1997 ACURA NSX Service Repair Manual

A/T:

Intake Valve Dimensions

A Standard (New): 34.9 - 35.1 mm

(1.374 - 1.382 in)

B Standard (New):

C Standard (New):

C Service Limit:

D Standard (New):

D Service Limit:
111.10-111.40 mm

(4.374 - 4.386 in)

5.475-5.485 mm

(0.2156-0.2159 in)

5.445 mm (0.2144 in)

1.05—1.35 mm

(0.041-0.053 in)

0.85 mm (0.033 in)

Exhaust Valve Dimensions

A
Standard (New):
29.9-30.1
mm

(1.177-1.185 in)

109.60-109.90
mm

(4.315-4.327 in)

5.45-5.46
mm

(0.2146-0.2150 in)

5.42 mm (0.2134 in)

1.65-1.95
mm

(0.065-0.077 in)

1.45 mm (0.057 in)
B Standard (New):

C Standard (New):

C Service Limit:

D Standard (New):

D Service Limit:ProCarManuals.com

Cylinder Head s
Warpag e
NOTE: I f camshaft-to-holde r oi l clearance s (se e page s
6-35 , 6-36 ) ar e no t withi n specification , th e cylinde r hea d
canno t b e resurfaced .
I f camshaft-to-holde r oi l clearance s ar e withi n specifica -
tions , chec k th e cylinde r hea d fo r warpage .
• I f warpag e i s les s tha n 0.0 5 m m (0.00 2 in ) cylinde r
head resurfacin g i s no t required .
• I f warpag e i s betwee n 0.0 5 m m (0.00 2 in ) an d 0. 2
mm (0.00 8 in) , resurfac e cylinde r head .
• Maximu m resurfac e limi t i s 0. 2 m m (0.00 8 in ) base d
on a heigh t o f 1 51 m m (5.94 5 in) .
PRECISIO N STRAIGH T EDG E
Measur e alon g edges , an d thre e way s acros s center .
Cylinde r Hea d Height :
Standar d (New) : 150.9 5 - 151.0 5 m m
(5.94 3 - 5.94 7 in )
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Valve Seat s
Reconditionin g
1. Rene w th e valv e seat s i n th e cylinde r hea d usin g a
valv e sea t grinder .
NOTE : I f guide s ar e wor n (se e pag e 6-41 ), replac e
the m (se e pag e 6-42 ) befor e grindin g th e valv e seats .
2 . Carefull y grin d a 45 ° seat , removin g onl y enoug h
materia l t o ensur e a smoot h an d concentri c seat .
3 . Beve l th e uppe r edg e o f th e sea t wit h th e 30 ° stone .
Beve l th e lowe r edg e i t tw o angles .
Firs t grin d th e edg e wit h th e 60 ° stone , the n grin d
th e botto m edg e wit h th e 67.5 ° stone .
Chec k widt h o f sea t an d adjus t accordingly .
4 . Mak e on e mor e ver y ligh t pas s wit h th e 45 ° ston e t o
remov e an y possibl e burr s cause d b y th e othe r
stones .
Valv e Sea t Width :
Standar d (New) :
Intak e 0.8 0 - 1.0 0 m m (0.03 1 - 0.03 9 in )
Exhaus t 1.2 5 - 1.5 5 m m (0.04 9 - 0.06 1 in )
Servic e Limit :
Intak e 1. 5 m m (0.05 9 in )
Exhaus t 2. 0 m m (0.07 9 in )
SEA T WIDT H
5. Afte r resurfacin g th e seat , inspec t fo r eve n valv e
seating : Appl y Prussia n Blu e compoun d t o th e valv e
face , an d inser t valv e i n origina l locatio n i n th e head ,
the n lif t i t an d sna p i t close d agains t th e sea t sever -
a l times .
ACTUA L
SEATIN G
SURFAC E
VALVESEAT
PRUSSIA N BLU E COMPOUN D
6. Th e actua l valv e seatin g surface , a s show n b y th e
blu e compound , shoul d b e centere d o n th e seat .
• I f i t i s to o hig h (close r t o th e valv e stem) , yo u
mus t mak e a secon d cu t wit h th e 60 ° ston e t o
mov e it down , the n on e mor e cu t wit h th e 45 °
ston e t o restor e sea t width .
• I f i t i s to o lo w (close r t o th e valv e edge) , yo u mus t
make a secon d cu t wit h th e 30 ° ston e t o mov e
it up , the n on e mor e cu t wit h th e 45 ° ston e t o
restor e sea t width .
NOTE : Th e fina l cu t shoul d alway s b e mad e wit h
th e 45 ° stone .
7 . Inser t intak e an d exhaus t valve s i n th e hea d an d
measur e valv e ste m installe d height .
Valv e Ste m Installe d Heigh t (Intak e an d Exhaust) :
Standard (New) : 41.55-42.3 5 m m
(1.6358-1.667 3 in )
Servic e Limit : 42.43 5 m m (1.670 7 in )
VALV E STE M
INSTALLE D HEIGH T
8. I f valv e ste m installe d heigh t i s ove r th e servic e limit ,
replac e th e valv e an d recheck . I f stil l ove r th e servic e
limit , replac e th e cylinde r head ; th e valv e sea t i n th e
hea d is to o deep .
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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)ProCarManuals.com

