Jeep Cherokee 1999 Electronic Service Manual page 1156

X J
CLEAN I N G AN D I N SPECT I ON (Cont inue d)
Fig. 73 Checking Cylinder Head Flatness
ROCKER ARMS AND PUSH RODS
CLEANING
Clea n a ll t h e com pon en t s (F ig. 74) wit h clea n in g
solven t .
Fig. 74 Rocker Arm Components
Use com pr essed a ir t o blow ou t t h e oil pa ssa ges in
t h e r ocker a r m s a n d pu sh r ods.
INSPECTION
In spect t h e pivot su r fa ce a r ea of ea ch r ocker a r m .
Repla ce a n y t h a t a r e scu ffed, pit t ed, cr a cked or
excessively wor n .
In spect t h e va lve st em t ip con t a ct su r fa ce of ea ch
r ocker a r m a n d r epla ce a n y r ocker a r m t h a t is deeply
pit t ed.
In spect ea ch pu sh r od en d for excessive wea r a n d
r epla ce a s r equ ir ed. If a n y pu sh r od is excessively
wor n beca u se of la ck of oil, r epla ce it a n d in spect t h e
cor r espon din g h ydr a u lic t a ppet for excessive wea r.
In spect t h e pu sh r ods for st r a igh t n ess by r ollin g
t h em on a fla t su r fa ce or by sh in in g a ligh t bet ween
t h e pu sh r od a n d t h e fla t su r fa ce.
A wea r pa t t er n a lon g t h e len gt h of t h e pu sh r od is
n ot n or m a l. In spect t h e en gin e cylin der h ea d for
obst r u ct ion if t h is con dit ion exist s.
PISTONS AND CONNECTING ROD ASSEMBL Y
INSPECTION—PISTONS
(1) P ist on Dia m et er : Size Gr ou p A: 91.93-91.94m m
(3.6191-3.6196 in .) Size Gr ou p B: 91.94-91.95m m
(3.6196-3.6200 in .). Ma xim u m wea r lim it .05m m
(.0019 in .).
(2) Ch eck pist on pin bor es in pist on for r ou n dn ess.
Ma ke 3 ch ecks a t 120° in t er va ls. Ma xim u m ou t of
r ou n dn ess .05m m (.0019 in .).
(3) Th e pist on dia m et er
a ppr oxim a t ely 15 m m (.590 in .) u p fr om t h e ba se.
(4) Skir t wea r sh ou ld n ot exceed 0.1 m m (.00039
in .).
(5) Th e clea r a n ce bet ween t h e cylin der lin er a n d
pist on sh ou ld n ot exceed 0.25 m m (.0009 in .).
(6) Ma ke su r e t h e weigh t of t h e pist on s does n ot
differ by m or e t h a n 5 g.
INSPECTION—CONNECTING ROD
(1) Assem ble bea r in g sh ells a n d bea r in g ca ps t o
t h eir r espect ive con n ect in g r ods en su r in g t h a t t h e
ser r a t ion s on t h e ca p a n d r efer en ce m a r ks a r e
a lign ed.
(2) Tigh t en bea r in g ca p bolt s t o 29N·m (21 ft . lbs.)
plu s 60°.
(3) Ch eck a n d r ecor d in t er n a l dia m et er of cr a n k
en d of con n ect in g r od.
NOTE: When changing connecting rods, all four
must have the same weight and be stamped with
the same number. Replacement connecting rods
will only be supplied in sets of four.
Con n ect in g r ods a r e su pplied in set s of fou r sin ce
t h ey a ll m u st be of t h e sa m e weigh t ca t egor y. Ma x
a llowa ble weigh t differ en ce is 18 gr.
ENGINE 9 - 43
sh ou ld be m ea su r ed