DS 19 OPERATION No. DS 100-3 : Overhauling an engine 56
TOOLS
h) Fit the short cylinder head fixing screws. Screw up without tightening.
i) Tighten the screws in the order indicated (see Pl. 7), first tightening 21.75 ft/lbs (3 m.kg), second tightening
43.5 ft/lbs (6 m.kg). These tightening torsions are very important, (torsion spanner 2471-T, see Pl. 7, fig. 2) . . . . Torsion spanner
2471-T
Observe the order indicated. Do not exceed the tightening torsion of 43.5 ft/lbs (6 m.kg) . . . . . . . . . . . . . . . . . . 14 mm socket.
NOTE – After having travelled 300 miles (500 km), then 1,250 miles (2,000 km), it is necessary to retighten the
cylinder head. Loosen the screws, then proceed as indented line “i”. One should drain the radiator.
j) Turn the engine over (stand MR-3505-170, see Pl. 18, fig. 1).
Check the barrel bores for deformation (dial gauge 2440-T for checking bores): the distortion or ovality must
not exceed 0.03 mm except in the part 20 mm from the bottom where 0.05 mm is admissible . . . . . . . . . . . . . . . Stand MR-3053-170
Dial gauge 2440-T
35 To fit the crankshaft and pistons into the cylinder block (see Pl. 13 and 14) :
a) Cut from shim steel 0,10 mm thick, a shim 200 mm long and 10 mm wide.
b) Fit the top half bearing (13) on the cylinder block and the lower half bearing (14) on the bearing cap (smear the
faces of the shells with Festinol).
Insert the fixing screws (40) without tightening (no washers under the head of the screws).
c) Fit the main bearings, making sure that the bores in the cylinder block are clean, oil with an oil-can.
d) Oil the pistons. Place the gap of the 1st and 3
rd
ring at 180° in relation to the gaps in the 2
nd
and 4
th
rings.
Fit the ring clips on the pistons (ring clip 1656-T, see Pl. 13, fig. 1).
Fit the bearing thrust ring (8) (see Pl. 1) on the crankshaft, with the chamfer towards the ground face of the
crankshaft, the slot for retaining the washer towards the bearing cap.
Fit the crankshaft by guiding the pistons so as to avoid pinching or breaking the rings. Also ease the bearing
thrust ring into position. Remove the piston ring clip.
e) Insert the shim steel strip (prepared as shown in paragraph “a”) around the oil thrower on the crankshaft as
shown on Pl. 14, fig. 1. Fit the crankshaft on its bearings.
f) Fit the bearing cap. Tighten the two assembly screws (11) of the half shells. Tighten the bearing cap screws
to 72 lb/ft (10 m.kg) (torsion spanner 2471-T, see Pl. 7, fig. 2) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 mm box spanner
Torsion spanner 2471-T
17 mm socket spanner
NOTE – Do not turn the crankshaft during the centring of the half shells.
g) Tighten the shell fixing screws (40) alternately up to 9.5 ft/lbs (1.3 m,kg).
h) Remove the assembly screws (11) from the half shells. Remove the bearing cap. Lift the crankshaft in order
to remove the shim steel strip.
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