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Thread: Rings

  1. #1
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    Default Rings

    Guys

    Just a technical question, can't elaborate right now as to why i'm asking (research).

    Scenario, if someone was to take a brand new production SBC with regular cast iron rings run only on the gas fired test bed, and then have to pull it down due to damage. Assume the bore hone is OK, or if not it has been re-honed for factory cast iron rings.

    What would happen if chrome (GM high mileage replacement) or Moly (GM performance as used in the 60's fuel injected Corvette 327) rings were used?

    Am I correct that Moly needs a different bore surface finish?
    Last edited by HK1837; 20-02-2018 at 10:00 AM.

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    You restorer types really go the extra the mile on a build, kudos.

    Just kiddin'

    Depending how long it has sat, I doubt even the best hone job is still good after X years with no care taken to protect it. Even if it has been oiled regularly it still needs to be checked at a minimum and a hone is cheap.

    Get the bore measured, run a ball hone through and re-ring with whatever you like (as long as its period correct )

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    Sorry, I wasn't quite clear. This is an historical question! I'm talking a new engine in 1968-1970, gets built in the USA and test fired in the engine plant on gas. Gets shipped to Australia but cannot be used due to salt water damage. So has to be rebuilt then (not now) for re-use. So we are assuming the bores are still fine as they only have seen a few minutes running time. What would happen if they were rebuilt with the factory bore finish using premium (Moly) rings as used in the factory hipo 4" bore small blocks of the 60's?

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    In that case, my understanding is that moly rings typically require a finer finish compared to cast. If this was not done then ring seal/longevity may be compromised.

    Or it may not, since the bores have been rubbed already by the cast rings.

    I would like to think whoever did the repair already though of this and accommodated for it.

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    That was my thinking. And no, it appears that this was a real mistake that happened too on a large scale. Will elaborate later.

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    All good, I think I have a idea on why you're asking.

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    [QUOTE=HK1837;744321]Sorry, I wasn't quite clear. This is an historical question! I'm talking a new engine in 1968

    Even after a few minutes run time, I would assume fresh moly rings would not have enough to bed on the bores.

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