ARMY TM 9-2815-253-24 AIR FORCE TO 38G1-93-2 MARINE CORPS TM 2815-24/3 3-27.5.  Assembly. a. Using standard valve spring compressor tool install each valve (15 or 16, FIGURE 3-28) as follows: (1) Lightly lubricate valve stem with engine lubricating oil (MIL-L-2104) and insert valve (15 or 16). (2) Lay head (6), upright on bench and place a block of wood under head of valve being replaced. (3) Place valve spring plate (21) in position. (4) Install  a  new  valve  stem  seal  (20)  to  valve  guide  (22)  taking  care  to  ensure  it  is  correctly  located  over valve guide and is not distorted. (5) Install valve spring (19) and spring carrier (18). (6) Push down on tool until collets (17) can be installed in position with their tops slightly sunk in valve spring carrier (18). (7) Gently release tool and check that collets (17) are correctly located. b. If removed, install capscrew (13), washer (14), and breather tubes (23). 3-27.6.    Installation.    When  installing  cylinder  head,  valve  to  piston  contact  can  be  avoided  by  waiting  for  up  to  45 minutes for lubricating oil to bleed down. a. Ensure cylinder head (6, FIGURE 3-28) and crankcase mating surfaces are clean and dry. CAUTION Removal  of  any  part  of  the  valve  gear  will  allow  the  hydraulic  tappet  to  extend  and  hydraulically lock. NOTE When new tappets have been installed, the engine must be cranked for at least 15 seconds before attempting to start it. b. Install hydraulic tappets (11) (solid end first) and new washers (10) in crankcase. NOTE Seal (12) has a lip on one side and seal (9) has no lip. c. Install new pushrod seal (12) in cylinder head (6) and new pushrod seal (9) in crankcase. d. Lightly coat bore of seals (9 and 12) with general purpose grease (630AA). CAUTION Use   extreme   care   to   ensure   pushrod   tubes   (8)   are   centered   and   fully   Installed   in   seals   (9). Misalignment of pushrod tubes can cause serious damage to seals. e. Install pushrod tubes (8) into crankcase. f. Install cylinder head guide studs in opposite comers of engine block deck. NOTE If old head gasket size is not known, perform Check Cylinder Head Clearance.  Refer to paragraph 3-27.3. g. Three  head  gaskets  (7)  are  available.    Check  old  gasket  for  number  of  identification  holes  in  one  corner  of gasket.  One hole - 0.053 in.  (1.35 mm); 2 holes - 0.058 in.  (1.47 mm); and 3 holes - 0.063 in.  (1.60 mm). 3-54