SECTION K Timing Case and Drive TIMING CASE AND DRIVE To Remove the Timing Case Cover 1. Slacken  the  dynamo/alternator  mounting  bolts, release  the  adjusting  arm  and  ease  the  driving belt from the pulleys. 2. Remove   the   four   setscrews   which   secure   the power   take-off   shaft   to   the   crankshaft   pulley front face and remove the power take-off shaft. 3. Remove the tachometer drive and heat exchanger  support  bracket  which  are  mounted on the face of the timing cover. 4. Remove the crankshaft pulley retaining setscrew and  washer,  and  withdraw  the  pulley.    Remove the  setscrews  and  nuts  which  secure  the  timing case  cover  to  the  timing  case.    Withdraw  the timing case cover taking care not to damage the crankshaft  front  oil  seal  which  is  located  in  the cover. To Renew the Crankshaft Front Oil Seal 1. Using  a  suitable  dolly  and  press,  remove  the  oil seal from  the timing case cover. 2. Locate  the  new  seal   in   the   bore   of   the   cover from the front. 3. Press  the  new  seal  into  position  until  the  front face of the heal is 1 in (6.35 mm) below the front face of the cover. The  seal  is  designed  to  function  correctly  with the  direction  of  rotation  of  the  engine  and  for identification  purposes,  the  seal  is  marked  with an arrow. Earlier   engines   were   fitted   with   a   black   nitrile seal and a crankshaft oil thrower. Current   engines   have   a   red   silicone   seal   and ,the oil thrower is replaced with a distance piece. Under  no  circumstances  should  the  latest  red seal be fitted with an oil thrower. Tachometer Drive The  tachometer  angle  drive  mounted  on  the  timing case  front  cover  should  be  greased  with  a  high  melting point grease in accordance with Preventive Maintenance given on Page C.3. Grease starvation of the angle drive gears can result in overloading and subsequent failure, but overloading is more  frequently  caused  by  the  flexible  drive  itself  due  to its  corrosion  resulting  from  the  drive  cable  lying  in  bilge water  or  being  allowed  to  arc  on  battery  terminals  etc. No bend in the flexible drive should be less than one foot radius. Fig. K.1. Showing markings for correct positioning of Crankshaft Pulley in relation to Crankshaft. With earlier engines.  failure of the angle drive could result in fragments of the drive tag falling into the timing gear  train  and  as  a  protective  measure,  a  sleeve  shield was  introduced  around  the  tachometer  drive  shaft  and tag.    It  would  be  of  advantage  to  introduce  this  safety shield on early engines whenever it becomes necessary to remove the timing case cover. To Refit the Timing Case Cover 1. Thoroughly  clean  the  faces  of  the  timing  case front cover and timing case. 2. Position   the   timing   case   cover   on   the   timing case  by  means  of  two  opposite  setscrews  fitted loosely.      Centralise   the   cover   by   locating   the centralising tool PD.162 on the crankshaft and in the  seal  housing  and  tighten  the  assembly  by means   of   the   crankshaft   pulley   setscrew   and washer — do not overtighten. Tighten  all  the  timing  case  cover  setscrews  and remove  the  tool.    If  the  centralising  tool  is  not available,  the  crankshaft  pulley  can  be  used  to centralise  the  cover  but,  as  this  method  utilizes the  inside  diameter  of  the  seal  and  the  latest seal  is  soft,  the  cover  may  not  be  truly  central and leaks may occur.