TM 10-3930-671-24 9. Check  each  bearing,  one  at  a  time,  by  using  a piece  of  Plastigage  of  a  diameter  specified  to check certain clearances. By   placing   the   Plastigage   on   the   crankshaft   bearing surface  and  tightening  the  bearing  and  cap  in  place  the width  of  the  Plastigage  after  crushing  will  determine  the bearing clearance. CAUTION When   using   Plastigage   method   DO NOT   TURN   the   crankshaft   as   that would destroy the Plastigage. If   crankshaft   is   scored,   or   worn   enough   so   that   new bearings will not fit with the required clearance, it should be removed and reground. Standard  crankshafts  may  be  reground  to  decrease  the diameter a maximum of 1.0mm (.040"). Before    shaft    is    reground,    it    must    be    checked    for straightness  and  straightened  if  necessary  to  be  within 0.05mm  (.002")  indicator  reading.    When  reground,  the fillet radii must be within dimensional limits and must be perfectly    blended    into    thrust    and    bearing    surfaces. Crankshafts must be nitempered after regrinding. CAMSHAFT 1. Remove the screws holding the camshaft  thrust plate   to   the   front   of   the   cylinder   block,   which makes  it  possible  to  pull  the  camshaft  forward out of the bearings. 2. Measure    the    camshaft    bearing    journals    and bores.  If clearance is equal to orgreaterthan the amount   indicated   underwear   limits,   check   the diameter  of  the  camshaft  journals  to  determine the  next  step.    Excess  wear  at  these  positions require replacement of the shaft. 3. If the front camshaft journal bore becomes worn beyond    limits,    there    is    a    service    camshaft bushing available. 4. Tappets  can  then  be  lifted  out  and  lined  up  in sequence,  for  installation  in  the  same  location unless     inspection     shows     that     they     require replacement. F-180