Chevrolet 10 Series 1970, Service Manual

Page: 323 / 671

SECTION 6
ENGINE
CONTENTS OF THIS SECTION
Page
Engine Tune-Up ......................................................... ........................ 6-1 Engine Mechanical ( V
8
) ..................................................................... 6-25
Engine Mechanical (In L i n e ) .............................................................. 6-13 Special T o o l s ......................................................................................... 6-38
ENGINE TUNE-UP
INDEX
Page
General D e s c rip tio n ...................................................................................... 6-1
Mechanical Checks and A d ju s tm e n ts ......................................................... 6-1
Spark Plug R e m o v a l......................................................................... ........ 6-1
Test C om p re s s io n ...................................................................................... 6-1
Service and Install Spark P lu g s ....................................................... ........ 6-2
Service Ignition System .................................................................. ........ 6-2
Service Battery and Battery C a b le s ......................................................... 6-4
Service D elcotron and Regulator ................................................... ........ 6-5
Service B e lt s ...................................................................................... ........ 6-5
Service M anifold Heat V a l v e ............................................................ ........ 6-5
Tighten M a n i f o l d ...................................................................................... 6-5
Service Fuel Lines and Fuel F ilter ..........................................................
6-6
Service C ooling System ...........................................................................
6-6
Check and Adjust A ccelerator L in k a g e .......................................... .........
6-6
Service Crankcase Ven tilation ....................................................... .........
6-6
Service A ir Injection R eactor S y s t e m ............................................ .........6-7
Page
Choke A d ju s tm e n t........................................................................... ..... 6-7
Instrument C h ec k -O u t......................................................................... ......6-7
Instrument H ook-U p ....................................................................... ......6-7
Check and Adjust D w e l l .................................................................. ......6-7
Check D w ell V a r ia t io n .................................................................... ......
6-8
Check and Adjust T i m i n g ................................................................ ......
6-8
Adjust Idle Speed and M ix t u r e ....................................................... ......
6-8
A dd ition a l Checks and A d ju s t m e n t s ................................................ ......6-10
Testing Crankcase V en tila tion V alve ............................................ ......6-10
Cylinder Balance T e s t .............................................................................6-10
B a t t e r y ............................................................................................... ...... 6-10
Ignition ................................................................................................... 6-10
C a r b u r e t o r ........................................................................................ ...... 6-11
Fuel P u m p ........................................................................................ ...... 6-11
C oolin g S y s t e m .................................................................................... ...... 6-11
Cylinder Head Torqu e and V alve Adjustm ent ................................... 6-12
GENERAL DESCRIPTION
The engine tune-up is im portant to the modern auto­
m otive engine with its va stly im proved pow er and p e r ­
form an ce.
The higher com p ression ra tios, im proved
e le c tr ic a l system s and other advances in design, make
today’ s engines m ore sen sitive and have a decided effect
on pow er, p erform an ce and fuel consumption.
It is seldom advisable to attem pt a tune up by c o rrectio n
o f one o r two item s only. T im e w ill norm ally be saved
and m ore lasting resu lts assured i f the technician w ill
fo llo w a defin ite and thorough procedu re o f analysis and
c o rre c tio n o f a ll item s a ffectin g pow er, p erform an ce
and econom y.
Tne tune-up w ill be p erfo rm ed in two parts. The fir s t
part w ill consist o f m echanical checks and adjustments;
the second part w ill consist o f an instrument checkout
that can be p erfo rm ed with any one o f the units o f s e rv ic e
equipment availab le fo r this purpose. A lw ays follow the
instructions p rovided by the m anufacturer o f the p a r ­
ticu lar equipment to be used.
Additional checks and adjustments a re included in the
la tte r part o f this section fo r use as requ ired . Many o f
these operations can be used to isolate and c o r r e c t
trouble located during the tune-up. W here conditions
a re uncovered requ irin g m ajor c o r r e c tiv e action, r e fe r
to the appropriate section o f this manual o r the C hassis
Overhaul Manual fo r detailed s e rv ic e inform ation.
T y p ica l illu stration s and p rocedu res are used except
w here sp e c ific illu stration s o r p rocedu res a re n ecessary
to c la r ify the operation.
Illu stration s showing bench
operations a re used fo r c la rifica tio n s, h ow ever, a ll
operations can be p e rfo rm e d on the veh icle.
MECHANICAL CHECKS AND ADJUSTMENTS
Spark Plug Removal
Rem ove any fo reig n m atter from around spark plugs
by blowing out with com p ressed a ir, then disconnect
w ir e s and rem ove plugs.
Test Compression (Fig. 1)
The com pression check is im portant because an engine
with low o r uneven com p ression cannot be tuned su ccess­
fu lly. It is essen tial that im p ro p er com pression be c o r ­
rected b e fo re proceedin g with the engine tune up.
CHEVROLET TRUCK SERVICE MANUAL