Cylinder head and Valves/Valve seats LAPPING VALVE SEATS Check seat width and contact pattern between seat and valve with blueing. If necessary lap the valve onto its seat using a lapping tool and lapping compound. CD30380 -UN-10MAY95 IMPORTANT: Always check valve recess in cylinder head after lapping, as described in this group. CTM3274 (01JUL99) 05-12 Saran Liter Engines CD,3274,G05,55 -19-01FEB94 060799 PN=49 MEASURE VALVE GUIDES Using a micrometer, measure valve guides then compare with specifications. -UN-04MAY98 VALVE GUIDE SPECIFICATIONS Valve guide bore diameter in a new cylinder head . . . . . . . . . . . . . . . . .
7.912—7.938 mm (0.312—0.313in.) New guide-to-valve CD30550 stem clearance . . . . . . . . . . . . . . . . . . . . . . . . 0.05—0.10 mm (0.002—0.004 in.) Maximum permissible clearance . . . . . . . . . . . . . . . . . . . . . . . . . 0.15 mm (0.006 in.) If valve guide-to-stem oil clearance exceeds the wear limit, 0.38 mm (0.015 in.) and 0.76 mm (0.030 in.) oversize valve stems are available. Have valve guides reamed by a qualified workshop to assure a proper guide-to-stem clearance. NOTE: Production valve guides have a very shallow spiral cut (arrow), similar to a thread, to lubricate the valve stem with a metered supply of oil.
Be sure, when valve guides are reamed that this groove is restored. -UN-19MAY98 CD30548 CD,CTM125,027 -19-01DEC97 05 12