TM 9-2815-250-24&P 3-5. CYLINDER HEADS REPAIR (continued). 4. Inspect valves and valve seats for cracks, burns, or bends.  Replace any cracked, burned, or bent valves.  If valve seats are cracked or burned, replace cylinder head. c. ADJUSTMENT CAUTION If,  after  removing  the  cylinder  head,  you  have  replaced  the  combustion  chamber liner, piston, connecting rod, or crankshaft, the valve-to-piston clearance must be checked. Too  little  clearance  will  result  in  damage  to  pistons,  cylinder  heads,  and  valves. Too much clearance will cause the engine to lose power and be difficult to start. NOTE · There  are  two  pistons  on  the  engine.    Follow  steps  1  through  4  to  adjust  the valve-to-piston clearance on each of them. · Gaskets  come  in  various  thicknesses.    It  may  be  necessary  to  try  several different  gaskets  to  achieve  the  desired  valve-to-piston  clearance.    Use  only one gasket on each combustion chamber liner. 1. Install new gasket (7), with a thickness of 0.60 mm, and cylinder alignment bracket (18) on combustion chamber liner (9). NOTE Make sure piston is as high as possible in the combustion chamber. 2. Place bottom of depth gage rule (17) across piston (20) and gasket (7).  Loosen screw (19) and slide depth gage rule  (17)  down  to  crown  of  piston  (20).    Be  sure  to  measure  highest  part  of  piston  (20).    Tighten  screw  (19)  and read measurement.  Clearance should be no less than 0.024 inch (0.61 mm) and no greater than 0.026 inch (0.66 mm). 3. If clearance is incorrect, repeat steps 1 and 2 using a gasket with a different thickness. 4. When  clearance  is  correct,  remove  cylinder  alignment  bracket  (18)  from  combustion  chamber  liner  (9),  leaving gasket (7) in place. 3-17