Valve Guides - Honda Acura NSX 1991 Service Manual

Valve Guides

. Replacement
1 . As illustrated, in the removal steps of this procedure
use a commercially-available air-impact driver at-
tachment which may need to be modified to fit the
diameter of the valve guides. In most cases, the
same procedure can be done using Valve Guide
Drivers and a conventional hammer. Tool numbers
are at the end of this procedure.
VALVE GUIDE DRIVER
mm-
87
in.)
(3.43
2.
Select the proper replacement guides and chill them
in the freezer section of a refrigerator for about an
hour.
3. Use a hot plate or oven to evenly heat the cylinder
head to 1 50°C J3OO"F). Monitor the temperature
with a cooking thermometer.
CAUTION:
excessive heat may loosen the valve seats.
the heated cylinder head.
6-44
mm
5 . 3
in)
(0.21
mm 4
57
- l -
in.)
(2.24
mm
1 0 . 8
in)
(0.42
4. Use the driver and an air hammer working from the
camshaft side to drive the guide about 2 mm towards
the combustion chamber. This will knock off some
of the carbon and make removal easier.
VALVE GUIDE DRIVER
07742-0010100
CAUTION:
using the air hammer.
Hold the air hammer directly in line with the valve
l
guide to prevent damaging the driver.
5. Turn the head over and drive the guide out toward
the camshaft side of head.
If a valve guide still won't move, drill it out with a
CAUTION: Drill guides only in extreme cases: you
could damage the cylinder head if the guide breaks.
6. Remove the new guide(s) from the refrigerator, one
at a time, as you need them.