big valve heads on seibenrockr80/1000cc conversion, will they work?

Discussion in 'Old's Cool' started by pack, Jan 16, 2007.

  1. pack

    pack Banned

    Joined:
    Oct 31, 2006
    Oddometer:
    224
    Location:
    OFallon, Mo.
    a good question was raised in a previous posting, will RS 44mm/42mm heads work in conjunction with my recently installed seibenrock 1000cc-r80rt conversion? any mods i need to do first or is it just bolt on and go?
    Thanks, Pack
    #1
  2. Bernd Bauer

    Bernd Bauer Adventurer

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    Oct 27, 2003
    Oddometer:
    84
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    Cologne, Germany
    It is just bolt on. (If the other parts are stock, read no hot camshafts etc.)


    Regards

    Bernd
    #2
  3. R-dubb

    R-dubb Dubbious Adventurer

    Joined:
    Aug 4, 2001
    Oddometer:
    5,165
    Location:
    San Francisco
    Agreed.

    You can use the Siebenrock asymmetrical cam, but can not use the BMW 336 without substantially modifying the heads. I would not use big heads unless you are also putting on big carbs.

    Expect a somewhat fussier idle, a slight mid-range flat spot and stronger top-end. Throttle response with the big valves may not be as snappy but should pull harder overall if the intake and exhaust are opened up to match.
    #3
  4. pack

    pack Banned

    Joined:
    Oct 31, 2006
    Oddometer:
    224
    Location:
    OFallon, Mo.
    carb and exhaust changes will coincide with the head swap........then camshaft. just want to see what the old girl has to give.
    #4