Chevrolet 10 Series 1970, Service Manual

Page: 427 / 671

ENGINE-ELECTRICAL 6Y-35
BUSHING
.....■»««...»..J
CONTACT
FINGER
SOLENOID
PLUNGER
BRUSH
RETURN SPRING
SHIFT
LEVER
GROMMET
SPIRAL
SPLINES
BUSHING
INSULATED BRUSH HOLDER \ FIELD COIL
BRUSH SPRING ARMATURE
GROUNDED BRUSH HOLDER
PINION
STOP
OVERRUNNING
ASSIST CLUTCH
SPRING
F ig . Is —S ta rtin g M o to r Cross S e c tio n — L ig h t D uty
plunger m echanism , protectin g them fro m d irt, splash,
and icing. The flange mounted solenoid switch operates
the overrunning clutch d riv e by means o f a linkage to the
shift le v e r .
V aria tion s o f the enclosed shift le v e r type starting
m otor a re used in the C h evrolet Tru ck P ro g ra m s . G as­
oline pow ered engines use the conventional starting
m otor o f eith er the flange o r pad mounted (fig s . 2s and
3s) type housing. D iesel pow ered truck engines use a
flange mounted starting m otor but a much h ea vier duty
design (fig. 3s). Specific mention is made w here d iffe r ­
ences in s e rv ic e p rocedu res between the two types of
m otors occur.
MAINTENANCE AND ADJUSTMENTS
LUBRICATION
The gasoline engine type starting m otors have graphite
and o il im pregnated b ron ze b earin gs and th erefo re r e ­
q u ire no p erio d ic lu brication between m ajor overhauls.
The V -6 D iesel engine type m otors have pipe plug o ile r s
and should have 8-10 drops o f ligh t engine o il ev e ry
5000 m ile s o r e v e ry 300 hours o f operation.
RESISTANCE CHECKS
Although the starting m otor cannot be checked against
sp ecification s on the car, a check can be made fo r ex ­
ce s s iv e resista n ce in the starting circu it. P la c e a v o lt­
m eter a c ro s s points in the cranking circu it as outlined
below and o b serve the reading with the starting switch
closed and the m otor cranking (distribu tor p rim a ry lead
grounded to preven t engine firin g ).
1. F rom battery p o sitive post to solenoid battery
term in al.
2. F ro m battery negative post to starting m otor
housing.
3. From solenoid b attery term in al to solenoid m otor
term in al.
If voltage drop is any of above, check exceeds 0.2 volts,
ex c e s s iv e resistan ce is indicated in that portion o f s ta rt­
ing circu it and the cause o f the e x c e s s iv e resistan ce
could be located and c o rrected in o rd e r to obtain m a xi­
mum e fficien cy in the circu it.
CAUTION:
Do not operate the starting m otor
continuously fo r m ore than 30 seconds to avoid
overheating.
When the solenoid fa ils to pull in, the trouble may be
due to e x c essive voltage drop in the solenoid control
circu it. T o check fo r this condition, close the starting
sw itch and m easure the voltage drop between the B A T ­
T E R Y term in al o f the solenoid and the SW ITCH (S)
term in a l o f the solenoid.
1. If this voltage drop exceeds 3.5 volts, excessive r e ­
sistance in the solenoid control circu it is indicated
and should be co rre c te d .
CHEVROLET TRUCK SERVICE MANUAL