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DESCRIPTION & OPERATION
VALVE SEALS
The engines are produced with a valve stem seal
that features a multi-lip upper section, combined
with a second lip to significantly reduce
crankcase blow-by. This seal can easily be
identified by the steel retainer band around the
top of the seal lip.
To improve seal-to-guide retention, the guides
have three sharp ridges machined into the upper
outside diameter surface. Refer to Figure 26.
26
Figure 26 — Valve Seal
VALVE SPRINGS, ROTATORS AND
PUSH RODS
E-Tech™ valve springs and rotators have heavier
spring tension (pressure) than the E7 to
accommodate the more aggressive cam profiles.
Push rod design also incorporates a larger
diameter to handle the increased loads.
YOKES
Pin-Type Yokes
During February of 1999, the welded wear pad-
style yoke was supplemented in production with a
headed pin (“button”) type yoke. The material of
the pin-type yoke remains ductile iron.
Both the new configuration and the previous
configuration valve yokes are being used in
current E-Tech™ engine production, but the
yokes will not be intermixed on the same engine.
27
Figure 27 — Current Valve Yokes
For service purposes, it is acceptable to intermix
the different configuration yokes on the same
engine.
5_106_00.bk Page 28 Friday, August 4, 2000 11:17 AM
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