TM    5-2815-241-34&P CYLINDER  HEAD  -  CONTINUED ACTION LOCATION ITEM REMARKS CAUTION Never  vacuum  test  cylinder  head  with  injectors  installed.  Installation  of  injectors  while head is removed from block could cause misalinement of valves in valve seat area and result  in  leakage  during  testing  which  would  not  necessarily  occur  during  actual  engine operation. NOTE Steps 60 thru 64 are typical for all valves. (Vacuum tester operating instructions are provided  with  tester.) 60.  Cylinder  head  (5) Valve (12) Using  ST-417,  ST-417-A,  or  ST-1257 vacuum  testers,  hold  vacuum  cup  (13)  over head of valve and seat flat on cylinder head surface surrounding valve. 61. Vacuum  pump  (14) a. b. c. Operate  vacuum  pump  until  hand  (15) on  vacuum  gage  (16)  reaches  18  to 25 inches vacuum, then close shutoff valve  (17)  and  stop  pump. Start timing when hand on gage reaches l&inches   vacuum. Stop timing when hand on gage reaches 8-inches   vacuum. If  elapsed  time  is  less  than  10  sec- onds, valve seat is unsatisfactory. T A     2 4 2 4 8 1 2-211