Chevrolet 1977 light duty truck, Руководство по обслуживанию

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4. Remove fuel p u m p push rod as outlined in
Section 6C.
5. C om plete ca m sh a ft removal as follows:
N O T E : Sprocket is a light fit on cam shaft. If
sprocket does not come off easily a light blow on
the lower edge o f the sprocket (with a plastic
mallet) should dislodge the sprocket.
6. Install two 5 /1 6 " x 18 x 4" bolts in cam shaft
bolt holes then remove ca m sh a ft (fig. 6A-45V).
C A U T IO N :^ // cam shaft jou rn a ls are the same
diam eter a n d care m ust be used in removing
cam shaft to avoid dam age to bearings.
Inspection
The c a m sh a ft b earin g jo u rn a ls should be m easured
with a m icrom eter for an out-of-round condition. If the
jo u rn a ls exceed .001" out-of-round, the ca m sh a ft should
be replaced.
The c a m s h a ft should also be checked for alignment.
The best m ethod is by use o f " V " blocks and a dial
indicator (fig. 6A-46V). T he dial indicator will indicate
the exact a m o u n t the cam sh aft is out o f true. If it is out
m ore th an .0015" dial indicator reading, the cam sh aft
should be replaced.
Installation
N O T E : W henever a new cam sh aft is installed coat
c a m s h a ft lobes with " M o ly k o te" or its equivalent.
W h en ev er a new c a m sh a ft is installed, replacement
o f all valve lifters is recom m ended to insure
durability o f the cam sh aft lobes and lifter feet.
1. Lubricate c a m sh a ft jo u rn als with engine oil and
install cam shaft.
2. Install tim ing chain on cam sh aft sprocket. Hold
the sprocket vertically w ith the chain h an g in g down and
align m arks on c am sh aft and cran k sh aft sprockets.
(R e fe r to fig. 6A-47V 6A-48V).
3. Align dowel in c a m sh a ft with dowel hole in
ca m sh a ft sprocket then install sprocket on cam shaft.
4. D raw the cam sh aft sprocket onto cam shaft
using the m o u n tin g bolts. T orque to specifications.
5. Lubricate timing chain with engine oil.
6. Install fuel pu m p push rod as outlined in
Section 6C.
7. Install grille as outlined in Section 6B.
Fig. 6A 47 V --T im in g Sprocket A lign m e n t M arks
8. Install crankcase front cover as previously
outlined.
9. Install valve lifters as previously outlined.
C A M S H A F T BEARINGS
Removal
C am sh aft bearings can be replaced while engine is
disassembled for overhaul or without complete disassem­
bly o f the engine. To replace bearings w ithout complete
disassembly remove the cam shaft an d crankshaft leaving
cylinder heads attached and pistons in place. Before
removing crankshaft, tape threads o f connecting rod
bolts to prevent d am ag e to crankshaft. Fasten connecting
rods against sides o f engine so they will not be in the
way while replacing cam sh aft bearings.
1. W ith cam shaft and crankshaft removed, drive
cam shaft rear plug from cylinder block.
N O TE: This procedure is based on removal o f the
bearings nearest center o f the engine first. W ith
this method a m inim um am ount o f turns are
necessary to remove all bearings.
2. Using Tool J-6098, with nut and thrust washer
installed to end o f threads, index pilot in cam sh aft front
bearing and install puller screw through pilot.
3. Install rem over and installer tool with shoulder
toward bearing, m aking sure a sufficient am o u n t o f
threads are engaged.
4. Using two wrenches, hold puller screw while
turn in g nut. W hen bearing has been pulled from bore,
remove rem over and installer tool and bearing from
puller screw (fig. 6A-49V).