Engine Tune-Up
DETROIT DIESEL
V A R I A B L E S P E E D M E C H A N I C A L G O V E R N O R AN D I N J E C T O R R A C K
C O N T R O L AD J U S T M E N T
6V-53ENGINE
The variable speed mechanical governor assembly is mounted at the rear of the 6V engine, between the flywheel
housing and the blower (Fig. 1). The governor is driven by the right-hand blower rotor drive gear.
After adjusting the exhaust valves and timing the fuel injectors, adjust the governor and position the injector rack control
levers.
NOTE: Before proceeding with the governor and injector rack adjustments,
disconnect any supplementary governing device. After the adjustments are
completed, reconnect and adjust the supplementary governing device.
Adjust Governor Gap
With the engine stopped and at normal operating temperature, adjust the governor gap as follows:
1. Disconnect any linkage attached to the governor levers.
2. Back out the buffer screw until it extends approximately 5/8" from the lock nut.
3. Clean and remove the governor cover and the valve rocker covers. Discard the gaskets.
4. Place the speed control lever in the maximum speed position.
5. Insert a .006" feeler gage between the spring plunger and the plunger guide as shown in Fig. 2. If required, loosen
the lock nut and turn the adjusting screw in or out until a slight drag is noted on the feeler gage.
6. Hold the adjusting screw and tighten the lock nut. Check the gap and readjust if necessary.
7. Use a new gasket and install the governor cover.
Position Injector Rack Control Levers
The position of the injector control racks must be correctly set in relation to the governor. Their position determines the
amount of fuel injected into each cylinder and ensures equal distribution of the load. Properly positioned injector rack
control levers with the engine at full-load will result in the following:
1. Speed control lever at the maximum speed position.
Fig. 1 Variable Speed Governor Mounting
Fig. 2 - Adjusting Governor Gap
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