Chevrolet Light - Page 25

when the truck comes in from a run or after the engine has
been run at a fast idle for 30 minutes.
1. Remove rocker arm cover attaching nuts and rocker arm
cover.
2. Lubricate the valve stems with engine oil to insure free
movement of the va l ves in their guides.
3. Check the clearance between the rocker anus and the
valve ste ms with a feeler gauge (fig. 26). The clearance should
be as follows:
Norma l Operation.
Heavy-Duty Operation .
4. When adjustment is
necessary loosen the rocker
arm adjusting screw lock nut
and turn the screw clock-
wise sligh tl y to d ecrease
clearance and counterclock -
wise to increase ' clearance
(fig. 26). Tighten lock nut
and recheck clearance.
5. Adjust remain ing valve
clearances in the same man-
6. Install the rocker arm
cover using a new gasket.
Intak e Valves
.006" to .008"
.010"
Exhaust Valves '
.013" to .015"
.020"
Make sure cover seats properly on gasket and tighten retain-
ing nu ts. Check for oil l eaks.
Carburetor
Description-Do~draft Carburetor. The downdraft carburetor
used on all Chevrolet trucks (except Cab~Over-Engine and
Forward Control mode ls) contributes m~terially to Chevrolet's
economy an d performance. It is comparatively simple in de-
sign and constructio n; therefore, requires very little care or
attention.
A concentric f ue l bowl is used in which the main metering
jet is submerged. Twin floats contro l the fuel level in the
carburetor. A common passage for both the id le and main
metering systems provi d es for a continuous flow from the idle
to the main metering system resulting in continua l s mooth
p erfo rmance.
' 23'