Basic Engine
ADJUSTMENTS
HYDRAULIC VALVE CLEARANCE
A 0.060-inch shorter than standard push rod and a 0.060-
inch longer than standard push rod are available for service to
provide a means of compensating for dimensional changes in
the valve mechanism. Refer to the Master Parts List or the
specifications for the pertinent color code.
Valve stem to valve rocker arm clearance should be within
specifications with the hydraulic lifter completely collapsed.
Repeated valve reconditioning operations (valve and/or valve
seat refacing) will decrease the clearance to the point that. if
not compensated for, the hydraulic valve lifter will cease to
function and the valve will be held open.
To determine whether a shorter or a longer push rod is
necessary, make the following check:
1. Connect an auxiliary starter switch in the starting circuit.
FIG 30 Checking Valve Clearance
Crank the engine with the ignition switch OFF until
the No. 1 piston is on TDC after the compression
4. Now rotate the crankshaft until the No. 6 piston is on TDC
stroke.
after the compression stroke (one revolution of the crankshaft).
2. With the crankshaft in the position designated in Steps 3
By using the procedure in Step 2. check the following valves:
and 4, position the hydraulic lifter until the plunger is
No. 2 Exhaust
completely bottomed (Figure 30). Take care to avoid
No. 3 Intake
excessive pressure that might bend the push rod.
No. 4 Exhaust
Hold the lifter in this position and check the available
No. 5 Intake
clearance between the rocker arm and the valve stem tip
No. 6 Intake
with a feeler gauge.
No. 6 Exhaust
If the clearance is less than specified, Install an under-
5. When compressing the valve spring to remove the push
size push rod. If the clearance is greater than specified,
rods. be sure the piston in the individual cylinder is below
install an oversize push rod.
TDC to avoid contact between the valve and the piston. To
3. With the No. 1 piston on TDC after the compression
replace a push rod. it will be necessary to remove the valve
stroke, use the procedure in Step 2 and check the
rocker arm shaft assembly. Upon replacement of a valve push
following valves:
rod, valve rocker arm shaft assembly or hydraulic valve lifter,
No. 1 Intake
the engine should not be cranked or rotated until the hydraulic
No. 1 Exhaust
lifters have had an opportunity to leak down to their normal
No.2 Intake
operating position. The leak down rate can be accelerated by
No.3 Exhaust
using the tool shown in Figure 30 on the valve rocker arm and
No. 4 Intake
applying pressure in a direction to collapse the lifter.
No. 5 Exhaust
Installation
REMOVAL AND INSTALLATION
1. Install the vent hose on the fitting in the carburetor spacer
When installing nuts or bolts that must be torqued, refer to
and the regulator valve in the hose.
the Specifications. Oil threads with lightweight engine oil. Do
2. Insert the regulator valve into the rocker arm cover
not oil threads that require oil-resistant or water-resistant
mounting grommet.
sealer. Refer to page 1-07 for cleaning and inspection and to
3. Install the air cleaner.
page 1-03 for engine test procedures.
4. Connect the inlet hose to the air cleaner and the oil filler
CRANKCASE VENTILATION SYSTEM
cap. Connect the fresh air intake tube and the heat
The closed crankcase ventilation system components are
shroud tube.
shown in Figure 31. (if so equipped).
5. Operate the engine and check for leaks.
Removal
1. Remove the inlet hose from the air cleaner and the oil
VALVE ROCKER ARM COVER AND ROCKER
filler cap. Remove the fresh air intake tube and the heat
ARM
shroud tube.
Removal
2. Remove the air cleaner.
1. Remove the air cleaner and the crankcase ventilation
3. Grasp the crankcase vent hose near the rocker arm cover
system. Remove the accelerator control cable bracket.
grommet and pull the regulator valve from the rocker arm
2. Remove the valve rocker arm cover and discard the
cover.
gasket.
4. Remove the regulator valve from the vent hose and re-
move the vent hose from the hose fitting in the carburetor
spacer.
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