Wrangler 4WD L4-150 2.5L VIN P MFI (1998)
Measurement Of Valve Seat Runout
3. Control valve seat runout to a maximum of 0.0635 mm (0.0025 in.).
VALVE STEM OIL SEAL REPLACEMENT
Valve stem oil seals are installed on each valve stem to prevent rocker arm lubricating oil from entering the combustion chamber through the valve
guide bores. One seal is marked INT (intake valve) and the other is marked EXH (exhaust valve).
Replace the oil seals whenever valve service is performed or if the seals have deteriorated.
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. Service valves with oversize stems are available in
0.076 mm (0.003 in. and 0.381 mm (0.015 in.) increments.
Corresponding oversize valve stem seals are also available and must be used with valves having 0.381 mm (0.015 in. 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.
