TABLE 6-2 TM9-2815-202-34 6-34.   PISTON   AND   CONNECTING   ROD   MAINTENANCE   (TRUNK   TYPE)   (Cont) • • (2) (3) NOTE Use feeler gage to check piston to liner  clearance.  Use  a  spring  scale attached to feeler gage to measure amount of force in pounds required to withdraw  feeler  gage  from between  piston  and  liner.  Select feeler  gage  with  thickness  requiring six pounds pull to move. Piston to liner  clearance  is  0.001  inch  greater than thickness of feeler gage used. For example, a 0.004 inch feeler gage  indicates  0.005  inch  clearance when withdrawn with a six pound pull. Feeler gage must be perfectly flat and free of nicks and bends. With  cylinder  liner  (1)  installed  in cylinder block (6), hold piston (10) upside  down  in  liner  and  measure clearance  in  four  places,  90  degrees apart. Clearance must be 0.0045 to 0.0083 inch with new parts. Allow a maximum  clearance  of  0.0120  inch for used parts. If  binding  occurs  between  piston  and liner,  remove  piston  and  examine piston and liner for burrs. Remove burrs on piston with  a fine  stone. Remove burrs in liner with fine flat hone  and  recheck  clearance. f.   Fitting   Piston   Rings (1) Insert ring inside cylinder liner in normal area of ring travel. Using piston to push ring down, measure ring gap with feeler gage. Refer to Table 6-2 for ring gap specifications. Repeat  procedure  for  balance  of compression  and  oil  rings. File or stone both ends of compression  ring  from  outer  surface to  inner  surface  to  prevent  chipping or peeling of chrome plating on ring. (2) File ends of compression ring if ring gap is too small. Ends of ring must remain  square,  and  chamfer  on  outer edge  must  be  approximately  0.015 inch. 6-36