TM 10-3930-653-14&P (2)  INSTALLING VALVE ROCKER SHAFT Install   the   bracket   and   inner   spring   on   the   valve rocker  shaft.    The  shaft  has  four  installation  bolt  holes. Face the side with the larger hole (which also serves as a  lubrication  hole)  to  the  front.    Install  the  lock  washer. spacer,  and  cotter  pin  in  that  sequence  to  both  ends  of the rocker arms. (3)  INSTALLING CAM BUSHINGS (1)  Installing center bushing Face notch toward distributor drive side  (downward) match block and jig caulking hole and tap on bushing. Fig. 4-80.  Installing Rear Bushing. (2)  Installing rear bushing Face  arrow  mark  on  end  of  bushing,  upward. Align  oil  hole  with  oil  hole  in  cylinder  block  and  tap  rear bushing into position, as shown in figure 2-68.  Diameter of  bushing  is  slightly  larger  toward  rear  and  bushing  is press fit in block. (4) CRANKSHAFT REAR BEARING OIL SEAL (1)      Using   oil   seal   replacer,   install   rear   oil   seals   into cylinder block groove and rear bearing cap respectively. When   seal   is   fully   inserted,   ends   of   seal   protruding above  bearing  supports  should  be  cut  off  so  that  seal ends line up with each other. Fig. 4-81.  Oil Seal Installation. Fig. 4-82.  Oil Seal Installation. (2)    Install  main  bearings  and  thrust  bushings  in  main bearing caps and cylinder block. WARNING Dry, cleaning solvent P-D 680 is toxic and   flammable.      protective   goggles and gloves and use only in a ventilated  area.    Avoid  contact  with skin,    eyes,    and    clothes    and    don’t breathe   vapors.      Do   not   use   near open flame or excessive heat.  If you become    dizzy    while    cleaning    with solvent,    get    fresh    air    immediately! and  get  medical  aid.    If  contact  with skin  or  clothing  is  made,  flush  with water.    If  contact,  with  eyes  is  made, flush   your   eyes   with   water   and   get medical aid immediately. WARNING Compressed    air    used    for    cleaning purposes   not   exceed   30   PSI.      Use only with effective chip guarding and personal protective equipment (goggles, shield, gloves, etc.). (3)    Thoroughly  clean  reverse  side  of  upper  and  lower bearing  shells  and  make  sure  that  notch  and  tang  on bearing shells are properly matched. 4-44