CITROEN DS 19 - Page 77

DS 19 OPERATION No. DS 112-3 : Overhauling a cylinder head. Op. DS 112-3 75
TOOLS
Exhaust valve seating:
For the seating . . . . . . . . . . . . . . . . . . . . . 90° wheel . . . . . . . . . . . . . . . . . . 1627-T
For the top clearance . . . . . . . . . . . . . . . . . 150° biconical wheel . . . . . . . . . . . 1627-T
For the bottom clearance . . . . . . . . . . . . . . . 60° biconical wheel . . . . . . . . . . . 1633-T Wheels 1627-T,
1633-T
It is essential that the large diameter seating must be equal to the largest diameter of the valve (see fig. 1 and 2).
5 Grind the valves (suction valve grinder 1615-T, see Pl. 4 fig. 4).
This attachment can be driven by an electrically, pneumatically or manually operated grinder . . . . . . . . . . . . . . . Suction valve
grinder 1615-T
6 Clean the cylinder head with great care so as to eliminate all traces of emery in the valve chambers or gas passages.
This operation must be carried out with very great care. Powdered emery (even in very small quantities) entering
the engine, will cause rapid wear.
ASSEMBLY
7 To calibrate the valve springs (spring calibration fixture 2420-T, see Pl. 6).
a) Outer springs :
Length = 37 mm under load of 24.2 ± 1.350 kg.
Length = 28.5 mm under load of 52 ± 0.600 kg.
b) Inner springs :
Length = 24.5 mm under load of 5.250 ± 0.300 kg.
Length = 16 mm under load of 11 ± 2.800 kg. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spring calibration
fixture 2420-T
8 To assemble the cylinder head (see Pl. 3) :
a) Fit the valves (spring compressor 1614-T and support and base assembly 1616-T, see Pl. 5).
Oil the faces and stems of the valves. Place the valves in position, fit a sealing ring (30) on the stems of the
inlet valves only (see fig. 2).
For each valve, fit one thrust washer (31) for the outer spring and one shouldered thrust washer (32) for the
inner spring.
Fit the exhaust valve springs. Fit the spring thrust cups, the cup retaining the split cotters, the split cotters (see
fig. 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spring compressor
1614-T
Support and base
assembly 1616-T
NOTE – It is important not to fit sealing rings on the exhaust valves.