Chevrolet 1980 Light Duty Truck Service Manual page 502

6A 5-14 M AR K IV
Fig. 6A5-1 8-Compressing Valve Spring
tool and remove rotators or spring caps, springs and spring
damper, then remove oil seals and valve spring shims.
3. Remove valves from cylinder head and place them
in a rack in their proper sequence so that they can be
assembled in their original positions.
Cleaning
1. Clean all carbon from combustion chambers and
valve ports using Tool J-8089 (fig. 6A5-19).
2. Thoroughly clean the valve guides using Tool J-
8101 (fig. 6A5-20).
3. Clean all carbon and sludge from push rods, rocker
arms and push rod guides.
4. Clean valve stems and heads on a buffing wheel.
5. Clean carbon deposits from head gasket mating
surface.
Fig. 6 A 5 - 1 9 - C l e a n i n g Combustion Chambers
Inspection
1. Inspect the cylinder head for cracks in the exhaust
ports, combustion chambers, or external cracks to the
coolant chamber.
2. Inspect the valves for burned heads, cracked faces
or damaged stems.
Excessive valve stem to bore clearance will
NOTICE:
cause excessive oil consumption and may cause valve
breakage. Insufficient clearance will result in noisy and
sticky functioning of the valve and disturb engine
smoothness.
3. Measure valve stem clearance (fig. 6A5-21) as
Fig. 6 A 5 - 2 1 - M e a s u r i n g Va lve Stem Cle arances
LIG H T T R U C K S ER V IC E M AN UAL