TM 10-3930-669-34 3-4. CRANKCASE REPAIR (CONT). c. Repair. NOTE Main   bearings   are   of   thin-shell   type.      Their   proper   installation   requires   that   webs   in crankcase  be  in  alignment  and  for  bearing  bores  to  be  preloaded.    No  attempt  should  be made to adjust or recondition bearing shells. (1)   Check preloading of bearing bores as follows: (a) Position    and    install    main    bearing    caps, washers, and screws making sure that their identification    numbers    match    with    those stamped  in  crankcase.    Using  a  tightening gauge,  torque  screws  in  accordance  with instructions given in Appendix D, Table D-1. (b) Using    a    precision    gauge,    set    gauge    to 2.933 inches (74.50 mm). (c) Measure  each  main  bearing  bore  at  points 1 and 2 in plane "a," and in plane "b" offset by 90 degrees. (d) If    main    bearing     bore     measurement     is between    2.933    inches    (74.50    mm)    and 2.934     inches     (74.519     mm),     respective bearing    is    in    acceptable    condition    and required    preload    will    be    obtained    when bearing halves are installed. (e) If  main  bearing  bore  measurement  is  not between    2.933    inches    (74.50    mm)    and 2.934 inches (74.519 mm), repeat measurements    with    new    bearing    halves installed. (f) Insert new main bearings. 3-30