines

®

Timing indicator

'y0°5°10°15°20°

L 3.5b

The number one piston

Red painted

Timing mark designations on the KA24E engine

TDC on

the compression the crankshaft pulley is aligned with the

3.5a

is at

stroke when the notch in on the timing plate and the rotor is pointing at the number one spark plug terminal in the distributor cap

Clean the engine compartment and the exterior of the engine with of pressure washer before any work is done. It'll make the job easier and help keep dirt out of the internal areas of the engine. Remove the hood to improve access to the engine as repairs are performed (refer to Chapter 12 necessary). If vacuum, exhaust, oil or coolant leaks develop, indicating a need for gasket or seal replacement, the repairs can generally be made with the engine in the vehicle. The oil pan gasket, cylinder head gasket, intake and exhaust manifold gaskets, engine front cover gaskets and the crankshaft oil seals are accessible with the engine in place. Exterior engine components, such as the water pump, the starter motor, the alternator, the distributor and the fuel system components, as well as the intake and exhaust manifolds, can be removed for repair with the engine in place. Since the cylinder head can be removed without pulling the engine, camshaft and valve component sen/icing can also be accomplished with the engine in the vehicle. Replacement of, repairs to or inspection of the timing chain and sprockets and the oil pump are all possible with the engine in place. In extreme cases caused by a lack of necessary equipment, repair or replacement of piston rings, pistons, connecting rods and rod bearings is possible with the engine in the vehicle. However, this practice is not recommended because of the cleaning and preparation work that must be

some type

In 1980, the first year of the 720 Series pick-up. the truck came equipped with the L20B engine, a carry-over from the 620 Series. In 1 981 the N APS-Z engine was introduced to the pick-up line. Both types are four-

cylinder

OHC

inline

engines.

The cast iron engine block contains the four cylinder bores and acts as a ngid support for the five main bearing crankshaft. The machined cylinder bores are surrounded by water jackets to dissipate heat and control operating temperature.

The cylinder head tion

chambers.

In

the

is

aluminum and incorporates wedge-type combus-

NAPS-Z engines, two spark plugs are used for each

cylinder to burn the fuel/air mixture with greater efficiency

Two valves per cylinder are mounted at a slight angle in the cylinder head and are actuated by a rocker arm in direct contact with the camshaft. Double springs are installed on each valve. The camshaft is driven by a roller chain from the front of the crankshaft. Chain tension is controlled by a tensioner, which is operated by oil and spnng pressure. The rubber shoe type tensioner controls vibration and tension of the chain.

The pistons are a special aluminum casting with struts to control thermal expansion. There are two compression rings and one oil control ring. The piston pin is a hollow steel shaft which is fully floating in the piston and a press fit in the connecting rod. The pistons are attached to the crankshaft by forged steel connecting rods. The distributor, which is mounted on the left-hand side of the engine block, is dnven by a helical gear mounted on the front of the crankshaft. The oil pump, which is mounted low on the right-hand side of the block is on a common centerline with the distributor and is dnven by the same helical gear.

if

done

3

to the

components

involved.

Top Dead Center (TDC)

Reier

to illustration

for

number one piston -

locating

3.5a and 3.5b

Top Dead Center (TDC) is the highest point in the cylinder that each piston reaches as travels up-and-down when the crankshaft turns. Each piston reaches TDC on the compression stroke and again on the exhaust stroke, but TDC generally refers to piston position on the compression stroke. The timing marks on the pulley installed on the front of the crankshaft are referenced to the number one piston at TDC on the compression 1

The crankshaft, which is made of special forged steel, has internal oil passages to provide lubrication to the mam and connecting rod bearings. Oil IS delivered, via the filter and pressure relief valve, to the main oil gallery from which it passes to the main bearing journals and then to the connecting rod bearing journals through holes in the crankshaft. Oil throw off from the connecting rod lower ends, as well as a jet hole drilled through each connecting rod into the lower end. provides lubrication for the pistons and connecting rod upper ends At the top of the engine, galleries drilled in the camshaft supports provide oil for the five bearings, while a pipe that runs along the length of the camshaft, delivers oil to each cam pad surface, to

provide lubncation for the rocker arm and pivot.

it

stroke.

Positioning the piston(s) at TDC is an essential part of many proce2 dures such as rocker arm removal, camshaft and timing chain/ sprocket removal and distnbutor removal. In order to bnng any piston to TDC, the crankshaft must be turned us3

one of the methods outlined below. When looking at the front of the enis clockwise. Warning: Before beginning procedure, be sure to place the transmission in Neutral. Also, detach the coil wire from the center terminal of the distributor cap and ground m on the block with a jumper wire. a) The preferred method is to turn the crankshaft with a large socket and breaker bar attached to the crankshaft pulley hub bolt threaded

ing

gine, normal crankshaft rotation this

2

Repair operations possible with the engine

in

the vehicle

Many major repair operations can be accomplished without removing the engine from the vehicle.

into the front of the crankshaft.

Chapter 2 Part A

2A-5

Four-cylinder engines

Rocker arm cover and related components - exploded view

4.4

A remote

b)

starter switch,

which may save some time, can also be

Once the TDC, use a socket and breaker bar as described

used. Attach the switch leads to the solenoid terminals. piston

If

close to

2A

the previous paragraph.

in

c)

is

an assistant

is

available to turn the ignition switch to the Start po-

you can get the piston close to TDC without a remote starter switch. Use a socket and breaker bar as described in Paragraph a) to complete the procedure. 4 Note the position of the terminal for the number one spark plug wire on the distributor cap. Use a felt-tip pen or chalk to make a mark on the distributor body directly under the terminal. Detach the cap from the distributor sition in short bursts,

and set 5

it

aside.

Turn the crankshaft (see Paragraph 3 above)

crankshaft pulley

is

aligned with the

until

the notch

on the timing plate (located

in

the

at the

front of the engine)

(see illustrations). Look at the distributor rotor - it should be pointing directly at the mark 6 you made on the distributor body. If the rotor is pointing at the terminal for the number four spark plug, the number one piston is at TDC on the ex-

4.9

Step

1

On KA24E engines, tighten bolts then tighten ALL the bolts to 5.1 shown

in

1

and 2

to 2.2 ft-lbs

on

to 7.2 ft-lbs in the order

Step 2

Place the new gasket in position on top of the cylinder head, then place the rocker arm cover on the gasket. While the sealant is still wet, inthe mounting bolts and tighten them to the specified torque. Complete the installation by reversing the removal procedure (see il9 8

stall

lustration).

haust stroke.

