TM 55-1930-209-14&P-21
(7) If necessary, replace cylinder head water nozzles as follows:
(a) Make sure water inlet ports in bottom of water holes at each end of head can be cleaned with 5/8
inch drill, and all other water holes can be cleaned with 13/16 inch drill. Break edges of holes slightly.
(b) Make sure nozzles fit tight in cylinder head. If water holes in head have been enlarged by
corrosion, use a wooden plug or other suitable tool to expand nozzles, so that they will remain tight after installation.
(c) Press nozzles into place with nozzle openings parallel to longitudinal center line. Install 1/2-inch
diameter nozzles at ends of cylinder head with their openings toward center of engine.
6-17 Cylinder head reassembly and installation
a. Reassembly
(1) Cylinder Head Plugs and Studs.
(a) Install all cylinder plugs (Figure 6-15) and studs. Install gaskets and covers over water holes and
secure with bolts and washers.
(b) When installing plugs in fuel manifold, apply a small amount of sealant as a "dual purpose sealer"
to threads of plugs only. Work sealant into threads and wipe off excess sealant with a clean lint-free cloth so that sealant
will not be washed into fuel system and result in serious damage to fuel injectors.
(2) Exhaust Valve Seats
(a) Clean valve seat insert counterbores in cylinder head and valve seat inserts with cleaning solvent
and dry thoroughly.
(b) Inspect counterbores for cleanliness, concentricity, flatness and cracks. Refer to Table 1-1 for
counterbore dimensions.
(c) Immerse cylinder head for at least 3 minutes in water heated from 180°F to 200°F.
(d) Rest cylinder head, bottom side up, on a work bench and locate insert squarely in counterbore
seating, face up. Install insert in cylinder while head is still hot and insert is at room temperature. Drive insert into place
with installing tool.
(3) Exhaust Valve Guide. Turn cylinder head right side up and install exhaust valve guides as follows:
(a) Install threaded end of valve guide in proper guide installation tool.
(b) Position valve guide squarely in bore of cylinder head and tap installation tool gently and drive
guide into cylinder head. Refer to Figure 6-16 for proper valve guide position.
CAUTION
Do not use valve guides as a means of turning cylinder head over or handling the cylinder head.
6-33
