ACURA NSX 1997 Service Repair Manual

Piston/Connecting Ro d Assemblie s an d Crankshaf t
Removal (cont'd )
• Remov e th e connectin g ro d cap s afte r settin g
the cran k pi n a t BD C fo r eac h cylinder . Remov e
the pisto n assembl y b y pushin g o n th e connec -
ting rod .
CAUTION : Tak e car e no t t o damag e th e cran k pi n
o r cylinde r wit h th e connectin g rod .
CORREC TPISTONS
INCORREC T
8. Remov e th e bearin g fro m th e cap . Kee p al l
caps/bearing s i n order .
9 . Remov e th e uppe r bearin g halve s fro m th e connect -
in g rods . Se t the m asid e wit h thei r respectiv e caps .
10 . Reinstal l th e ca p o n th e ro d afte r removin g eac h
piston/connectin g ro d assembly .
11 . Mar k th e piston/connectin g ro d assemblie s wit h
thei r cylinde r number s t o avoi d mixu p o n reassem -
bly.
NOTE : Th e existin g numbe r o n th e connectin g ro d
doe s no t indicat e it s positio n i n th e engine , i t in -
dicate s th e ro d bor e size . 12
. Remov e th e bearin g ca p bolt s an d bearin g ca p sid e
bolts , the n remov e th e bearin g caps .
BEARIN G CA P
BEARIN G CA PBOL T
BEARIN G CA PSIDE BOL T
• T o hel p wit h remova l o f th e caps , instal l th e bear -
in g ca p bridg e bolt s i n th e bearin g ca p bol t holes .
BEARIN G CA PBRIDG E BOL T
BEARIN G CAP S
13. Lif t th e crankshaf t ou t o f engine , bein g carefu l no t
t o damag e th e journals .
14 . Reinstal l th e mai n cap s an d bearing s o n th e bloc k in
prope r order .
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Crankshaft
Inspection
• Clea n th e crankshaf t oi l passage s wit h pip e
cleaner s o r a suitabl e brush .
• Chec k th e keywa y an d threads .
Alignmen t
• Measur e runou t o n al l mai n journal s t o mak e
sur e th e cran k i s no t bent .
• Th e differenc e betwee n measurement s o n eac h
journa l mus t no t b e mor e tha n th e servic e limit .
Crankshaf t Tota l Indicate d Runout :
Standard (New) : 0.01 5 m m (0.000 6 in ) max .
Servic e Limit : 0.0 3 m m (0.001 2 in )
DIA L INDICATO R
Rotat e tw o complet e
revolutions .
Support wit h lathe -type too l o r V-blocks .
Out-of-Roun d an d Tape r
• Measur e out-of-roun d a t th e middl e o f eac h ro d
and mai n journa l i n tw o places .
• Th e differenc e betwee n measurement s o n eac h
journa l mus t no t b e mor e tha n th e servic e limit .
Journa l Out-of-Round :
Standard (New) : 0.00 4 m m (0.000 2 in ) max .
Servic e Limit : 0.00 6 m m (0.000 2 in )
Measur e out-of -round a t middle .
• Measur e tape r a t edge s o f eac h ro d an d mai n
journal .
• Th e differenc e betwee n measurement s o n eac h
journa l mus t no t b e mor e tha n th e servic e limit .
Journa l Taper :
Standar d (New) : 0.00 5 m m (0.000 2 in ) max .
Servic e Limit : 0.01 0 m m (0.000 4 in )
Measur e tape rat edges .
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Cylinder Bloc k
Inspectio n
1. Measur e wea r an d tape r i n direction s X an d Y at
thre e level s i n eac h cylinde r a s shown .
CYLINDE R BOR E SIZE S ( A o r B )
NOTE : T o maintai n prope r pisto n
clearance , matc h thes e letter s wit h
th e letter s o n th e pistons . Th e let -
ter s o n th e bloc k rea d fro m lef t t o
right , No . 1 throug h No . 3 cylinder s
on th e firs t lin e an d No . 4 throug hNo. 6 cylinder s o n th e secon d line .
Cylinde r Bor e Siz e
M/T:
Standar d (New) :
A o r I 93.01 0 - 93.02 0 m m (3.661 8 -3.662 2 in )
B o r i l 93.00 0 - 93.01 0 m m (3.6614-3.661 8 in )
Servic e Limit : 93.0 7 m m (3.66 4 in )
A/T :
Standard (New):
A o r I 90.01 0 - 90.02 0 m m (3.543 7 -3.544 1 in )
B o r i l 90.00 0 - 90.01 0 m m (3.543 3 -3.543 7 in )
Servic e Limit : 90.0 7 m m (3.54 6 in )
Oversize (A/T):
0.25: 90.2 5 - 90.2 6 m m (3.55 3 - 3.55 4 in )
0.50 : 90.5 0 - 90.5 1 m m (3.56 3 - 3.56 3 in ) Bor
e Tape r
Limit : (Differenc e betwee n firs t an d thir d measure -
ment ) 0.0 5 m m (0.00 2 in )
• I f measurement s i n an y cylinde r ar e beyon d
Oversize Bor e Servic e Limit , replac e th e block .
• I f bloc k i s t o b e rebored , refe r t o Pisto n Clear -
anc e Inspectio n (se e pag e 7-13 ) afte r reboring .
NOTE : Score d o r scratche d cylinde r bore s mus t b e
honed .
Reborin g Limi t (A/T) : 0.5 0 m m (0.02 0 in )
2 . Chec k th e to p o f th e bloc k fo r warpage .
Measur e alon g th e edge s an d acros s th e cente r a s
shown .
SURFACE S T O B E MEASURE D
Engine Bloc k Warpage :
Standar d (New) : 0.0 7 m m (0.00 3 in ) max .
Servic e Limit : 0.1 0 m m (0.00 4 in )
PRECISIO N STRAIGH T EDG E
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Bore Honin g (A/T )
NOTE : Onl y score d o r scratche d cylinde r bore s mus t b e
honed .
1 . Measur e cylinde r bore s a s show n o n pag e 7-12 . I f
th e bloc k i s t o b e reused , hon e th e cylinder s an d
remeasur e th e bores .
2 . Hon e cylinde r bore s wit h honin g oi l an d a fin e (40 0
grit ) ston e in a 60 degre e cross-hatc h pattern .
NOTE :
• Us e onl y a rigi d hon e wit h 40 0 gri t o r fine r ston e
such a s Sunnen , Ammco , o r equivalent .
• D o no t us e stone s tha t ar e wor n o r broken .
3 . Whe n honin g i s complete , thoroughl y clea n th e
cylinde r bloc k o f al l meta l particles . Was h th e cylin -
de r bore s wit h ho t soap y water , the n dr y an d oi l
the m immediatel y t o preven t rusting .
NOTE : Neve r us e solvent , i t wil l onl y redistribut e
th e gri t o n th e cylinde r walls .
4 . I f scorin g o r scratche s ar e stil l presen t i n cylinde r
bore s afte r honin g t o servic e limit , rebor e th e cylin -
de r block .
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Piston/Connecting Rod

