Sleeving a block question (not F car) | FerrariChat

Sleeving a block question (not F car)

Discussion in 'Technical Q&A' started by DoubleD33, Dec 12, 2022.

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  1. DoubleD33

    DoubleD33 F1 Rookie
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    May 2, 2012
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    Pasadena, CA / Oahu, HI
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    Dan D
    A video on my YT popped up forms Jim’s automotive machine shop. He is sleeving a 396 BB Chevy with valve relief cuts in the block. It looks like the OD of the sleeve is partly in / partly out of the valve relief cut.

    My brain thinks this would be an issue with combustion pressure escaping where the sleeve meets the block. Also would the head gasket fire ring be sealing across a “seam” on the radius edges?

    Am I right or is this a non issue?

    Also why would you not use a top hat liner in this situation?
     
  2. wmuno

    wmuno Formula Junior
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    Dec 24, 2007
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    Bill Muno
    I assume these guys know what they are doing. I don't know anything about this Chevy block, but I have to assume that the OEM head gasket goes on the outside of the relief cuts. With a tight interference fit, combustion gas escaping between the block and the sleve shoudn't be a concern given the height of the sleve.
     
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  3. Ferrari Tech

    Ferrari Tech Formula 3

    Mar 5, 2010
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    Wade Williams
    It is a non issue. The sleeve edge will not let any pressure by. The head gasket fire ring is outside the area of the sleeve. Even if it went over the parting line, it would cause no issues. The small bore of the 396 makes the cut out necessary, however the larger 427 +.250 on the bore size means there is plenty of room for the valve in the bore. It is very rare to have a sleeve failure in iron blocks. As this was a numbers matching block restoration, it was worth the effort. A performance build would have replaced the block, probably with something with way more C.I.
     
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  4. 020147

    020147 F1 Rookie
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    Jun 12, 2006
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    Did you watch the Jaguar block that they put top hats in to @DoubleD33? IMO, that was a much more complicated block to machine. I’ve liked that channel for some time, they do nice work and a cool variety of different projects. I had no concerns about the 396 build @Ferrari Tech outlined the reasoning very well.
     
  5. DoubleD33

    DoubleD33 F1 Rookie
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    I did see the Jaguar block and agree they do some nice work and was not trying to discredit their efforts but rather looking to see what I was missing.

    I have my E type block on my stand at the house that I did not sleeve or top hat sleeve. After watching that video I am contemplating top hat sleeves for that block… but now being in HI and not in CA I am sure I won’t find the talent here for top hats….
     
  6. Tegethoff

    Tegethoff Formula Junior

    Jul 19, 2014
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    Adam
    JAMSI is cool, I like that the son is quite frank about what he knows and how he educates himself on things he hasn't seen before.

    As Ferraritech pointed out, an iron liner in an iron block has a very low failure rate, as the material's expansion rate is virtually identical.

    The other point is that unlike most aluminum blocks or even iron blocks with a semi/open deck, the length of contact between the sleeve and block is 7"+, a leak anywhere but the head gasket would have to travel the entire length of the sleeve, as it is 100% surrounded in iron.

    Most aluminum blocks or even some iron blocks (like a 3.8/4.2 Jag) will have coolant in contact with the sleeve.

    As long as the deck, liner and head are flat, the press fit seam will be sealed by the distortion of the head gasket's fire ring when installed.

    If it were to leak at the seam, the conditions involved (heat+pressure) are probably already beyond any reasonable operation, and a completely original engine block would probably leak under the same conditions.
     

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