TM 5-3895-346-14
ENGINE OVERHAUL
RUN-IN INSTRUCTIONS
Check the normal air intake vacuum at various speeds (at no-load) and compare the results with the Engine
Operating Conditions Specifications. Record these readings on the Engine Test Report.
Check the exhaust back pressure (except turbocharged engines) at the exhaust manifold companion flange or
within one inch of this location. This check should be made with a mercury manometer through a tube adapter
installed at the tapped hole. If the exhaust manifold does not provide a 1/8 inch pipe-tapped hole, such a hole
can be incorporated by reworking the exhaust manifold. Install a fitting for a pressure gage or manometer in
this hole. Care should be exercised so that the fitting does not protrude into the stack. On turbocharged
engines, check the exhaust back pressure in the exhaust piping 6 to 12 inches from the turbine outlet. The
tapped hole must be in a comparatively straight area for an accurate measurement. The manometer check
should produce a reading in inches that is below the Maximum Exhaust Back Pressure for the engine (refer to
Engine Operating Conditions Specifications).
Turbocharger compressor outlet pressure and turbine inlet pressures are taken at full-load and no-load speeds.
Refer to the Engine Run-In Schedule and determine the maximum rated brake horsepower and the full-load
speed to be used during the final run-in. Apply the load thus determined to the dynamometer. If a hydraulic
governor is used, the droop may be adjusted at this time by following the prescribed procedure. The engine
should be run at this speed and load for 1/2 hour. While making the final run-in, the engine should develop,
within 5%, the maximum-rated brake horsepower indicated for the speed at which it is operating. If this brake
horsepower is not developed, the cause should be determined and corrections made.
When the above conditions have been met, adjust the maximum no-load speed to conform with that specified
for the particular engine. This speed may be either higher or lower than the maximum speed used during the
basic run-in. This will ordinarily require a governor adjustment.
All information required in Section E, Final Run-In, of the Engine Test Report should be determined and filled
in. After the prescribed time for the final run-in has elapsed, remove the load from the dynamometer and
reduce the engine speed gradually to idle speed and then stop the engine. The final run-in is complete.
F. INSPECTION AFTER FINAL RUN-IN
After the final run-in and before the Engine Test Report is completed, a final inspection must be made. This
inspection will provide final assurance that the engine is in proper working order. During this inspection, the
engine is also made ready for any brief delay in delivery or installation which may occur. This is accomplished
by rustproofing the fuel system as outlined in Storage and adding a rust inhibitor into the cooling system (refer
to Coolant Specifications). The lubricating oil filters should also be changed.
CAUTION
A rust inhibitor in the coolant system of a Series 53 engine is particularly important
because of the wet cylinder liners. Omission of a rust inhibitor will cause rusting of
the outside diameter of the cylinder liners and interference with liner heat transfer.
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