Assemblies

Inspection

1. Check the piston for distortion or cracks.

NOTE: If cylinder is bored, an oversized piston

must be used.

2. Measure piston diameter at a point 17 mm (0.67 in)

from the bottom of the skirt.

NOTE: There are two standard-size pistons (A =

no letter and B). The letter is stamped on the top of

the piston. These letters are also stamped on the

block as cylinder bore sizes.

M/T:

Piston A (no letter) Diameter

Standard (New): 92.990 - 93.003 mm

(3.6610-3.6615 in)

Service Limit: 92.97 mm (3.6602 in)

Piston B Diameter

Standard (New): 92.980 - 92.993 mm

(3.6606-3.6611 in)

Service Limit: 92.96 mm (3.6598 in)

A/T:

Piston A (no letter) Diameter

Standard (New): 89.986 - 90.004 mm

(3.5427 - 3.5435 in)

Service Limit: 89.97 mm (3.5421 in)

Piston B Diameter

Standard (New): 89.976 - 89.994 mm

(3.5424 - 3.5431 in)

Service Limit: 89.96 mm (3.5417 in)ProCarManuals.com

Piston/Connecting Ro d
Assemblie s
Inspection (cont'd )
3. Calculat e th e differenc e betwee n cylinde r bor e diam -
ete r o n pag e 7-1 2 an d pisto n diameter .
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Connecting Rods

Selection

Each rod is sorted into one of four tolerance ranges

(from O to 0.024 mm, in 0.006 mm increments) depen-

ding on the size of its big end bore. It's then stamped

with a number (1, 2, 3 or 4) indicating that tolerance.

