Cylinder Head, Valves and Manifolds Inspection/Replacement Before inspection, thoroughly clean all components of carbon or dirt. Cylinder Head: Measure cylinder head flatness. Place a straight- edge along each of the four sides and each diagonal. Measure clearance between straight edge and combustion surface with a feeler gauge. Valve Seat Width 1 Valve Seat Width - 3TN66: Intake Valve Standard . . . . . . . . . . . . . 1.15 mm (0.045 in.) Wear Limit. . . . . . . . . . . . 1.65 mm (0.065 in.) Exhaust Valve Standard . . . . . . . . . . . . . 1.41 mm (0.056 in.) Wear Limit. . . . . . . . . . . . 1.91 mm (0.075 in.) Cylinder Head Distortion: Valve Seat Width - 3TNA72 (3009): Standard . . . . .
. . 0.05 mm (0.002 in.) or less Wear Limit. . . . . . . . . . . . 0.15 mm (0.006 in.) Intake Valve Standard . . . . . . . . . . . . . 1.44 mm (0.057 in.) Wear Limit. . . . . . . . . . . . 1.98 mm (0.078 in.) If distortion exceeds the wear limit, resurface or replace cylinder head. Remove only enough metal to make cylinder head flat; but do not remove more than 0.20 mm (0.008 in.) . Exhaust Valve Standard . . . . . . . . . . . . . 1.77 mm (0.070 in.) Wear Limit. . . . . . . . . . . . 2.27 mm (0.089 in.) If cylinder head was resurfaced: If necessary, grind valve seats to meet specifications. (See GRIND VALVE SEATS procedure.) Measure piston-to-cylinder head clearance.
(See procedure in this group.) Intake and Exhaust Valves: Measure valve recession. (See procedure in this group.) Check valve for out-of-round, bent or warped condition using a valve inspection center. Replace valve if necessary. Measure valve seat width. 1-24 4/7/95 AllTractorManuals.com ht-Edge Feeler M820 Straig ht-Edge Feeler Gauge M820 28A M8202 9A