Be  careful  not  to  cut  into  counterbore  bottom.  See figure  7-12.  Thoroughly  clean  valve  seat  counterbore and remove any burrs from the edges. Drive new valve seat inserts into place. Be certain that each seat rests solidly  on  bottom  of  counterbore  at  all  points.  To make installation easier, heat cylinder head in an oven at 325 °F (163 ºC) for about l/2-hour. Face each  new seat to the value given in table 1-2. The finished seat face  should  contact  approximately  center  of  the  valve face. Use Prussian Blue on each valve face to check this.  Make  any  corrections  on  the  seat,  not  the  valve face.  When  new  seats  are  installed  and  faced,  insert valve into each seat and check clearance from valve head to the face of cylinder head. If it is not the value given  in  table  1-2,  regrind  the  seat. (4)  Valve  Springs.  Check  valve  springs  (5,  figure 7-11)  on  a  compression  scale.  Valve  spring  data  is given in the table 1-2. Replace any spring that is weak, cracked or pitted or has ends out of square. (5) Push Rods. Check that push rod is absolute- ly straight. Replace bent or worn push rods. e.   Reassemble. (1) Push a valve stem oil seal assembly (4) onto each intake valve guide (6, figure 7-11). Then oil inside surface  of  each  seal. (2) Oil the stem of each valve (8 and 10, figure 7-11) and insert each in its own guide (6 and 9). If in- take valve (8) is removed with seal in place on guide, wrap  sharp  edge  of  valve  notch  with  cellophane  tape to protect seal bore. (3) Check each valve for a tight seat. (4) Using a valve spring compressor (see figure 7-10),  compress  each  valve  spring  and  insert  the  valve spring retainer (3, figure 7-11) and retainer locks (2). Install valve rotator (l). f. Install (see figure 7-9). (1) Place head assembly (8) and gasket (10) on cylinder block (9). Install springs (18), washers (19) and packings (16) on push rod shields (17) and install assembled push rod shields in cylinder block. Lift back side of cylinder head and place push rod shields in place, lower cylinder head in place. Use an anti-seize compound on head bolt threads and thread bolts (4 and 6) and washer (7) into cylinder block (9). Do not tighten head bolts at this time. (2)  Refer  to  Operator  and  Organizational Maintenance  Manual  and  install  intake  manifold.  Tor- que bolts 13-15 ft-lbs (see table l-l). Bend over lock tabs. Now tighten head bolts 44 to 46 ft-lbs (see table 1-1)  following  the  sequence  in  figure  7-13. TM  5-6115-584-34 NAVFAC  P-8-622-34 TO-35C2-3-456-2 TM-05682C-34 Figure  7-12.  Valve  Seat  Replacement (3)  Refer  to  Operator  and  Organizational -- Maintenance  Manual  and  install  mufflers. Install push rod with longer shouldered end toward rocker arm. Improper installa- tion causes push rods to bend or break. (4) Install push rods (15, figure 7-9), rocker arms (3),  rocker  arm  balls  (2)  and  rocker  arm  nuts  (l). (5)  Set  valve  clearance  per  Operator  and Organizational   Maintenance   Manual. (6)  Refer  to  Operator  and  Organizational Maintenance Manual and install air shutter assembly and  shroud  assembly. NOTE After the first 50-hours of operation, read- just valve clearance. 7-10. PISTON AND CONNECTING ROD. a. General (see figure 7-14). Each piston (7) is fit- ted with three compression rings and an oil control ring (4). Full floating piston pins connect the piston to the connecting rod. The pins are held in place with retaining  ring  (5)  at  each  end.  The  lower  end  of  each connecting  rod  contains  half  shell  precision  bearings (11)  and  the  upper  end  contains  reamed  bushings  (13). Change 5 7-13