TM 5-2420-230-24-2
B3.9 and B5.9 Series Engines
Engine Testing (In Chassis) (014-008)
Section 14 - Engine Testing - Group 14
Page 14-23
Piston Ring Sealing
If the compression is low but can be increased significantly
by squirting oil into the cylinder, the cause is inadequate
sealing between the rings and the cylinder walls.
Refer to Procedure 001-047 for piston ring replacement.
Intake and Exhaust Valve Sealing
If the compression is low on one or more nonadjacent
cylinders, and the pressure can not be increased by oiling
the rings, poor valve sealing is suspected.
Refer to Procedure 002-004 for cylinder head replacement.
Valve leakage is often an audible sound from the intake and
Cylinder Head Gasket Sealing
If the compression is low on adjacent cylinders, and the
pressure can not be increased by oiling the rings, the
cylinder head gasket is probably leaking between the cyl-
inders.
Refer to Procedure 002-021 for cylinder gasket replacement.
L-1321