7

To get the piston to TDC on the compression stroke, turn the crankone complete turn (360-degrees) clockwise. The rotor should now

Rocker arm assembly (1980 models) - removal and installation

shaft

at the mark on the distributor. When the rotor is pointing at the number one spark plug wire terminal in the distributor cap and the ignition number one piston is at TDC on the com-

be pointing

timing marks are aligned, the

5.4a and 5.4b arm cover as described in Section 4. The crankshaft must be turned until the cam lobe contacting the rock2 er arm to be removed is pointing straight up. This can be done by operating

Refer 1

pression stroke. piston has been positioned at TDC on the comany of the remaining pistons can be located by turning the crankshaft 1 80-degrees at a time and following the firing order.

8

After the

number one

pression stroke,

TDC

for

the starter

Rocker arm cover - removal and

Refer 1

2

to illustration 4.4

in

the rocker

short bursts or by turning the large bolt

in

the front of the

crankshaft with a socket attached to a breaker bar. 3

4

to illustrations 5.3,

Remove

Remove

the valve rocker spring (see illustration).

installation

and 4.9

Remove the air cleaner (Chapter 4). Remove the spark plug wires from all spark plugs and remove the wire

supports from the rocker arm cover. Don't disconnect the wires from the supports.

On 1981 and hose and position

3

later it

models, disconnect the brake booster vacuum

out of the way.

Remove the rocker arm cover mounting bolts (see illustration). 5 Remove the rocker arm cover. Caution: // the cover is stuck to the head, bump the end with a block of wood and a hammer to jar loose. If

4

it

that doesn't work, try to slip a flexible putty knife between the head and cover to break the gasket seal. Don tpry at the cover to-head joint or damage to the sealing surfaces may occur, leading to oil leaks in the future. 6 The mating surfaces of the head and rocker arm cover must be perfectly clean when the cover is installed. Use a gasket scraper to remove all traces of sealant and old gasket material, then clean the mating surfaces with lacquer thinner or acetone. If there's sealant or oil on the mating sur-

when the cover is installed, oil leaks may develop. Apply a continuous bead of sealant to the cover-to-head mating surBe sure to apply it to the inside of the mounting bolt holes.

faces 7

face of the cover.

5.3

Removing the valve rocker spring (L20B engine)

.

2A-6

Chapter 2 Part A

Four-cylinder engines

&'r^

O

5.4b To remove the rocker arms on 1980 models (L20B engine), a screwdriver positioned as shown can be used to depress each valve spring

Once

3

all

mounting bolts are loose,

lift

the valve rocker assembly

off

the cylinder head. If the valve rocker assembly must be disassembled for inspection or replacement of parts, refer to Section 7. If the valve rocker assembly isn't going to be disassembled, don't remove the four bolts at either end of the assembly (it'll come apart if the bolts are removed). When installing the valve rocker assembly, first tighten the bolts until 5 they're finger tight, working in from both ends. Continue to tighten the bolts 1/4-turn at a time until they're all at the specified torque.

4

Camshaft and valve train components view (L20B engine)

5.4a

Camshaft / 2 Valve rocker spring 3 Rocker arm 4 Valve rocker guide 5 Valve keepers 6 Valve spring retainer 7

Outer valve spring

8 Inner valve spring

9

exploded

Valve guide oil seal Outer valve spring seat Inner valve spring seat Valve Valve rocker pivot Rocker pivot locknut Rocker spring retainer Rocker pivot bushing

W n

12 13 14 15 16

Valve rocker assembly (1981 and later models) - disassembly

7

and reassembly 7. 5d and 7.6 remove all of the valve rocker assembly mount-

Refer

to illustrations 7.5a, 7.5b. 7.5c,

1

not previously done,

If

two on either end. While holding the assembly together, carefully remove the two bolts from one end of the assembly and allow the springs to expand. 3 Remove the components from the shafts, noting the installed order. Don't mix up the rocker arms: they must be installed in their original locaing bolts except the

2

4

Loosen the rocker pivot locl^nut (see illustration). Then use a screwdepress the valve spring so the rocker arm can be lifted off (see Caution: Don't lever the screwdriver against the machined

driver to

illustration).

surfaces of the

5

If

cam

more than one rocker arm is being removed, be sure to keep them

order so they can be reinstalled

in their original

head. The valve rocker guides can be 6

keep them 7

in

in

positions on the cylinder

the valves, but be sure to

order.

Inspect the contact surfaces of the rocker arms, rocker guides and

damage and excessive wear. Replace as necessary. To replace the rocker pivot, loosen the pivot locknut and unscrew the pivot from the bushing (see illustration 5.4a). Don't remove the pivot bushing from the cylinder head. rocker pivots for

Prior to installation, apply a

dab

of

grease

to the contact surfaces of

1

Installation

is

the reverse of the removal procedure. Adjust the valve

Cold specifications and then the Hot specifications Chapter 1

first

as detailed

in

to the

and

new

damaged or

ones.

To reassemble the rocker arm assembly, hold one of the end brackets it. Line up the bolt holes and insert the two end The intake shaft has a slit on the front surface to identify it, while the exhaust shaft has no identification mark. Both rocker shafts should be as5

insert both shafts into

bolts.

sembled so the punch marks on the front are at the top (see illustration) Also, be sure the brackets are in their original locations. To ensure this, identification marks are provided on the cylinder head, as well as each bracket (see illustration).

6

Install

rect order,

the valve rocker assembly components on the shafts

compressing the springs as needed

until

in

the cor

the remaining end

nience sake the remainder of the mounting bolts can also be installed (see illustration)

Camshaft - removal and

8 Valve rocker assembly (1981 and later models)

the valve rocker assembly shafts are excessively worn,

bracket can be installed along with the two mounting bolts. For conve-

the rocker arms, rocker guides and rocker pivots.

clearances

If

scored, they should be replaced with

and

lifted off

8

9

tions.

