DS 19 OPERATION No. DS 112-3 : Overhauling a cylinder head. Op. DS 112-3 73
PARTICULAR POINTS
Dismantling.
1 Since the cylinder head is made of aluminium, one cannot replace he sparking plug tubes or the valve seats without he use of special tools.
Do not remove the studs.
One can replace the valve guides (see paragraph 2). If a thread is damaged (except sparking plug holes) it is possible to replace it by a
“Heli-Coil” thread (see note MR-4279).
Assembly.
7 Characteristics of the valve springs.
Outer springs: L = 37 mm under load of 24.200±1.350 kg and L = 28.5 mm under load of 52 ± 2.800 kg.
Inner springs L = 24.5 mm under load of 5.250 ± 0.300 kg and L = 16 mm under load of 11 ± 0.600 kg.
8 Do not fit the rubber sealing ring on the exhaust valves
TOOLS
DISMANTLING
1 Stripping down the cylinder head (see Pl. 3).
a) Remove the short screws fixing he cylinder head, the inlet rockershaft and the rockershaft supports.
b) Stripping the inlet rockershaft assembly :
Remove the fixing screws (5), the caps (33), the washers (38), the springs (39), the rocker arms (34 and 35).
Drive out the plugs from the rockershaft by means of a pin punch passing through the fixing screw holes.
Clean the interior of the shaft using a metal pin and make sure that the lubrication holes of the inlet and
exhaust shafts as well as those of the rocker arms and shaft supports are clear.
c) Remove the water pump and water pump cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14-17 mm box
spanners
d) Remove the exhaust manifold and the manifold screen fixing brackets.
Remove the inlet manifold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 mm box spanner
e) Remove the valves (spring compressor 1614-T, and support and base assembly 161-T, see Pl. 5) . . . . . . Spring compressor
1614-T
f) Remove the rear closing plate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 mm box spanner
To Next Page
Loading...
