18. Reface the valve seats as described in this chap-
ter.
19. Install the intake manifold. Use new O-rings,
and torque the intake manifold bolts to 10 N•m (89
in.-lb.).
20. When servicing a rear cylinder head, install the
exhaust manifold with a new exhaust gasket.
Torque the exhaust manifold nuts to 20 N•m (15
ft.-lb.).
Valve Seat Inspection
1. Remove the valves as described in this chapter.
2. The most accurate means for checking the valve
seal is to use marking compound, available from
automotive parts stores or machine shops. Check
the valve seal with marking compound as follows:
a. Thoroughly clean all carbon deposits from
the valve face with solvent or detergent.
Completely dry the valve face.
b. Spread a thin layer of marking compound
evenly on the valve face.
c. Insert the valve into its guide.
d. Support the valve by hand (
Figure 97
), and
tap the valve up and down in the cylinder
head. Do not rotate the valve or the impres-
sion will not be accurate.
e. Remove the valve and examine the impres-
sion left by the marking compound. If the im-
pression left in the dye (on the valve or in the
cylinder head) is not even and continuous,
and if the valve seat width (
Figure 98
) is not
within the tolerance specified in
Table 2
, the
valve seat must be reconditioned.
3. Closely examine the valve seat in the cylinder
head (
Figure 93
). It should be smooth and even,
with a polished seating surface.
4. Measure the valve seat width (
Figure 98
) with a
vernier caliper.
5. If the valve seat is within specification, install
the valves as described in this section.
6. If the valve seat is not correct, recondition the
valve seat in the cylinder head as described in this
chapter.
Valve Seat Reconditioning
Special valve cutters and considerable expertise
are required to properly recondition the valve seats
in the cylinder head. You can save money by remov-
ENGINE TOP END
117
4
96
97
98
Valve seat
width