TM 10-3930-659-34 2-24.  BEARING CLEARANCE GAGE. a.    A   soft   plastic   bearing   clearance   gage   (Items   29,   30,   and   31,   Appendix   B)   (plastigage) squeezed between parts such as a crankshaft journal and a connecting rod or main bearing may be used to measure clearance. b.    The  bearing  clearance  gage  is  a  specially  molded  plastic  "wire"  and  is  available  in  three measuring ranges and colors (see Table 2-1). Table 2-1.  Bearing Clearance Gage. Color (CAGE) Part Number Measuring Range Reference Green (77220) PG-1 0.001-0.003 in.  (0.0254-0.0762 mm) (Item 29, Appendix B) Red (77220) PLASTIGAGEPR1 0.002-0.006 in.  (0.0508-0.1524 mm) (Item 30, Appendix B) Blue (77220) PLASTIGAGEPB1 0.004-0.009 in.  (0.1016-0.2286 mm) (Item 31, Appendix B) c.    Check clearance as follows: (1) Remove bearing cap and wipe oil from bearing shell and crankshaft journal. NOTE When checking main bearing clearance with engine in position and main bearing caps supporting  weight  of  crankshaft  and  flywheel,  an  incorrect  reading  may  result  due  to weight of crankshaft and flywheel.  Avoid an incorrect reading by placing a jack under the counterweight next to the bearing being checked. (2) Place bearing clearance gage in the center of the bearing cap and across three-quarters of the width of the bearing. 2-14