Valve Guide s
Replacemen t
1. A s illustrate d below , us e a commerciall y availabl e
air-impac t valv e guid e drive r attachmen t modifie d t o
fi t th e diamete r o f th e valv e guides . I n mos t cases ,
th e sam e procedur e ca n b e don e usin g th e specia l
too l an d a conventiona l hammer .
IMPACT VALV E GUID E DRIVE R
(Commerciall y available )
orVALV E GUID E DRIVER , 5. 5 m m07742-0010100
2. Selec t th e prope r replacemen t guides , an d chil l the m
in th e freeze r sectio n o f a refrigerato r fo r abou t a n
hour .
3 . Us e a ho t plat e o r ove n t o evenl y hea t th e cylinde r
head t o 300° F (150°C) . Monito r th e temperatur e
with a cookin g thermometer .
CAUTION:
• D o no t us e a torch ; i t ma y war p th e head .
• D o no t ge t th e hea d hotte r tha n 30 0°F (150°C) ;
excessiv e hea t ma y loose n th e valv e seats .
• T o avoi d burns , us e heav y glove s whe n handlin g
th e heate d cylinde r head . 4
. Workin g fro m th e camshaf t side , us e th e drive r an d
a n ai r hamme r t o driv e th e guid e abou t 2 m m (0. 1 in )
toward s th e combustion chamber. Thi s wil l knoc k of f
som e o f th e carbo n an d mak e remova l easier .
CAUTION :
• Alway s wea r safet y goggle s o r a fac e shiel d
whe n drivin g valv e guides .
• Hol d th e ai r hamme r directl y i n lin e wit h th e
valv e guid e t o preven t damagin g th e driver .
5 . Tur n th e hea d over , an d driv e th e guid e ou t towar d
th e camshaf t sid e o f head .
VALV E GUID E DRIVER , 5. 5 m m07742-001010 0
If a valv e guid e stil l won' t move , dril l i t ou t wit h a
8 m m (5/1 6 inch ) bit , the n tr y again .
CAUTION : Dril l guide s onl y i n extrem e cases ; yo u
coul d damag e th e cylinde r hea d if th e guid e breaks .
6 . Remov e th e ne w guide s fro m th e freezer , on e a t a
time , a s yo u nee d them .
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7. Appl y a thi n coa t o f clea n engin e oi l t o th e outsid e o f
th e ne w valv e guide . Instal l th e guid e fro m th e
camshaf t sid e o f th e head ; us e th e specia l too l t o
driv e th e guid e i n t o th e specifie d installe d height . I f
yo u hav e al l 1 2 guide s t o do , yo u ma y hav e t o rehea t
th e head .
VALV E GUID EDRIVER , 5. 5 m m07742-001010 0
Valve Guid e Installe d Height :
Intake: 13.75-14.2 5 m m (0.541-0.56 1 in )
Exhaust : 13.75-14.2 5 m m (0.541-0.56 1 in )
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Reaming
NOTE: Fo r ne w valv e guide s only .
1 . Coa t bot h reame r an d valv e guid e wit h cuttin g oil .
2 . Rotat e th e reame r clockwis e th e ful l lengt h o f th e
valv e guid e bore .
3 . Continu e t o rotat e th e reame r clockwis e whil e
removin g i t fro m th e bore .
4 . Thoroughl y was h th e guid e i n detergen t an d wate r
t o remov e an y cuttin g residue .
5 . Chec k clearanc e wit h a valv e (se e pag e 6-41 ).
— Verif y tha t th e valv e slide s in th e intak e an d exhaus t
valv e guide s withou t exertin g pressure .
REAMER HANDL E VALV
E GUID E
REAMER , 5. 5 m m
07HAH-PJ7010 B
Tur n reame r i n
clockwis e directio nonly.
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Valves, Valve Springs and Valve Seals

Installation Sequence

NOTE: Exhaust and intake valve seals are NOT interchangeable.

INTAKE VALVE SPRING
VALVE KEEPERS

VALVE SPRING

RETAINER

VALVE SPRING

EXHAUST VALVE SEAL

(BLACK SPRING)

Replace.

NOTE: Place the end of valve

spring with closely wound coils

toward the cylinder head.

INTAKE VALVE SEAL

(WHITE SPRING)

Replace.

SPRING SEAT

NOTE: Install the valve spring seats

before installing the valve seals.

VALVE SEAL INSTALLER

(Commercially available)

KD-2899

NOTE: Use small ID end of tool

VALVE SEAL

Replace.ProCarManuals.com