Jeep Cherokee 1999 Electronic Service Manual page 1041

9 - 24 2.5L ENGINE
SERV I CE PROCEDU RES (Cont inue d)
NOTE: When replacing inserts, the odd size inserts
must be either all on the top (in cylinder block) or
all on the bottom (in main bearing cap).
On ce t h e bea r in gs h a ve been pr oper ly fit t ed, pr o-
ceed t o Cr a n ksh a ft Ma in Bea r in g—In st a lla t ion .
BEARING-TO-JOURNAL CLEARANCE (CRANKSHAFT
INSTALLED)
Wh en u sin g P la st iga ge, ch eck on ly on e bea r in g
clea r a n ce a t a t im e.
In st a ll t h e gr ooved m a in bea r in gs in t o t h e cylin der
block a n d t h e n on -gr ooved bea r in gs in t o t h e bea r in g
ca ps.
In st a ll t h e cr a n ksh a ft in t o t h e u pper bea r in gs dr y.
P la ce a st r ip of P la st iga ge a cr oss fu ll widt h of t h e
cr a n ksh a ft jou r n a l t o be ch ecked.
In st a ll t h e bea r in g ca p a n d t igh t en t h e bolt s t o 108
N·m (80 ft . lbs.) t or qu e.
NOTE: DO NOT rotate the crankshaft. This will
cause the Plastigage to shift, resulting in an inaccu-
rate reading. Plastigage must not be permitted to
crumble. If brittle, obtain fresh stock.
Rem ove t h e bea r in g ca p. Det er m in e t h e a m ou n t of
clea r a n ce by m ea su r in g t h e widt h of t h e com pr essed
P la st iga ge wit h t h e sca le on t h e P la st iga ge en velope
(F ig. 21). Refer t o E n gin e Specifica t ion s for t h e
pr oper clea r a n ce.
Fig. 21 Measuring Bearing Clearance with Plastigage
P la st iga ge sh ou ld in dica t e t h e sa m e clea r a n ce
a cr oss t h e en t ir e widt h of t h e in ser t . If clea r a n ce va r-
ies, it m a y in dica t e a t a per ed jou r n a l or for eign
m a t er ia l t r a pped beh in d t h e in ser t .
If t h e specified clea r a n ce is in dica t ed a n d t h er e a r e
n o a bn or m a l wea r pa t t er n s, r epla cem en t of t h e bea r-
in g in ser t s is n ot n ecessa r y. Rem ove t h e P la st iga ge
fr om t h e cr a n ksh a ft jou r n a l a n d bea r in g in ser t . P r o-
ceed t o Cr a n ksh a ft Ma in Bea r in g—In st a lla t ion .
If t h e clea r a n ce exceeds specifica t ion , in st a ll a pa ir
of 0.025 m m (0.001 in ch ) u n der size bea r in g in ser t s
a n d m ea su r e t h e clea r a n ce a s descr ibed in t h e pr evi-
ou s st eps.
Th e clea r a n ce in dica t ed wit h t h e 0.025 m m (0.001
in ch ) u n der size in ser t pa ir in st a lled will det er m in e if
t h is in ser t size or som e ot h er com bin a t ion will pr o-
vide t h e specified clea r a n ce. F OR EXAMP LE: If t h e
clea r a n ce wa s 0.0762 m m (0.003 in ch ) or igin a lly, a
pa ir of 0.0254 m m (0.001 in ch ) u n der size in ser t s
wou ld r edu ce t h e clea r a n ce by 0.0254 m m (0.001
in ch ). Th e clea r a n ce wou ld t h en be 0.0508 m m (0.002
in ch ) a n d wit h in t h e specifica t ion . A 0.051 m m (0.002
in ch ) u n der size bea r in g in ser t a n d a 0.0254 m m
(0.001 in ch ) u n der size in ser t wou ld r edu ce t h e or igi-
n a l clea r a n ce a n a ddit ion a l 0.0127 m m (0.0005 in ch ).
Th e clea r a n ce wou ld t h en be 0.0381 m m (0.0015
in ch ).
CAUTION: Never use a pair of inserts that differ
more than one bearing size as a pair.
F OR EXAMP LE: DO NOT u se a st a n da r d size
u pper in ser t a n d a 0.051 m m (0.002 in ch ) u n der size
lower in ser t .
If t h e clea r a n ce exceeds specifica t ion u sin g a pa ir
of 0.051 m m (0.002 in ch ) u n der size bea r in g in ser t s,
m ea su r e cr a n ksh a ft
m icr om et er. If t h e jou r n a l dia m et er is cor r ect , t h e
cr a n ksh a ft bor e in t h e cylin der block m a y be m is-
a lign ed, wh ich r equ ir es cylin der block r epla cem en t or
m a ch in in g t o t r u e bor e.
If jou r n a ls 1 t h r ou gh 5 dia m et er s a r e less t h a n
63.4517 m m (2.4981 in ch es), r epla ce cr a n ksh a ft or
gr in d cr a n ksh a ft down t o a ccept t h e a ppr opr ia t e
u n der size bea r in g in ser t s.
On ce t h e pr oper clea r a n ces h a ve been obt a in ed,
pr oceed t o Cr a n ksh a ft Ma in Bea r in g—In st a lla t ion .
MAIN BEARING JOURNAL DIAMETER
(CRANKSHAFT REMOVED)
Rem ove t h e cr a n ksh a ft fr om t h e cylin der block
(r efer t o Cylin der Block - Disa ssem ble).
Clea n t h e oil off t h e m a in bea r in g jou r n a l.
Det er m in e t h e m a xim u m dia m et er of t h e jou r n a l
wit h a m icr om et er. Mea su r e a t t wo loca t ion s 90°
a pa r t a t ea ch en d of t h e jou r n a l.
Th e m a xim u m a llowa ble t a per a n d ou t of r ou n d is
0.013 m m (0.0005 in ch ). Com pa r e t h e m ea su r ed
dia m et er wit h t h e jou r n a l dia m et er specifica t ion
(Ma in Bea r in g F it t in g Ch a r t ). Select in ser t s r equ ir ed
t o obt a in t h e specified bea r in g-t o-jou r n a l clea r a n ce.
On ce t h e pr oper clea r a n ces h a ve been obt a in ed,
pr oceed t o Cr a n ksh a ft Ma in Bea r in g—In st a lla t ion .
jou r n a l dia m et er wit h
X J
a