Mack E7, Service Manual

Page: 175 / 303

200 ENGINE ASSEMBLY
Page 6-17
[211 HA] CYLINDER BLOCK
DOWEL PINS
Description
The diamond locating dowel pins used to install
the front timing gear cover, flywheel and flywheel
housing, have been replaced in production by
blade-style locating dowel pins. The diamond
pins were dual-diameter type pins with a smaller
diameter at the round end that goes into the
cylinder block. The blade-style pins are the same
diameter at the round end and the blade end.
There are no changes in the size of the hole in
the front timing cover. However, the cylinder
block has a larger hole to accept the blade-style
dowel pins. The cylinder block timing gear cover
old pin number is 183GC221 and the new
number, starting with serial number 2T (August
1992), is 183GC238.
Use a dowel size and type that is appropriate for
the block being used. (Service old with old and
new with new.) Install the blade-style dowel with
the blade in a vertical direction (pointing up and
down).
Special Tools Required
앫
Flywheel Housing Diamond Dowel Aligner
J 37711
앫
Flywheel Housing/Timing Cover Locating Pin
Driver J 37712
Removal
If it is necessary to remove the timing cover or
flywheel housing locating dowel pins, do so as
follows:
1. Securely clamp the pin with a pair of vise-
grip pliers.
2. While exerting an outward force, rotate pin
back and forth until the pin works free from
the hole.
Installation
Two precision-made dowel pins are used to
locate the flywheel housing to the cylinder block.
One dowel is round, the other is a diamond shape
or blade type, as described earlier, depending on
the production date.
The dowels used for timing gear cover installation
are similar except for the size. The smaller
dowels are used for the timing cover. The larger
dowels are used for the flywheel housing.
ROUND DOWEL PIN INSTALLATION
Refer to Figure 6-18.
1. Insert round dowel pin (2) into the flywheel
housing/timing cover locating pin driver
J 37712 (1). The pin must be positioned in
the driver with tapered end of the dowel
facing outward.
2. Position exposed end of dowel into the left
dowel pin hole (4) in cylinder block (3).
3. Using a hammer, drive the pin into the block
until the driver contacts the cylinder block.
When the driver has made contact with the
block, the dowel pin will be at the correct
dimension above the block.
Figure 6-18 — Round Dowel Pin Installation
1. Locating pin driver
2. Round dowel pin
3. Cylinder block
4. Dowel pin hole
5-101.bk Page 17 Friday, March 17, 2006 11:05 AM