this speed, a stock governor should be installed for the
3. A preliminary valve clearance adjustment must be
made before the engine is started.
After checking the engine performance at idle speed
and being certain the engine and dynamometer are
4. A preliminary injector timing check must be made
operating properly, increase the engine speed to half
before starting the engine. See Fuel Injector Timing on
speed and apply the load indicated on the Basic Engine
5. Preliminary governor adjustments must be made as
The engine should be run at this speed and load for 10
outlined in Chapter 10.
minutes to allow sufficient time for the coolant
temperature to reach the normal operating range.
6. Preliminary injector rack adjustment must be made
Record length of time, speed, brake horsepower,
coolant temperature and lubricating oil pressure on the
Engine Test Report.
B. BASIC ENGINE RUN-IN
The operator should be observant at all times, so that
Run the engine at each speed and rating for the length
any malfunction which may develop will be detected.
of time indicated in the Basic Engine Run-In Schedule.
This is the Basic Run-In. During this time, engine
Since the engine has just been reconditioned, this Run-
performance will improve as new parts begin to "seat
In will be a test of the workmanship of the serviceman
in". Record all of the required data.
who performed the overhaul. Minor difficulties should
be detected and corrected so that a major problem will
C. BASIC RUN-IN INSPECTION
While the engine is undergoing the Basic Run-In, check
each item indicated in Section "C" of the Engine Test
After performing the preliminary steps, be sure all water
Report. Check for fuel oil or water leaks in the rocker
valves, fuel valves, etc. are open. Also inspect the
exhaust system, being sure that it is properly connected
to the engine. Always start the engine with minimum
During the final portion of the Basic Run-In, the engine
should be inspected for fuel oil, lubricating oil and water
After the engine starts, if using a water brake type
dynamometer, allow sufficient water, by means of the
Upon completion of the Basic Run-In and Inspection,
control loading valves, into the dynamometer absorption
remove the load from the dynamometer and reduce the
unit to show a reading of approximately 5 Ib-ft on the
engine speed gradually to idle and then stop the engine.
is necessary, on some units, to lubricate the absorption
unit seals and to protect them from damage.
D. INSPECTION AFTER BASIC RUN-IN
The primary purpose of this inspection is to provide a
fine engine tune-up. First, tighten the cylinder head and
Set the engine throttle at idle speed, check the
rocker arm shaft bolts to the proper torque. Next,
lubricating oil pressure and check all connections to be
complete the applicable tune-up procedure. Refer to
sure there are no leaks.
Refer to the Engine Test Report sample which
establishes the sequence of events for the test and Run-
E. FINAL RUN-IN
After all of the tests have been made and the Engine
In, and to the Basic Engine Run-In Schedule which
Test Report is completed through Section "D", the
indicates the speed (rpm), length of time and the brake
engine is ready for final test. This portion of the test and
horsepower required for each phase of the test. Also
Run-In procedure will assure the engine owner that his
engine has been rebuilt to deliver factory rated
presents the engine operating characteristics. These
performance at the same maximum speed and load
characteristics will be a guide for tracing faulty operation
which will be experienced in the installation.
or lack of power.
If the engine has been shut down for one hour or longer,
Any four or six cylinder engine to be run at speeds in
it will be necessary to have a warm-up period of 10
excess of 1800 rpm must be equipped with a vibration
minutes at the same speed and load used for warm-up
in the Basic Run-In. If piston rings, cylinder liners or
bearings have been replaced as a result of
Engine governors in most cases must be reset at the
maximum full-load speed designated for the Run-In. If
a governor is encountered which cannot be adjusted to