Jeep Cherokee 2000 Service Manual - page 991
VALVE GUIDES
The valve guides are an integral part of the engine
cylinder head and are not replaceable.
When the valve stem guide clearance is excessive,
the valve guide bores must be reamed oversize. Ser-
vice valves with oversize stems are available in 0.076
mm (0.003 inch) and 0.381 mm (0.015 inch) incre-
ments.
Corresponding oversize valve stem seals are also
available and must be used with valves having 0.381
mm (0.015 inch) oversize stems, 0.076mm (.003in.)
oversize stems do not require oversize seals.
NOTE: If the valve guides are reamed oversize, the
valve seats must be ground to ensure that the valve
seat is concentric to the valve guide.
VALVE STEM-TO-GUIDE CLEARANCE
MEASUREMENT
Valve stem-to-guide clearance may be measured by
either of the following two methods.
PREFERRED METHOD:
(1) Remove the valve from the head.
(2) Clean the valve stem guide bore with solvent
and a bristle brush.
(3) Insert a telescoping gauge into the valve stem
guide bore approximately 9.525 mm (.375 inch) from
the valve spring side of the head (Fig. 15).
(4) Remove and measure telescoping gauge with a
micrometer.
(5) Repeat the measurement with contacts length-
wise to engine cylinder head.
(6) Compare the crosswise to lengthwise measure-
ments to determine out-of-roundness. If the measure-
ments differ by more than 0.0635 mm (0.0025 in.),
ream the guide bore to accommodate an oversize
valve stem.
(7) Compare the measured valve guide bore diam-
eter with specifications (7.95-7.97 mm or 0.313-0.314
Fig. 13 Valve Facing Margin
1 – 0.787 MM (1/32 INCH) VALVE MARGIN
2 – NO MARGIN
Fig. 14 Measurement of Valve Seat Runout
1 – DIAL INDICATOR
Fig. 15 Measurement of Valve Guide Bore Diameter
1 – GAUGE
2 – 9.525 MM (3/8 INCH)
3 – VALVE STEM GUIDE
4 – CYLINDER HEAD
9 - 16
2.5L ENGINE
XJ
SERVICE PROCEDURES (Continued)