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Thread: Jaguar XK head

  1. #1
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    Jaguar XK head

    A question for Rob -

    On another forum, a member said he made the mistake of setting the head from an XK motor on a flat surface (I assume his workbench), implying this was a bad thing to do.

    Can you tell me why?

    Because I'm thinking the bottom of the head need to be flat to get a good seal with the gasket against the cylinder casting. And that the valves probably aren't sticking out the bottom of the head, as they're usually recessed to get a good combustion chamber.

    Chip H.

    Former owner: 2012 Honda Civic LX, 2006 Honda Ridgeline RTL, 2000 Honda CR-V EX, 2003 MINI Cooper S, 1992 Honda Accord LX, 1999 Mercedes ML-320, 1995 VW Jetta GLX, 1991 Mercury Capri XR2, 1981 Mercury Zephyr, 1975 Chevrolet Impala

  2. #2
    Vulture of The Western World Eric's Avatar
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    Re: Jaguar XK head

    Quote Originally Posted by chiph
    A question for Rob -

    On another forum, a member said he made the mistake of setting the head from an XK motor on a flat surface (I assume his workbench), implying this was a bad thing to do.

    Can you tell me why?

    Because I'm thinking the bottom of the head need to be flat to get a good seal with the gasket against the cylinder casting. And that the valves probably aren't sticking out the bottom of the head, as they're usually recessed to get a good combustion chamber.

    Chip H.
    How would setting a head on a workbench cause damage? Even if the head is aluminum, unless you beat on it or something, what would cause damage to what is essentially a big hunk of alloy? I have left the alloy head of my motorcycle sitting on my workbench - didn't seem to cause any trouble...

  3. #3
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    Re: Jaguar XK head

    That's what I'm wondering.

    Perhaps it easily warps if it's not 100% flat ???

    Chip H.

    Former owner: 2012 Honda Civic LX, 2006 Honda Ridgeline RTL, 2000 Honda CR-V EX, 2003 MINI Cooper S, 1992 Honda Accord LX, 1999 Mercedes ML-320, 1995 VW Jetta GLX, 1991 Mercury Capri XR2, 1981 Mercury Zephyr, 1975 Chevrolet Impala

  4. #4
    Vulture of The Western World Eric's Avatar
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    Re: Jaguar XK head

    Quote Originally Posted by chiph
    That's what I'm wondering.

    Perhaps it easily warps if it's not 100% flat ???

    Chip H.
    Maybe if there was a 100 pounds of deadweight placed on top of it!

  5. #5
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    Re: Jaguar XK head

    The guy in the other forum said the valves stick out the bottom just a little bit, and the weight of it is enough to bend the stems just a teensy weensy bit, to where they won't work freely any more.

    Chip H.

    Former owner: 2012 Honda Civic LX, 2006 Honda Ridgeline RTL, 2000 Honda CR-V EX, 2003 MINI Cooper S, 1992 Honda Accord LX, 1999 Mercedes ML-320, 1995 VW Jetta GLX, 1991 Mercury Capri XR2, 1981 Mercury Zephyr, 1975 Chevrolet Impala

  6. #6
    MikeHalloran
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    Re: Jaguar XK head

    I think the valve axes are not parallel to the cylinder axes, and the valve stems are delicate.

    Other interesting failure mechanisms chronicled here:

    http://www.jag-lovers.org/xk-lovers/...sion_zero.html


  7. #7
    Vulture of The Western World Eric's Avatar
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    Re: Jaguar XK head

    Quote Originally Posted by chiph
    The guy in the other forum said the valves stick out the bottom just a little bit, and the weight of it is enough to bend the stems just a teensy weensy bit, to where they won't work freely any more.

    Chip H.
    Ah. I guess then so long as you lay it on its side you're ok?

  8. #8
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    Re: Jaguar XK head

    Quote Originally Posted by MikeHalloran
    I think the valve axes are not parallel to the cylinder axes, and the valve stems are delicate.

    Other interesting failure mechanisms chronicled here:

    http://www.jag-lovers.org/xk-lovers/...sion_zero.html
    Interesting reading, Mike.

    Who knew the things would be so fragile?

    Chip H.

    Former owner: 2012 Honda Civic LX, 2006 Honda Ridgeline RTL, 2000 Honda CR-V EX, 2003 MINI Cooper S, 1992 Honda Accord LX, 1999 Mercedes ML-320, 1995 VW Jetta GLX, 1991 Mercury Capri XR2, 1981 Mercury Zephyr, 1975 Chevrolet Impala

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