Chevrolet 70 1969 Series, Shop Manual

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ENGINE ELECTRICAL 6Y-29
Point Opening , ..-
Armature Stop
(Bend if Necessary)
.030 Inch
Feeler G au ge \ Q /
Figure 15— Adjusting Field Relay Air G ap
or equivalent folded over, then pulled back and
forth between contacts.
It is not necessary to remove the cavities en­
tirely. The lower contacts are of softer material;
use a piece of cloth with solvent to remove any
discoloration.
IM P O R T A N T : D O N O T USE A N A B R A S IV E
O N T H E S E POIN TS.
After contacts have been cleaned, they should
be washed with a solvent (non-toxic type) to re­
move any foreign material.
C H E C K IN G A N D A D JU ST IN G
C O N T A C T P O IN T O P E N IN G
With the lower contacts touching, measure the
point opening between the upper contacts as shown
in Figure 13. Point opening should measure 0.014”.
Adjust by bending the upper contact arm as shown.
C H E C K IN G A N D A D JU S T IN G A IR G A P
Measure air gap with a 0.057-inch feeler gauge
between the armature and the core when lower
contacts are just touching as shown in figure 14.
To adjust the air gap, turn the adjustment nut lo­
cated on the contact support.
N O T E : Only an approximate air gap setting
should be made by the feeler gauge method above.
The final setting must be whatever is required to
obtain the specified difference in voltage between
the upper and lower contacts. Instructions for
making final setting are explained previously. See
"Regulator Voltage Test (On Vehicle).”
Figure 16— Adjusting Field Relay Contact Points
FIELD RELAY UNIT CHECK
Four checks are required on the field relay:
(1) Checking and cleaning contact points, (2) Check­
ing and adjusting air gap, (3) Checking and adjust­
ing contact point gap, (4) Checking and adjusting
the closing voltage.
N O T E : Check closing voltage as explained
previously under "Regulator Unit Field Relay Test
on Vehicle."
C H E C K IN G A N D C L E A N IN G
C O N T A C T PO IN T S
If points appear to be pitted or burned, clean
points using a thin cut file.
I M P O R T A N T : Remove only enough material to
clean points. N E V E R use emery cloth or sandpaper
to clean points.
C H E C K IN G A N D A D JU S T IN G AIR G A P
Referring to Figure 15, insert a 0.030 inch
gauge between the armature and core and exert
just enough pressure on the armature to allow it
to touch the gauge. The contact set should just
close at this time. Adjust by bending the flat con­
tact support spring.
C H E C K IN G A N D A D JU S TIN G
C O N T A C T P O IN T G A P
Referring to Figure 16, insert an 0.030 inch
feeler gauge between the contact points with the
armature in its normal rest position.
The point opening can be adjusted by bending
the relay heel iron.
CHEVROLET SERIES 70 -80 H EAVY DUTY TRUCK SH O P M A N U A L