1991 ACURA NSX torque

Additional Torque Value Specifications:

NOTE: For manifold replacement, refer to section 9.

ENGINE HANGER

8 x
1.25
mm

30 N .
m
(3.0 kg-m,

22 Ib-ft)
A/T TRANSMISSION HANGERS

8 x
1.25
mm
30 N .
m

(3.0 kg-m,

22 Ib-ft)

M/T TRANSMISSION

HANGERS

12 x
1.25
mm

75 N .
m (7.5 kg-m, 54 Ib-ft)

6 x 1.0 mm

10 N .
m (1.0 kg-m, 7 Ib-ft)

8 x
1.25
mm

22 N .
m
(2.2 kg-m,

16 Ib-ft) HALF SHAFT
SUPPORT BASE

(cont'd)

HALF SHAFT
HEAT COVER

8 x
1.25
mm

22 N
.
m
(2.2 kg-m,

16 Ib-ft)
A/C BRACKET

HALF SHAFT

10 x
1.25
mm

45 N .
m
(4.5 kg-m,

33 Ib-ft)

ALTERNATOR

BRACKET

STIFFENER

8 x
1.25
mm

22 N
.
m
(2.2 kg-m,

16 Ib-ft)
8x
1.25
mm

22 N .
m
(2.2 kg-m,

16 Ib-ft)
10 x
1.25
mm

45 N .
m
(4.5 kg-m,

33 Ib-ft)

ALTERNATOR

BRACKET

8 x
1.25
mm

22 N .
m
(2.2 kg-m,

16 Ib-ft)ProCarManuals.com

Engine Removal/Installation

(cont'd)

Sub-frame Torque Value Specifications:

RIGHT REAR

BRACKET

10 x
1.25
mm

60 N .
m
(6.0 kg-m.

43 Ib-ft)
LEFT REAR

BRACKET

10 x
1.25
mm

60 N .
m
(6.0 kg-m

43 Ib-ft)

10 x 1.25mm

60 N .
m (6.0 kg-m, 43 Ib-ft)
CORROSION RESISTANT BOLT/NUT

12 x
1.25
mm
95 N.m (9.5 kg-m, 69 Ib-ft)

10 x
1.25
mm

60 N .
m (6.0 kg-m, 43 Ib-ft)
ROD A

10 x
1.25
mm

60 N .
m
(6.0 kg-m,
43 Ib-ft)

FRONT BEAM
REAR BEAM

12 x
1.25
mm

95 N .
m

(9.5 kg-m,
69 Ib-ft) ROD B

10 x
1.25
mm

60 N .
m (6.0 kg-m, 43 Ib-ft)
CENTER RODProCarManuals.com

Cylinder Head/Valve Train
Illustrated Index

CAUTION: To avoid damaging the cylinder head, wait

until the engine coolant temperature drops below
100 °F (38 °C) before removing it.NOTE:

CAP NUT

6 x 1.0 mm
10 N .
m
(1.0 kg-m,

7 Ib-ft)
CYLINDER

HEAD COVER

WASHER AND

GROMMET

After installation, fill the engine with oil up to the

specified level, run the engine for more than 3

minutes, then check for oil leakage.

When installing the new crankshaft;

tighten the crankshaft pulley bolt to 280 N .
m (28

kg-m, 203 Ib-ft),

loosen bolt.


retighten it to

250 N .
m (25 kg-m, 181 Ib-ft).

CYLINDER HEAD

COVER
RUBBER SEALS
Replace when damaged

or deteriorated.

6 x 1.0 mm
12N .
m (1.2 kg-m,

9 Ib-ft)

TIMING BELT
REAR MIDDLE

COVER

TIMING BELT
FRONT MIDDLE

COVER
ADJUSTING BOLT

10 x
1.25
mm

43N .
m (4.3 kg-m,

31 Ib-ft)

For adjustment only,
do not remove.

ALTERNATOR

BELT

Adjustment,
section 23

6 x 1.0 mm
12N .
m
(12
kg-m.

9 Ib-ft)

CRANKSHAFT PULLEY
Remove any oil.

SPECIAL BOLT
16x 1.5 mm

250N .
m (25 kg-m,

181 Ib-ft

Tightening torque for
a new crankshaft.

203

Apply oil to
the bolt threads, but not
to the surface that contacts the washer.
6 x 1.0 mm

12N .
m (1.2 kg-m,

9 Ib-ft)
AIR CONDITIONING (A/C) BELT
Adjustment, section 22
6x 1.0 mm

12N .
m (1.2 kg-m, 9 Ib-ft)

(cont'd)

A/C ADJUSTING

PULLEY BRACKET

RUBBER SEAL
Install with concave

surface facing out.

