Mack E7, Service Manual, Page: 242 / 303

Page 7-2
200 SETUP AND ADJUSTMENTS
[213 NB] VALVE YOKE AND
VALVE LASH ADJUSTMENTS
(NON-JAKE BRAKE ENGINE
AND DYNATARD EQUIPPED)
Description
Yoke and valve adjustments are done in two
stages on E7 engines. Adjust the yoke clearance
first, then adjust the valve lash. Make sure both
adjustments are done in firing order sequence.
Manually rotate the engine in normal rotation
direction until pointer in flywheel housing aligns
with valves 1 and 6 mark on the flywheel and the
No. 1 piston on the compression stroke.
The flywheel has a stamped timing scale
consisting of TC through 45 degrees of engine
travel for setting and checking pump-to-engine
timing. Also, the flywheel has three stamped
locations at 120-degree intervals for valve settings.
Some E7 engines are equipped with a pointer on
the timing gear cover and marks on the vibration
damper. To adjust the yoke and valves on these
engines, bar engine in normal rotation direction
until the TC mark on the damper (with the No. 1
piston on the compression stroke) aligns with
pointer marked VALVE. This provides the 30-
degrees-after-TDC relationship for valve lash
adjustment necessary with the E7 camshaft
design.
Yoke and valve adjustments must be made under
static conditions with coolant temperature below
100°F (37°C).
E7 engine firing order is 1-5-3-6-2-4.
Special Tool Required
앫
Engine Barring Socket J 38587-A
Locating and Marking Flywheel
Valve Adjustment Markings
Some E7 engines built in early 1995 may be
equipped with flywheels that have missing or
illegible valve adjustment markings. If this
problem is encountered, a typical flywheel can be
marked while the engine is in the chassis.
TYPICAL FLYWHEELS
On a typical flywheel, the TC markings, and the
valve adjustment markings, are directly in line
with the clutch mounting bolt/bolt holes. To
determine if the engine is equipped with a typical
flywheel, view the flywheel through the timing
access hole in the flywheel housing. Align the TC
markings with the timing pointer. If the flywheel is
typical, there should be a clutch mounting bolt/
bolt hole directly in line with the TC marking. In
this case, the valve adjustment markings should
be in line with a clutch mounting bolt at three
locations. (Refer to Figure 7-2 Flywheel Marks.)
There are 12 clutch mounting bolt holes in the
flywheel, but only 8 of these holes are used to
mount the clutch. Every third bolt hole, for a total
of four, is not used. These holes are in an open
area between the clutch mounting flanges. The
unused holes are easy to see through the timing
access hole in the flywheel housing. The bolt
holes where there is a clutch mounting bolt are
more difficult to see because the clutch mounting
bolt head is somewhat rearward of the timing
access opening. To aid in counting the clutch
mounting bolt/bolt holes, keep in mind that there
is slightly over four inches between one bolt hole
and the next. Locating the clutch mounting bolts
may be made easier by removing the bell housing
inspection cover and viewing or feeling for the
bolts through the bell housing.
5-101.bk Page 2 Friday, March 17, 2006 11:05 AM