ENGINE-ELECTRICAL 6Y-20
cause oxidized contact points. Check for these conditions
where burned contacts are experienced. An
out-of-
balance condition in the ignition system, often the result
of too much or too little condenser capacity, is indicated
where point pitting is encountered.
REPLACEMENT
Four and Six Cylinder Engine Distributor
1.
Release distributor cap hold-down screws, remove
cap and place it out of work area.
2.
Remove rotor.
3.
Pull primary and condenser lead wires from contact
point quick disconnect terminal (fig. 4i).
4.
Remove contact set attaching screw, lift contact point
set from breaker plate.
5.
Clean breaker plate of oil smudge and dirt.
6. Place new contact point assembly in position on
breaker plate, install attaching screw.
CAUTION: Carefully wipe protective film from
point set prior to installation.
NOTE: Pilot on contact set must engage match-
ing hole in breaker plate.
7.
Connect primary and condenser lead wires to quick
disconnect terminal on contact point set. .
8. Check and adjust points for proper alignment and
breaker arm spring tension (fig. 5i). Use an aligning
tool to bend stationary contact support if points need
alignment.
NOTE: The contact point pressure must fall
within specified limits. Weak tension will cause
CONTACT SET
ATTACHING
SCREW
QUICK
DISCONNECT
TERMINAL
BREAKER PLATE
ATTACHING SCREWS
chatter, resulting in arcing and burning of-the
points and an ignition miss at high speed, while
excessive tension will cause undue wear of the
contact points, cam and rubbing block. Breaker
arm spring tension should be 19-23 ounces. The
contact point pressure should be checked with a
spring gauge. The scale should be hooked to the
breaker lever and the pull exerted at 90 degrees
to the breaker lever as shown in Figure 5i. The
reading should be taken just as the points sepa-
rate.
The pressure can be adjusted by bending
the breaker lever spring. If the pressure is ex-
cessive, it can be decreased by pinching the
spring carefully. To increase pressure,, the
lever must be' removed from the distributor so
the spring can be bent away from the lever.
Avoid excessive spring distortion.
9. Set point opening (.019" for new points).
10.
Reinstall rotor, position and lock distributor cap to
housing.
11.
$tart engine and test dwell and ignition timing.
Eight Cylinder Engine Distributor
1.
The contact point set is replaced as one complete
assembly and only dwell angle requires adjustment
after replacement. Breaker lever spring tension and
point alignment are factory set.
2.
Remove the distributor cap by placing a screw driver
in the slot head of the latch, press down and turn 1/4
turn in either direction.
3.
Remove the two attaching screws which hold the base
of the contact set assembly in place.
4.
Remove the primary and condenser leads from their
nylon insulated connection (fig. 6i) in contact set.
5.
Reverse Steps 2, 3 and 4 to install new contact set.
CAUTION:. Install the primary and condenser
leads as shown in Figure 6i. Improper installa-
tion will cause lead interference between the
cap,
weight base and breaker advance plate.
6. If car has 20,000 to 25^000 miles (or sooner if
desired) the cam lubricator wick (fig. 7i) should be
changed. Using long nosed pliers squeeze assembly
together at base and lift out. Remove all old lubri-
cant from cam surface. Replace in same manner.
Fig.
4i—Breaker Plate and Attaching Parts
Fig. 5i—-Checking Breaker Arm Spring Tension
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL
6Y-21
Fig.
6i—Distributor Lead Arrangements
NOTE:
End of cam
lubricant wick should
be
adjusted
to
just touch
cam
lobes. Over lubrica-
tion
of cam
resulting
in
grease
on
contact points
can-
be
caused
by cam
lubrication wick bearing
too hard against
cam
surface.
A
correctly
ad-
justed
cam
lubricator wick will provide adequate
lubrication
for cam. Do not
apply additional
grease
to cam
surface.
7.
Start engine
and
check point dwell
and
ignition
timing.
ACTUAL
POINT OPENING
.021
.016
FEELER GAUGE
LOCATOR ___JH^H
(ROUND)
V~^3H|
CENTRIFUGAL
\
jdft
ADVANCE
-~-»JBlMBl
MECHANISM
«H
CAM g^k. / X
LUBRICATOR
V^^^
REPLACEMENT
^£9
^-ADJUST
SQUARELY
AND
JUST
TOUCHING
LOBE
OF
CAM
.ROTOR
I^^I^BL
LOCATOR
(PBV 7
(SQUARE)
SBSSF
/
WWjga^/
^/
LUBRICATOR
H^f
CAUTION!
