Chevrolet 70 1969 Series, Shop Manual

Page: 677 / 913

E N G IN E 6-6
PISTON AND CON NECTING ROD REMOVAL
1. Inspect top of cylinder bore for piston ring travel
ridge. If ridge is present, use ridge reamer to cut out
top of bore to provide smooth surface.
2. Position crankshaft so a pair of connecting rods can
be removed without interference, then remove nuts
from connecting rod cap bolts. Remove rod cap and
bearing lower half, install handle and protector on rod
bolt threads (fig. 5). Use light ham m er to drive on
tool as shown to remove piston. Repeat procedure to
remove each pair of pistons.
3. Install caps on respective rods referring to numbers
stamped on sides of rods and caps (fig. 50).
REMOVING WATER PUMP
N O T E : E n g in e w a t e r p u m p m a y re m ain in
p lace on e n g in e front cover a n d be re m o ve d as
a n a sse m b ly w ith the front cover. H e a v y d u ty
w a t e r p u m p is u sed on all 4 0 1 M e n gin e s. Drive
pulley on h e a v y d u ty w a t e r p u m p is ke ye d to
tap e re d sh a ft a n d retained b y self-lock in g nut
a s s h o w n in Figure 35. A socket a n d extension
m a y be used th ro u gh holes in pulley to rem ove
p u m p m o u n tin g stud nuts.
1. Remove mounting stud nuts and lockwashers.
2. Remove water pum p assembly and gasket from en­
gine front cover.
CRANKSHAFT PULLEY AND ENGINE
FRONT COVER REMOVAL
1. If the fan adapter used on some Tilt C a b Model ve­
hicles has not been removed, remove the bolts which
attach adapter to pulley and remove adapter. Block
crankshaft and remove retaining bolt and washer at
front side of crankshaft pulley.
2. Assemble puller and center plug in manner shown in
Figure 6. Turn puller screw to remove pulley assem­
bly from crankshaft.
3. Remove cap from top of cylinder block, at rear side
of front cover.
4. Remove bolts attaching front cover to cylinder block,
then jar cover loose with lead ham m er and remove
cover and gasket.
TIMING IDLER GEAR AND SHAFT
INSTALLATION (401 M AND 478M ENGINES)
Refer to Figure 39.
1. Bend lock away from idler gear plate bolts, then re­
move bolts, lock, and plate.
2. Remove idler gear assembly from idler gear shaft.
3. Remove three bolts attaching idler gear shaft to cylin­
der block and remove idler gear shaft (fig. 7) which is
tight fit in counterbore in block.
FLYWHEEL AND HOUSING REMOVAL
N O T E : Either of tw o ty p e s o f fly w h e e l h o u sin g s
d e s ig n a t e d a s tw o-p iece, a n d a p ro n type,
for con ve n tio n al tran sm issio n s are used. Re­
m o v a l o f e ach type is covered se p a ra te ly
b e lo w u n d e r respective h e a d in g s.
;i. T w o - P i e c e H o usin g.
Remove flywheel bolts and lock
plates then remove flywheel, then remove housing to cyl­
inder block bolts and washers. Separate housing from
block.
h.
Ap ro n T y p e H ousing.
Through opening in housing re­
move the flywheel to crankshaft bolts and lock plates,
then remove flywheel. Remove the housing to cylinder
block bolts and separate the housing from cylinder block.
(1) To remove adapter plate from cylinder block, re­
move attaching bolts and washers.
N O T E : Plates located a s s h o w n in F igure 4 3 are
attach e d to a d a p t e r plate a n d fly w h e e l h o u s­
in g. A t tim e of rem oval, check to see th a t the
serial n u m b e r on each p late c orrespond s w ith
the e n g in e serial n u m b e r. A t tim e o f m a n u f ­
acture fly w h e e l h o u s in g a n d a d a p t e r plate are
bolted to cylinder block before finish m a c h in in g
is d o n e on h ou sin g , a n d e n g in e serial n u m b e r
is s ta m p e d on a fo re m e n tio n e d plates.
REMOVING CRANKSHAFT AND BEARINGS
1. A t crankshaft rear bearing, remove plugs which seal
rear bolt holes in bearing cap. Use 1/2 - inch 12 point
socket to remove two rear bolts.
2. Remove balance of crankshaft bearing cap bolts, then
remove bearing caps and bearing lower halves. Caps
fit snugly in broached seats. Use main bearing cap re­
mover (J-21675) and slide h a m m er to pull crankshaft
thrust bearing cap straight out of crankcase. This cap
is aligned by two dowel pins.
3. Remove crankshaft from cylinder block, using care to
lift straight away to prevent any binding which could
dam age thrust flanges on thrust bearing.
4. Remove bearing upper halves from block.
5. Lay out bearings and caps so they may be reinstalled
in original positions if inspection shows bearings to be
in good condition.
CAMSHAFT AND TIMING GEAR REMOVAL
1. Remove thrust plate attaching bolts at front end of
camshaft.
N O T E : O n all e n gin e s, the c a m s h a ft tim in g
g e a r a n d fuel p u m p eccentric (fig . 3 9) m a y re­
m a in on c a m sh a ft d u r in g inspection. C r a n k ­
sh a ft g e a r sh o u ld rem ain on cran ksh aft.
2. Pull camshaft forward to remove from cylinder block.
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L