nsxb06039a.pdf

Valve Guides
Valve Movement
Measure the guide-to-stem clearance with a dial indicator
while rocking the stem in the direction of normal thrust
(wobble method).
Intake Valve Stem-to-Guide Clearance:
Standard (New): 0.05 — 0.11 mm
(0.002 — 0.004 in)
Service Limit: 0.16 mm (0.006 in)
Exhaust Valve Stem-to-Guide Clearance:
Standard (New): 0.10 — 0.16 mm
(0.004 — 0.006 in)
Service Limit: 0.22 mm (0.009 in)
Valve extended 10 mm out from seat.
If measurement exceeds the service limit, recheck
using a new valve.
If measurement is now within the service limit,
reassemble using a new valve.
If measurement still exceeds limit, recheck using
alternate method below, then replace valve and
guide, if necessary.
NOTE: An alternate method of checking guide to
stem clearance is to subtract the O.D. of the valve
stem, measured with a micrometer, from the I.D. of
the valve guide, measured with an inside microme-
ter or ball gauge.
Take the measurements in three places along the
valve stem and three places inside the valve guide.
The difference between the largest guide measure-
ment and the smallest stem measurement should
not exceed the service limit.
Intake Valve Stem-to-Guide Clearance:
Standard (New): 0.025 — 0.055 mm
(0.001 — 0.002 in)
Service Limit: 0.08 mm (0.003 in)
Exhaust Valve Stem-to-Guide Clearance:
Standard (New): 0.05 — 0.08 mm
(0.002 — 0.003 in)
Service Limit: 0.11 mm (0.004 in)