Chevrolet 1977 light duty truck, Service Manual

Page: 466 / 861

removed fro m the cam shaft. This operation requires the
use o f c am sh aft g ear removed J-971.
2. Place the c am sh aft through the gear remover,
place end o f rem over on table o f a press and press shaft
out o f gear (fig. 6A-41).
C A U T IO N :
Thrust p la te m ust he positioned so
that w oodruff key in shaft does not dam age it
when the sh a ft is pressed out o f gear. Also
support the huh o f the gear or the gear will be
seriously damaged.
3. To assemble c am sh aft g ear thrust plate and gear
spacer ring to c a m sh a ft firmly support c am sh aft at back
o f front jo u rn a l in an a rb o r press.
4. Place g ear spacer ring and thrust plate over end
o f shaft, an d install w oodruff key in shaft keyway. Install
c a m sh a ft g ear and press it onto the shaft until it bottoms
against the gear spacer ring. The end clearance o f the
thrust plate should be .001" to .005" (fig. 6A-40).
In s ta lla tio n
Fig. 6A-41 -Removing C am shaft Gear
1. Install the cam shaft and gear assembly in the
engine block, being careful not to d am ag e cam shaft
bearings or camshaft.
2. Turn crankshaft and cam shaft so that the valve
tim ing m arks on the gear teeth will line up (fig. 6A-38).
Push cam shaft into position. Install cam shaft thrust
plate-to-block bolts and torque to specifications.
3. Check cam sh aft and cran k sh aft gear run out
with a dial indicator (fig. 6A-42). The cam shaft gear run
out should not exceed .004" and the cran k sh aft gear run
out should not exceed .003".
4. If gear run out is excessive, the g ear will have to
be removed and any burrs cleaned from the shaft or the
g ear will have to be replaced.
5. Check the backlash between the timing gear
teeth with a dial indicator (fig. 6A-43). The backlash
should be not less th an .004" nor more th an .006".
6. Install fuel pum p.
7. Install crankcase front cover.
8. Install lifters.