Jeep Cherokee 1999 Electronic Service Manual page 1157

9 - 44 ENGINE
CLEAN I N G AN D I N SPECT I ON (Cont inue d)
NOTE: On one side of the big end of the con-rod
there is a two-digit number which refers to the
weight category. On the other side of the big end
there is a four digit number on both the rod and the
cap. These numbers must both face the camshaft
as well as the recess on the piston crown (Fig. 76).
Lightly heat the piston in oven. Insert piston pin in
position and secure it with provided snap rings.
Th e F o u r d ig it n u m be rs m a rk e d o n c o n ro d
big e n d a n d ro d c a p m u s t be o n th e s a m e s id e
a s th e c a m s h a ft (F ig . 76). Aft er h a vin g coa t ed
t h r ea ds wit h Molygu a r d, t igh t en con r od bolt s t o 29
N·m (21 ft . lbs.) plu s 60°.
Fig. 75 Connecting Rod Identification
Fig. 76 Piston and Connecting Rod Assembly
INSPECTION—PISTON PIN
(1) Mea su r e t h e dia m et er of pist on pin in t h e cen -
t er a n d bot h en ds.
(2) P ist on pin dia m et er is 29.990 t o 29.996m m
(1.1807 t o 1.1809 in .).
INSPECTION—CRANKSHAFT JOURNALS
(1) Usin g a m icr om et er, m ea su r e a n d r ecor d cr a n k-
sh a ft con n ect in g r od jou r n a ls, t a ke r ea din g of ea ch
jou r n a l 120° a pa r t . Cr a n ksh a ft jou r n a l dia m et er is
53.84 t o 53.955m m (2.1196 t o 2.1242 in .).
(2) Cr a n ksh a ft jou r n a ls wor n beyon d lim it s or
sh ow sign s of ou t of r ou n dn ess m u st be r egr ou n d or
r epla ced. Min im u m r egr ou n d dia m et er is 53.69m m
(2.1137 in .).
BEARING-TO-JOURNAL CLEARANCE
Com pa r e in t er n a l dia m et er s of con n ect in g r od wit h
cr a n ksh a ft jou r n a l dia m et er. Ma xim u m clea r a n ce
bet ween con n ect in g r od a n d cr a n ksh a ft jou r n a ls .022
t o .076m m (.0008 t o .0029 in .).
Fig. 77 Bearing Clearance
CYLINDER WALL LINER ASSEMBL Y
INSPECTION
Th e cylin der wa lls sh ou ld be ch ecked for ou t -of-
r ou n d a n d t a per wit h da il bor e ga u ge. Th e cylin der
bor e ou t -of-r ou n d is 0.100 m m (.0039 in ch ) m a xim u m
a n d cylin der bor e t a per is 0.100 m m (0.0039 in ch )
m a xim u m . If t h e cylin der wa lls a r e ba dly scu ffed or
scor ed, n ew lin er s sh ou ld be in st a lled a n d h on ed, a n d
n ew pist on s a n d r in gs fit t ed.
Mea su r e t h e cylin der bor e a t t h r ee levels in dir ec-
t ion s A a n d B (F ig. 78). Top m ea su r em en t sh ou ld be
10 m m ( 3/8 in ch ) down a n d bot t om m ea su r em en t
sh ou ld be 10 m m ( 3/8 in ch .) u p fr om bot t om of bor e.
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