DETROIT DIESEL
ENGINE TUNE-UP PROCEDURES
between adjustments to maintain normal operating
There is no scheduled interval for performing an engine
temperature.
tune-up.
As long as the engine performance is
satisfactory, no tune-up should be needed. Minor
adjustments in the valve and injector operating
Tune-Up Sequence for Mechanical Governor
mechanisms, governor, etc. should only be required
periodically to compensate for normal wear on parts.
1.
Adjust the exhaust valve clearance.
2.
Time the fuel injectors.
Three types of governors are used.
Since each
3.
Adjust the governor gap.
governor has different characteristics, .the tune-up
4.
Position the injector rack control levers.
procedure varies accordingly. The three types are:
5.
Adjust the maximum no-load speed.
6.
Adjust the idle speed.
1.
Limiting speed mechanical.
7.
Adjust the buffer screw.
8.
Adjust the throttle booster spring (variable
2.
Variable speed mechanical.
speed governor only).
9.
Adjust the supplementary governing device (if
3.
Hydraulic.
used).
The mechanical engine governors are identified by a
Tune-Up Sequence for Hydraulic Governor
name plate attached to the governor housing. The
letters D.W.-L.S. stamped on the name plate denote a
1.
Adjust the exhaust valve clearance.
double-weight limiting speed governor. A single-weight
variable speed governor name plate is stamped S.W.-
2.
Time the fuel injectors.
V.S.
3.
Adjust the fuel rod.
Normally, when performing a tune-up on an engine in
service, it is only necessary to check the various
4.
Position the injector rack control levers.
adjustments for a possible change in the settings.
However, if the cylinder head, governor or injectors
5.
Adjust the load limit screw.
have been replaced or overhauled, then certain
preliminary adjustments are required before the engine
6.
Adjust the speed droop.
is started.
7.
Adjust the maximum no-load speed.
The preliminary adjustments consist of the first four
items in the tune-up sequence. The procedures are the
NOTE:
Use
new
valve
rocker
cover
same except that the valve clearance is greater for a
gasket(s)after each tune-up.
cold engine.
To tune-up an engine completely, all of the adjustments
are made by following the applicable tune-up sequence
given below after the engine has reached the normal
operating temperature.
Since the adjustments are
normally made while the engine is stopped, it may be
necessary to run the engine
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