TM 5-2420-230-24-2
Engine Testing (In Chassis) (014-008)
B3.9 and B5.9 Series Engines
Page 14-22
Section 14 - Engine Testing - Group 14
Shut off the engine.
Engine Testing (In Chassis) (014-008)
Initial Check (014-008-001)
It is very time consuming and expensive to remove internal
engine components to diagnose failures. A compression
gauge and adapter can be used as an aid in checking for
failures.
Use the compression gauge and adapter to check for fol-
lowing component failures:
1. Piston ring sealing
2. Intake and exhaust valve sealing
3. Cylinder head gasket sealing
4. Cylinder head cracked.
Refer to the appropriate procedures for the replacement of
failed components.
NOTE: Due to variables such as starter and battery con-
ditions that affect engine cranking speed, it is difficult to
establish an absolute value for compression pressure; how-
ever, the following values can be used as guidelines:
New engine (cranking speed @ 250 rpm) 2413 kPa
[350 psi]
Used engine (cranking speed @ 250 rpm) 2068 kPa
[300 psi].
It is recommended that the compression pressure be
checked on all cylinders and then compared to specifica-
tion. All cylinders must be within 690 kPa [100 psi] of each
other.
L-1320