Remove any oil.
TIMING BELT

DRIVE PULLEY

Remove any oil.

Install with concave
surface facing in.
Remove any oil.

TIMING BELT

Inspection, page 6-22
Adjustment, page 6-22 Replacement, page 6-23 to 26
RUBBER SEALS

Replace when damaged
or deteriorated.
CAP NUT

6 x 1.0 mm

10N .
m (1.0 kg-m,

7 Ib-ft)

TIMING BELT

LOWER COVER

RUBBER SEAL
KEY

Remove any oil.

TENSIONER

280

250N.m

25
kg-m,
181 Ib-ft)

(28
0
0
0

Use new O-rings and gaskets when reassembling.

Replace rubber seals, if damaged or deteriorated.

Prior to installing the cylinder head cover, apply a thin

layer of liquid gasket to the mating surface of the

cylinder head cover and rubber seals to prevent the
rubber seal from falling off.ProCarManuals.com

Remove any oil.
TIMING BELT

Inspection, page 6-22

Adjustment, page 6-22

6 x 1.0 mm
12N .
m(1.2kg-m,9 Ib-ft)
Timing Belt
Illustrated Index
Turn the crankshaft so that the No. 1 piston is at top
dead center (TDC) (page 6-25, 26)
Replace rubber seals if damaged or deteriorated.
Prior to installing the cylinder head cover, apply a thin
layer of liquid gasket to the mating surface of the cylinder head cover and rubber seals to prevent the
rubber seal from falling of.
CYLINDER HEAD COVER
CAP NUT

6x 1.0 mm

10N .
m (1.0 kg-m, 7 Ib-ft)
CAP NUT

6 x 1.0 mm

10N .
m (1.0 kg-m,
7 Ib-ft)

WASHER

RUBBER SEALS
Replace when damaged

or deteriorated.

ADJUSTING BOLT
10 x
1.25
mm

43N .
m (4.3 kg-m,31 Ib-ft)

For adjustment only,

do not remove.
Remove any oil.

COLLARS

RUBBER SEALS

Replace when damaged
or deteriorated.

6 x 1.0 mm
12N .
m (1.2 kg-m.
9 Ib-ft)
6x1.0
mm
12N .
m (1.2 kg-m.
9 Ib-ft)

TIMING BELT
FRONT MIDDLE

COVER

CRANKSHAFT
PULLEY

Remove any oil.
6 x 1.0 mm

12N .
m (1.2 kg-m.

9 Ib-ft)

SPECIAL BOLT
16 x 1.5 mm

250N .
m (2.5 kg-m,

181 Ib-ft)

Tightening torque for
a new crankshaft.

Apply oil to the bolt threads,
but not to the surface

that contacts the washer.

280


0

250N.m

28

0

25
kg-m.

203

0

181 Ib-ft LOWER COVER

RUBBER SEAL
After installation, fill the engine with oil up to the

specified level, run the engine for more than 3
minutes, then check for oil leakage.
When installing a new crankshaft; i tighten the crankshaft pulley bolt to 280N.m (28
kg-m, 203 Ib-ft), loosen it, retighten it to 250
N.m (25 kg-m, 181 Ib-ft).ProCarManuals.com

Rotate pulley and

Inspect belt.
for wear.

1 . Remove the ignition coil covers and harness clamps.
2. Disconnect the connectors, then remove the ignition
coils.
3. Remove the cylinder head covers.
4. Inspect the timing belt for cracks and coolant or oil

soaking.

NOTE:

TDC MARK
BLUE MARK

ADJUSTING BOLT

43N
.
m (4.3 kg-m.

31 Ib-ft)

Direction

of rotation

POINTER ON

LOWER COVER
Tension Adjustment

Always adjust timing belt tension with the engine cold.

Do not rotate the crankshaft when adjusting bolt is

loose (the timing belt will skid over the teeth of the
rear intake camshaft pulley).

Never adjust the belt tension on any other occasion

than when the belt is removed.

shaft pulley.
3. Loosen the timing belt adjusting bolt 180° (the slack
Then, tighten the timing belt adjusting bolt.

4. Verify the No. 1 piston at TDC (page 6-26).

5. Rotate the crankshaft clockwise 9-teeth on cam- shaft pulley (The blue mark on crankshaft pulley
should line up with the pointer on lower cover).
6. Loosen the timing belt adjusting bolt.
7. Retighten the adjusting bolt, torque to 43 N .
m (4.3
kg-m, 31 Ib-ft).

at


should be eliminated).

quence of


and

by turning each cam-
Replace the belt if coolant or oil soaked.
Remove any oil or solvent that gets on the belt.

