ARMY TM 9-2815-253-24 AIR FORCE TO 38G1-93-2 MARINE CORPS TM 2815-24/3 3-27.2.  Disassembly. a. Remove pushrod tubes (8, FIGURE 3-28), seals (9), washers (10) and tappets (11) from crankcase. b. Remove seals (12) from cylinder head (6).  Discard seals (12). c. If necessary, remove capscrew (13) and washer (14). d. Position head upright on bench and place a suitable block of wood under head of valve (15 or 16). WARNING Do not stand in front of valve springs while compressing them.  Failure to follow this warning could result In personal Injury. e. Using standard valve spring compressor tool remove each valve as follows: (1) Push down on tool until collets (17) can be removed. (2) Gently release tool.  Remove carrier (18), spring (19), seal (20), and plate (21).  Discard seal. (3) Turn cylinder head (6) over and remove valve (15 or 16). NOTE If   valves   are   to   be   reused,   tag   them   with   cylinder   number   from   which   they   were   removed. Manufacturer recommends that all valves and springs be replaced during a major overhaul. f. Insert  hex  key  (allen  wrench)  into  breather  tube  (23)  to  support  bore  of  tube.    Using  pliers,  remove  breather tube(s) (23). 3-27.3.  Inspect and Measure. a. Using appropriate measuring devices, check components listed in TABLE 3-4 for wear.  Replace components that exceed maximum clearance. NOTE Replace the spring if the length is 1.67 in.  (42.5 mm) or less. b. Check that intake valve seat is sunk 0.037 to 0.05 in.  (0.95 to 1.26 mm) and exhaust valve seat is sunk 0.052 to 0.065 in.  (1.33 to 1.64 mm) below combustion surface.  If not, regrind valve seats.  Refer to paragraph 3-27.4. c. Check cylinder head clearance as follows: NOTE This  procedure  is  used  to  determine  what  size  head  gasket  is  required.    Start  with  medium  size gasket. (1) Place  head  gasket  onto  crankcase.    Align  holes  in  gasket  with  those  in  crankcase.    Rotate  engine  so pistons are below cylinder head deck (2) Using a very small amount of general purpose grease (630AA), place four pieces of solder (SN60WRAP2) size 0.062 in.  (1.58 mm) thick on pistons as shown in FIGURE 3-30.  Space solder on outer edge and as near as possible in line with piston pin.  Care must be taken to ensure that solder will be clear of valve recesses. (3) Install cylinder head and torque bolts.  Refer to paragraph 3-27.6. (4) Manually rotate engine through two complete revolutions. (5) Remove cylinder head and measure the thickness of solder.  This should be 0.0276 to 0.0354 in.  (0.7 to 0.9 mm) and is obtained by a single gasket under head. 3-51