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 TM 55-1905-223-24-5
(2)
Valve grinding.
(a)
Use a valve facing machine to grind the face of the valve. Check the
setting of the facing machine by using a new valve and an indicator
gauge.
(b)
Put the valve to be ground in the chuck of the machine. Tighten the
chuck on the grind area of the valve stem.
(c)
Position the tip of the indicator against the valve face.
(d)
Turn the valve. Put a mark on the valve face where the indicator shows
the highest reading.
(e)
Remove the valve from the chuck.
(f)
Turn the valve 180 degrees from the original position in the chuck.
(g)
Put the valve in the chuck and tighten the chuck.
(h)
Repeat steps (b) and (c).
(i)
If the highest indicator reading is the same, and in the same location
of the face when the valve is positioned as in steps (a) and (d), the
valve is distorted.
(j)
If the highest readings are at different locations on the valve face in
steps (a) and (d), the chuck is not in alignment.
(k)
The indicator must not show more than 0.001 inch (0.02 mm) difference
around the circumference of the valve face.
(1)
Grind the face of the valve. Make sure the coolant will spray on the
valve head, not on the grinding wheel.
(m)
Grind the valve face to an angle exactly 30 degrees from the horizontal
position of the valve.
(n)
Check the thickness of the valve head rim, FIGURE 4-9 to be sure that.
the rim thickness is not less than 0.124 inch (3.15 mm). Do not repair
any valve with cracks or other damage or any valve whose rim thickness
is less than 0.124 inch (3.15 mm).
(o)
Make sure the valve face has the correct contact against the valve
seat.
(p)
Put marks on the valve face as shown in FIGURE 4-9. Use a liquid metal
marker.
(q)
Install the valve in the valve guide.
(r)
Hold the valve against the valve seat and rotate the valve at least 10
degrees. The correct contact against the set will cause the marks on
the valve face to be broken.
4-18
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