ENGINE DIVISION SERVICE MANUAL TM 5-4210-230-14&P-1 ENGINE plunger  into  the  cylinder  (do  not  install  the  plunger spring) with the other.  Depress the plunger with your finger   and   release   quickly.      The   plunger   is   now operating against air which is sealed in by the check valve   and   by   the   close   fit   of   the   cylinder   to   the plunger.  It should yield slightly to the pressure of the finger  on  the  plunger,  but  the  plunger  should  kick- back upon release of the pressure.  If no kick-back of the   plunger   occurs,   the   unit   may   or   may   not   be defective.    The  lack  of  kick-back  is  due  to  one  of three conditions. First, air is escaping past the check valve because of presence of dirt which prevents proper seating of the valve.  Second, air is escaping past the check valve because  of  a  damaged  seat.    Third,  air  is  escaping because   the   clearance   between   the   plunger   and cylinder  wall  is  too  great,  which  indicates  excessive leakdown rate. Rewash the unit to eliminate any dirt which might still be  on  the  check  valve  seat  and  repeat  the  test.    If there is still no kickback, the check valve is damaged and  the  entire  lifter,  consisting  of  cylinder  body  and plunger, may need to be discarded. NOTE: In    the    event    check    valve    leakage    is encountered due to wear on the surface of the  check  valve,  the  valve  can  be  turned over  to  the  unworn  side.    This  procedure will  extend  the  useful  service  life  of  the lifter assembly, provided all other parts of the lifter are in good condition. In  the  above  test  procedure  it  is  important  that  the pressure   on   the   plunger   be   released   immediately after it is depressed.  If the plunger is held down too long,  all  the  air  trapped  under  the  plunger  will  leak out and the test would be inaccurate. The  unit  is  suitable  for  reinstallation  in  the  engine  if the test is satisfactory. Crankshaft Wash and clean the crankshaft with cleaning solvent or steam. Inspect the crankshaft for cracks, scored, grooved or worn main bearing and    ' connecting rod journals.  If journals show wear or out-of-round in excess of .002", the shaft should be     reground     and     undersize     bearings     installed     or     the crankshaft replaced.  Use a micrometer for checking. Examine the crankshaft timing gear teeth and replace the gears if the teeth are worn or damaged. NOTE: Replace  the  timing  gear  on  the  camshaft when replacing the crankshaft gear.  These gears are serviced in matched sets. Camshaft Wash  the  camshaft  in  cleaning  solvent  and  remove all sludge or carbon deposits with a soft brush. Inspect  the  camshaft  journals  for  signs  of  wear  or out-of-round   and   replace   if   wear   warrants.      See   ENGINE OVERHAUL Cylinder Block. Inspect   the   camshaft   lobes.      If   worn,   chipped   or scored, replace the camshaft. Inspect the distributor  drive  gear  and  camshaft  gear and  replace  if  wear  warrants  or  the  gear  teeth  are  nicked  or otherwise damaged. Inspect   the   fuel   pump   cam.      If   worn,   chipped   or scored, replace the cam. NOTE: If the distributor drive gear, fuel pump cam and  camshaft  gear  were  removed  without complete   engine   disassembly,   they   may be reinstalled as follows: 1. Install  distributor  drive  gear  against  thrust  flange  on camshaft  using  SE-1900-14  sleeve  with  SE1900-16 adapter,  Figure  123.    A  thrust  bearing  is  also  used under the forcing screw nut to reduce friction. IMPORTANT: Use extreme caution so as not to chip the distributor gear teeth. CGES-210  Page 48 PRINTED IN UNITED STATES OF AMERICA