Spark Plug Cleaning; Adjusting Spark Plug Gap - Chevrolet 10 1971 Series Chassis Service Manual

ENGINE-ELECTRICAL 6Y-22
2. Carefully inspect the insulator and electrodes of all
spark plugs. Replace any spark plug which has a
cracked or broken insulator. If the insulator is worn
away around the center electrode, or the electrodes
are burned or worn, the spark plug is worn out and
should be discarded. Spark plugs which are in good
condition except for carbon or oxide deposits should
be thoroughly cleaned and adjusted.
3. The spark plug wires are of a special resistance type.
The core is carbon-impregnated linen. This wire is
designed to eliminate radio and television interfer­
ence radiation, but is also superior in resistance to
cross fire. The resistance type wire, however, is
more easily damaged than copper core wire. For
this reason care must be taken that the spark plug
wires are removed by pulling on the spark plug boots
rather than on the wire insulation. Also, when it is
necessary to replace a spark plug boot, the old boot
should be carefully cut from the wire and a small
amount of silicone lubricant used to aid in installing
the new boot. If the wire is stretched, the core may
broken with no evidence of damage on the outer in­
sulation. The terminal may also pull off the wire.
If the core is broken, it will cause missing. In the
case of wire damage, it is necessary to replace the
complete wire assembly as a satisfactory repair
cannot be made.
4. Wipe ignition wires and cloth moistened with kerosene,
and wipe dry. Carefully bend wires to check for
brittle, cracked, or loose insulation. Defective insula­
tion will permit missing or cross-firing of engine,
therefore defective wires should be replaced.
5. If the wires are in good condition, clean any terminals
that are corroded and replace any terminals that are
broken or distorted. Replace any borken or deterio­
rated cable nipples or spark plug boots.

Spark Plug Cleaning

Spark plugs which have carbon or oxide deposits should
be cleaned in a blast type spark plug cleaner. Scraping
with a pointed tool will not properly remove the deposits
and may damage the insulator. If spark plugs have a wet
or oily deposit dip them in a degreasing solvent and then
dry thoroughly with dry compressed air. Oily plugs will
cause the cleaning compound to pack in the shell. Care­
fully follow the instructions of the manufacturer of the
Fig. 11 i-A d va n ce Weights Installed (V -8)
Fig. 12 i—Six Cylinder Engine Distributor Installed
cleaner being used, cleaning each plug until the interior
of the shell and the entire insulator are clean; however,
avoid excessive blasting.
Examine interior of plug in good light. Remove any
cleaning compound with compressed air.
carbon oxide remain in plug, finish the cleaning with a
light blasting operation. Clean firing surfaces of center
and side electrodes with several strokes of a fine file.
Vhen spark plugs have been thoroughly cleaned, care­
fully inspect for cracks or other defects which may not
have been visible before cleaning.

Adjusting Spark Plug Gap

Use round wire feeler gages to check the gap between
spark plug electrodes of used plugs (fig. 13i). Flat feeler
Fig. 13i-Setting Spark Plug G ap
If traces of
10-30 CHEVROLET TRUCK SERVICE MANUAL