1997 ACURA NSX Service Repair Manual

Valve Installation

NOTE: Tap the valve stem only along its axis so you do

not bend the stem.

• When installing valves in the cylinder head, coat valve

stems with oil before inserting into valve guides, and

make sure all valves move up and down smoothly.

• When valves and springs are in place, lightly tap the

end of each valve stem two or three times to ensure

proper seating of valve and valve keepers (use ham-

mer handle bottom).

VALVE STEMS

HAMMER HANDLE

BOTTOMProCarManuals.com

Cylinder Head s
Installatio n
Install th e cylinde r head s i n th e revers e orde r o f removal :
• Alway s us e ne w hea d gaskets .
• Cylinde r head s an d engin e bloc k surfac e mus t b e
clean .
• Tur n th e crankshaf t s o tha t No . 1 pisto n i s a t TD C
(se e pag e 6-19 ).
• D o no t us e th e middl e cove r an d lowe r cove r t o
stor e remove d items .
• Clea n th e middl e cove r an d lowe r cove r befor e
installation .
1 . Instal l th e fron t an d rea r exhaus t manifold s t o eac h
cylinde r head , the n tighte n th e self-lockin g nut s i n a
crisscros s patter n i n tw o o r thre e steps , beginnin g
wit h th e inne r nu t (A/T) .
• Appl y oi l t o th e self-lockin g nu t threads .
• Alway s us e ne w exhaus t manifol d gaskets .
2 . Instal l th e exhaus t manifol d cover s (A/T) .
Front:
FRON T PRIMAR Y
HEATE D OXYGEN
SENSO R (FRON T PRIMAR Y HO2S )
4 4 N- m (4. 5 kgf-m , 3 3 Ibf-ft )
B e carefu l no t t o damage .
6 x 1. 0 m m12 N- m (1. 2 kgf- r8.7 Ibf-ft )
GASKE TReplace .
SELF-LOCKIN GNUT8 x 1.2 5 mm30 N- m (3. 1 kgf-m ,22 Ibf-ft )
FRON T EXHAUS T
EXHAUS T MANIFOL D
COVER
8 x 1.2 5 mm22 N- m (2. 2 kgf-m ,16 Ibf-ft )
(cont'd )
ProCarManuals.com

Cylinder Heads

Installation (cont'd)

Rear:

8 x
1.25
mm

22 N-m (2.2 kgf-m,

16 Ibf-ft)
REAR PRIMARY

HEATED OXYGEN SENSOR

(REAR PRIMARY HO2S)

44 N-m (4.5 kgf-m,

33 Ibf-ft)

Be careful not to damage.

GASKET

Replace.

REAR EXHAUST

MANIFOLD

EXHAUST

MANIFOLD

COVER

SELF-LOCKING NUT

8 x
1.25
mm

30 N-m (3.1 kgf-m,

22 Ibf-ft)

Replace.

3. Install the cylinder heads on the engine block.

The cylinder head dowel pins and the head oil con-

trol orifice must be aligned.

• Always use a new cylinder head gasket.

• Clean the oil control orifice before installing.

CYLINDER HEAD

GASKET

Replace.
OIL CONTROL

ORIFICES

Clean.
CYLINDER HEAD

GASKET

Replace.

DOWEL PIN
DOWEL

PINS

O-RING

Replace.
4. Tighten the cylinder head bolts sequentially in two

or three steps.

• Apply clean engine oil to the bolt threads and

washer contact surfaces.

Specified Torque

M/T:
11 x 1.5 mm

96 N-m (9.8 kgf-m, 71 Ibf ft)

A/T:
11 x 1.5 mm

76 N-m (7.8 kgf-m, 56 Ibf ft)

NOTE: We recommend using a beam-type torque

wrench. When using a preset-type torque wrench,

be sure to tighten slowly and not to over-tighten.

CYLINDER HEAD BOLTS TORQUE SEQUENCE

CYLINDER HEAD BOLT

M/T:
11 x 1.5 mm

96 N-m (9.8 kgf-m, 71 Ibf-ft)

A/T:
11 x 1.5 mm

76 N-m (7.8 kgf-m, 56 Ibf-ft)

Apply clean engine oil to the

bolt threads and washer contact

surfaces.ProCarManuals.com

Rocker Arms

Installation

Install the rocker arms in the reverse order of removal:

• Valve adjusting locknuts should be loosened and

adjusting screws backed off before installation.

• The component parts must be installed in the

original locations.

1. Install the lost motion assemblies.

2. Install the rocker arms while passing the rocker arm

shaft through the cylinder head.

ROCKER ARMS

ROCKER SHAFT

ROCKER SHAFT

O-RING

Replace.

CAUTION:

• After installing the rocker shaft orifice, try to turn

the rocker shaft to make sure that the orifice has

been inserted in the hole of the rocker shaft cor-

rectly. If the orifice is in place, it should not turn.

• Remove the rubber bands after installing the

rocker arms.
RUBBER BAND

3. Install the orifices. If the holes in the rocker arm

shafts and the cylinder head are not in line with

each other, use a 12 x 1.25 mm bolt in the rocker

arm shaft to rotate the shaft.

O-RING

Replace.

ROCKER SHAFT

OIL CONTROL

ORIFICES

Clean.ProCarManuals.com

Camshafts

Installation

CAUTION: Valve locknuts should be loosened and ad-

justing screws backed off before installation.

1. After wiping down the camshaft and journals in the

cylinder head, lubricate both surfaces and install the

camshafts and rubber caps.

NOTE: Apply liquid gasket around the rubber cap.

