ARMY TM 9-2815-252-24 AIR FORCE TO 38G1-92-2 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. CAUTION Removal of any part of the valve gear will allow the hydraulic tappet to extend and hydraulically lock. CAUTION Ensure  that  no  piston  is  at  TDC  when  replacing  head.    Failure  to  follow  this  procedure  could cause misalignment of the head. NOTE When  new  tappets  have  been  installed,  the  engine  must  be  cranked  for  at  least  15  seconds before attempting to start it. a.  Ensure cylinder head (6, FIGURE 3-28) and crankcase mating surfaces are clean and dry. b.  Install hydraulic tappets (11) (solid end first) and new washers (10) in crankcase. c.  Install new pushrod seal (12) in cylinder head (6) and new pushrod seal (9) in crankcase. NOTE Seal (12) has a lip on one side and seal (9) has no lip. 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 corners of engine block deck. NOTE If old head gasket size is not known, perform Check Cylinder Head Clearance, refer to paragraph 3-27.3. 3-60