Chevrolet 70 Series 1970, Service Manual

Page: 381 / 841

GASOLINE ENGINES 6A-10
k *
1 End Bracket
2 Adjusting Screw
3 Push Rod
4 Rocker Arm Shaft Bracket
5 Intake Manifold
6 Rocker Arm Shaft
7 Spring
8 Bracket Bolt
9 Flat W asher
10 Exhaust Manifold
11 Exhaust Manifold Bolt Lock
12 Rocker Arm
13 Special Bolt
TPM-9875
Figure 7 —Valve Rocker Arms and Shaft Assembly Installed on V6 Engine
VALVE ROCKER ARM COVER
REPLACEMENT
REMOVAL
R em ove valve rock er arm cover sc r e w s , then
rem ove rocker arm co v er . On tilt cab m od els, it
w ill be n e c e ssa r y to rem ove tra n sm issio n shift
rod s in order to rem ove co v er from left-h an d
cylin d er head.
NOTE: If cover is stuck in p la c e, lo o sen by
strik in g with palm of hand or a rubber m allet. Do
not pry on cover flange sin c e the flange m ay be
d istorted .
INSTALLATION
U sing new rock er arm cover gask et, in sta ll
rock er arm cover and tighten cover sc r e w s uni­
form ly.
ROCKER ARM AND SHAFT
ASSEMBLY REPLACEMENT
REMOVAL
1. R em ove rock er arm co v ers, r eferrin g to
in stru ctio n s p reviou sly given.
2. L oosen rock er arm shaft bracket bolts
gradually until sp rin g p r e ssu r e is fully reliev ed
at rock er a rm s. L ift off the rock er arm shaft and
b rack ets, with attaching b olts, a s an a ssem b ly .
3. Rem ove push rods and identify in som e
manner so they can be returned to origin al p o s i­
tion at a ssem b ly .
INSTALLATION
1. P la c e push rods in origin al p o sitio n s, then
place rock er arm shaft and bracket a ssem b ly
(fig. 7) on cylin d er head, being carefu l to engage
rock er arm sc r e w s with so ck ets in push rods.
Tighten bracket b olts to 25 foot-pounds torque.
2. Check clea ra n ce between rock er arm end
brack ets and adjacent rocker arm . If a clea ra n ce
of approxim ately 0.030 inch does not e x ist, loosen
end bracket bolts and relo ca te brackets a s allow ed
by clea ra n ce in bracket h ole, then tighten b olts to
sp ecified torque.
3. Make in itia l adjustm ent to provide c le a r ­
ance of 0.014 inch at intake v a lv e s, and 0.022 inch
at exhaust v a lv es.
4. Lubricate rocker arm s with engine o il.
5. In stall rocker arm co v ers tem porarily
w hile engine is run to w arm up to operating tem p­
eratu re. With engine idling and tem perature at
160 , adjust valve la sh . Set exhaust valve c le a r ­
ance at 0.18 inch. On V6 engines la sh in ta k e valves
to 0.012 inch. A fter valve clea ra n ce adjustment
i s made, in sta ll rocker arm co v er using new
gasket.
CHEVROLET SERIES 70-90 HEAVY DUTY TRUCK SHOP MANUAL