Inspect this area

Timing Belt
Inspection
CAUTION:

NOTE:
Tensioner is spring-loaded to apply proper tension to
the belt automatically after making the following ad-
justment.
Inspect the timing belt before adjusting the belt
tension.
Always rotate the crankshaft clockwise. Rotating it
counterclockwise may result in improper adjustment
of the belt tension or cause the belt to jump a tooth on the camshaft pulleys.
1 . Install the timing belt with the No. 1 piston at TDC
(page 6-25, 26).

2. Fix the crankshaft, remove the slack in the se-ProCarManuals.com

Camshafts

Inspection

1. Put the camshafts, the camshaft holders and holder pipes on the cylinder head, and then tighten

the bolts to the specified torque.

NOTE: Apply clean engine oil to 8 mm bolt threads.
Specified torque: 8 mm x 1.25 mm bolts:
22N .
m (2.2 kg-m, 16 Ib-ft)
6 mm x 1.0 mm bolts: 10N .
m (1.0 kg-m, 7 Ib-ft)

CAMSHAFT HOLDER BOLTS TORQUE
SEQNUENCE

FRONT:

REAR:
PLASTIGAGE STRIP
2. Seat the camshaft by pushing it toward left end of
cylinder head.
3. Zero the dial indicator against the left end, then push the camshaft back and forth, and read the end play.Camshaft End Play:
Standard (New): 0.05—0.15 mm

(0.002-0.006
in)

Service Limit: 0.5 mm (0.02 in)
4. Remove the bolts, then remove the camshaft holders from the cylinder head.
Do not rotate the camshaft during inspection.
Remove the rocker arms and rocker shafts.

NOTE:

Lift camshaft out of cylinder head, wipe clean,
then inspect lift ramps. Replace camshaft if lobes
are pitted, scored, or excessively worn. Clean the camshaft bearing surfaces in the
cylinder head, then set camshaft back in place.
Insert plastigage strip across each journal.

5. Install the camshaft holders, and then tighten the

bolts to the specified torque, as shown in the left
column on this page.
6. Remove the camshaft holders and measure widest portion of plastigage on each journal.
Camshaft-to-Holder Oil Clearance:
Standard (New):
0.050-0.089
mm

(0.002-0.004 in)

Service Limit: 0.15 mm (0.006 in)ProCarManuals.com

Cylinder Heads
Installation (cont'd)
Rear:
8 x
1.25
mm
22 N .
m
(2.2 kg-m,
16 Ib-ft)

HEATED OXYGEN

SENSOR

45 N .
m
(4.5 kg-m,
33 Ib-ft) Be careful not to damage.

GASKET
Replace.

REAR EXHAUST
MANIFOLD

EXHAUST

MANIFOLD

COVER
SELF LOCKING NUTS
8 x
1.25
mm

34 N .
m
(3.4 kg-m,

25 Ib-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.

CYLINDER HEAD

GASKET (METAL)
Replace.
CYLINDER HEAD

GASKET (METAL)

Replace.

HEAD ORIFICES

DOWEL

PIN

DOWEL PIN
O-RING
Replace.
DOWEL

PINS
CYLINDER HEAD BOLTS

11 x 1.5 mm

78 N .
m (7.8 kg-m. 56 Ib-ft)

Apply clean engine oil to the bolt threads and washer contact

surfaces.

CYLINDER HEAD BOLTS TORQUE SEQUENCE

Specified Torque

11 x 1.5 mm

78 N .
m (7.8 kg-m, 56 Ib-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.
Always use a new cylinder head gasket. Apply clean engine oil to the bolt threads and
washer contact surfaces.
4. Tighten the cylinder head bolts sequentially in two
or three steps.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.Apply liquid gasket to the shaded areas.
6. Place the camshaft holders.

REAR:
No. 4 No. 3 No. 2 No. 1
CAMSHAFT CAMSHAFT CAMSHAFT CAMSHAFT
HOLDER HOLDER HOLDER HOLDER
REAR:
7. Place the cam holder pipes.
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 kg-m, 16 Ib-ft)

6 mm x 1.0 mm bolts:
10 N .
m (1.0 kg-m, 7 Ib-ft)

CAMSHAFT HOLDER BOLT TORQUE SEQUENCE

FRONT:

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 HOLDERProCarManuals.com