You may find any combination of 1, 2, 3 or 4 in any

engine.

Normal Bore Size: 55 mm (2.17 in)

NOTE:

• Reference numbers are for big end bore size and

do NOT indicate the position of the rod in the

engine.

• Inspect each connecting rod for cracks and heat

damage.ProCarManuals.com

Piston Ring s
End Ga p
1. Usin g a piston , pus h a ne w rin g int o th e cylinde r
bore 15-2 0 m m (0. 6 - 0. 8 in ) fro m th e bottom .
2 . Measur e th e pisto n rin g end-ga p wit h a feele r
gauge :
• I f th e ga p i s to o small , chec k t o se e i f yo u hav e
th e prope r ring s fo r you r engine .
• I f th e ga p i s to o large , rechec k th e cylinde r bor e
diamete r agains t th e wea r limit s o n pag e 7-12 . I f
th e bor e i s ove r limit , th e cylinde r bloc k mus t b e
rebored .
Pisto n Rin g End-Gap :
To p Rin g
M/T:
Standar d (New) :
Servic e Limit :
A/T:
Standar d (New) :
Servic e Limit :
Secon d Rin g
Standar d (New) :
Servic e Limit :
Oi l Rin g
Standar d (New) :
Servic e Limit :
0.20 - 0.3 0 mm
(0.008-0.01 2 in )
0.5 0 m m (0.02 0 in )
0.2 5 - 0.4 0 mm
(0.010-0.01 6 in )
0.6 0 m m (0.02 4 in )
0.3 5 - 0.5 0 mm
(0.014-0.02 0 in )
0.75 mm (0.0 3 in)
0.2 0 - 0.7 0 mm
(0.00 8 - 0.02 8 in )
0.8 0 m m (0.03 1 in )
Replacemen t
1. Usin g a rin g expander , remov e th e ol d pisto n rings .
2. Clea n al l rin g groove s thoroughly .
NOTE:
• Us e a squared-of f broke n rin g o r rin g groov e
cleane r wit h blad e t o fi t pisto n grooves .
• To p an d 2n d rin g groove s ar e 1. 2 m m (0.0 5 in )
wid e an d th e oi l rin g groov e i s M/T : 2. 5 m m (0.1 0
in) , A/T : 2. 8 m m (0.1 1 in ) wide .
• Fil e dow n th e blad e i f necessary .
CAUTION : D o no t us e a wir e brus h to clea n th e rin g
grooves , o r cu t rin g groove s deepe r wit h a cleanin g
tool .
3 . Instal l ne w ring s i n th e prope r sequenc e an d posi -
tio n (se e pag e 7-16 ).
NOTE : D o no t reus e ol d pisto n rings .
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Piston Rings

Ring-to-Groove Clearances

After installing a new set of rings, measure ring-to-groove

clearances:

Top Ring Clearance

M/T:

Standard (New): 0.035 - 0.065 mm

(0.0014-0.0026 in)

Service Limit: 0.13 mm (0.005 in)

A/T:

Standard (New): 0.030 - 0.055 mm

(0.0012 - 0.0022 in)

Service Limit: 0.13 mm (0.005 in)

Second Ring Clearance

M/T:

Standard (New): 0.030 - 0.060 mm

(0.0012-0.0024 in)

Service Limit: 0.13 mm (0.005 in)

A/T:

Standard (New): 0.030 - 0.055 mm

(0.0012-0.0022 in)

Service Limit: 0.13 mm (0.005 in)ProCarManuals.com

Alignment
1. Instal l th e ring s a s shown .
NOTE:
• Th e to p rin g ha s a n R 1 o r R mark .
• Th e secon d rin g ha s a n R 2 o r R N mark .
NOTE : Th e manufacturin g mark s mus t b e facin g
upward .
Piston Ring s
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