Allis-Chalmers Model G - Oil Pressure Relief Valve; Valves Removal; Roto Valve

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OIL PRESSURE RELIEF VALVE
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Removal
The oil pressure relief valve is located on the
flange of the cylinder block near the oil pump.
It may be removed by use of a heavy duty screw
driver. Beneaththe plug is the spring and plunger
asserrbly.
Inspection
Check the relief valve spring for its free length,
which should be 2". The spring is painted red
for identification. A neoprene seal is used on
the plug to prevent leakage.
Assembly
The oil pressure relief valve should not be used
to increase the pressure of the system until
all other sources of low oil pressure are invest-
igated. The minimum allowable oil pressure
7 pounds. The desired operating pressure 15
to 20 pounds. The gauge is not calibrated in
pounds, but the center of the indicator needle
travel on the gauge face is approximately 15
pounds. The pressure may be regulated by
placing washers between the spring and the
retaining plug.
Removal
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INTAKE VALVE
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VALVES
der head. Remove the distributor, the throttle
rod and the carburetor and the valve cover.
Use a valve lifter or spring compressor to
remove the keepers from the valve stems. The
valves may then be lifted out.
ROTO VALVE
The engine is equipped with roto caps on the
exhaust valves. These caps provide a means
of relieving the spring pressure from the valve
when it is in the open position, allowing the
valve to rotate on its seat. These caps increase
valve life. Set exhaust valve clearance to .010"
cold when equipped with roto caps.
The valve guides are removable and can be
driven from the cylinder block if necessary.
Always use a suitable driver.
Drain the cooling system and remove the cylin-
G-21