Valve & Valve Guide Servicing

Guides are integral with head. Some valves with oversize stems are used. They are identified by marks on inboard side of cylinder head on machined surface just above intake manifold. Service valves are available in standard, .003", .005", .010" and .013" oversizes.
Valve guide reamers are available in .003", .005" and .013" oversize. Use reamers in sequence. DO NOT use too large a reamer and remove spiraling in guide, or lack of oil to valve will result.
With head removed and disassembled, check valve stem-to-guide clearance. If clearance exceeds specifications, ream guide to next oversize. Inspect valve stem end for wear. Valve stem end may be reconditioned by grinding to proper dimension at 90° angle.
If valve seat face is reground, check margin width dimension. Check seats for proper angle and width. Measure valve seat runout. Runout should be within .002" (.05 mm) for intake and exhaust. Intake seat width is .037-.075" (.94-1.90 mm). Exhaust seat width is .050-.090" (1.27-2.29 mm). Use scraper to break (lightly chamfer or bevel) sharp top inside edge of guide.
Check valve head for warpage. Do not reface valve. If edge of valve head is less than .031" (.8 mm) thick, replace valve. Whenever new valves are installed or after grinding seats, measure valve stem height.
Using Valve Stem Height Gauge (J-25289), check there is .015" (.381 mm) minimum clearance between gauge surface and end of valve stem. Check distance between gauge surface and spring rotator is .030" (.762 mm) minimum.
If gauge-to-stem clearance is less than specification, remove valve and grind tip of valve stem at 90° angle to gain proper clearance. If valve stem end-to-spring retainer is less than .005" (.127 mm) above spring retainer, replace valve.