Repair Manual

10
10 - 41
ENGINE AND LOWER ENGINE UNITS
NOTE: The parts contained in the repair
kit are in pairs ( jackets-piston-piston shaft )
according to colours.
The colour (1) marked on the piston head
must correspond to the colour marked on the
jacket.
The colour (2) marked represents the piston
weight and must be the same for all the pis-
tons.
The colour (3) marked on the piston head
must correspond to the one marked on the head
of the piston shaft.
The piston-jacket clearance 0,045 - 0,065
mm (
valid for new pistons and valves).
The measurement of the piston is done in
the area ( see the figure) in perpendicular plane
on bolt hole axle.
The masurement of the jacket is done in two
separate sections ( see the figure) in perpen-
dicu
lar plane with external flattenings. For
calculation
of the piston – jacket clearance the
average diameter ( D ) is to be considered:
D = D1 + D2
2
For the engines with the sealing of the
cylinder jackets by “ 0” ring, the checking is done
without the gasket. At these engines,the rubber
gasket is used only for sealing.
The height of the jackets over the level of the
gasket is:
0,02 - 0,09 mm
Place the jackets without gaskets in their
respective seats in the block.
Measure the height of the jackets over the
gasket level.
If the height of the jackets over the
gasket level is not within the prescribed limits,the
jacket-block assembling values are to be checked.
THE HEIGHT OF THE JACKETS OVER THE GASKET LEVEL
The checking of the jackets height over the gasket level is performed by means of the MOT
252 setting plate, the MOT 251 support and a comparison item.
zonã de
mãsurare
D2
D1
DISMOUNTING – MOUNTING
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