Basic Engine
FIG 31. Closed Crankcase Ventilation System Components
retainers may be replaced without removing the cylinder head
providing damage to the valve or valve seat has not occurred.
Removal
1. Remove the air cleaner.
Remove the crankcase
ventilation regulator valve from the valve rocker arm
cover. Remove the valve rocker arm cover. Remove the
FIG. 32. Valve Rocker Arm Shaft Removal
applicable spark plug.
3. Remove the rocker arm shaft support bolts by loosening
2. Loosen the valve rocker arm shaft support bolts two turns
the bolts two turns at a time in sequence. Remove the rocker
at a time, in sequence, until the valve spring pressure is
arm shaft assembly (Figure 32). Remove the valve push rods.
relieved. Remove both valve push rods of the cylinder to
Make sure the push rods are identified before removal so
be serviced.
they can be returned to the same location when they are
3. Install an air line with an adapter in the spark plug hole.
installed.
4. Tighten the attaching bolts just enough to seat the rocker
Installation
arm shaft supports on the cylinder head. Push the rocker
1. Apply Lubriplate or equivalent to both ends of the push
arm to one side and secure it in this position (Figure 33).
rods and to the valve stem tip.
To move the rocker arm on either end of the shaft, it will
2. Install the valve push rods. Position the valve rocker arm
be necessary to remove the retaining pin and spring
shaft assembly on the cylinder head.
washer and slide the rocker arm off the shaft.
3. Install and tighten all valve rocker arm support bolts, two
5. Turn on the air supply. Air pressure may turn the
turns at a time in sequence, until the supports fully contact the
crankshaft until the piston reaches the bottom stroke.
cylinder head. Torque the bolts to specifications.
Using the valve spring compression tool shown in Figure
4. If any part which could affect the valve clearance has
33, compress the valve and remove the valve spring
been changed, check the valve clearance following the
retainer locks, the sleeve, spring retainer and the valve
procedure outlined under Hydraulic Valve Lifter Adjustment.
spring. If air pressure fails to hold the valve in the
5. Clean the valve rocker arm cover and cylinder head
closed position during this operation, it can be
gasket surfaces. Install the gasket in the cover making sure
presumed that the valve is not seating or is damaged.
that all of the tangs of the gasket are engaged in the notches
If this condition occurs, remove the cylinder head for
provided in the cover.
Connect all vacuum lines and
further inspection.
components using previous identification for proper
6. Remove the valve stem seal (Figure 34). If air pressure
connection. Tighten the cover attaching bolts in two steps.
has forced the piston to the bottom of the cylinder, any re-
First, torque the bolts to specifications; then, re-torque to the
moval of air pressure will allow the valve(s) to fall into the
same specifications two minutes after initial tightening. Install
cylinder. A rubber band, tape or string wrapped around
the accelerator control cable bracket.
the end of the valve stem will prevent this condition and
6. Install the crankcase ventilation system and the air
will still allow enough travel to check the valve for binds.
cleaner.
VALVE SPRING, RETAINER AND STEM SEAL
Broken valve springs or leaking valve stem seals and
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