Honda Acura NSX 1991 Service Manual page 117

Valves
. Valve Movement
Measure the guide-to-stem clearance with a dial indica-
tor while rocking the stem in the direction of normal thrust
(wobble method).
Intake Valve Stem-to-Guide Clearance:
Standard (New): 0.0125-0.0275 mm
(0.0005-0.0011
Service Limit: 0.08 mm (0.003 in1
Exhaust Valve Stem-to-Guide Clearance:
Standard (New): 0.025-0.04 mm
(0.001-0.0016
Service Limit: 0.055 in (0.0022 in)
Valve extended IO mm out from seat.
If measurement exceeds the service limit, recheck
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using a new valve.
reassemble using a new valve.
If measurement still exceeds limit, recheck using
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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, meas-
ured with a micrometer, from the I.D. of the valve guide,
measured with an inside micrometer or ball gauge.
Take the measurements in three places along the valve
stem and three places inside the valve guide. The differ-
ence between the largest guide measurement and the
smallest stem measurement should not exceed the serv-
ice 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 in1
Service Limit: 0.11 mm (0.004 in)
l eeo
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