TM 5-3825-226-24 CYLINDER, VALVE, AND PUMP LOCATION 2. Turn  the  crankshaft  COUNTERCLOCKWISE  (as seen from rear of engine) until No.  1 piston is at top center on the compression stroke.  The TDC-1 mark     on     the     damper     assembly     will     be     in alignment with the timing pointer. 3. Make adjustment to the valves for No.  I and No. 2   cylinders.      To   make   the   adjustment,   loosen locknut  (2).    Turn  the  adjustment  screw  (1)  until the  feeler  gauge  (3)  will  go  between  the  end  of the valve stem and the rocker arm. VALVE LASH ADJUSTMENT 1.  Adjustment screw.  2.  Locknut.  3.  Feeler gauge. 4. After the adjustment is complete, hold adjustment screw (1) and tighten locknut (2) to 24 ±  5 lb.  ft. (32  ±   7   N•m).      After   the   locknut   is   tightened, check the adjustment again. 5. Turn the crankshaft 180 ° COUNTERCLOCKWISE   (as   seen   from   rear   of engine).    The  VS  mark  on  the  damper  assembly will be in alignment with the timing pointer.  Make adjustment  to  the  valves  for  No.    3  and  No.    7 cylinders. 6. Turn the crankshaft 180° COUNTERCLOCKWISE   (as   seen   from   rear   of engine).        The    TDC1    mark    on    the    damper assembly   will   be   in   alignment   with   the   timing pointer.  Make adjustment to the valves for No.  4 and No.  5 cylinders. TIGHTENING LOCKNUT 7. Turn the crankshaft 1800 COUNTERCLOCKWISE   (as   seen   from   rear   of engine).    The  VS  mark  on  damper  assembly  will be  in  alignment  with  the  timing  pointer.    Make adjustment  to  the  valves  for  No.    6  and  No.    8 cylinders. When  the  adjustment  of  the  valve  lash  needs  to be done several times in a short period of time, it can be an  indication  of  wear  in  a  different  part  of  the  engine. Find   the   problem   and   make   any   necessary   repairs   to prevent more damage to the engine. Not  enough  valve  lash,  if  not  corrected,  can  be the   cause   of   rapid   wear   of   the   camshaft   and   cam followers.        Not    enough    valve    lash    can    also    be    an indication  of  the  seats  for  the  valves  being  bad.    Some reasons  for  the  seats  for  the  valves  becoming  bad  are fuel  injection  nozzles  with  defects,  restriction  to  the  inlet air   or   dirty   air   filters,   wrong   fuel   setting,   or   using   the engine on loads that are too large for the engine. Too much valve lash, if not corrected, can be the cause   for   broken   valve   stems,   push   rods,   or   spring retainers.      A   fast   increase   in   valve   lash   can   be   an indication of any of the following: a. Camshaft and cam follower with wear. b. Rocker arms with wear. c. Push rods that are bent. d. Loose adjustment screw for the valve lash. e. Broken  socket  on  the  upper  end  of  a  push rod. If  the  camshaft  and  cam  followers  show  signs  of rapid   wear,   look   for   fuel   in   the   lubrication   oil   or   dirty lubrication   oil   as   a   possible   cause   when   making   the necessary repairs. 2-66