4

lobes.

installation

removal

installation

1980 models (L20B engine) arm cover as described in Section 4. 2 The valve rocker assembly is held to the cylinder head by ten mounting bolts. The bolts should be loosened 1 /4-turn at a time, working toward the center from both ends. Loosen the bolts until they're free of the cylinder head, but don't remove them from the valve rocker assembly. 1

Remove

the rocker

Refer

to illustrations 8.4.

Remove Remove

8.6

and 8. 13

arm cover as described in Section 4. the rocker arms as described in Section 5. Bring the number one piston to TDC by referring to Section 3,

1

2

3 sary.

the rocker

if

neces-

Chapter 2 Part

Slits

(A

Punched marks

-

A

2A-7

Four-cylinder engines

Z) Marked on cylinder head

Cutout

Front

(A-Z) (A-Z)(2A-2Z)(A-Z>(A-Z) Fron

7.5a

Exhaust

When

installed, the rocker shaft

should be on the intake side and the punch marks on both shafts should be in the 12 o'clock position (on top) (NAPS-Z engine shown) with the

slits

Marked on brackets

Cutout Exhaust

7.5b To ensure the valve rocker assembly brackets are installed in their correct positions, identification marks are provided on both the brackets and the cylinder head (NAPS-Z engine shown)

install

facing out

2A

lo

o

o

O

Ol

fo

o

o

O

Ol

® ® ® ® ®

Exhaust

Exhaust 7.6

On KA24E

engines, be sure to the retainers with the cutouts

© ® © ® ®

Intake

7.5d

On KA24E

7.5c

Tighten the rocker arm assembly

starting inside

engines, the punch marks face up and toward the front

and work your way

to

the outside bolts

4

If

you intend

cylinder head,

remove the camshaft only, without disassembly of the

to

DO NOT alter the timing sprocket position in relationship to

Mark both the timing chain and the camshaft sprocket to preserve the original installed position of the two (see illustration). The chain must be reinstalled on the camshaft sprocket in the exact same rela-

the timing chain!

a major overhaul is being done, then the sprocket/chain relahave to be maintained. 5 Before removing the camshaft sprocket, cut a piece of wood 1 inches long, 3/4 inch thick, 1-1/2 inches wide at the top and approximately 1 -inch wide at the bottom. 6 Now remove the camshaft sprocket bolt and fuel pump drive cam, if

tionship.

If

tionship doesn't

8.4

Prior to

removing the timing chain from the camshaft made to ensure correct installation

sprocket, marks should be

equipped (see illustration). A rod can be positioned through the camshaft keep from turning while the bolt is loosened. 7 Insert the piece of wood into the timing case (small end down) until it's wedged between the two runs of the chain. Be sure it's wedged securely in place. The timing chain must not be allowed to separate from the crankshaft sprocket, as would necessitate removal of the front cover in order to

it

it

to reinstall the timing chain.

On models equipped with a mechanical fuel pump, a fuel pump drive cam is installed with the camshaft sprocket bolt

8.6

18 2 3 4 6 7

.

.

2A-8

Chapter 2 Part A

Four-cylinder engines 19 Following installation, warm up the engine and readjust the valve clearances to the Hot specifications as described in Chapter 1

Oblong groove

1981 and later models (NAPS-Z engine and KA24E engine) Refer

8.27 and 8.31 arm cover as described

to illustrations 8.25,

Remove Remove

the rocker

21

22

Bring the

number one piston to TDC by referring to Section 3, neces-

20

all

in

Section

4.

spark plugs. if

sary.

23

If

you intend

to

remove the camshaft only, without disassembly of the

DO NOT alter the timing sprocket position in relationship to

cylinder head,

the timing chain! Mark both the timing chain and the camshaft sprocket to

On 1980 models (L20B

8.13

thrust plate

must

preserve the original installed position of the two. The chain must be reinstalled on the camshaft sprocket in the exact same relationship. If a major

engine), the camshaft sprocket

l>e installed with the

oblong groove on top

overhaul

and facing out

remove the camshaft sprocket from the camshaft and work until the sprocket can be removed. The chain can be left the chain off resting on the piece of wood. Remove the bolts and detach the camshaft thrust plate. 9 1 Note the position of the small dowel pin in the end of the camshaft, then remove the pin. Carefully pull the camshaft out of the cam towers. 8

Carefully

it

Support it so the lobes don't scratch or nick the bearing surfaces. Caution: DO NOT loosen the cam bearing tower mounting bolts! They are align

bored after installation and must be

left in

place.

fied torque.

1

Adjust the valve clearances to the Cold specifications as described

8.25

it

it

to reinstall the timing chain.

27

Carefully

the chain

off

remove the camshaft sprocket from the camshaft and work until the sprocket can be removed. The chain can be left

it

of wood (see illustration). Remove the valve rocker assembly as described in Section 6. Note the position of the small dowel pin in the end of the camshaft, then lift out the cam. 30 Camshaft, rocker arm and cam bearing inspection instructions can be found in Section 9. 31 When installing the camshaft, lubricate the beanng surfaces with moly-base grease or engine assembly lube (see illustration) and place in the head. Turn until the dowel pin is positioned the same way was be-

resting

on the piece

28 29

it

it

it

fore removal. Reinstall the valve rocker assembly. Tighten the mounting bolts finger Temporarily tighten the two center bolts to 14 ft-lbs. With the piece of wood still in place, carefully work the timing chain over the camshaft sprocket and attach the sprocket to the end of the camshaft, with the cam dowel pin located in the number two sprocket hole. Be sure the marks made on the chain and sprocket during removal line up.

32 33

Reinstall the rocker arms.

1

Reinstall the rocker

24 Before removing the camshaft sprocket, cut a piece of wood 10 inches long, 3/4 inch thick, 1-1/2 inches wide at the top and approximately 1 -inch wide at the bottom. 25 Now remove the camshaft sprocket bolt and fuel pump drive cam, if equipped. A rod can be inserted through the camshaft sprocket to keep from turning while the bolt is broken loose (see illustration). In order to remove the bolt, the rubber plug located in front of must be removed first. 26 Insert the piece of wood into the timing case (small end down) until it's wedged between the two runs of the chain. Be sure it's wedged securely in place. The timing chain must not be allowed to separate from the crankshaft sprocket, as would necessitate removal of the front cover in order

tight only.

