Bore out stock 81mm liner | FerrariChat

Bore out stock 81mm liner

Discussion in '308/328' started by waymar, Dec 27, 2020.

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  1. waymar

    waymar Formula 3

    Sep 2, 2008
    1,324
    Northeast, PA - USA
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    Wayne Martin
    #1 waymar, Dec 27, 2020
    1982 308GTSi stock 81mm liner. Can this be bored to 81.5mm or 82mm? Can the stock head gasket be used or is a customer gasket needed? Many thanks.....
     
  2. ferrariowner

    ferrariowner Formula 3

    Feb 21, 2014
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    Ron
    #2 ferrariowner, Dec 27, 2020
    It’s probably not worth it to try and bore out the liners. You would need a fixture like a torque plate to do the job properly. Also, they would need to be retreated with nikasil coating since the cylinders are aluminum. 1 and 2 mm oversized pistons and cylinders are readily available.
     
  3. derekw

    derekw Formula 3
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    Sep 7, 2010
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    Derek W
    #3 derekw, Dec 28, 2020
    Yes, you can bore them. Ferrari didn't bore them in situ but I measured a couple of thou distortion once clamped with a torque plate on my first engine. On this second engine which is low miles, I can see the hone scratches in some places but not others (and not only related to the thrust faces of the cylinder.) You can borrow my plate for shipping costs or I can send you the drawing. Mine cost $30 for an offcut thick plate and $75 for water jet cutting.
    The head gasket fire ring is at 84mm diameter but liners get dangerously thin beyond 83mm. I'm thinking of getting a small batch of 83mm forged pistons and 141mm (longer) rods as it seems a waste to fit new pistons that are taller than necessary and not have the benefits of a better rod ratio.
     
  4. waymar

    waymar Formula 3

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    #4 waymar, Dec 28, 2020
    Thank you gentlemen. My liners are not Ni liners. The plate theory appeals to me. When time comes thinking JE 82mm 10:1 compression ratio. That’s about as wild as I would get. LOL. Currently no cats and have David F’s MED802A modules.
     
  5. wilkrod

    wilkrod Karting

    May 9, 2012
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    Ocala, Fl
    #5 wilkrod, Dec 28, 2020
    From where are they readily available? I can't find them anywhere.
     
  6. ferrariowner

    ferrariowner Formula 3

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    #6 ferrariowner, Dec 28, 2020
    Try Superformance
     
  7. wilkrod

    wilkrod Karting

    May 9, 2012
    179
    Ocala, Fl
    #7 wilkrod, Dec 28, 2020
    They only have steel liners.
     
  8. waymar

    waymar Formula 3

    Sep 2, 2008
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    Wayne Martin
    #8 waymar, Dec 28, 2020
    My 1982 308GTSi has steel liners so this is not problem for me. Thank you everyone for your input.
     
  9. kiwiokie

    kiwiokie Formula 3

    Aug 19, 2013
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    John McDermott
    #9 kiwiokie, Dec 28, 2020
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  10. kcabpilot

    kcabpilot Formula 3

    Apr 17, 2014
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    Paul
    #10 kcabpilot, Dec 29, 2020
    Yea I'm pretty sure Nikasil started with the QV's - 1983-1985
     
    waymar likes this.
  11. waymar

    waymar Formula 3

    Sep 2, 2008
    1,324
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    Wayne Martin
    #11 waymar, Feb 9, 2021
    Update - I ordered JE 10:1 - 81.5mm pistons, will be using stock cams. I had already had the digiplex units reworked to the euro spec. No air pump or cats on the car. 82 GTSi - Thank you to everyone for the input.....
     
    Ferraripilot likes this.

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