Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Measurement Of Valve Guide Bore Diameter
3. Insert a telescoping gauge into the valve stem guide bore approximately 9.525 mm (.375 in.) from the valve spring side of the head.
4. Remove and measure telescoping gauge with a micrometer.
5. Repeat the measurement with contacts lengthwise to engine cylinder head.
6. Compare the crosswise to lengthwise measurements to determine out-of-roundness. If the measurements 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 diameter with specifications (7.95-7.97 mm or 0.313-0.314 in.). If the measurement differs from
specification by more than 0.076 mm (0.003 in.), ream the guide bore to accommodate an oversize valve stem.
ALTERNATIVE METHOD:
Measurement Of Lateral Movement Of Valve Stem
1. Use a dial indicator to measure the lateral movement of the valve stem (stem-to-guide clearance). This must be done with the valve installed in its
guide and just off the valve seat
2. Correct clearance is 0.025-0.0762 mm (0.001-0.003 in.) If indicated movement exceeds the specification ream the valve guide to accommodate an
oversize valve stem.
NOTE: Valve seats must be ground after reaming the valve guides to ensure that the valve seat is concentric to the valve guide.
VALVE SPRING TENSION TEST
