Lister Petter TR1, Workshop Manual

Page: 22 / 121

page 22
02.13 THE VALVE ROCKER STUB
SHAFTS - TS/TR
The removal of the stub shafts is necessary when
it is required to examine or change the valves, valve
seats, rocker arms or rocker arm bushes.
Removing Stub Shafts
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
tool while it is being used
1. Screw the small end of the adapter (A) into the
screw thread of the stub shaft and tighten.
Figure 2.13.1 Stub Shaft Tool
2. Preferably place the cylinder head into a vice, and
screw the slide hammer tool onto the adapter.
3. Grip the slide hammer in one hand and strike the
sleeve in the required direction until the stub shaft
has been removed.
4. Lift out the rocker arm.
Refitting the Stub Shaft
Before fitting check the oil holes are clear, fit a
new '0' ring to the recess on the inside face of the stub
shaft and coat the sealing groove nearest to the bolt
hole with Wellseal or Hylomar PL32/M.
When refitting, the mark 'TOP' on the outside face
of the stub shaft must be positioned towards the top
of the cylinder head.
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
tool while it is being used
CAUTION
When refitting the stub shafts using the slide hammer,
great care must be taken not to dislodge the 'O' ring on
the inside face recess of the shaft.
1. Fit the small end of the adapter (A) into the screw
thread of the stub shaft and tighten.
Ensure 'TOP' is correctly positioned.
2. Place the cylinder on its side on a bench and place
the rocker arm into position for refitting the stub
shaft.
3. Fit the slide hammer tool on to adaptor.
4. Align the stub shaft with the stub shaft hole.
Section 02
Engine Servicing and Adjustments
- valve rocker stub shafts
5. Grasp the slide hammer with one hand while
positioning the rocker arm with the other and refit
the stub shaft by striking the end of the tool nearest
the cylinder head with the slide hammer.
If the rocker lever bush is not correctly lined up
and is preventing the stub shaft being refitted gently
strike either end of the tool with the slide hammer
while repositioning the rocker arm.
Note:
Ideally, after fitting, the stub shaft hole and internal hole
of the rocker arm bush will be perfectly aligned. Small 'G'
clamps or a second pair of hands may be required.
02.14 THE VALVE ROCKERS - TX
The removal of the valve rocker assembly is
necessary when it is required to examine or change
the valves, valve seats, rocker arms or rocker arm
bushes.
Removing an Individual Rocker Arm
Individual rocker arms can be removed without
removing the rocker assembly.
1. Remove the rocker cover.
2. With the piston at TDC on the firing stroke screw
the rocker adjusting screw (A) anti-clockwise until
the valve spring is not tensioned.
Figure 2.14.1 Valve Rocker
3. Using suitable circlip pliers remove the circlip (B)
and slide the rocker lever off the stub shaft.
4. With the piston at TDC on the firing stroke and the
adjusting screw turned fully anti-clockwise slide
the rocker lever onto the stub shaft.
5. Using suitable circlip pliers replace the circlip and
check that it is fully seated in the groove.
6. Check and reset the valve clearance.
7. Replace the valve rocker cover.