1

1

being done, then the sprocket/

it

1 Camshaft, rocker arm and cam bearing inspection instructions can be found in Section 9. 1 Prior to installing the camshaft, apply a coat of moly-base grease or engine assembly lube to the camshaft bearing surfaces, then carefully install the camshaft in the head. Turn it until the dowel pin is positioned correctly. 1 Reinstall the thrust plate with the oblong groove facing the front of the engine (see illustration). 1 With the piece of wood still in place, carefully work the timing chain over the camshaft sprocket and attach the sprocket to the end of the camshaft with the cam dowel located in the number one sprocket hole. Be sure the marks made on the chain and sprocket during removal line up. 15 Carefully remove the piece of wood and install the fuel pump drive cam, if equipped, and camshaft sprocket bolt. Tighten the bolt to the speci-

Chapter

is

chain relationship doesn't have to be maintained.

arm

cover.

Keep the camshaft from turning by

inserting an extension bar through one of the camshaft holes and resting the bar

against the rocker arm shaft pedestal

in

8.27 A piece of wood, cut to the dimensions listed in the text, must be used to hold the timing chain in place while the camshaft sprocket is off

8.31 The camshaft bearing surfaces should be lubricated prior to installation of the camshaft

7

.

6 2 3 5

.

.

Chapter 2 Part A Carefully remove the piece of wood, then install the fuel pump drive cam (if equipped) and camshaft sprocket bolt. Tighten the bolt to the speci-

34

fied torque.

Apply sealant

to the

rubber plug and

reinstall

it

in

the cylinder

head.

35 Tighten the valve rocker assembly bolts to the specified torque. 36 Adjust the valve clearances to the Cold specifications as described in Chapter 1 37 Reinstall the rocker arm cover and spark plugs. 38 Following installation, warm up the engine and readjust the valve clearances to the Hot specifications as described

in

Chapter

1

Apply compressed

5

place by the

may

leaks

Camshaft, bearings and rocker arms - inspection

resistance

magnet (see

The camshaft, bearing surface and rocker arm inspection procedures in the V6 engine, so refer to Chapter 2, Part B, Section 1 5, for instructions and illustrations. Be sure to refer to the Specifications here in Part A. Note that Paragraphs 5 through 8 can be ignored, since the four-cylinder engines don't have lifters.

If

in

the affected cylinder

at top

is

dead center on the compression stroke (refer to Section 3 for instructions). If you're replacing all of the valve stem seals, begin with cylinder number one and work on the valves for one cylinder at a time. Move from cylinderto-cylinder following the firing order sequence (1-3-4-2). 4 Thread an adapter into the spark plug hole and connect an air hose from a compressed air source to (see illustration). Most auto parts stores can supply the air hose adapter. Note: Many cylinder compression gauges utilize a screw-in fitting that may work with your air hose quick-disit

connect

hold the valve in the

the valve face or seat

have

to

be removed

into the

fall

or tape around the top of the valve stem so the combustion chamber, then release the air pres-

Inspect the valve stem for

bent.

Move

11

bind.

If

aged.

the valve up-and-down

Reapply

1

in

the guide and

the valve stem binds, either the valve

In either

position, then

case, the head

air

will

have

to

air

pressure, rotate the crankshaft

Lubricate the valve stem with engine seal.

11 in

14 pitch 1

sure

Compressed

.

doesn't is

dam-

in

the normal

is felt.

oil

and

install

a new valve guide

A special tool is needed for the intake valve seals - refer to Section

Parte. Install

end

in

position over the valve. is

Make sure

the narrow

against the cylinder head.

Compress the valve springs and posikeepers in the groove. Apply a small dab of grease to the inside of

Install

tion the

the springs

of the outer spring

the valve spring retainer.

each keeper to hold in place if necessary. Remove the pressure from the spring tool and make sure the keepers are seated. 1 Disconnect the air hose and remove the adapter from the spark plug hole. If a rope was used in place of air pressure, pull out of the cylinder. 17 Install the camshaft (1980 models) or the valve rocker assembly (1981 and later models). 18 Install the spark plug(s) and hook up the wire(s). it

it

air

springs are

compressed

it

for repair.

pressure to the cylinder to retain the valve in the closed or rubber band from the valve stem. If a

direction of rotation until slight resistance

oil

make

bent or the guide

remove the tape

rope was used instead of

1

is

be removed

can be used to hold the valves shut as the .

wm^^ Compressed

probably

If

fitting.

10.4

is

for additional

a rope was used instead of air pressure, turn the crankshaft opposite normal rotation. damage. Rotate the valve in the guide and check the end for eccentric movement, which would indicate that the valve

used to keep the valves from falling into the cylinder during this procedure. 1 Refer to Section 3 and remove the rocker arm cover. On 1 980 models, remove the camshaft (Section 8). On 1 981 and later models, remove the valve rocker assembly (Section 6). 2 Remove the spark plug from the cylinder with the defective component. If all of the valve stem seals are being replaced, all of the spark plugs should be removed. On engines with two plugs per cylinder, remove one of the plugs from each cylinder. the piston

will

Wrap a rubber band

9

is

until

air pressure fails to

head

repair operations.

to illustrations 10.4 arid 10.

Turn the crankshaft

If

this operation,

so. the cylinder

slightly in the direction

vehicle

Note: Broken valve springs and defective valve stem seals can be replaced without removing ttie cylinder tiead. Two special tools and a compressed air source are normally required to perform thiis operation, so read througfi this Section carefully and rent or buy the tools before beginning the job. If compressed air isn't available, a length of nylon rope can be

3

in

illustration).

closed position during

damaged.

1

Refer

The valves should be held

is felt.

umbrella type guide seal. Note:

sure. Note:

in

the cylinder.

If the valve faces or seats are in poor condition, pressure from retaining the valves - refer to the

Remove the valve, spring retainer and valve springs, then remove the

8

valve won't

Valve springs and seals - replacement

air

7 Stuff shop rags into the cylinder head holes to prevent parts and tools from falling into the engine, then use a valve spring compressor to compress the spring. Remove the keepers with small needle-nose pliers or a

are identical to the procedures for the equivalent components

10

air to

pressure.

air

prevent the

alternative procedure below. If you don't have access to compressed air, an alternative method can 6 be used. Position the piston at a point just before TDC on the compression stroke, then feed a long piece of nylon rope through the spark plug hole until it fills the combustion chamber. Be sure to leave the end of the rope hanging out of the engine so it can be removed easily. Use a large breaker bar and socket to rotate the crankshaft in the normal direction of rotation until slight

9

2A-9

Four-cylinder engines

air

10.7

..

