Chevrolet 70 1969 Series, Shop Manual

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SECTION 6A
GASOLINE ENGINES
Contents of this section are listed in index below:
Subject Page No.
General Information ......................................................................6A-1
Engine Maintenance and Tune-up ................................................6A-1
Tune-up, Checks, and Adjustments ......................................... ...6A-2
Engine Replacement ......................................................................6A-6
In-Vehicle Service O p e r a t io n s ................................................... ...6A-7
Trouble Diagnosis C h a r t ............................................................ ...6A-17
GENERAL INFORMATION
To assure maximum engine performance, the
engine must be properly tuned at regular intervals.
Frequency of tune-up is largely dependent upon
the type of service in which the vehicle is used.
In addition to the regular engine tune-up, the
other units and systems which relate to engine per-
GASOLINE ENGINE.
T R U C K SERIES
H M 8 0 ................................
J M 8 0 ................................
T M 8 0 ................................
formance must be serviced periodically as part of
the engine maintenance program.
This section of manual provides instructions
for servicing the various items and tuning the en­
gine. Unless otherwise stated, the procedures are
applicable to all gasoline engines used in vehicles
covered by this manual. To adequately accomplish
a satisfactory tune-up, reliable test equipment in
the hands of trained personnel is necessary.
APPLICATION CHART
EN G IN E
STD. O P T .
401M 478M
401M 478M
401M 478M
ENGINE MAINTENANCE AND TUNE-UP
ENGINE MAINTENANCE
SERVICING AIR C L E A N E R S
Carburetor air cleaners on all vehicles are
oil bath type. For location of air cleaners, rec­
ommended service intervals, and servicing pro­
cedures, refer to LUBR ICATION (SEC. 0) in this
manual.
C H E C K IN G A N D M AINTAINING
C R A N K C A S E OIL L E V E L
Daily, or oftener if necessary, check oil level.
Check when at operating temperature, and after
engine has been stopped for at least five minutes.
Remove dipstick, wipe clean, reinsert and remove
again. The upper mark on dipstick (fig. 1) is
" F U L L ," the lower " A D D " or "A D D O I L ." Keep
level as close as possible to " F U L L " markwithout
over-filling. Do not operate with level below " A D D "
or "A D D O I L " mark. Dipstick is at the right side
of engine. Add oil through filler cap opening in
CHEVROLET SERIES 70-80 HEAVY DUTY TRUCK SHOP M ANUAL