Mack E7 Service Manual page 101

5-101.bk Page 11 Friday, March 17, 2006 11:05 AM
All new service replacement crankshafts, short
blocks or basic engines will have a dowel pin in
the crankshaft rear flange. In nearly all cases, the
flywheel will already have a hole in it to accept the
dowel pin. If, in an earlier version, the flywheel or
torque converter drive flange does not have a
hole in it for a dowel pin, it must be reworked.
If it is necessary to rework the flywheel or torque
converter drive flange, two holes must be added
using a 19/32-inch drill bit. One hole is for the
dowel pin, and another directly opposite the first
hole is to maintain balance of the flywheel/torque
converter drive flange.
Refer to Figure 5-7.
2" x .651"
2" x 2.500"
.594"
HOLE
2" x 2.500"
Figure 5-7 — Dowel Pin Hole Dimensions (Flywheel or
Torque Converter Drive Flange)
200 BENCH PROCEDURES
4" x 2.165"
4" x 1.250"
.594"
HOLE
5.000"
BASE
CIRCLE
200651a
Crankshafts used in early mechanically governed
engines, part No. 4566C5127M, did not have a
dowel pin or dowel pin hole. It is acceptable to
use this early non-pinned crankshaft design in
any mechanically governed engine, even when
the original installation may have had dowel pins.
DOWEL PIN REMOVAL
To remove rear crankshaft dowel pin:
1. Using vise grips, securely grip dowel pin.
2. Rotate dowel pin back and forth while
exerting outward pressure until pin is
removed.
DOWEL PIN INSTALLATION
Refer to Figure 5-8.
To install a replacement crankshaft dowel pin:
1. Position dowel pin in a 0.5562-inch
(14.1275 mm) diameter unthreaded hole in
rear of crankshaft. The pin must be installed
with the flat surface aligned parallel to the
center of crankshaft, as shown in Figure 5-8.
2. Use a suitable tool to drive the pin into the
hole. The pin must be firmly seated and
protrude 0.77 inch (19.56 mm) from the
crankshaft.
Figure 5-8 — Dowel Pin Alignment
200337a
Page 5-11