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REPAIR INSTRUCTIONS
Piston Inspection and Cleaning
[212 NP]
GENERAL INFORMATION
The E-Tech™ engine uses a two-piece piston
design with the crown made from forged steel
and the skirt from cast aluminum. The forged
steel crown incorporates two compression ring
grooves and one oil ring groove. An oil
accumulator relief is machined into the lower half
of the third ring land face, 360 degrees around
the piston circumference.
A plasma-faced, keystone-type compression ring
is used in the top groove of the crown and a
tapered chrome, rectangular-type compression
ring is used in the second groove. The oil control
ring is located in the third groove, nearest the
wrist pin bore.
Early-production piston crowns were fitted with
steel-backed bronze bushings in the wrist pin
bores. A redesign of the piston crown for current
production eliminates the bushings from the
bores. This change was phased into production
beginning July 1999.
The wrist pin bore pedestal of the crown and the
piston skirt are stamped FRONT, and must be
installed facing the front of engine.
A radius is cut in the lower edge of the piston skirt
to provide clearance for the piston cooling nozzle.
The piston must be installed with the word
FRONT facing the front of engine.
SPECIAL TOOLS REQUIRED
r
Piston Ring Expander PT6587
r
Keystone Ring Groove Gauge J 29510
DISASSEMBLY
Refer to Figure 169.
1. Using piston ring expander PT6587, remove
the piston rings.
169
Figure 169 — Piston Ring Removal
2. Thoroughly clean the piston ring grooves,
combustion bowl area and snap ring
grooves. All carbon must be removed.
Carbon left in the piston ring grooves will
reduce ring clearance and prevent
replacement rings from seating properly.
Be sure that the cleaning solvent is approved for
steel and aluminum. Incompatible solvents may
cause damage to the pistons or skirts.
3. Clean the pistons with the approved solution
and a brass brush. Take care to avoid
damaging the pistons while cleaning.
5_106_00.bk Page 176 Friday, August 4, 2000 11:17 AM
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