TM 5-3810-300-24&P-3
2.7.1.2
LIMITING SPEED MECHANICAL GOVERNOR
(DUAL HIGH SPEED RANGE)
The limiting speed mechanical double weight dual range
governor is similar to the limiting speed governor shown
in Fig. 1 in Section 2.7.1 except for the spring and piston
assemblies illustrated in Figs. 1 and 2.
The dual range governor is used on highway vehicle
engines that require a high maximum speed part of the
time and a low maximum speed the remainder of the
time.
Due to the governors dual speed feature, it permits a
high engine speed in the lower gear ratios for maximum
vehicle acceleration while providing a conservative
Fig. 2 - Spring and Piston Assembly of Current Dual
vehicle speed in the higher gears. The valve for
Range Governor
controlling the high and low speed ranges of the
governor is usually connected to the transmission.
control housing, the riser thrust bearings and the weight
Shifting the transmission from a lower gear to a higher
shaft end bearing. Oil picked up from a reservoir in the
gear will automatically shift the governor from its high
blower front end plate by a slinger attached to the lower
maximum speed range to the low maximum speed
rotor shaft, provide lubrication for the governor weights
range. This two speed operation is accomplished by the
and weight carrier.
use of air pressure behind a piston (Figs. 1 and 2) to
increase the tension on the governor high speed spring.
Pressure lubrication has been provided for the weight
The removal of air pressure from behind the piston
housing bearings on current engines by an oil tube
permits the governor high speed spring to force the
attached between the oil gallery in the cylinder block and
piston against the low maximum speed adjusting screw
the weight housing.
that retains enough tension in the governor high speed
spring to operate the engine at the desired lower speed.
Remove Governor
Governor operation should be checked as outlined in
Lubrication
Section 2.7 before the governor is removed from the
Surplus oil returning from the cylinder head provides
engine. If, after performing these checks, the governor
lubrication for the parts in the governor
fails to control the engine properly, it should be removed
and reconditioned.
1.
Disconnect linkage attached to the governor levers.
2.
Remove breather tube.
3.
Remove four screws and lock washers and lift the
governor cover and gasket from the control
housing.
4.
Disconnect the fuel rod from the differential lever
and the injector control tube lever.
5.
Disconnect the oil tube at the governor weight
housing or cover and remove the cover, if used.
6.
Remove both governor-to-cylinder head bolts.
7.
Remove the governor control housing from the
cylinder head and governor weight housing.
Fig. 1 - Spring and Piston Assembly of Former Dual
Range Governor
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