TM 5-3805-261-34
ENGINE MAINTENANCE.
13-3.
Cylinder Head Assembly Overhaul. (Sheet 4 of 6)
INSPECTION/REPAIR
4.
Using magnetic particle,
magnaflux or dye penetrant
method, inspect combustion
surface. Magnetic particle is
preferred. Discard and replace
head if cracks appear between
valve seats or between valve
seats and injector adapter holes.
If cracks are in other areas and
are less than 0.25 inch long and
0.125 inch deep, repair by
welding.
5.
Inspect combustion surface for
damage and erosion across fire
ring, seat area, between injector
nozzle hole and valve seat area
(Figure 13-9). Discard and
replace head if erosion is
severe. If erosion is slight,
refer to step 11 for grinding
instructions.
6.
Using valve guide gage group,
plug gage or equivalent measure
inner diameter of both ends of
each of eight valve guides.
Maximum diameter is 0.3772 inch,
minimum diameter is 0.3723 inch.
Remove and replace guides worn
beyond limits. Refer to
paragraph 3-8.
7.
Inspect all threaded holes for
damaged threads, broken bolts or
studs. Extract all broken bolts
and studs. Repair damaged
threads with threaded inserts.
Figure 13-9.
Go to Sheet 5
13-13