S5y
NEVER
OIL
•-^
CAM
LUBRICATOR-
REPLACE
WICK
WHEN
NECESSARY
Fig.
8i—Inaccurate Gauging
of
Rough Points
SETTING DWELL ANGLE
Four
and Six
Cylinder Engine Distributors
The point opening
of new
points
can be
checked with
a
feeler gauge,
but the use of a
feeler gauge
on
rough
or
uncleaned used points
is not
recommended since accurate
mechanical gauging cannot
be
done
on
such points (fig. 8i).
Contact points must
be set to the
proper opening.
Points
set too
close
may
tend
to
burn and
pit
rapidly.
Points with excessive separation tend
to
cause
a
weak
spark
at
high speed. Proper point setting
for all
models
are:
.019"
for new
points
.016"
for
used points
New points must
be set to the
larger opening
as the
rubbing block will wear down slightly while seating
to the
cam. Contact points should
be
cleaned before adjusting
if
they have been
in
service.
LATERAL
MISALIGNMENT
PROPER
LATERAL
ALIGNMENT
pCORRECT
LATERAL MISALIGNMENT
BY
M
BENDING FIXED CONTACT SUPPORT
[NEVER
BEND BREAKER LEVER
Fig.
7i—Top View
of
Distributor
Fig.
9i—Alignment
of
Points
CHEVROLET
CHASSIS SERVICE /MANUAL
ENGINE-ELECTRICAL 6Y-22
ADJUST DWELL
ANGLE SETTING OR
POINT OPENING
Fig.
lOi—Settihg Point Opening
To adjust the contact point opening:
1.
If necessary, align points (fig. 9i) by bending the
fixed contact support. Do not bend the breaker lever.
Do not attempt to align used points; replace them
where serious misalignment is observed. Use an
aligning tool if available.
2.
Turn or crank the distributor shaft until the breaker
arm rubbing block is on the high point of the cam
lobe.
This will provide maximum point opening.
3.
Loosen the contact support lock screw.
4.
Use a screw driver (fig. lOi) to move the point sup-
port to obtain a .019" opening for new points and a
.016"
opening for used points.
5.
Tighten the contact support lock screw and recheck
the point opening.
6. After checking and adjusting the contact point open-
ing to specifications, the cam angle or dwell should
be checked with a dwell angle meter if such equip-
ment is available (see Specifications for proper dwell
angle).
If the cam angle is less than the specified
minimum, check for defective or misaligned contact
points or worn distributor cam lobes. The variation
in cam angle readings between idle speed and 1750
engine rpm should not exceed 3°. Excessive varia-
tion in this speed range indicates wear- in the
distributor.
NOTE:
Cam angle readings taken at speeds
above 1750 engine rpm may prove unreliable
on some cam angle meters.
Eight Cylinder Engine Distributor
On the Vehicle
With the engine running at idle and operating tempera-
tures normalized, the dwell is adjusted by first raising
the window provided in the cap and inserting a "Hex"
type wrench into the adjusting screw head (fig. Hi).
WINDOW
r- "HEX" TYPE
WRENCH
ADJUSTING
SCREW
Fig.
-lli—Adjusting Dwell Angle
1.
Preferred Method - Turn the adjusting screw until
the specified dwell angle is obtained as measured in
degrees (28° to 32°, 30° preferred) by a dwell angle
meter.
2.
Alternate Method - Turn adjusting screw in (clock-
wise) until the engine begins to misfire, then turn
screw 1/2 turn in the opposite direction (counter-
clockwise). This will give the approximate dwell
angle required. (Use only when meter is not
available.)
Off the Vehicle
1.
Distributor Test Method:
a. With the distributor mounted on a distributor
testing machine, connect the dwell meter to the
distributor primary lead.
b.
Turn the adjusting screw (fig. lli) to set the dwell
angle to 30 degrees.
2.
Test Light Method:
a. With the distributor mounted in a vise, connect a
testing lamp to the primary lead.
b.
