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REPAIR INSTRUCTIONS
Page 161
CRANKSHAFT AND FLYWHEEL
BENCH PROCEDURES
General Information
Initially, flywheels used with E-Tech™ engines
have six timing grooves milled into the face
surface for standardization with the E7 PLN
engines. However, the grooves are not required
for E-Tech™ engines and are eliminated on
current-production flywheels.
Crankshaft Inspection
[212 HP]
GENERAL INSTRUCTIONS
All bearing surfaces must be free of grit and
burrs. Small particles of dust and dirt left between
the crankshaft and bearings will cause rapid wear
and scoring of the crankshaft journal and inserts.
Any foreign material left between the crankshaft
bearing inserts and caps will cause distortion of
the insert and a reduction in operating clearance
at that point. The resulting frictional heat at the
point of distortion will cause the bearing material
to melt away from steel backing of the bearing.
Such melted material will create further hot spots
until complete bearing failure occurs. Anything
that interferes with the operating clearance of any
bearing and proper heat dissipation affects
bearing life. Cleanliness cannot be overstressed.
INSPECTION
1. Inspect the crankshaft journals for out of
round, taper and poor surface finish.
2. Visually check the crankshaft for any
apparent cracks, worn journals and damage
to threads, dowel pin or main drive gear.
3. Magnaflux the crankshaft to check further for
cracks. This process requires special
equipment and application methods.
4. Using standard machinists’ inspection
practice, check the crankshaft to ensure it is
straight.
5. Measure the crankshaft journals with a
micrometer. Measure each journal in two
locations, 90 degrees apart, and record the
measurements.
6. Check the measurements against
specifications listed under Fits and Limits in
the SPECIFICATIONS section.
7. If the crankshaft journals are worn, out of
round, or tapered, replace the crankshaft.
New or exchange crankshafts are available
from MACK Parts Distribution Centers.
Crankshaft regrinding by anyone other than Mack
Trucks, Inc. is NOT recommended due to the tight
control required on maintaining geometrical
tolerances, and the hardened characteristics of
crankshaft journals and journal fillets.
If crankshaft main journals or connecting rod
journals are not a standard size, be sure to use
properly sized bearing inserts when reassembling
the engine. Bearing insert sizing is identified with
a “P” following the part number, and is stamped
on the back side of the bearing insert. For
example, if a journal is 0.010 inch (0.254 mm)
undersize, a 0.010-inch undersize bearing is
required and will be stamped “P10.”
Some crankshafts may have journals which are
0.002 inch (0.0508 mm) undersize. These
crankshafts are marked by a streak of white paint
adjacent to the journal. Always check the journals
to ensure using bearing inserts of the proper size.
5_106_00.bk Page 161 Friday, August 4, 2000 11:17 AM
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