Chevrolet Light Duty Truck 1973 Service Manual page 370

6 -3 4 ENGINE
crankshaft slowly, or attach an auxiliary starter
switch and "bump" the engine over, until the push
rod is in the fully raised position.
Whenever the engine i s cranked
CAUTIO N:
remotely at the s t a r t e r , with a special jumper
cable or other means, the distributor primary
lead must be disconnected from the negative
post on the c o i l .
5. Compare the total lift recorded from the dial
indicator with specifications.
. Continue to rotate the crankshaft until the indicator
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reads zero. This will be a check on the accuracy of
the original indicator reading.
7. If camshaft readings for all lobes are within
specifications, remove dial indicator assembly.
. Install and adjust valve mechanism as outlined.
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Removal
1. Remove valve lifters as outlined.
2. Remove crankcase front cover as outlined.
3. Remove grille as outlined in Section 13.
4. Remove fuel pump as outlined in Section
5. Align timing gear marks then remove the two
camshaft thrust plates screws by working through
holes in the camshaft gear (fig. 25L).
. Remove the camshaft and gear assembly by pulling
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it out through the front of the block.
NOTE: Support camshaft carefully when
removing so as not to damage camshaft
bearings.
Fig. 26L—Checking Camshaft Gear Runout
Fig. 27L—Checking Timing Gear Backlash
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Installation
1. Install the camshaft and gear assembly in the
engine block, being careful not to damage camshaft
bearings or camshaft.
2. Turn crankshaft and camshaft so that the valve
timing marks on the gear teeth will line up (fig.
25L). Push camshaft into position. Install camshaft
thrust plate to block screws and torque to
specifications.
3. Check camshaft and crankshaft gear runout with a
dial indicator (fig. 26L). The camshaft gear run out
should not exceed .004" and the crankshaft gear
run out should not exceed .003".
4. If gear run out is excessive, the gear will have to be
removed and any burrs cleaned from the shaft or
the gear will have to be replaced.
5. Check the backlash between the timing gear teeth
with a dial indicator (fig. 27L). The backlash should
be not less than .004" nor more than .006".
. Install fuel pump as outlined in Section
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7. Install grille as outlined in Section 13.
Fig. 28L—Removing Crankshaft Gear
LIGHT DUTY TRUCK SERVICE MANUAL
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