Rotate the shaft until one of the circuit breaker
cam lobes is under the center of the rubbing block
of the breaker lever.
c. Turn the adjusting screw clockwise (fig. lli) until
the lamp lights, then give the wrench 1/2 turn in
the opposite direction (counter-clockwise) to ob-
tain the proper dwell angle.
DISTRIBUTOR CONDENSER
PERFORMANCE DIAGNOSIS
The following four factors affect condenser perform-
ance,
and each factor must be considered in making any
condenser test.
1.
Breakdown - A failure of the insulating material. A
direct short between the metallic elements of the
condenser. This prevents any' condenser action.
2.
Low Insulating Resistance (Leakage) - Low insula-
tion resistance prevents the condenser from holding
a charge. All condensers are subject to leakage
which, up to a certain limit, is not objectionable.
3.
High Series Resistance - Excessive resistance in
the condenser circuit due to broken strands in the
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-23
condenser leak or to a defective connection. This
will cause burned points and ignition failure upon
initial starts and at high speeds.
4.
Capacity - Capacity is determined by the area of
the metallic elements and the insulating and im-
pregnating materials.
For a complete check of the condenser, use a tester
which will check for all of the above conditions. Follow
the instructions given by the manufacturer of the
test equipment. Condenser capacity should be
.18-:
23
microfarads.
REPLACEMENT
Four and Six Cylinder Engine Distributor (Fig. 4i)
1.
Release distributor cap hold-down screws, remove
cap and place it out of the work area.
2.
Remove rotor.
3.
Disconnect condenser lead wire from contact point
quick-disconnect terminal.
4.
Remove condenser attaching screw, lift.condenser
from breaker plate and wipe breaker plate clean.
5. Install new condenser using reverse of procedure
outlined above.
Eight Cylinder Engine Distributor
1.
Remove distributor cap.
2.
Loosen condenser lead attaching screw (fig. 6i) and
lift out condenser lead clip.
3.
Remove screw holding condenser bracket to breaker
plate and slide condenser from bracket.
4.
To replace condenser reverse the above procedure.
NOTE:
Make sure that new condenser lead is
installed in proper position (fig. 6i).
DISTRIBUTOR
(BREAKER POINT TYPE)
REMOVAL
1.
On radio equipped Corvettes, remove ignition shield
from over distributor and coil. One bolt is accessible
from top of shield, the other two are at rear of
shield, facing firewall.
2.
Release the distributor cap hold-down screws, re-
move the cap and place it clear of the work area.
NOTE:
If necessary, remove secondary leads
from the distributor cap after first marking the
cap tower for the lead to No. 1 cylinder. This
will aid in the reinstallation of leads in the cap.
3.
Disconnect the distributor primary lead from the coil
terminal.
4.
Scribe a realignment mark on the distributor bowl
and engine in line with the rotor segment.
5. Disconnect vacuum line to distributor and tachometer
drive cable (Corvette). Remove the distributor hold-
down bolt and elamp and remove the distributor from
the engine. Note position of vacuum advance mecha-
nism relative to the engine.
CAUTION: Avoid rotating the engine with the
distributor removed as the ignition timing will
be upset.
Rg.
121-L-6 Distributor-Exploded View
1.
Breaker Plate Attaching
Screws
2.
Condenser Attaching
Screws
3. Condenser
4.
Breaker Plate Assembly
4a.
Cam Lubricator
5. Vacuum Control Assembly
6. Vacuum Control
Attaching Screws
7. Housing
8. Cap
9. Rotor
DISASSEMBLY
10.
Contact Point
Attaching Screw
11.
Contact Point Assembly
12.
Weight Cover
Attaching Screws
13.
Weight Cover
14.
Weight Springs
15.
Advance Weights
16. Cam Assembly
17.
Main Shaft Assembly
18.
Roll Pin
19.
Drive Gear
It is advisable to place the distributor in a distributor
testing machine or synchroscope prior to disassembly.
CHEVROLET CU
SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-24
Fig.
13I-V-8 Distributor (Typical)-Exploded View
1.
2.
2a.
3.
4.
Condenser
Contact Point Assembly
Cam Lubricator
Retaining Ring
Breaker Plate
5.
5a.
6.
7.
