Mack ASET AC, Service Manual, Page: 304 / 536

REPAIR INSTRUCTIONS, PART 1
Page 291
18. Recheck the end play to ensure the thrust
washers have been installed correctly and
that end play is within specification. Rotate
the crankshaft to ensure there is no binding.
CHECKING RUNNING CLEARANCE
When using the Plastigage method of checking
running clearance, do not turn the crankshaft.
Doing so will destroy the Plastigage.
If checking the main bearing clearance with the
engine in the upright position (such as in the
chassis), the weight of the crankshaft must be
removed from the lower half of the bearing being
checked. To do this, place cardboard under the
crankshaft journal in the main caps adjacent to
the journal to be checked and tighten the
adjacent caps until the journal to be checked
seats against the upper bearing. Do not fully
torque screws. Capscrews on the bearing being
checked should be torqued to specification after
the Plastigage strip has been positioned on the
bearing shell and the cap reinstalled. Support the
crankshaft at Nos. 1, 4 and 7 main journals, while
checking Nos. 2, 3, 5 and 6 bearings. Support the
crankshaft at the Nos. 3 and 5 journals, while
checking the Nos. 1, 4 and 7 bearings.
Engine Out of Chassis and Inverted
1. Use Plastigage to check the main bearing
clearance. Check each bearing, one at a
time, by placing a piece of Plastigage on the
journal and tightening the cap in place. The
bearing clearance is determined by
measuring the width of the crushed
Plastigage with the supplied gauge.
2. Place a section of Plastigage on the journal
to be checked and assemble the main
bearing cap to the cylinder block as shown
in Figure 327.
3. Apply a light coat of oil on the threads of the
bearing cap capscrews and secure the cap.
4. Tighten the capscrews to the specified
torque, 210 lb-ft (285 N
폷
m), using torque
wrench J 24407, or equivalent. The
Plastigage strip will be crushed between the
bearing insert and the crankshaft journal.
327
Figure 327 — Checking Running Clearance with
Plastigage
5. Remove the capscrews and cap, and check
the bearing running clearance.
6. Check the width of the Plastigage using a
Plastigage width chart. After measuring the
width, remove the Plastigage from the
bearing.
1. Main Bearing Cap
2. Plastigage 3. Bearing Insert
4. Crankshaft Journal
5-111.bk Page 291 Monday, July 10, 2006 2:26 PM