.

and the keepers (arrow) are removed

96 7 8 9

2A-10

Chapter 2 Part A

Four-cylinder engines

11.18 Location of EGR tube (arrow), positioned under the intake manifold on

the

1980 models

Remove the exhaust

21

11.9

BPT

valve, air injection gallery pipe,

passage and AB valve locations Refer to Section 4 and

1

install

the rocker

arm

valve,

injectors.

EGR

(1980 models only)

(left-to-right)

20 Start and run the engine, then check coming from the rocker arm cover area.

11

EGR

cover.

for oil leaks

If

manifold, complete with air injection pipes

the manifold must be replaced, transfer

new

manifold prior to installation.

22 23

Remove Before

them

and

directly to the

the manifold gasket.

installing the manifolds, stuff clean, lint-free

rags

in

the engine

and remove all traces of the old gasket and sealant with a scraper. Glean the mating surfaces with lacquer thinner or acetone. 24 Begin installation by placing the new gasket in position on the engine and reinstalling the exhaust manifold. Be sure the chamfered side of each washer faces the engine and tighten the mounting bolts only until they support the manifold. The bolts that are common to both manifolds should be ports

and unusual sounds

Intake manifold - removal and installation

finger tight only!

1980 models (L20B engine) Refer

to illustrations 11.9

Note:

Thie intake

and

11.18

and exhaust manifolds on

this

engine share a

common

must be replaced whenever either manifold is removed - the manifolds must be removed and installed together The engine must be completely

when

this

procedure

is

done.

Disconnect the negative battery cable from the battery. Drain the cooling system. 2 3 Remove the air cleaner 4 Disconnect the fuel and vacuum lines from the carburetor Plug the fuel lines immediately to prevent fuel leakage and to keep dirt from entering the lines, f^ark ail lines and hoses before removal to ensure correct 1

6 7

the remaining bolts, again tightening

Disconnect all hoses from the intake manifold. Unplug all wiring connectors leading to the carburetor Disconnect the brake booster hose from the intake manifold.

1981 and later models (NAPS-Z engine and KA24E engine) Refer

31

32

tion.

34

EGR

and BPT valves (see

illustra-

tion).

BPT

10

Remove

11

Disconnect the hose that attaches to the Remove the rear engine lift bracket.

12 13 14

the

valve and bracket. air injection gallery

pipes

Remove the EGR valve, along with the EGR passage it's attached to. Remove the anti-backfire (AB) valve and bracket located behind the

carburetor

15 Remove the duct that runs tietween the exhaust manifold and cleaner Raise the front of the truck and support it on jackstands. 1 1 Disconnect the front exhaust pipe from the exhaust manifold. Remove the EGR tube (see illustration) 1 Remove the heat shield from the exhaust manifold. 1

air

20 Remove the mounting txDits and detach the manifold from the engine complete with carburetor and other attached components. If the manifold must be replaced, the components can be transferred directly to the new manifold prior to installation.

to illustration 11.36

Disconnect the negative battery cable from the battery. Drain the cooling system. Remove the air cleaner Disconnect the brake booster vacuum hose where it joins the metal

pipe.

Disconnect the hoses from the

head and inthem only enough to support the

position against the cylinder

ter 1.

Disconnect the hoses from the fuel/vacuum tube assembly attached to the front of the cylinder head. Then remove the mounting bolts and detach the assembly. Note: The hoses should be plugged after disconnec-

8

9

in

26 Once both manifolds are installed, the mounting bolts can be tightened to the specified torque (work from the center toward the ends and work up to the final torque in three or four steps). 27 The remainder of installation is the reverse of the removal procedure. 28 Fill the radiator with coolant, start the engine and check for leaks. Also check and adjust the idle speed and throttle linkage as described in Chap-

29 30

installation.

5

Place the intake manifold

stall

manifold.

gasket. To prevent air leaks and possible damage to the valves, the gasket

cool

25

Disconnect all vacuum lines from the carburetor or throttle body and Mark them before removal to ensure correct installation. Disconnect the rubber fuel hoses where they connect to the metal lines below the intake manifold. Warning: On fuel injected vehicles, the fuel system pressure must be relieved before loosening any fittings or disconnecting any lines' Refer to Chapter 4 for instructions.

33

intake manifold.

35 36

Disconnect the vacuum lines leading to the VVT and EGR tubes. Disconnect the EGR exhaust pipe from the EGR valve, and the POV PCV valve (see illustration). Disconnect the throttle cable from the carburetor or throttle body.

tube from the

37 38 Disconnect any wire harnesses leading to the carburetor or throttle body and intake manifold. 39 Remove the upper radiator hose. 40 Disconnect the battery ground cable from the lower thermostat housing

txjit.

Disconnectthe heater hose from the underside of the intake manifold. Disconnect the hose from the PCV valve. Remove the intake manifold mounting bolts and detach the manifold from the engine complete with carburetor/throttle body, EGR valve and other components. If the manifold must be replaced, the components can 41

42 43

be transferred

directly to the

new

manifold prior to installation.

1 2

4 3

.

Chapter 2 Part A

11.36

44

Location of the

PCV tubes on

Before installing the manifold,

and remove Clean the mating ports

all

1981 and later models

stuff clean, lint-free

rags

in

12.4

\he engine

(NAPS-Z shown)

new

intake manifold gasket

in

of

on the manifold and and washers. Be sure the

position

loosely install the lower manifold mounting bolts

chamfered side

2A

Location of the air induction tubes (left) and EGR tube the exhaust manifold (1981 and later models)

(right) at

traces of the old gasket and sealant with a scraper.

Install

1

Place a

2A-11

Four-cylinder engines

surfaces with lacquer thinner or acetone.

45

.

each washer is facing the engine. Place the manifold in head and install the remaining mounting

the remaining components.

The remainder of installation

is

the

reverse of the removal procedure. 1 Start the engine and check for exhaust leaks between the manifold and cylinder head and between the manifold and exhaust pipe.

position against the cylinder bolts.