Felt Washer
Plastic Seal
Vacuum Advance
Unit
Housing
8.^
Shim
Washer
9. Drive Gear Pin
10.
Drive Gear
11.
Cap
12.
Rotor
13.
Weight Springs
14.
Mainshaft
15.
Advance Weights
16.
Cam Weight
Base Assembly
When mounting distributors for tests, first secure the
gear in the test drive mechanism, then push the distribu-
tor housing downward toward the gear to take up any end
play between the gear and the housing.
NOTE:
When testing distributors that have
their lower shaft support bushing located in the
engine block (6 cylinder engines), a special
adapter should be used to insure the shaft will
run true in its housing.
Test the distributor for variation of spark, correct
centrifugal and vacuum advance and condition of contacts.
This test will give valuable information on distributor
condition and indicate parts replacement which may be
necessary. Check the area on the breaker plate just
beneath the contact points. A smudgy line indicates that
oil or crankcase vapors have been present between the
points.
Four and Six Cylinder Engines
Refer to Figure 12i.
1.
Remove the rotor.
2.
3.
Remove the vacuum control assembly retaining
screws, detach the unit from the distributor housing.
Disconnect the primary and condenser leads from the
contact point quick disconnect terminal, remove the
contact point set attaching screw, condenser attach-
ing screw. Remove the point set and condenser from
the breaker plate.
Remove the breaker plate attaching screws, remove
the breaker plate from the distributor housing (fig.
NOTE:
Do not disassemble breaker plate any
further.
5. Remove the roll pin retaining the driven gear to the
mainshaft, slide the gear from the shaft.
6. Slide the cam and mainshaft from the distributor
housing.
7. Remove the weight cover, and stop plate screws, re-
move the cover, weight springs, weights and slide
cam assembly from the mainshaft.
V-8 Engines
Refer to Figure 13i.
CHEVROLET CHASStS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-25
1.
Remove the rotor.
2.
Remove both weight springs and advance weights.
3.
Remove roll pin retaining driven gear to distributor
shaft, slide the gear and spacers from the shaft.
Remove tachometer drive gear on Corvette models.
4.
Before sliding the distributor shaft from the hous-
ing, check for and remove any burrs on the shaft.
This will prevent damage to the seals and bushing
still positioned in the housing.
5. Slide the distributor mainshaft and cam-weight base
assembly from the housing.
6. Remove vacuum advance mechanism retaining
screws, remove the vacuum advance assembly.
7. Remove the spring retainer, remove the breaker
plate assembly from the distributor housing. Re-
move the contact point and condenser from the
breaker plate. Remove the felt washer and plastic
seal located beneath the breaker plate.
CLEANING AND INSPECTION
1.
Wash all parts in cleaning solvent except cap, rotor,
condenser, breaker plate assembly and vacuum con-
trol unit. Degreasing compounds may damage insula-
tion of these parts or saturate the lubricating felt in
the case of the breaker plate assembly.
2.
Inspect the breaker plate assembly for damage or
wear and replace if necessary.
3.
Inspect the shaft for wear and check its fit in the
bushings in the distributor body. If the shaft or bush-
ings are worn, the parts should be replaced.
4.
Mount the shaft in "V" blocks and check the shaft
alignment with a dial guage. The run-out should not
exceed .002".
5. Inspect the advance weights for wear or burrs and
free fit on their pivot pins.
6. Inspect the cam for wear or roughness. Then check
its fit on the end of the shaft. It should be absolutely
free without any roughness.
7. Inspect
the •
condition of the distributor points. Dirty
points should be cleaned and badly pitted points
should be replaced. (See Distributor Contact Points.)
8. Test the condenser for series resistance, micro-
farad capacity (.18 to .23) and leakage or breakdown,
following the instructions given by the manufacturer
of the test equipment used.
9. Inspect the distributor cap and sparkplug wires for
damage and replace if necessary.
ASSEMBLY
Four and Six Cylinder Engine
Refer to Figure 12i for Exploded View of Distributor.
1.
Replace cam assembly to mainshaft.
NOTE:
Lubricate top end of shaft with Delco
cam and ball bearing grease or equivalent prior
to replacing.
2.
Install governor weights on their pivot pins, replace
weight springs. Install weight cover and stop plate.
3.
Lubricate mainshaft and install it in distributor
housing.
