Run In (Rev 1/97)
119
•
A Schrader valve must be installed in the end of the
adapter that is facing the combustion chamber.
•
The compression tester and connecting hose must have
a small internal volume.
An adapter can be fabricated, but it must meet those guide-
lines. If not, the compression readings will not be accurate.
Refer to Service Bulletin No. T&T 068 for more informa-
tion.
1. Run the engine until it reaches the normal operating
temperature and then stop the engine.
NOTE: The compression should be tested when the
engine is near the normal operating temperature. If it
is not possible to run the engine, follow the rest of this
procedure. The compression pressures will be approx-
imately 10% lower than those on a warm engine.
2. Remove the wire from the fuel solenoid and loosen the
injection lines at the injection nozzles.
CAUTION: The fuel solenoid must be disconnected
and the injection lines must be loosened to prevent the
injection of fuel into the cylinders during the test. If a
cylinder fires during the test, the resulting pressure
will destroy the test equipment. The manufacturer of
the test equipment disclaims all responsibility for
damage or injury resulting from a cylinder firing dur-
ing the test.
3. Remove all of the glow plugs.
4. Disconnect the air cleaner.
5. Connect the compression tester (P/N 204-542) to a cyl-
inder with an acceptable adapter.
6. Turn the engine over with the starter and observe the
pressure gauge. Stop cranking the engine when the
pressure stabilizes.
7. Note the final reading, release the pressure, and discon-
nect the tester.
8. Repeat this procedure on each cylinder.
9. Compare the final readings of all the cylinders.
10. An engine in good condition will have a minimum
compression pressure of approximately 400 psi (2758
kPa) at cranking speed (250 rpm) using the Thermo
King compression tester (Part No. 204-542) and an
acceptable adapter.
11. Because the compression pressures will vary depending
on what kind of equipment is used, the most important
factor is the variation between cylinders. The variation
between cylinders should not exceed 10%.