POWER BRAKE 5-52
NOTE: DO NOT file or lap bearing caps or rods
to take up clearance; always use new bearing
inserts if clearances are excessive.
CRANKSHAFT
C rankshaft journals should not be out-of-round more
than 0.001 inches, ridged or scored. If grinding is neces
sary, do not grind fillets at ends of journals. Connecting
rod bearing inserts are available in 0.010 inches, 0.020
inches, and 0.030 inches undersize for reground crank
shafts. Check main bearing journals for excessive wear.
Dimensions should be such that ball bearing is a press fit
on journal.
CRANKSHAFT BEARING
Exam ine bearing for wear or flat spots by rotating
races. If any roughness is detected bearing should be re
placed with new bearing.
COMPRESSOR REPAIR
DISCHARGE VALVES AND SEATS
1. Rem ove slight scratches and pits from discharge valve
seats. Use lapping stone, grinding com pound, lapping
disc, and valve grinding tool.
2. Place discharge valves on valve seats, install discharge
valve springs in cap nuts, and thread cap nuts firmly
into cylinder head. To test discharge valves for leak
age, connect air line to discharge port in cylinder
head. Apply 100 pounds air pressure to valves and
apply soap suds to discharge valve openings in bottom
of cylinder head. Leakage in excess of a one-inch
bubble in one second is not permissible. If leakage is
excessive, leave air pressure applied. Using a fiber or
a hardw ood dowel and a light ham m er, tap valves off
seats several times. This should improve fit of valve
on seat. Check leakage around top of discharge valve
cap nuts by applying soap suds to this area. N o leak
age is permissible. Shut off air pressure and discon
nect line from cylinder head.
3. Remove discharge valve seats too badly worn for re
facing. T hread new seats into head and tighten firmly.
With new valves, discharge valve travel should be
from 0.056 inches to 0.070 inches for 12 cu.-ft. mod-
ASSEMBLY OF
NOTE: Refer to Figure 15 while assembling air
compressor.
CRANKSHAFT INSTALLATION
BELT-DRIVEN TYPE
1. Install ball bearing on front of crankshaft. Press bear-
T~m
i
P L A S T IG A G E S C A L E
C O N N E C T IN G H
R O D C A P S
Figure 14 — C h e c k in g C le a ra n c e U s in g P la st ig a g e
els and .036 inches - .058 inches for 7 - 1 / 4 cu.-ft.
models.
INLET VALVES A N D SEATS
1. Remove slight scratches or pits from inlet valve seats.
Use lapping stone, grinding com pound, lapping disc,
and valve grinding tool. R eplace seats that cannot be
repaired. Dimension from the top of the cylinder
block to the inlet valve seat should not exceed 0.145
inches, nor be less than 0.101 inches.
2. Inlet valves not badly worn or dam aged can be re
paired by lapping valves on a piece of crocus cloth
held on a flat surface.
CONNECTING ROD BUSHINGS
If piston pin bushings in connecting rods require re
placement, press old bushings out of connecting rods.
Press new bushings in, m aking sure the oil holes in the
bushings line up with the oil passages in the connecting
rods. Bushings m ust then be ream ed, honed, or bored to
provide 0,0001 inches to 0.0006 inches clearance on piston
pin.
W ipe the bushing, which has been honed, with a clean
cloth to remove all abrasive m aterial.
IMPORTANT
Make sure not to overlook any of the above
"Cleaning, Inspection, and Repair" items be
fore assembling the air compressor.
CO M PRESSO R
ing on crankshaft until inner race is seated firmly
against shoulder on crankshaft.
2. Position thrust washer on the rear end of crankshaft
with oil grooves tow ard shoulder on shaft.
3. Install rear end cover oil seal in groove of end cover.
4. Install rear end cover and bearing assembly against
the crankcase.
5. Install cap screws and washers attaching end cover to
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHO P M A N UA L
Содержание 70 1969 Series
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Страница 11: ...LUBRICATION 0 4 CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SHOP MANUAL...
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Страница 807: ...TRANSMISSION AND CLUTCH 7 61 CHEVROLET SERIES 70 80 HEAVY DUTY TRUCK SHOP M AN U AL Kgure 2 Clark 401 Transmission...
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