Engine Tune-Up
DETROIT DIESEL
THROTTLE DELAY MECHANISM
The throttle delay mechanism is used to retard fullfuel
injection when the engine is accelerated. This reduces
exhaust smoke and also helps to improve fuel economy.
The throttle delay mechanism (Fig. 2) is installed
between the No. I and No. 2 cylinders on three cylinder
engines, between the No. 2 and No. 3 cylinders on four
cylinder engines, or between the No. 1 and No. 2
cylinders on the right-bank cylinder head of V-type
engines. It consists of a special rocker arm shaft
bracket (which incorporates the throttle delay cylinder),
a piston, throttle delay lever, connecting link, oil supply
plug, ball check valve and U-bolt.
A yield lever and spring assembly replaces the standard
lever and pin assembly on the rear end of the injector
control tube on In-line engines (Fig. 3). A yield lever
replaces the standard operating lever in the governor of
the 6V-53 engine (Fig. 4).
Operation
Fig. 3 Throttle Delay Yield Lever (In-Line
Engine)
Oil is supplied to a reservoir above the throttle delay
cylinder through a special plug in the drilled oil passage
engine is accelerated, movement of the injector racks
in the rocker arm shaft bracket (Fig. 2). As the injector
toward the full-fuel position is momentarily retarded
racks are moved toward the no-fuel position, free
while the piston expels the oil from the cylinder through
movement of the throttle delay piston is assured by air
a .016"orifice.
To permit full accelerator, travel,
drawn into the cylinder through the ball check valve.
regardless of the retarded injector rack position, a spring
Further movement of the piston uncovers an opening
loaded yield lever or link assembly replaces the
which permits oil from the reservoir to enter the cylinder
standard operating lever connecting link to the governor.
and displace the air. When the
Fig. 4 - Throttle Delay Yield Lever (6V Engine)
Fig. 2 - Throttle Delay Cylinder
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