Question on nitro bore sleeves 4.187 bore

Discussion in 'PSI Superchargers Tech Questions' started by John byob, Dec 12, 2021.

  1. John byob

    John byob Member

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    hi first what is the largest u can over bore a 4.187 sleeve? Next is what is the most compression you can make with a piston that is in a bore size with buying custom pistons. Stroke is 3.750 bore 4.187 bae fuel heads 180cc and not sure what rod lenght yet. Thx guys
     
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  2. REEHL EQUIPMENT

    REEHL EQUIPMENT Authorized Merchant

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    What block?

    KB sleeves are different than TFX or BAE.

    TFX and BAE 4.187 sleeves have at least 3 different O.D.'s.

    What OD do you have? It matters....
     
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  3. John byob

    John byob Member

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    . Ohh ok have t check rob, but what about the compression question? Thx
     
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  4. John byob

    John byob Member

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    I have 4.490 OD sleeve. In a 4.187 bore, what can it be bored out to? If at all thx rob
     
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  5. REEHL EQUIPMENT

    REEHL EQUIPMENT Authorized Merchant

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    4.490 at the bottom?

    What block?
     
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  6. John byob

    John byob Member

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    on the sleeves I took that measurement. Can that sleeve be bored? If yes what’s the max? I need min 4:250! PS the newer top fuel blocks do they all come with 4.550 sleeves? Say a John force block?
     
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  7. John byob

    John byob Member

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    PS not sure what block the 4.90 sleeves came frm?
     
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  8. REEHL EQUIPMENT

    REEHL EQUIPMENT Authorized Merchant

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    There are 2 dimensions.

    Just under the register, and at the bottom.

    What are your 2 numbers?

    What block?
     
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  9. John byob

    John byob Member

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    have older KB dry and newer KB wet
    But have two older 2000 Brad billet too. But will measure the registers after work thx rob
     
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  10. Mike Kern

    Mike Kern Member

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    Go to the Darton website and check their sleeve sizes. There are all sorts of different sleeve sizes available, so it depends on your block and ultimately what wall thickness you will be left with. You'll most likely be better served buying new sleeves if the wall thickness is getting too thin. Lastly, you can always overbore the block to run a thicker wall sleeve. Structurally this is the more sound way to go if weight is not of concern.
     
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  11. John byob

    John byob Member

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    oh fr sure, but I got a lot of 4.187 sleeves. And can get 4.250 bore high compression pistons fr my needs. If I can get away with that over bore? Thx
     
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  12. Dave Koehler

    Dave Koehler Member

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    You are only talking about .063 over or .0315 per side.
     
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  13. Mike Kern

    Mike Kern Member

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    Per my calcs, even with the thinnest wall 4.187 bore sleeve, you will be at .120" wall at 4.250 bore. That's as thin as Darton goes on a sleeve except for their big bore, short deck alcohol stuff where they go down to .104" wall. You can probably get away with it if you keep everything squared up. You just can cry about it if one fails.
     
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  14. John byob

    John byob Member

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    . Thx dave
     
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  15. John byob

    John byob Member

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    it will only be fr injection only, and small stroke. Non boosted.
     
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  16. John byob

    John byob Member

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    and that’s on their blown short deck alcohol engine?
     
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  17. John byob

    John byob Member

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    My sleeve thickness is .150 and need to bore them to 4.250, so I am left with .083 thick? Not sure if that’s good enough to run a injection motor?
     
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  18. John byob

    John byob Member

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    yes that’s sound advice but not making a ton of hp. Un blown 900, blown if possible 1200?
     
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