Holley Sight Glass

Discussion in 'High Performance Modifications' started by ultimateoffroad, Aug 12, 2015.

  1. Orange71

    Orange71 Veteran Member Lifetime Gold Member

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    Same here. The site glass is much different diameter (larger) than the screw type site hole.

    This is what Patrick recommended the carb he built for me.
    [​IMG]
     
  2. GoldenOne7710

    GoldenOne7710 Equal Opportunity Offender Lifetime Gold Member

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    I'd say it really depends on the application. For a mostly street driven mild engine, it'd likely have better idling quality in stop and go traffic with the level at the bottom of the holes where it would barely trickle out if you shook it.

    On a bigger engine with a bigger cam that sees a lot of wide open throttle, then half way up inside the sight hole would probably work better for that particular application.

    I've personally always run my floats to keep the bowl levels at the bottom of the sight holes.
     
  3. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

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    .


    Unless the car is really moving, I highly doubt any street car is pushing fuel out, except maybe in an emergency braking situation???
    So high, middle, bottom, I've never really worried too much.
    Again, I like to see where it is, so I'm a run it slightly higher guy.
    Drag cars I can see it being an issue, which is why most of us with fast cars have to run extensions.


    .
     
  4. 1981gMachine

    1981gMachine Veteran Member Lifetime Gold Member

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    If it's bogging when the secondaries are opening then check your vacuum at idle. Divide by 2 and and that should be the size power valve you need. Most holley's are a 6.5 factory power valve, meaning you should be pulling about 13in of vacuum at idle. I had a slight bog for the longest time and it was because I needed a lower power valve since my car has a cam, lower idle vacuum.

    manual check in neutral
    auto check in drive, block a wheel or have someone sit with the brake on.
     
  5. Double J

    Double J Veteran Member

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    I had the site glasses at one time. Won't do that again They deteriorated over time (melted). The best way to judge your float level is bottom of the threads as mentioned earlier.
     
  6. krabben1

    krabben1 Veteran Member Lifetime Gold Member

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    Ive experienced the highs and lows of float level adjustment with my 770,lol.
    I had them low(at the bottom of the sight GLASS),and under throttle the bowls would suck dry,causing my car to almost shut off.Id have to two step the peddle to keep it alive.
    Then when they would be in the middle,extreme heat would make them boil up after shut off.
    It took me awhile to find that perfect spot for what I had goin on.
    I should add,that all adjustments were made with the car past warmup.
     
  7. hhott71

    hhott71 R.I.P 11/19/18 Lifetime Gold Member

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    Original style Small diameter removable metal sight plugs go to the bottom of the threads.

    The new repositioned OE Holley Large diameter clear sight glasses go to the center of the glass.
     
  8. mrdragster1970

    mrdragster1970 Veteran Member Lifetime Gold Member

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    Never had boil over issues, did you ever try a wood isolator or extensions???


    .
     
  9. krabben1

    krabben1 Veteran Member Lifetime Gold Member

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    I have a carb plate in there now.

    Edit-They were doing boilovers on shutdown when I was running the float levels a hair high.
     
    Last edited: Aug 16, 2015

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