Inlet And Exhaust Valve Installation - Mack E7 Service Manual

5-101.bk Page 45 Friday, March 17, 2006 11:05 AM
Refer to Figures 5-57 and 5-58.
The following (Figures 5-57 and 5-58) show a
remanufactured cylinder head assembly ID and
20-degree intake valve ID.
Figure 5-57 — Remanufactured Cylinder Head
Assembly ID
Figure 5-58 — 20-Degree Intake Valve ID
Refer to Figure 5-57.
Any remanufactured cylinder head produced prior
to 12/13/96 will not have the assembly ID
stamped on it. Heads which do not have
assembly ID stamps are 30-degree intake valves
and seats.
200 BENCH PROCEDURES

Inlet and Exhaust Valve Installation

The inlet and exhaust valve head diameters are
nearly the same size. It is important, therefore, that
extra care be taken when assembling these valves.
With the new, more effective valve stem seals
(446GC328), pre-lubing the seals and valve
stems during installation is extremely important.
Perform the following:
Valve Stem to Guide — If valves are
removed, lubricate the inside diameter of the
valve guides by using a "bottle brush" coated
with graphite grease. This is particularly
important when both the valves and the valve
guides are new. With an on-engine seal
replacement, pre-lube the valve stems with
engine oil while moving the valve up and
down, prior to installation of the valve spring.
Valve Stem to Seal Lip — The inside
diameter of the seal lip and outside diameter
of the valve stem should be well-lubricated
with clean engine oil when installing the seal
over the valve stem.
It is essential that the J 42453 Valve Stem Seal
Installation tool be used to install the seals. This
tool bottoms on the cylinder head rocker arm
mounting bracket surface when the seal is
installed to the proper depth on the valve guide.
Using any non-bottoming type seal driver (such
as a socket) may result in distorting the top
surface of the seal casing which permanently
distorts the seal lip and prevents proper sealing,
or in the top rubber portion of the seal being cut
off. Also, do not use seal installer J 41150, or seal
damage will result. Tool J 41150 should be
discarded immediately after receiving tool
J 42453.
Before installing valve stem seals, be sure the
rotator has been installed. The rotator will not fit
over the valve stem seal.
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