A-10 INA NKIB 5906 CONVERSION CHECKLIST
11 JANUARY 1990
1.  Remove old timing side main bearing,  remove grub screw and check valve, and spring at oil pump outlet.
2.  Clean cases.
3.  Heli-arc area “K” to insure no break-through when drilling “G”.
4.  Drill and tap dowel in “R”, remove dowel.
5.  Drill “R” to a depth of 1-1/8” (.3125).
6.a  Grind away a flat spot to start  “G”.
6.b  Drill “G”  CL 1.00” below edge of case, insure you stay deep enough so not to break through to “K” (you need an aircraft drill), #10 drill.
      Note. I have made the centerline of “G” to the rear edge of “R” and aimed for the rear edge of pump feed outlet ”P”. To stay away from TS bearing bore for strength, it should be well below oil pump feed inlet  passageway.
     H’  try to grind flat spot for two threads up from bottom of relief valve bore.
7.   Drill  “H” (you need an aircraft drill #10) .  Start 5/8 to 3/4 below edge of case, aim to break into “R” 7/8” below edge of case. Aim between  1/4-20 BSW  oil pump stud hole and case edge, this will put you in the high side or center of “R” if you grind H enough.
8.   Plug A-1  and A-2.
      This roller bearing will be oiled  by A.  Splash only, since the bearing and gear cavity should be full of oil to a level indicated by “W” and filled by “bypass” oil from hole “E”.
       A&B.  Low pressure feed with “bypass” oil from passageway “C” by drilling optional hole “M” (Plug hole             outer) When installing bearing however put hole at “6” o’clock position, to prevent filling grove with sludge              and stagnate oil. Grove case if necessary to get  oil from case into groove in outer bearing race.
       C.  I think a high pressure feed is probably unnecessary.
9.  Bore case to accept bearing  (1.849-1.8498”)
       1.8503  to .903 depth.
9.a  Mill off “O” tabs.
10.  Make counter sink (to take  3/8” UNC Whit. Slotted bevel-head screw ) on the inside of the case in the check           valve bore “P”.
       Install Bearing (oil hole 6-o’clock).
       With dremel tool grind bearing housing to accept bevel head screw to prevent rotation of bearing housing.
        Later when installing spring ball and screw use blue loctite on screw.
11.  Drill check valve (from inside case) deeper to accommodate for deeper bevel head screw. Or GO TO A-65 style
       (drill all the way through). Modify pump to put seat on pump A-65 style.

INTERMEDIATE  COVER

1.  Drill intermediate cover where dowel “R” goes, with .318”
2.  Counter bore 7/16 dia to depth of .060  (for o-ring)

OUTER  COVER MODIFICATIONS
1. Fabricate seal holder block.
2.  Drill hole,  Plug end.
3.  Weld in housing.
4.  Mill flush to end of cover.
5.  Line bore for seal.
6.  Cut groove for circlip.
7.  Drill 5/16”  hole, 1/8 deep.
8.  Drill #10 connection hole.
A.  Original oil passage    (.221” #2 )
B.  Relief oil passage-way 1st. drilling  (.125” )
C.  Relief oil passage horizontal drilling, plugged at front.
D.  Relief oil passage diagonal toward center of cases to cam valley.
E.  Geartrain oiller hole.  (  .0595”  #53 )
F.  Threaded plug for passage D.
G.  Pump to crank high pressure oil feeder.
H.  G to relief valve feeder.
K.  Pocket void, should be filled with heli-arc.
M.  Bearing feeder from C, initial entry must be plugged.
R.  Rod bearing crank feed gallery.
W. Theorretical oil level line
P.  Oil feed/ check valve bore  .302  N drill