Valve Spring Installed heights

Discussion in 'PSI Superchargers Tech Questions' started by lucky devil, Mar 17, 2021.

  1. lucky devil

    lucky devil Member

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    BAE 6 Alcohol Heads .
    2.1 installed height , what is considered to be the maximum amount of shims you would use ?

    Thanks
     
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  2. h2b puller

    h2b puller Member

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    Depends on what lobe lift and rocker arm ratio you have.
     
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  3. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    there's no one set install height. depends on the following:

    - valve spring coil bind height
    - cam lift x rocker ratio is your theoretical lift

    I like to set up springs .050 to .065 off bind based on full lift. I use valve lash as a buffer, so I don't use it in the equation.

    Due to deflection and pushrod angularity, you will not achieve the "theoretical" lift number you come up with multiplying the cam card lift by mfg rocker ratio.

    I highly doubt with a BAE 6 you are going to use too many shims. If you are running a dual spring, a locator is recommended, and the thinnest is a .030. You need to run at a minimum a .015 shim.
     
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  4. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    Install height -

    Not saying you are making this mistake, but I have seen more than one new team over the years calculate install height incorrectly.

    spring install height is the distance between the seating surface of the retainer and the shims.

    Like I said I have seen it more than once where someone uses shims to get a target pressure like 450, and includes those shims in the install height number.
     
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  5. lucky devil

    lucky devil Member

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    Thank you for the replies , yes the installed height is understood to be the height of the spring not including any shims. I guess what I am asking is for peoples own experience in what they have used as a maximum amount of shims to get the installed height 50 , 100,150 thou etc etc
     
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