ARMY TM 9-2815-259-24 AIR FORCE TO 38G1-125-2 MARINE CORPS 09249A/09246A-24 5-111 __________ WARNING Cleaning solvent is flammable and toxic to eyes, skin, and respiratory tract. Skin and eye protection are required.  Avoid repeated/prolonged contact.   Provide adequate ventilation.  Failure to comply could result in serious injury or death. __________ WARNING Compressed air used for cleaning can create airborne particles that may enter the eyes.  Never exceed 30 psi (207 kPa) of pressure.  Eye protection required.  Failure to comply could result in serious eye damage or blindness. (d) Clean cylinder head in chemical hot tank if available, or with solvent and brush if hot tank is not available.  Dry cylinder head with compressed air and blow out all passages. (e) Check cylinder head flatness as follows: 1 Check cylinder head flatness with precision straightedge and feeler gage.  Check lengthwise, crosswise, and diagonally in several places. 2 Maximum acceptable out of flat measurements are 0.003 in. (0.08 mm) for entire length or width of cylinder head and 0.001 in. (0.03 mm) for every 5.90 in. (150 mm). 3 If any measurement exceeds specifications, cylinder head must be resurfaced or replaced.  To determine if cylinder head can be resurfaced, refer to step 4 (f). (Measure cylinder head thickness). (f) Measure cylinder head thickness from valve cover gasket rail-to-combustion face using outer diameter micrometer.  Minimum acceptable cylinder head thickness is 4.104 in. (104.24 mm).  Replace cylinder head if out of specifications.  Refer to Figure 5-91. NOTE Resurfacing cylinder head is only necessary if cylinder head fails cylinder head flatness test, refer to step 4 (e). (g) Resurface cylinder head as follows: 1 Resurface cylinder head if cylinder head thickness is less than the minimum acceptable thickness of 4.104 in. (104.24 mm).  Remove only what is necessary to restore flatness. 2 Combustion face surface finish (surface grind only) should be 31 - 125 micro-in. (0.7 - 3.2 micrometers).  Maximum wave depth is 0.0005 in. (0.012 mm).