TM 5-4310-386-14
5-39. Cylinder Head Assembly (Cont).
(13)
Tighten screwplugs (2) to 59.04 to 66.42 ft. pounds (80 to 90 Nm).
c.
Repair. (figure 5-60)
(1)
Clean cylinder head (1) in diesel fuel. Using brush to remove dirt and grime from fins and ridges. Blow dry
with compressed air.
(2)
Check the cylinder head seating (2) surface. It must be flat and square. The seating surface (3) can be
refaced provided the distance from the seating surface to the sealing surface (3) is not less than .03937
inches (1 mm). If cylinder head seating surface was refaced, the cylinder head adjust procedures (para.
a.) must be performed prior to head installation.
(3) Slight damage to cylinder head seating (2) surface can be removed by grinding cylinder head (1) on
cylinder with fine abrasive paste. If cylinder head seating surface was refaced, the cylinder head adjust
procedures (para. a.) must be performed prior to head installation.
(4) If cylinder head seating area is more severely damaged, recut with hand operated plate mill or rework on
lathe using turning fixture attached to cylinder head. If cylinder head seating surface was refaced, the
cylinder head adjust procedures (para. a.) must be performed prior to head installation.
(5)
Install new valve in valve seat ring and install intermediate ring (4) on cylinder head sealing surface (3).
(6) Measure distance between valve plate and cylinder head seating surface. Should measure .09999 to
.22047 inches (5.08 to 5.6 mm).
(7) If measurement is within specifications, reface valve seat rings. If measurement is greater than .22047
inches (5.6 mm), replace valve seat rings.
(8)
Reface valve seat rings with drift and holder for inlet valve seat ring and drift and holder for exhaust valve
seat ring. When refacing do not exceed .22047 inches (5.6 mm) distance between valve plate and
cylinder head sealing surface.
(9)
Reface valve seat rings by installing cylinder head on mandrel, and chucking mandrel with cylinder head
on lathe.
(10)
Drill out valve seat rings by fitting drilling device to drilling machine for cutting out rings. Place on cylinder
head and insert pilot pin with drilling bushings.
(11)
Drill out valve seat rings by means of hard metal special cutter.
NOTE
To replace valve seat rings and valve guides, cylinder head should be heated up only once.
(12)
Heat cylinder head uniformly in heating cabinet or oven to a temperature of 428°F (220°C).
5-168
