Perkins 4.99 - SECTION G Cylinder Block and Liners; Cylinder Liner Specifications and Renewal

SECTION G
Cylinder Block and Liners
CYLINDER LINERS (4.108 ENGINES)
The cylinder liners fitted to the 4.108 series engines are
centrifugally cast alloy iron, they are an interference
fit in the cylinder block parent bore and of the thinwall
dry type.
Reboring of these liners is not possible and new liners
should be fitted when a rebore would normally be con-
sidered necessary.
The
exception is 4.108 refrigeration unit engines which
can be rebored to 0.020 in (0,51 mm) oversize. It must
be noted that the oversize pistons for these engines
are only suitable for this type of application due to the
special operating conditions.
Dimensional checks of the cylinder bore are carried
out by means of the gauge tool shown in Fig. G.1.
When
checking liners each one should be measured
in
three positions - top, centre and bottom; the read-
ings being taken parallel and at
right angles to the
centre line of the cylinder block giving six readings
for each cyl inder bore.
When checking the fitted internal bore of a new thin-
wall
liner it is advisable to allow a period of time to
elapse for the I iner to settle.
To Renew Cylinder liners
1. Remove all the various components from the cylin-
der block. (Refer to the appropriate sections for
details of their removal).
2. Using a shouldered metal disc slightly smaller on
the
outside diameter than the parent bore dia-
meter and a suitable press, press the liners care-
fully out through the top of the cylinder block.
NOTE: Support the block locally in the area of the
top of the liner.
3. Lightly lubricate the outside of the liner with clean
engine oil ready for fitting,
4. As the liner must protrude above the cylinder block
top face and not be pressed fully home when fitted
correctly, a solid stop washer should be available
designed to give the correct liner protrusion.
NOTE: The limits for liner protrusion are given on
page B.3 and may be checked as shown in Fig.
G.2.
5. Press the liner into the bore progressively until it
reaches the
solid stop washer.
6.
Bore and finish hone the liners to the dimension
quoted on Page B.3.
NOTE: Where
boring equipment is mounted on tile
top face of the cylinder block fit a parallel plate
between the boring bar and cylinder block face.
Such a plate should be thicker than 0.027 in
(0,686
mm).
7. Re-assemble the engine components to the cylinder
block. (Refer to the appropriate sections for
assembly of these).
CYLINDER LINERS
07 and 4.99)
Cylinder liners fitted to 4.107 and 4.99 engines are of
the centrifugal cast iron wet type. They have flanges
at the top and are sealed at the bottom by means of
two rubber sealing rings which fit in machined re-
G1
Earlier 4.99 engines had only one seating ring at the
bottom of the liner (see Fig. G.3).
4.107 and 4.99 cylinder liners have pre-finished bores.
Under normal circumstances, the liner would only
need to be renewed during major overhaul, but should
it be necessary to remove the liner for any other
reason, this can be carried out without removal of the
crankshaft.
If at any time, the cylinder liners are removed and
these same liners are to be refitted, then before they
are removed from the cylinder block, they should be
cesses in the cylinder block. G2