46

Tighten the mounting bolts

in

three or four steps to the specified

Work from the center out toward the ends. 47 The remainder of installation is the reverse of the removal procedure. torque.

48 Fill the radiator with coolant, start the engine and check for leaks. Also check and adjust the idle speed as described in Chapter 1

1

1980 models (L20B engine)

installation

to illustration

13.10

3

Remove the intake and exhaust manifolds as described in Section Remove the upper radiator hose. Remove the thermostat housing.

4

Disconnect the heater hose from the

2

Exhaust manifold - removal and

Cylinder head - removal

Refer 1

12

3

fitting

on the

right rear

1 1

corner of

the cylinder head.

1980 models (L20B engine)

5

Since the exhaust manifold shares a common gasket with the intake manifold, and the gasket must be replaced when either manifold is removed, both manifolds should always be removed together. Refer to Sec-

them out

tion 11 for the

procedure.

6

Refer 1

2

9

to illustration 12.4

Remove Remove

the

air

induction pipes

and valve case,

if

equipped.

the duct that runs between the exhaust manifold and

air

cleaner.

3

4

Remove

the fuel pump.

Remove the bolt that retains the battery ground cable and front en7 gine lifting bracket to the cylinder head. 8

1981 and later models (NAPS-Z engine and KA24E engine)

Disconnect the spark plug wires from the spark plugs and position of the way, then remove the spark plugs.

Remove the rocker arm cover. Bnng the number one piston to TDC (see Section

3)

and remove the

camshaft sprocket - be sure to follow the procedure in Section 8. 1 Using a new head gasket, outline the cylinders and bolt pattern on a piece of cardboard, be sure to indicate the front of the engine for reference. Punch holes at the bolt locations. Loosen the ten cylinder head bolts in 1/4-turn increments until they can be removed by hand. Be sure to follow the recommended sequence (see illustration). Store the bolts in the

Remove

the heat shield. Disconnect the EGR tube from the rear of the exhaust manifold (see

illustration).

Raise the front of the vehicle and support it on jackstands. Disconnect the front exhaust pipe from the exhaust manifold. 7 Remove the spark plug wires from the exhaust side spark plugs for access to the exhaust manifold bolts/nuts. 8 Remove the bolts and nuts that retain the exhaust manifold to the cyl5 6

inder head.

9

Detach the exhaust manifold.

Before installing the manifold, remove all traces of the old gasket with a scraper. Clean the mating surfaces with lacquer thinner or acetone. 1 Place a new exhaust manifold gasket in position on the cylinder head 1

then hold the manifold

in

place and

install

the mounting bolts/nuts finger

tight. 1

Tighten the mounting bolts/nuts, in three or four steps, to the specified Work from the center of the manifold out toward the ends to pre-

torque.

vent distortion of the manifold.

Cylinder head bolt LOOSENING sequence (1980 L20B engine) - a 10 Allen head socket will be needed to loosen tighten the bolts

13.10

mm

3

2

1

2A-12

Chapter 2 Part A

®

(7)

13.26a

Four-cylinder engines

(I)

(2)

®

(8)

(5)

(3)

® ©

®

Cylinder head bolt

LOOSENING sequence

1

Cylinder bolt

3.26b

LOOSENING sequence

(KA24E engine)

(1981 and later models)

Valve rocker cove

14.2

Exploded view of the KA24E engine Rocker cover gasket

Cylirxlar head

Cylinder head gasket

cardboard holder as they're removed stalled 1

in their

this will

ensure that they're

rein-

onginal locations.

Remove the

small bolts that attach the cylinder head to the front cov-

er. 1

head, position a block of wood against it and strike the wood block with a hammer The timing chain should be left in place, resting on the wooden

wedge. 1

Lift

the head

off

the engine.

and block - damage

to the

If

its stuck,

DO NOT pry between the head

mating surfaces

will result!

To dislodge the

Remove the cylinder head gasket.

to

prevent damage.

14

Refer to Part

C

for cylinder

Place the head on a block of wood

head inspection procedures.

5 8 7

.

Chapter 2 Part A

o

A

o

A

2A-13

Four-cylinder engines

On 1980 models, two different length head bolts are used - make sure they're installed in the correct holes!

14.5

1981 and

later

models (NAPS-Z engine

and KA24E engine) Refer

to Illustration

2A

13.26a and 13.26b

Drain the cooling system. Refer to Chapter

1

16

Remove

and

idler

the air cleaner and,

if

1

,

if

necessary.

equipped, the power steering

pump

pulley

Disconnect the spark plug wires from the spark plugs and remove the brackets from the rocker arm cover. The spark plug wires do not have to be 1

removed from the brackets.

Remove Remove 20 Remove

the air induction pipes

19

the intake manifold as described the

compartment.

If

VVT

If

22

Remove

if

(top

equipped. 11

valve and bracket from the firewall

in

the engine

EGR pipe that runs behind the cylinder head.

the mechanical fuel

cylinder head,

if

Section

equipped.

equipped, remove the

21

in

Cylinder head bolt TIGHTENING sequence - 1980 models; bottom - 1981 and later models)

4.6a

1

and valve case,

1

pump

from the

right front

(D

23 Detach the exhaust manifold from the cylinder head. 24 Remove the rocker arm cover. 25 Bring the number one piston to TDC (see Section 3) and remove the camshaft sprocket. Be sure to use the procedure described in Section 8. 26 Using a new head gasket, outline the cylinders and bolt pattern on a piece of cardboard, be sure to indicate the front of the engine for reference. Punch holes at the bolt locations. Loosen the ten cylinder head bolts in 1/4-turn increments until they can be removed by hand. Be sure to follow the recommended sequence (see illustrations). Make several passes through the sequence to slowly release the tension. Store the bolts in the cardboard holder as they're removed - this will ensure that they're rein-

®

(D

(D

Remove the small

bolts that attach the cylinder

head

(D

(!)

1

4.6b

stalled in their original locations.

27

(3)

corner of the

equipped.

Cylinder head bolt TIGHTENING sequence for the KA24E engine

to the front cov-

er.

