TM  10-3930-638-24&P 4-2.   ENGINE   MAINTENANCE   (cont) b. Cylinder Head and Valves (cont). STEP LOCATION ITEM ACTION REMARKS INSPECTION AND REPAIR (cont) (cont) 8 Exhaust  valve (6)  and  intake valve  (7) h. Studs (13) Inspect Inspect for bent condition and damaged threads. If bent or threads damaged, re- place.  Replace  by  unscrewing  stud  and screwing  new  stud  into  cylinder  head a.  Overall Inspect Replace if valve stem is nicked, valve face grooved, heavy carbon and/or varnish deposits, rust or pitting on valve stem or valve  face,  burned  valve  face,  or  dished valve head. Fine pitting on surface of valve face or seat is normal b. Ret airier groove Inspect Replace if worn or if stem tip is worn c.  Stem  diameter Measure  stem Three  places  as  shown.  Replace  exhaust diameter valve (6) if less than 0.3389 inch. Re- place intake valve (7) if less than 0.3399 inch 4-13