Hole identification please

Discussion in 'Engine Topic' started by BlauZed, Sep 23, 2020.

  1. BlauZed

    BlauZed Member

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    8968A31C-0AF9-4D5E-97E8-371EC8D0A968.jpeg 8DCC0522-7F90-4C5E-A2DD-E89B3F8A0E5B.jpeg I can’t figure out what this hole is for. It is not threaded, smooth and about 5/8 diameter, on the bottom surface of block directly underneath fuel pump. Upper right portion of photo shows the bottom of the oil pan with blue Fel pro gasket, for reference . There is some corrosion in it and I’m afraid it’ll leak oil when I fill engine. Any help is appreciated. Thanks.
     
  2. Jodi

    Jodi Veteran Member

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    Nothing goes in that hole as far as I know but it should be solid and don't have a hole.
    Looks like there is a hole on yours from the pics. Is this a newly built engine?
     
  3. BlauZed

    BlauZed Member

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    Yes. Newly built never started. I had the lower end built . The shop put in all the galley plugs etc. don’t know what this hole is for or how to plug it . Thx
     
  4. Jodi

    Jodi Veteran Member

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    That hole shouldn't shouldn't protrude through the block, see if you can poke a screwdriver through.
    If the screwdriver goes in then that's not good.
    I would recommend plugging it with the right size frost plug and use plenty of flange sealant.
     
  5. wnmech

    wnmech Veteran Member

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    I don’t know if I’m thinking of something else but I thought at one time GM used to have a hole in that area to hold up the fuel pump rod up to make it easier to install the fuel pump arm
     
  6. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    That hole was used to align the tooling to bore the cylinders. There is another one like it on the oil pan surface. These dropped down on pins and then the boring bars machined the cylinder bores. Not used for anything else. They should be blind holes.
     
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  7. BlauZed

    BlauZed Member

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    Yup. It is a blind hole. But some corrosion has pitted through. Is there a risk of oil leaking out there? I guess I’ll figure a way to plug it.
     
  8. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    I've never seen one leak there.
     
  9. Jodi

    Jodi Veteran Member

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    Very curious to know what boring machine you are referring to.
    The ones that I'm familiar with is the old Kwik way that utilizes a bar through the mains with a floating head/cutter fixture.
     
  10. 70lt1z28

    70lt1z28 Veteran Member Gold Member

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    The side to side and along the length alignment was done off the mains. The pin holes set the block in kind of a front-to back relationship. At least that was how it was explained to me when we built the fixtures for these.
     

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