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Main Bearing Oil Feed Holes and Front Oil Feed to Cam Gear

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  • Main Bearing Oil Feed Holes and Front Oil Feed to Cam Gear

    I just added 3 pictures to the engine technical section to show the location of the oil feed holes to the main bearings. The location of the holes seems to come up quite often, and when some sludge is in the valve chamber, they can be hard to find. I also added a picture of the front hole where oil overflows onto the cam gear. Does anyone have a blueprint showing exactly how this opening was formed? It appears that a thin cast wall was left during the casting of the block, then the casting was punched out during the cleaning and machining process. Anyone know for sure what the process was to create the jagged opening?

  • #2
    Originally posted by Tom Wesenberg View Post
    Anyone know for sure what the process was to create the jagged opening?
    That area was the seat of a core print. The actual print, or core support was circular and somewhat smaller than the rectangular area seen as the opening. A slight gap was purposely left surrounding that core support. That permitted some angular movement while setting the core without contact of friable edges which would drop loose sand (inclusions) into the mold and casting. As you have stated, the resultant thin fin was manually knocked out (sometimes poorly!) during shakeout and rough cleaning.
    Mechanical engineering 101: If you put an adjustment knob, screw, bolt, or tolerance specs on something, some people will immediately fiddle with it. If you mark it DO NOT TOUCH everyone will mess with it.


    • Mitch
      Mitch commented
      Editing a comment
      That was a nice addition to that thread

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