2. Turn the camshaft until its keyway is facing up. (No. 1

cylinder
TDC).

3. Set a new O-ring and a dowel pin in the oil passage

of the No. 1 camshaft holder.

4. Install the camshaft seals with the open side

(spring) facing in.

Lubricate cam lobes after reassembly.

O-RING

(Replace)

and

DOWEL PIN
Keyways

facing up.

CAMSHAFT SEAL

Seal housing surface should be dry.

Apply a light coat of oil to camshaft

and inner lip of seal.
RUBBER CAPS

Replace for oil

leakage.ProCarManuals.com

Camshafts

Installation (cont'd)

5. Apply liquid gasket to the head mating surfaces of

the No. 1 and the No. 4 camshaft holders.

5. Apply liquid gasket to the shaded areas.

6. Install the camshaft holders.

NOTE:

• "F" or "R" marks are stamped on the camshaft

holders.

• The arrows must be pointing to the timing belt

side.

• Set two dowel pins in each camshaft holder.

FRONT:

No. 4 No. 3 No. 2 No. 1

CAMSHAFT CAMSHAFT CAMSHAFT CAMSHAFT

HOLDER HOLDER HOLDER HOLDER

No. 4 No. 3 No. 2 No. 1

CAMSHAFT CAMSHAFT CAMSHAFT CAMSHAFT

HOLDER HOLDER HOLDER HOLDER
7. Install the camshaft holder plates.

8. Tighten each bolt two turns at a time in the sequence

shown below to insure that the rockers do not bind

on the valves.

NOTE: Apply clean engine oil to 8 mm bolt threads.

Specified torque:

8 mm x 1.25 mm bolts:

22 N-m (2.2 kgf-m, 16 Ibf-ft)

6 mm x 1.0 mm bolts:

9.8 N-m (1.0 kgf-m, 7.2 Ibf-ft)

CAMSHAFT HOLDER BOLT TORQUE SEQUENCE

FRONT:ProCarManuals.com

9. Instal l th e CKP/CY P senso r o n th e fron t cylinde r
head .
CKP/CY P SENSO R
6 x 1. 0 m m12 N- m (1. 2 kgf-m , 8. 7 Ibf-ft )
10. Instal l th e fron t an d rea r bac k covers .
RUBBE R SEAL S
REA R BAC K COVE R
6 x 1. 0 m m12 N- m (1. 2 kgf-m ,
8. 7 Ibf-ft ) RUBBE
R SEAL S
FRON T BAC K COVE R
RUBBE R SEA L
11. Inser t th e dowe l pin s i n th e camshaf t pulley .
12 . Instal l th e camshaf t pulleys , the n tighte n th e retain -
in g bolt s t o th e torqu e specified .
CAMSHAF T PULLEY S
RETAININ G BOLT S
10 x 1.25 mm69 N- m (7. 0 kgf-m , 5 1 Ibf-ft )
13. Instal l th e timin g bel t (se e pag e 6-18 ).
14 . Adjus t th e valv e clearanc e (se e pag e 6-9 ).
15 . Inspec t th e rocke r arm s (se e page s 6-7 , 6-8 ).
16 . Instal l th e hea d cove r gaske t i n th e groov e o f th e
cylinde r hea d cover . Sea t th e recesse s fo r th e
camshaf t first , the n wor k i t int o th e groov e aroun d
th e outsid e edges .
NOTE:
• Befor e installin g th e hea d cove r gasket , thor -
oughl y clea n th e sea l an d th e groove .
• Whe n installing , mak e sur e th e hea d cove r gaske t
i s seate d securel y i n th e corner s o f th e recesse s
with n o gap .
HEA D COVE RGASKE TClean.
RUBBE RSEAL
CORNER S O F
TH E RECESSE S
CYLINDER HEA DCOVE R
CORNER S O F
TH E RECESSE S
(cont'd)
ProCarManuals.com

Camshafts

Installation (cont'd)

17. Apply liquid gasket to the head cover gasket at the

eight corners of the recesses.

NOTE:

• Use liquid gasket, Part No. 08718 - 0001 or 08718

- 0003.

• Check that the mating surfaces are clean and dry

before applying liquid gasket.

• Do not install the parts if five minutes or more

have elapsed since applying liquid gasket. Instead,

reapply liquid gasket after removing old residue.

• After assembly, wait at least 20 minutes before

filling the engine with oil.

Apply liquid gasket to

the shaded areas.

18. When installing the cylinder head cover, hold the

head cover gasket in the groove by placing your fin-

gers on the camshaft contacting surfaces (top of the

semicircles).

Once the cylinder head cover is on the camshaft

holder, slide the cover slightly back and forth to

seat the head cover gasket.

NOTE:

• Before installing the cylinder head cover, clean

the cylinder head contacting surfaces with a

shop towel.

• Do not touch the parts where liquid gasket was

applied.

• Replace the washer when damaged or deterio-

rated.

CYLINDER

HEAD COVER
WASHER

6 x 1.0 mm

12 N-m (1.2 kgf-m,

8.7 Ibf-ft)
19. Tighten the nuts in two or three steps. In the final step,

tighten all nuts, in sequence, to 12 N-m (1.2 kgf-m,

8.7 Ibf-ft).

NOTE: After assembly, wait at least 20 minutes

before filling the engine with oil.

20. After installation, check that all tubes, hoses and

connectors are installed correctly.

NOTE: After installation, fill the engine with oil up to

the specified level, run the engine for more than three

minutes, then check for oil leakage.ProCarManuals.com