using ST-667 Guide Puller which contains different-size
collets for the various guides, figure 3-260.
c. Inspection.
(1) Valve crossheads.
(a) Clean crossheads.
(b) Check for cracks with Magnaflux
process.
(c) With accurate micrometers, set a
small bore gage 0.0002 in. above worn replacement limit.
Use as a "No-Go" gage in crosshead bore to check if bore is
worn beyond wear limits as shown in table 2-2. Check for
out-of-round holes.
(d) Gage hole at several points 90 apart.
(e) Check reamed depth of crosshead
bore; it should be a minimum of 1.370 inch in depth.
(f) Check valve stem counterbore depth
in underside of crosshead; it should be a minimum of 0.090
Figure 3-260. Pulling crosshead guides.
in. deep.
(b) If not already done, install valve
(g) Mark crossheads for replacement
crosshead retainer under adjusting screw nuts on
that are not within worn replacement limits.
crossheads; these retainers keep crossheads from jumping
(h) Check for excessive wear on rocker
off valve stems during engine operation.
lever and valve contact surfaces.
(c) Use light finger pressure on rocker
(2) Crosshead guides.
lever contact surface (1) to hold crosshead in contact with
(a) Check guide Outside Diameter with
valve stem nearest push tubes (2); turn crosshead adjusting
micrometers. See table 2-2 for worn replacement limits.
screw (4) down until it contacts valve stem beneath it.
(d) If new crossheads and guides (5) are
used, advance adjusting screws one-third of one hex (20
degrees) to straighten valve stems on their guides and to
compensate for slack in threads. When worn crossheads
and guides are used, it may be necessary to advance
adjusting screws approximately one-half of one hex.
(e) Using ST-669 Wrench Adapter,
locknuts to 22/26 ft-lbs., figure 3-263. If ST-669 is not
available, hold screws with screwdriver and tighten locknuts
to 25/30 ft-lbs.
(f) Check clearance between each
crosshead and valve spring retainer with wire gage; a
minimum of 0.030 in. clearance is required at this point.
Figure 3-259. Valve crossheads removal.
(b) Check guide for straightness. It
should be at right angles with milled surface of head.
Replace if not straight or if worn beyond replacement limit.
(c) Check crosshead guide protrusion
above cylinder head (d below).
d. Installation.
(1) Cross head guides.
(a) Press in new solid guides with ST-
707 to 1.540/1.559 in. assembled height,
(b) If mandrels are not available, press
guides into head to obtain above protrusion.
(2) Valve crossheads.
(a) Install
proper
(right
or
left)
crossheads on crosshead guides with adjusting screws
resting on valves farthest from push tubes
Figure 3-261. Crosshead guide installation.
(3, fig. 3-262).
3-92
