14 Engine Tune-Up
DETROIT DIESEL 53
EXAUST VALUE CLEARENCE ADJUSTMENT
Normally, when performing a tune-up on an engine in service, it is only necessary to check the various adjustments for a
possible change in the settings. However, if the cylinder head, governor, or injectors have been replaced or overhauled,
then certain preliminary adjustments are required before the engine is started.
The preliminary adjustments consist of the first four items in the tune-up sequence. The procedures are the same except
that the valve clearance is greater for a 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 between adjustments to maintain normal operating
temperature.
Tune-Up Sequence for Mechanical Governor
1 Adjust the exhaust valve clearance.
2. Time the fuel injectors.
3. Adjust the governor gap.
4. Position the injector rack control levers.
5. Adjust the maximum no-load speed.
6. Adjust the idle speed.
7. Adjust the buffer screw.
NOTE: Use new valve rocker cover gasket(s) after each tune-up.
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