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DESCRIPTION & OPERATION
ROCKER ARMS
Early-production E-Tech™ used the older-style
E7 rocker arms. Effective second quarter 1997, a
newly designed rocker arm (Figure 33) on which
the slipper-end wear surface is a hardened,
headed pin pressed into the rocker arm, was
introduced and is currently used.
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Figure 33 — New-Style Rocker Arm
ROCKER ARM/SHAFT ASSEMBLY
Improved features of the E-Tech™ rocker arm/
shaft assemblies include:
r
No coil springs between rocker arms
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C-clips used to retain rocker arms
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Longer shaft lengths
r
Cup plugs in shaft ends
r
Improved centering of rocker arm slipper
feet over yoke pads
Low-Pressure Fuel System
The flow of fuel through the low-pressure side of
the fuel system is essentially the same as that in
the E7 engine for current-production engines with
the left-side mounted EECU. However, on early-
production engines with the right-side mounted
EECU, a cooling plate was added to the circuit
(Figure 34).
Fuel flows from the fuel tank to the primary filter,
the EECU cooling plate (if equipped), the supply
pump, the secondary filter and the unit pumps.
Unused fuel is collected in the fuel return gallery
in the cylinder block and returned to the fuel tank
by a fuel return line.
To decrease restriction in the low-pressure fuel
system, hoses and fittings with larger inside
diameters are used for all suction lines in the
E-Tech™ system.
To meet unit pump demands, the supply pump
provides a 100 gph fuel flow at 70 psi pressure.
This high level of flow and pressure is needed to
cool the unit pumps and EECU, and keep the fuel
supply gallery filled. A check valve fitting, located
on the fuel return gallery outlet on the cylinder
block right side, maintains fuel gallery pressure
and prevents the system from bleeding down
when the engine is not operating.
On current-production engines, a new fuel gallery
pressure regulating valve with a 70 psi spring
setting is used to reduce fuel gallery pressure and
fuel dilution.
The gear-type supply pump is located on the rear
side of the right-front flange of the cylinder block.
It is driven by the engine camshaft gear. A hand
primer pump is mounted on the supply pump.
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