TM 10-3930-669-34 3-6. CYLINDER HEAD REPAIR (CONT). c. Repair. CAUTION Perform all inspections before beginning repairs.  Do not reheat cylinder head.  Too much heating may warp head. NOTE • Use  the  following  procedure  to  make  sure  cylinder  head  seating  surface  is  flat  and square. • Remove as little material as possible to achieve a perfect sealing surface. (1)   Check     cylinder     head     seating     surface     (11). Surface must be flat and square.  Minor damage to  seating  surface  can  be  removed  by  grinding cylinder head on cylinder with abrasive stone. (2)   If   cylinder   head   seating   surface   (11)   is   more severely  damaged,  replace  cylinder  head  (Para 3-5). NOTE • Use the following procedure to make sure valve springs, valve rotators, spring caps, valves, and valve seats are within specification. • Measurement must be made with intermediate ring inserted. (3)   Inspect intermediate ring (12).  Replace if damaged. (4)   After refacing cylinder head seating surface (11), measure clearance between cylinder head bottom and cylinder head seating  surface.    If  measured  value  is  not  between  0.2323  in.  (5.9000  mm)  and  0.2519  in.    (6.4000  mm), replace valve seats (13). (5)   Inspect  valve  seats  (13).    Measure  distance  between  crown  of  valve  and  cylinder  head  seating  surface  (11).    If measured distance is not between 0.2000 in.  (5.0800 mm) and 0.2205 in. (5.6000 mm), replace valve seats. 3-44