Chevrolet 10 Series 1968, Service Manual

Page: 446 / 713

E NG IN E -E LE C TR IC A L 6Y-21
Governor
Since governing speed is a function of both the dis­
tributor spinner and the carburetor actuator, the only
positive method of accurately setting speed is to adjust
the spinnder on the vehicle. For extremely accurate full
throttle governing, road testing is necessary; however,
for practical purposes it can be assumed full throttle
governed speed will be about 200 rpm below no-load
governed speed. The adjustment can be made by “ rev­
ving” up the engine against the governor with the trans­
mission in neutral.
The spinner mechanism can be adjusted by holding
the slotted end of the valve with a screw driver (fig. 3i)
and turning the adjusting nut on the other end. Increase
the governing speed by turning the adjusting nut
clockwise, decrease the speed by turning the nut
counter-clockwise.
The governing system will operate satisfactorily for
long periods if:
1. Th e vacu u m p a s s a g e s a re kept fre e fro m d irt.
2. The governor air cleaner should be cleaned often
enough to prevent restrictions to the supply of clean
air necessary in operating the governing system.
3. Maintain tight cover bands or plugs on the dis­
tributor “ spinner” compartment. Since a partial
vacuum exists in this chamber, dirt could be drawn
F ig . 3 i—A djusting Spinner Governor
thru a leaking cover band and upset the operation of
the spinner valve.
SERVICE OPERATIONS
DISTRIBUTOR CONTACT POINTS
6
. Place new contact point assembly in position on
breaker plate, install attaching screw.
Cleaning
Dirty contact points should be dressed with a few
strokes of a clean, fine-cut contact file. The file should
not be used for other metals and should not be allowed to
become greasy or dirty. Never use emery cloth to clean
contact points. Contact surfaces, after considerable use,
may not appear bright and smooth, but this is not neces­
sarily an indication that they are not functioning satis­
factorily. Do not attempt to remove all roughness nor
dress the point surfaces down smooth; merely remove
scale or dirt.
Badly burned or pitted contact points should be re­
placed and the cause of trouble determined so it can be
eliminated. High resistance or loose connections in the
condenser circuit, oil or foreign materials on the contact
surfaces, improper point adjustment or high voltages may
cause oxidized contact points. Check for these conditions
where burned contacts are experienced. An out-of­
balance condition in the ignition system, often the result
of too much or too little condenser capacity, is indicated
where point pitting is encountered.
Replacement
Four and Six Cylinder Engine Distributor
1. Release distributor cap hold-down screws, remove
cap and place it out of work area.
2. Remove rotor.
3. Pull primary and condenser lead wires from contact
point quick disconnect terminal (fig. 4i).
4. Remove contact set attaching screw, lift contact
point set from breaker plate.
5. Clean breaker plate of oil smudge and dirt. F ig . 4 i—Breaker Plate and A ttaching Parts
CAM LUBRICATOR
CONTACT SET
ATTACHING
SCREW
QUICK
DISCONNECT
TERMINAL
BREAKER PLATE
ATTACHING SCREWS
CHEVROLET TRUCK SERVICE MANUAL