4.
Install distributor driven gear to mainshaft and in-
sert attaching roll pin. Check to see that shaft turns
freely.
5. Install breaker plate assembly in the distributor body
and attach retaining screws.
6. Attach condenser and contact point set in proper lo-
cation with appropriate attaching screws.
NOTE:
Contact point set pilot must engage
matching hole in breaker plate. Connect primary
and condenser leads to contact set quick-
disconnect terminal.
7. Attach vacuum control assembly to distributor
housing.
8. Check and adjust contact point opening and align-
ment (See setting and alignment of points.)
9. Check breaker lever spring tension which should
be.
19-23 ounces. (See contact point replacement.)
V-8 Assembly-(Fig. 13i)
1.
Fill housing lubricating cavity with proper compound,
press in new plastic seal and install felt washer.
2.
Replace the vacuum advance unit, install the breaker
plate in housing and install the spring retainer on
the upper bushing.
3.
Lubricate and slide weight cam over mainshaft and
install weights and spring (fig. 14i).
4.
Insert mainshaft into housing, indexing it with drive
gear and washers. Install tachometer drive gear on
Corvette models.
5. Slide distributor drive gear shims and gear over
shaft and install new pin. Tap new pin through gear
and mainshaft. Check shaft for free rotation.
NOTE:
Mainshaft end clearance should be
.002"-.007". Add or remove shims as necessary.
6. Install contact point set and condenser to breaker
plate. Connect leads as shown in Figure 6i.
NOTE:
Contact point spring tension is factory-
set above specifications to assure ease of final
adjustment. Correct tension is 19-23 oz.
7. Install rotor to cam assembly, indexing round and
square pilot holes.
Flg.
Hi-Advance Weights Installed
CHEVROLET CHASSIS SERVICE
ENGINE-ELECTRICAL 6Y-26
INSTALLATION-ENGINE NOT DISTURBED
(ALL MODELS)
1.
Turn the rotor about 1/8 turn in a clockwise direc-
tion past the mark previously placed on the distribu-
tor housing to locate rotor.
2.
Push the distributor down into position in the block
with the housing in a normal "installed" position
(fig. 15i).
NOTE: It may be necessary to move rotor
slightly to start gear into mesh with camshaft
gear, but rotor should line up with the mark
when distributor is down in place.
3.
Tighten the distributor clamp bolt snugly and con-
nect vacuum line. Connect primary wire to coil
terminal and install cap. Also install spark plug and
high tension wires if removed.
NOTE: It is important that the spark plug wires
be installed in their proper location in the
supports.
4.
Time ignition as previously described under Tune-
Up in Section 6.
INSTALLATION-ENGINE DISTURBED
(ALL MODELS)
1.
Locate No. 1 piston in firing position by either of two
methods described below,
a. Remove No. 1 spark plug and, with finger on plug
hole,
crank engine until compression is felt in the
No.
1 cylinder. Continue cranking until timing
mark on crankshaft pulley lines up with timing
tab attached to engine front cover.
b.
Remove rocker cover (left bank on V-8 engines)
and crank engine until No. 1 intake valve closes
and continue to crank slowly about 1/3 turn until
CENTRIFUGAL
jS ADVANCE
ROTATING
POLE PIECE
STATIONARY
POLE PIECE
MAGNETIC
PICKUP
ASSEMBLY
VACUUM
ADVANCE
DISTRIBUTOR
HOUSING
Fig.
151—Six Cylinder Engine Distributor
Fig.
16i—Magnetic Pulse Distributor Components
CHEVROLET CHASSIS SERVICE MANUAL
ENGINE-ELECTRICAL 6Y-27
timing mark on pulley lines up with timing tab.
2.
Position distributor to opening in block in normal
installed attitude (fig. 15i), noting position of vacuum
control unit.
3.
Position rotor to point toward front of engine (with
distributor housing held in installed attitude), then
turn rotor counter-clockwise approximately 1/8 turn
more toward left cylinder bank and push distributor
down to engine camshaft. It may be necessary to ro-
tate rotor slightly until camshaft engagement is felt.
4.
While pressing firmly down on distributor housing,
kick starter over a few times to make sure oil pump
shaft is engaged. Install hold-down clamp and bolt
and snug up bolt.
