TM 10-4320-307-24
4-12
CYLINDER HEAD ASSEMBLY REPAIR (CONT).
CLEANING:
Dry cleaning solvent P-D-680 (safety or Stoddard's Solvent) is potentially
dangerous. Avoid repeated and prolonged breathing of vapors and skin
contact with the liquid. Do not use near open flame, arcing equipment, or
other ignition source. Always wear eye protection and protective clothing.
The flash point of P-D-680 is 100° to 138°F (38° to 59°C).
Death or serious injury could occur if compressed air is directed against
the skin. Do not use compressed air for cleaning or drying unless the
pressure is/has been reduced to 30 psi (2.11 kgcm2)
or less. When working
with compressed air always use chip guards, eye protection, and other
personal protective equipment.
1.
Clean cylinder head assembly with dry cleaning solvent. Wire brush where necessary. Dry with compressed air.
2.
Clean fuel passages in cylinder head with cleaning brush and dry cleaning solvent. Dry with compressed air.
3.
Clean oil passages in cylinder head with cleaning brush and dry cleaning solvent. Dry with compressed air.
4.
Polish cylinder head surface with orbital sander.
INSPECTION:
1.
Inspect cylinder head for cracks using dye penetrant. Check for rust, corrosion, and excessive heat damage.
Remove any accumulated carbon deposits around injector spray hole. Replace cylinder head if it is damaged.
2.
Inspect for loose valve seat inserts, carefully hitting the cylinder head with a wood or rubber mallet. If insert is
loose enough so that it moves, replace insert.
3.
Check valve guides for damage.
4.
Inspect inside diameter of valve guide. Replace guide if bore is worn larger than 0.455 inch (11.56 mm).
5.
Use bore gage to check bore at four points spaced 90 degrees apart to find if bore is out-of-round. Check the full
length of the bore.
6.
Inspect valve head (1) for damage. Discard valve
if rim measurement (2) is less than 0.105 inch
(2.67 mm).
7.
Inspect outside diameter of valve stem (3). Dis-
card valve if outside diameter of valve stem mea-
sures less than 0.449 inch (11.44 mm).
8.
Inspect grooves (4) in valve stem for wear. Valve
collets (5) must fit tightly in grooves. Discard
valve and matching collets if grooves are worn
enough that collets are loose.
9.
Inspect valve spring free length. Discard any
spring having a free length shorter than 2.685 in-
ches (68.20 mm).
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