Yanmar 4TNV98, Service Manual

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4TNV98 & 4TNE98 Diesel Engine Section 3. Engine 98
Reassembly of Cylinder Head
Use new gaskets, O-rings, and seals on reassembly
of the cylinder head.
IMPORTANT
Liberally oil all components during reassembly to
prevent premature wear or damage.
Reassembly of Valve Guides
1. The valve guides are installed into the cylinder
head with an extremely tight press fit. Before
installing the valve guides, place the valve guides
in a freezer for at least twenty minutes This will
cause the valve guides to contract, making it
easier to install the valve guides into place.
2. Immediately after removing the valve guides from
the freezer, insert the valve guides (Figure 6-62,
(1)) in their proper positions.
4TNV98 Engine
4TNE98 Engine
Figure 6-62
3. Finish installing the valve guides (Figure 6-63,
(1)) into the cylinder head to the proper height
(Figure 6-63, (3)) using the valve guide installation
tool (Figure 6-63, (2)) . See Intake/Exhaust Valve
and Guide on page 67.
Figure 6-63
Reassembly of Intake and Exhaust Valves
IMPORTANT
Always install new valve stem seals. The exhaust
valve seals can be identified by having yellow paint.
Ensure they are installed in the correct locations.
1. Oil the lip of the valve stem seal (Figure 6-64, (2)) .
Using the valve stem seal installation tool (Figure
6-64, (1)) , install a new valve stem seal on each of
the valve guides (Figure 6-64, (3)) .
Figure 6-64