Lister Petter 0600123LPW3A01, Руководство по ремонту, Страница: 38 / 88

ALPHA series engines worksHoP mAnuAL
38
2. Screw on the depth plate (C); see the above
illustration.
3. Fit the slide hammer onto the guide threads.
4. Place the assembly squarely into the crankcase
bush bore from the outside of the crankcase.
5. Use the slide hammer to replace the bush.
wArning
Care must be taken to ensure that any part of the
hand is not likely to become trapped between the
two parts of the slide hammer while in use.
2.33 tHe Piston
The piston is made of low expansion alloy with a
recessed combustion chamber in the crown and is
fitted with three rings.
The piston crown is stamped ‘Camshaft Side’, to
ensure the piston is correctly assembled to the
engine, and with the part number.
The gudgeon pin is a clearance fit in the piston and
is retained by two circlips. The gudgeon pin runs in
a bush in the small end of the connecting rod.
CAution
The LPWT4 and LPWST4 piston and connecting
rod assemblies are not interchangeable with
any other.
2.33.1 the Piston rings
Piston rings are only available as sets and it is
recommended that they are only fitted as a set.
firing ring
A barrel lapped chrome ring is situated at the top
of the piston, one surface is marked ‘TOP’ and the
ring must be fitted the correct way up.
Compression ring
The compression ring has a tapered face in contact
with the barrel, one surface is marked ‘TOP’ and
the ring must be fitted the correct way up.
oil Control ring
A conformable type, with a spring expander, is fitted
above the gudgeon pin.
2.33.2 Piston Assemblies
LPwt4 and LPwst4 engines:
LPWT4 and LPWST4 engines have only been
fitted with controlled expansion piston assemblies
and these are not interchangeable with any other.
All other engines:
Mono-metal piston assemblies were fitted on
early engines but from the engines given below
controlled expansion piston assemblies have been
fitted. Either type of piston, with the correct rings,
can be used but the two piston types must not be
mixed within an engine.
2.33.3 removing a Piston
1. Isolate the fuel supply and remove the inlet and
outlet pipes from the fuel lift pump.
2. On LPWT4 engines remove the turbocharger oil
feed and return pipes.
3. Remove the crankcase door.
4. Remove the cylinder head.
5. If Number 1 piston is being removed it will
be necessary to unscrew and remove the oil
pressure relief valve and oil strainer.
6. Rotate the crankshaft sufficiently to give access
to the connecting rod bearing cap bolts.
7. Remove the two bearing cap bolts and the
bearing cap.
CAution
To avoid possible injury, due to the sharp edges
of the machined crankcase face, use a drive
socket and not a spanner.
8. Carefully scrape any build up of carbon from the
top of the cylinder bore.
9. Rotate the crankshaft until the piston is at TDC.
10. Screw the piston removal tool into the nearest
connecting rod bearing cap bolt hole.
Figure 2.33.3 Piston Lifting Tool 317-50113
11. Using a suitable lever against the crankcase
and the bottom end of the tool press down on the
end of the lever until the piston rings are clear of
the cylinder bore.
12. Lift out the piston and connecting rod.
13. Replace the bearing cap onto the connecting rod.
14. By using a standard ring expander the piston
rings can be removed.
15. The gudgeon pin may be removed by releasing
the circlip from one end and pushing out the pin.