Chevrolet 70 1969 Series, Shop Manual

Page: 678 / 913

EN G IN E 6-7
REPAIR AND ASSEMBLY OF ENGINE COMPONENTS
This section includes procedures necessary to clean, in­
spect, repair, and assemble the various parts and su­
bassemblies which were removed as previously explained
under “ Disassembly of Engine” . Procedures are in logical
sequence of assembly.
Reference should be made to “ Specifications” at end of
group for various fits and tolerances.
Information regarding sources and availability of spe­
cial tools mentioned in the text will be found in S P E ­
C IA L T O O L S section at end of this manual. Sam e pro­
cedure applies to all engines unless otherwise indicated.
CYLINDER BLOCK C L E A N IN G
This paragraph covers cleaning, inspection, and repair
of cylinder block, and inspection and replacement of c a m ­
shaft bearings.
Use suitable cleaner to remove all deposits from inside
and outside of crankcase and cylinder block. Remove
plugs and fittings from oil passages, then clean passages
thoroughly using suitable wire brush or prod. Use co m ­
pressed air to clean oil and water passages after loosening
deposits with brush. M ake sure oil passages from main oil
gallery to crankshaft bearings and passages between
crankshaft bearings and cam shaft bearings are clean and
unobstructed. Clean the oil drain holes which return to
crankcase the oil which lubricates overhead valve m echa­
nism and camshaft.
IN SP EC TIO N A N D REPAIR
OF CYLIN D ER BLOCK
CYLINDER BORE RECONDITIONING
Examine cylinder bores for scoring. Use dial indicator
Figure 8 — C h e c k in g C y lin d e r Bore w ith M ic ro m e te r to D eterm ine Extent
o f T ap e r a n d O u t o f R ou n d
(fig. 8) to check cylinder bores for taper and out-of-round
condition. If cylinder bores are worn, scored, tapered or
out-of-round in excess of specified limits, block should be
rebored to accom m odate larger size pistons. Finished pis­
tons are available for service in standard selective sizes
shown in “ Specifications” at end of this section, and in
0.020 - and 0.040 - inch oversizcs. To determine dim en­
sions to which cylinders should be rebored, add am ou nt of
oversize to standard cylinder bore dimensions. Use con­
ventional equipment for reboring cylinders. After boring,
finish cylinders with 350 grit hone, then wash with hot
soapy water, and a stiff scrub brush.
Additional details on how to fit pistons are given later
under the heading “ Fitting New Pistons.” Refer to
“ Specifications” at end of this group for standard dim en­
sions of cylinder bore and pistons.
LIFTER BORES
Examine lifter bores for scoring and wear. Bores must
F igu re 9 — C r a n k s h a ft No. 3 B e a r in g C a p D o w e l Pins (T ypical)
J-2 1 099-12
Figure 10 — Tool Set (J -2 1 0 9 9 -1 5 ) for R e p la c in g C a m s h a f t B e a r in g s
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SH O P M A N U A L