28 Lift the head off the engine. If it's stuck, DO NOT pry between the head and block - damage to the mating surfaces will result! To dislodge the head, position a block of wood against and strike the wood block with a hammer The timing chain should be left in place, resting on the wooden wedge. 29 Remove the cylinder head gasket. Place the head on a block of wood it

to

prevent damage.

30

Refer to Part

C

for cylinder

head inspection procedures.

Check the block and head mating surfaces for nicks, deep scratches and other damage (see illustration). If damage is slight, can be removed with a file; it's excessive, machining may be the only alternative. Use a tap of the correct size to chase the threads in the head bolt 3 holes. Mount each bolt in a vise and run a die down the threads to remove corrosion and restore the threads. Dirt, corrosion, sealant and damaged 2

it

if

threads

will affect torque readings. Place the gasket in place over the engine block dowel pins.

Make sure number one piston is still at TDC then carefully lower the cylinder head onto the engine, over the dowel pins and the gasket. Be careful not to move the gasket. 4

the

14

Cylinder head - installation

5

Refer

to illustrations 14.2. 14.5.

14.6a

and 14.6b

The mating surfaces of the cylinder head and block must be perfectly is installed. Use a gasket scraper to remove all traces and old gasket material then clean the mating surfaces with lacquer thinner or acetone. there's oil on the mating surfaces when the head is installed, the gasket may not seal correctly and leaks could develop. When working on the block, stuff the cylinders with clean shop rags to keep out debris. Use a vacuum cleaner to remove any debris that falls into 1

clean when the head of carbon

,

If

the cylinders.

,

Install

the cylinder head mounting bolts. Note that the bolts on

models are two rect holes

6

different lengths

- make sure they're

1

980

installed in the cor-

(see illustration)

Tighten the bolts

in

1

/4-turn increments, following the

recommended

sequence (see illustrations), until the specified torque is reached. On 1984 and later engines, follow the five step procedure outlined in the torque specifications. the camshaft sprocket as described

7

Install

8

The remainder

moval procedure.

of the installation

in

procedure

Section

is

8.

the reverse of the re-

1 2 3 4

.

.

2A-14

Chapter 2 Part A

Four-cylinder engines

16.1

Oil

pump ReguUtor

components - exploded 15.10 When installing the oil pump, the punch mark on the side of the spindle should be aligned with the pump's oil hole (arrows)

9

(typical)

Be

the radiator with coolant, start the engine and check for leaks.

Fill

sure to recheck the coolant level once the engine has

view

warmed up to oper-

check and adjust the idle speed as described in Chapter 1 1 Readjust the valve clearances to the Hot specifications as described in Chapter 1 ating temperature. Also

15

pump - removal and

Oil

Refer

to illustrations

installation

15.10

piston at TDC on the compression stroke. Refer to Section 3 if necessary. Remove the distributor cap and mark the position of the rotor in rela2 1

number one

Position the

tion to the distributor body.

Raise the front of the truck and support it with jackstands. 4 Remove the splash shields from the underside of the engine compartment. Dram the engine oil. 5 On 4WD models, support the front differential with a jack. Then re6 move the differential mounting crossmember in order to gain enough clearance for removal of the oil pump. 7 Remove the pump-to-cover bolts and withdraw the oil pump/drive3

pump must be inspected or overhauled, refer to Section make sure that the number one piston is still

8

If

9

Prior to installation,

the

oil

Feeler gauges are used to check the

16.4

clearance

assembly

shaft

1

oil

pump's

rotor tip

outer rotor-to-body clearance (2) rotor end clearance (3) and body-to-straightedge clearance (4)

(1)

6.

at

TDC. 1

Fill

the

pump body with engine oil to prime and align the punch mark it

on the driveshaft with the oil hole below the drive gear (see illustration). 1 Install a new gasket and insert the pump into the recess in the engine front cover. 1

Tighten the

bolts

1

Fill

16

If

it

pump mounting

isn't,

rotor

is still

repeat the

aligned with the mark

oil

pump

installation

made on the dis-

procedure.

the engine with the proper quantity and grade of engine

Chapter 1

oil

and check that the

tributor body.

1,

Finally

Oil

if

Clean the pump components with solvent and dry them with com3 pressed air, if available. 4 Check all components for excessive wear and score marks. Insert the rotors into the pump body with the marked ends facing IN and check the rotor clearances in the following manner (see illustration): a) Check the clearance between the lobes on the inner and outer ro-

oil

tors

(refer to

b)

necessary).

check the

pump-

(1

Check

in illustration

the clearance

16.4).

between the outer

rotor

and the body

(2 in

il-

lustration 16.4).

ignition timing

as described

in

Chapter

1

.

c)

Check the rotor end clearance gauges (3 in illustration 16.4).

d)

Again, using the straightedge placed across the body, check the

with a straightedge

clearance between the body and the straightedge (4

inspection

and

feeler

in illustration

16.4).

5

Refer 1

to illustrations 16.

Remove

the

1

and

16.4

pump, then unbolt the cover and

out the inner and

Remove the pressure regulator valve cap and washer and extract the

spring

and

valve.

or

6

The inner and If the oil pump body is worn

the clearances aren't as specified, replace the pump.

outer rotors are only supplied as matched sets. pull

outer rotors (see illustration)

2

If

damaged, replace the complete pump assembly. Check the condition of the pressure regulator valve and spring. The necmust not be damaged or worn. Replace

sliding surface of the valve

essary.

it if

1 2 4

Chapter 2 Part A

A puller such as the one shown may have to be used to remove the

17.6

here

18.2

After

removing the crankshaft

of the front

Crankshaft pulley - removal and installation

Refer

to illustration

1

7.6

3

leaks

will

the

new

seal with a large

hammer

2A

develop!

2

Remove

3

Drain the engine

4

Remove Remove Remove Remove

6 7

Remove the drivebelts (Chapter On manual transmission equipped models, put the transmission in High gear and apply the parking brake. On automatics, remove the starter and wedge a large screwdriver in the ring gear teeth. Remove the pulley 4

oil

5

Disconnect the negative battery cable from the battery. Remove the radiator and shroud (Chapter 3). Unbolt the lower front cover or skidplate (if equipped).

1

2

Install

socket or section of pipe and a

cover - don't scratch or nick

the crankshaft or

17

18.3

pulley, carefully pry the seal (arrow) out

crankshaft pulley.

