Chevrolet 10 Series 1968, Service Manual

Page: 456 / 713

ENGINE-ELECTRICAL 6Y-31
DISTRIBUTOR
HOUSING
STATIONARY
POLE PIECE
DRIVE
GEAR
ROTOR
ROTATING
POLE PIECE
MAGNETIC
PICKUP
ASSEMBLY
CENTRIFUGAL
ADVANCE
Fig. 23i — M agnetic Pulse Distributor Components
7. Remove connector from pick-up coil leads.
8 . Remove retaining ring which secures magnetic core
support plate to distributor shaft bushing in housing.
9. As a unit, remove the entire magnetic pick-up
assembly from the distributor housing.
10. Remove brass washer and felt pad.
NOTE: Before removing plastic seal, refer to
previous instructions provided in this article.
11. If necessary to replace the mainshaft seals refer to
the procedures previously described.
12. To reassemble distributor, perform the above steps
in reverse order.
Installation
1. Check to see that the engine is at firing position for
No. 1 cylinder (timing mark on harmonic balancer
indexed with pointer).
2. Position a new distributor-to-block gasket on the
block.
3. Before installing distributor, index rotor with hous­
ing as noted when distributor was removed.
4. Replace distributor clamp leaving screw loose
enough to allow distributor to be turned for timing
adjustment.
5. Install spark plug wires in distributor cap. Place
wire for No. 1 cylinder in tower (marked on old cap
during disassembly) then install remaining wires
clockwise around the cap according to the firing
order (1-8-4-3-6-5-7-2).
6
. Attach distributor to coil primary wires.
7. Replace distributor cap.
8 . Attach governor vacuum and air intake lines to
distributor.
9. Adjust timing and then fully tighten distributor clamp
screw.
IGNITION PULSE AMPLIFIER
Disassembly
To check the amplifier for defective components, pro­
ceed as follows:
1. Remove the bottom plate and gasket from the
amplifier.
2. To aid in reassembly, note the locations of the lead
connections to the panel board.
3. Remove the three panel board attaching screw, and
lift the assembly from the housing.
4. To aid in reassembly, note any identifying markings
on the two transistors and their respective locations
on the panel board and heat sink assembly.
5. Note the insulators between the transistors and the
heat sink, and the insulators separating the heat sink
from the panel board.
6 . Remove the transistor attaching screws, and sepa­
rate the two transistors and heat sink from the panel
board.
7. Carefully examine the panel board for evidence of
damage.
Component Checks (Figs. 24i and 25i)
With the two transistors separated from the assembly,
an ohmmeter may be used to check the transistors and
components on the panel board for defects. An ohmmeter
CHEVROLET TRUCK SERVICE MANUAL