GMC 4000 Series Service Manual page 309

Sec. 6B
Page 298
TORO-FLOW DIESEL ENGINE
1 End B racket
2 B racket Bolt and Plain W asher
3 R ock er A rm
CYLINDER HEAD REPLACEMENT
Unless otherwise stated in text, the replace­
ment procedure which follows applies to replacing
either the right-hand or left-hand cylinder head.
REMOVAL
1. Drain cooling system .
2. On tilt cab models, control island must be
removed to provide access to injection pump lines,
outlet manifold and head bolts. Disconnect and re­
move air intake system . If right-hand head is to be
removed, remove air cleaner assembly, disconnect
fuel supply line, and remove fuel secondary filter.
3. Remove rocker arm cover, and rocker arm
and shaft assem bly. Remove push rods and tag each
one so rods may be installed in original position.
4. Disconnect exhaust, pipe from manifold.
5. Remove clamps from fuel high pressure
lines, then loosen nuts attaching fuel lines to hy­
draulic head and fuel injection nozzles. Disconnect
and remove fuel high pressure lines, using care to
avoid bending lines. Cap all openings in hydraulic
head and nozzles to prevent entrance of dirt.
6. Remove fuel leak-off lines, then remove
injection nozzles from cylinder head. See applic­
able portion of ENGINE FUEL SYSTEM (SEC. 6M)
of this manual for illustrations on arrangement of
Figure 1 0 — Cylinder H e a d Bolt Tightening Sequence
G M C S E R V I C E M A N U A L
4 Spacer
5 Spring
R ock er A rm Shaft Bracket
6
Figure 9 — Rocker Arms, Shaft, and Brackets
fuel system item s.
then remove bolts, manifolds, and gaskets.
of cylinder head, and loosen hose.
inder head off dowel pins and remove from engine.
deposits from cylinder head, pistons, and cylinder
block. Do not scratch or gouge surfaces.
INSTALLATION
ing surface on block and head. Be certain that no
scratches are present on this surface.
9/16-12 bottom tap and remove all cuttings from
holes. When holes are properly cleaned, a 4-inch
head bolt will project not more than 2-31/32-inch
when screwed into any bolt hole.
pitted shank.
locate head gasket on cylinder block.
terference fit and must be pushed onto dowel with
fingers. If any of seals or rings are dislodged re­
position them carefully.
care not to dislocate any of seals.
heads and start bolts into block.
head bolts gradually to 90 foot-pounds torque.
sequence to 130 to 135 foot-pounds.
time % turn and immediately retighten to 130 to
135 foot-pounds. Be sure to retighten each bolt
before loosening next one.
7 A djusting S crew
S p ecia l Bolt
8
9 Shaft
7. Remove manifold attaching clamp bolts,
8. Remove water outlet hose clamps at front
9. Remove cylinder head bolts, then lift cyl­
10. Remove cylinder head gasket. Clean carbon
1. Use fine emery cloth and oil, to polish sea l­
2. Clean all head bolt holes in block with a
3. Discard any head bolts which have heavily
4. Use pilot pins in two head bolt holes and
IMPORTANT: The seal at hollow dowel is in­
5. Lower cylinder head onto engine, using
6. Oil head bolt threads and area under bolt
a. Following sequence in figure 10, tighten all
b. Further tighten all head bolts in proper
c. Beginning at No. 1 bolt loosen one bolt at a
T
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