2A-15

Four-cylinder engines

the fan and radiator as described

the

oil

in

Chapter

3.

oil.

the distributor as described

Chapter

in

5.

pump as described in Section 5. pump as described in Chapter 1

the water

the upper alternator adjusting

that attach the alternator adjusting

arm

bolt.

3.

Then remove the bolts cover and detach the

to the front

1 ).

5

mounting

They're usually very

bolt.

tight,

so use a six-point socket and a

1/2-inch drive breaker bar.

Use a puller to remove the pulley from the crankshaft (see illustraDo not use a gear puller that applies force to the outer edge of the

6

tion).

pulley!

7

Installation is the

reverse of removal.

grease or clean engine

oil

Be sure

to

to the seal contact surface

apply moly-base on the pulley hub

Front crankshaft

oil

and

position

to illustrations 18.2

seal - replacement

1

Remove

2

Carefully pry the

and

oil

ful

18.3

the pulley (Section

1

out of the way.

The

hydraulic hoses should not be discon-

Remove the water inlet from the right side of the front cover. Since the front cover is sandwiched between the cylinder head and the oil pan, the oil pan must be removed in order to remove the front cover. Refer to Section 21 for this procedure. 13 Remove the crankshaft pulley (Section 17) 1 Remove the mounting bolts that attach the front cover to the block and cylinder

Refer

it

nected from the pump. 1

Tighten the pulley bolt to the specified torque.

18

Disconnect the hoses from the fuel/vacuum pipe assembly attached remove the pipe assembly. If equipped, disconnect the air conditioning compressor from the 9 bracket and position it out of the way. Remove the compressor bracket and idler pulley. Warning: Don't disconnect the hoses from the compressor unless the system has been evacuated! 1 If equipped with power steering, remove the pump from the bracket 8

to the front cover, then

1

before installing the pulley on the crankshaft.

8

adjusting arm.

head and detach the front cover.

tapping with a soft-facp

hqmmpr

will

If it

doesn't

come off easily, care-

help (see illustrations).

7).

seal out of the front cover (see illustration) with a

damage new seal

seal removal tool or screwdriver. Don't scratch the cover bore or the crankshaft will

end up

3

the process

ameter

the crankshaft

(if

is

damaged

the

leaking).

Clean the bore

with engine

oil

in

the cover and coat the outer

edge

of the

new

seal

or multi-purpose grease. Using a socket with an outside di-

smaller than the outside diameter of the seal, carefully seal into place with a hammer (see illustration). If a socket

slightly

drive the isn't

in

new

available, a short section of large diameter pipe

seal after installation to

4

Reinstall the pulley.

5

The

parts

removed

be sure to gain

will

that the spring didn't

access

to the pulley

work.

pop out

Check the of place.

can now be

rein-

stalled.

6

19

Run

the engine and check for leaks.

Front cover - removal and installation

Refer to illustrations 1

19.

Ua.

19.

14b and

19.

19.14a

16

Drain the coolant from the engine and radiator (Chapter

1 ).

When removing

damage

the front cover, be careful not to bend or the front part of the cylinder head gasket (arrow)

5 6 8 7

2A-16

Chapter 2 Part A

Cham

Front

oil seal

Four-cylinder engines

tensionei

^

Crankshaft pulley

19.14b

Exploded view

of the front cover

a new seal in the front cover by referring to Section 1 8. Place the new gaskets in position on the cover, then apply RTV seaInstall

1 1

shown in the accompanying illustration. 1 Apply a small amount of grease to the oil seal lip. then place the front cover in position on the block and install the mounting bolts. Tighten them lant to the points

in

several steps to the specified torque.

1

20

The remainder of installation

is

the reverse of the removal procedure.

on the KA24E engine

quire the use of a puller (see illustration). Note that three Woodruff keys

are used for these components.

Examine the teeth on both the crankshaft sprocket and the camshaft V. If worn, the side of each will be slightly concave in shape when compared with the other side of the tooth (i.e. one side of the inverted V will be concave when compared with the other). the teeth appear to be worn, the sprockets must be replaced with new ones. 6

sprocket for wear. Each tooth forms an inverted

tooth under tension

If

Timing chain and sprockets - removal and installation

Refer to illustrations 20.2. 20.5. 20. 20.15b. 20.16a arid 20.16b

Apply sealant

to points

12. 20. 14a. 20. 14b. 20. 14c. 20. 15a.

Removal 1

2

Remove the front cover (Section 19) Remove the bolts that attach the chain tensioner and chain guides to

the block, then

3

Remove

Section 8

4

if

remove them (see

illustration)

the camshaft sprocket bolt and detach the sprocket (see

necessary).

Remove

the timing chain from the camshaft and crankshaft sprock-

ets.

5

Remove the oil thrower,

the

oil

pump dnve gear and

sprocket from the end of the crankshaft. The sprocket

Prior to installing the front cover and gasket, RTV sealant should be applied to the points shown here

19.16 the timing chain

will

most

likely re-

3 4 1 2

Chapter 2 Part

A

2A-17

Four-cylinder engines

The chain should be replaced with a new one the sprockets are worn is loose. It's a good idea to replace the chain at about 30,000 miles (48,000 km) and at lower mileage the engine is stripped down for a major overhaul. The rollers on a very badly worn chain may be slightly 7

if

or

if

the chain

if

grooved. To avoid future

difficulty,

chain's condition, replace

it

with a

if

there's

any doubt

at

all

about the

new one.

Reattach the camshaft sprocket to the camshaft and check the end The end play should not exceed 0.008-inch (0.2 mm). Examine the components of the chain tensioner and guides. Replace 9 any items that are worn or damaged. 8

play with a dial indicator.

Installation 10

To begin the

(front) cylinder

TDC), then 1

Bolt the

1

Install

on the

installation, turn the

until the number one number one piston at number one piston is at TDC.

camshaft

valves are closed (equivalent to

turn the crankshaft until the

two timing chain guides

the sprocket,

oil

to the block.

pump/distributor drive gear and the

front of the crankshaft.

oil

thrower

Make sure the timing marks on the sprocket

are visible from the front (see illustration). 1

20.2 /

Timing chain and related components

Chain tensioner

2 Slack side chain guide 3 Tension side chain guide 4 Oil thrower

5 Oil pump drive gear 6 Cranl