Sump plug P/N: 10269850 | FerrariChat
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Sump plug P/N: 10269850

Discussion in 'Technical Q&A' started by Cribbj, Jan 10, 2015.

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  1. Cribbj

    Cribbj Formula 3
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    #1 Cribbj, Jan 10, 2015
    Last edited by a moderator: Sep 7, 2017
    Most of our dry sump engines, and also the gearboxes have 1-2 of these 10269850 plugs. It's a tapered thread plug with an internal M10 hex head. No flange and no sealing washer, so it's a metal to metal seal, along with pipe dope or other thread sealer.

    Pretty sure the thread is M22, however I'd really like to know what the pitch is. The common pitch for this size thread on a plug is 1.5, however it seems coarser than this.

    I managed to get a 1/2" NPT plug started and threaded up to 4-5 threads before it tightened up significantly and didn't feel "right" anymore.

    I'm thinking this must be an M22 x 1.75 tapered metric thread, else it "might" be 1/2" BSPT. Anyone know if Ferrari ever used BSPT for their tapered plugs, or are they all tapered metric?

    Here's a pic showing where these plugs are on a 550 Maranello sump:
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  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    #2 Steve Magnusson, Jan 10, 2015
    The 14 TPI of 1/2" BSPT matches your thread pitch description pretty well. Two questions:

    1. Are the thread roots and crests on the old plug well-rounded? (BSPT is a Whitworth-based form), and

    2. Why are you even messing with this ;) -- no F part available, or is the F part stupid-price?
     
  3. Cribbj

    Cribbj Formula 3
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    #3 Cribbj, Jan 10, 2015
    Steve, thanks for your comments,

    1. My old plugs are too mangled to tell anything useful from them. I'll probably buy some new ones from Daniel, if for nothing else, to try to figure what the threads are - they're not expensive.

    2. I'm planning to use one or both of these fittings for an external prelube system and will need to eventually get to an AN thread. If I can't source a threaded adapter for these, then I'll Timesert the holes into something that is more common.
     
  4. Cribbj

    Cribbj Formula 3
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    #4 Cribbj, Jan 11, 2015
    As a follow up, I'm fairly sure it's NOT M22 x 1.75 as I don't find this thread/pitch combination in any thread charts or tap & die charts.

    So that leaves 1/2" BSPT or 1/2" NPT.
     
  5. yelcab

    yelcab F1 World Champ
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    #5 yelcab, Jan 11, 2015
    I seem to remember some old timer telling me that all pipe threads are standard size, not metric, even in Europe.
     
  6. Mark 328

    Mark 328 Formula Junior

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    #6 Mark 328, Jan 12, 2015
    The good thing about pipe threads is that they are tapered and you can always go deeper to get a decent percent of thread. It works good to put colored dye (like Dykem) in the old thread after it dries you can run the tap in and see where the threads clean-up to the new size. Tapered threads will pull and seal well even if they are not perfect.
     

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