5. Turn distributor body slightly until points just open
and tighten distributor clamp bolt.
6. Place distributor cap in position and check to see
that rotor lines up with terminal for No. 1 spark
plug.
7. Install cap, check all high tension wire connections
and connect spark plug wires if they have been re-
moved. It is important that the wires be installed in
their location in the supports.
NOTE:
The brackets are numbered to show the
correct installation. Wires must be installed as
indicated to prevent cross firing.
8. Connect vacuum line to distributor and distributor
primary wire to coil terminal.
9. Start engine and set timing as described under Turn-
Up in Section 6.
BREAKERLESS (MAGNETIC PULSE)
DISTRIBUTOR
REMOVAL (CORVETTE)
1.
If vehicle is equipped with radio, remove three bolts
securing ignition shield over distributor and coil.
One bolt is accessible from the top of shield, the
other two are at rear of shield, facing firewall.
2.
Disconnect tachometer drive cables from distributor
housing.
3.
Disconnect pickup coil leads at connector.
4.
Remove distributor cap.
5. Crank engine so rotor is in position to fire No. 1
cylinder and timing mark on harmonic balancer is
indexed with pointer.
6. Remove vacuum line from distributor.
7. Remove distributor clamping screw and hold-down
clamp.
8. Remove distributor and distributor-to-block gasket.
It will be noted that the rotor will rotate as the
distributor is pulled out of the block. Mark the re-
lationship of the rotor and the distributor housing
after removal so that the rotor can be set in the
same position when the distributor is being installed.
DISASSEMBLY (Fig. 16i)
NOTE:
If a distributor is being disassembled
for replacement of the stationary magnetic
pickup assembly only, it will be necessary to
perform only Steps 3, 4, 5, 7, 8, 9, and 12 of the
service procedure listed below.
1.
Remove screws securing rotor and remove rotor.
2.
Remove centrifugal weight springs and weights.
3.
Remove the tachometer drive gear from the distribu-
tor (Corvette only).
4.
Remove roll pin, then remove distributor drive gear
and washer.
CAUTION: To prevent
magnet, support drive gear
;e to the permanent
?n
driving out roll
pin.
5. Remove drive shaft assembly.
6. Remove centrifugal weight support and timer core
from drive shaft.
7. Remove connector from pickup coil leads.
8. Remove retaining ring which secures magnetic
core support plate to distributor shaft bushing in
housing.
9. As a unit, remove the entire magnetic pickup assem-
bly from the distributor housing.
10.
Remove brass washer and felt pad.
11.
Remove vacuum advance unit.
12.
To reassemble distributor, perform the above steps
in reverse order.
INSTALLATION (CORVETTE)
1.
Check to see that the engine is at firing position for
No.
1 cylinder (timing mark on harmonic balancer
indexed with pointer).
2.
Position a new distributor-to-block gasket on the
block.
3.
Before installing distributor, index rotor with hous-
ing as noted when distributor was removed. Install
distributor in block so that vacuum diaphragm faces
approximately 45° forward on the right side of the
engine and the rotor points toward contact in cap for
No.
1 cylinder.
4.
Replace distributor clamp leaving screw loose
enough to allow distributor to be turned for timing
adjustment.
5. Install spark plug wires in distributor cap. Place
wire for No. 1 cylinder in tower (marked on old cap
during disassembly) then install remaining wires
clockwise around the cap according to the firing
order (1-8-4-3-6-5-7-2).
6. Attach distributor to coil primary wires.
7. Replace distributor cap.
8. Adjust timing and then fully tighten distributor clamp
screw.
9. Attach vacuum line to distributor.
10.
Connect tachometer drive cables to distributor body.
11.
Replace ignition shields.
DISTRIBUTOR OFF-ENGINE TEST
The distributor's centrifugal and vacuum advance can
be checked in a distributor testing machine or synchro-
scope specially adapted or designed to accommodate this
type distributor. However, since this involves removing
the distributor from the engine, this test may be post-
poned until other system checks have been made. A dwell
reading cannot be obtained on this distributor and it is not
likely that the centrifugal or vacuum advance will be a
cause of trouble.
COIL REPLACEMENT
1.
Disconnect ignition switch and distributor leads from
CHEVROLET CHASSIS SERVICE MANUAL