New Holland CX720 Repair Manual page 1685

Valve drive - Overhaul (B.10.A.40 - F.10.A.40)
NOTE: Refacing the valve seat should always be co-ordinated with refacing of the valve to ensure a compression
tight fit.
1. Examine the valve seat inserts and reface if pitted,
renew if loose or damaged.
To install a new valve insert, the cylinder head must
be counter bored, as described in Cylinder head -
General specification (B.10.A.72 - D.40.A.10). The
new insert must be chilled in dry ice prior to installa-
tion.
Valve Seat Specifications, Fig. 1
1 Valve seat angle
Intake 30.0 °-30.30 °
Exhaust 45.0 °-45.30 °
2 Valve seat width
Intake 1.9-2.4 mm (0.078-0.098 in)
Exhaust 1.8-2.3 mm (0.072-0.092 in)
3 Valve Head Face to Cylinder Head Face Depth
Intake 0.89-1.29 mm (0.035-0.051 in)
Exhaust 1.2-1.6 mm (0.048-0.064 in)
NOTE: Valve inserts of 0.010 in (0.25 mm) and 0.020 in
(0.5 mm) oversize on diameter are sometimes installed
during manufacture. Cylinder Heads with oversize inserts
are stamped so10/os, so20/os, on the exhaust manifold
side in line with the valve seat concerned.
2. Check the width of the valve seat inserts, and as
required reface by grinding to dimensions detailed in
Cylinder head - General specification (B.10.A.72
- D.40.A.10).
3. Measure the concentricity of valve seats, using a dial
indicator and measure concentricity of seat to the
valve guide bore. Total Indicator Reading should not
exceed 0.051 mm (0.002 in), Fig. 2.
POWER PRODUCTION - ENGINE
2 4/7/2006
B.10.A / 139
1
TA6010013
2
TA6010015