GMC 4000 Series Service Manual page 278

10. Disconnect cooling system and heater
hoses.
11. Disconnect propeller shaft from trans­
m ission.
12. If air com pressor is used, disconnect air
lines from com pressor. In some cases the air
com pressor mounting bracket may be detached
from engine and compressor may remain with
chassis when engine is removed.
13. If power steering is used, the power steer­
ing pump may be detached from engine and lines
may remain connected to prevent fluid loss when
removing engine.
14. Attach overhead hoist securely to engine
sling, then raise power plant slightly to remove
weight from engine mountings. Remove mounting
bolts from front and rear mountings, then raise
power plant and remove from chassis.
15. Refer to applicable procedures in TRANS­
MISSIONS AND CLUTCHES (SEC. 7) for instruc­
tions, and remove transm ission and clutch from
engine.
9n-V ehicle Sesiuioe Op&uUionl
IN-LINE ENGINE IN-VEHICLE SERVICE OPERATIONS
MANIFOLD REPLACEMENT
REMOVAL
1. Remove air cleaner.
2. Disconnect both throttle rods at bellcrank
and remove throttle return spring.
3. Disconnect fuel and vacuum lines and choke
cable at carburetor.
4. Disconnect crankcase ventilation hose at
rocker arm cover.
5. Disconnect exhaust pipe at manifold flange
and discard packing.
6. On engines with sheet metal heat stove, re­
move the attaching screw s, and remove stove parts
(fig. 18) from exhaust manifold.
7. Remove manifold attaching bolts and clamps
then remove manifold assembly and discard gaskets.
8. Check for cracks in manifold castings.
9. If necessary to replace either the intake or
exhaust manifold, separate them by removing one
bolt and two nuts at center of assembly. Reassem ­
ble manifolds using a new gasket. Tighten finger-
tight and torque to "Specifications" after assembly
to cylinder head. Transfer all necessary parts.
INSTALLATION
1. Clean gasket surfaces on cylinder head and
manifolds. On engines with heat stove, assemble
stove bracket at manifold attaching parts.
2. Position new gasket over manifold end
G M C S E R V I C E M A N U A L
INSTALLATION
to engine referring to applicable instructions in
TRANSMISSIONS AND CLUTCHES (SEC. 7) in this
manual.
moval" procedure taking necessary precautions
to maintain cleanliness and to avoid damage to the
engine components.
control linkage, fill cooling system and check for
leaks.
grade and viscosity. Refer to LUBRICATION (SEC.
0) in this manual.
set ignition timing and adjust valve lash.
the foregoing adjustments will have been made
previously and need not be repeated.
studs on head and carefully install the manifold in
position making sure the gaskets are in place.
fold in place with hand.
new packing.
er arm cover.
GASOLINE ENGINES
Assem ble clutch components andtransmission
Install power plant by reversing order of "Re­
After engine is installed, check operation of
Fill crankcase with engine oil of recommended
Start engine, make adjustments at carburetor,
NOTE: If engine has been run in on test stand,
3. Install bolts and clamps while holding mani­
4. Torque bolts to specifications.
NOTE: Center bolt and end bolt torque differ.
5. Connect exhaust pipe to manifold using a
6. Connect crankcase ventilation hose at rock­
7. Connect fuel and vacuum lines at carburetor.
Figure 18— M a n ifo ld Heat Stove
Installation (In-Line Engine)
Sec. 6A
Page 267