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  1. #1
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    Default Valve spring selection? VN head 308 280-2

    Hi guys, I am in the process of piecing together a VN headed 308. I intend on running a solid cam, thinking along the lines of a Crane 272 or 280 or something in that vicinity.

    My question is, is there a valve spring available that does not require machining?

  2. #2
    427
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    Crow cams could tell you that.
    But i'm sure someone here will also know..

  3. #3
    Sure why not? 76lxhatch's Avatar
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    I'm using these with my early headed 355:
    https://www.summitracing.com/int/par...4000/overview/

    Cam is 242/252@.050, .548/.569" lift (.020 lash on solid cam) and no issues with spring bind at 1.75" installed height. It happily revs to the limit at 6300 (and wants to go higher).

    BUT... I did find that despite being supposedly standard size, I did have to machine a very small amount of the spring pocket in the head for clearance, particularly to the inside where the dampers were squirming around. Not sure if this would also be an issue with VN heads or whether the spring seat may be slightly larger?

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    Quote Originally Posted by Fieds83 View Post
    Hi guys, I am in the process of piecing together a VN headed 308. I intend on running a solid cam, thinking along the lines of a Crane 272 or 280 or something in that vicinity.

    My question is, is there a valve spring available that does not require machining?
    Question, are the VN heads you have already had a ‘reco’ valve job etc and are they fitted to the engine now or on the bench?

  5. #5
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    The heads have been reconditioned, as to the extent of that reconditioning I am not sure. They are off the engine.
    Thanks for the replies.
    Last edited by Fieds83; 09-01-2019 at 09:24 AM. Reason: Spelling error

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    254RWHP boat anchor EVL253's Avatar
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    honestly with a cam that size go the dual springs and be done with it. single to cope its getting limited selection
    11 second E85 bottle fed boat anchor

  7. #7
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    Have you considered beehive or conical springs? They reduce the spring rate reqd because the valve train 'sees' less weight. The lobes will live longer! I have a set of Comp Cams Conical springs #7228, new in the box, if interested.

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    Quote Originally Posted by Fieds83 View Post
    The heads have been reconditioned, as to the extent of that reconditioning I am not sure. They are off the engine.
    Thanks for the replies.
    In my opinion if you’re building or have a built bottom end that is suited to the rpm that a 280 Crane can deliver and the heads are a bit of an unknown I’d get them checked by a good head/engine shop.

    Get the valves & seats and guides checked. Bite the bullet and get the spring pockets machined for dual springs and top of the guides machined for positive seals. A cleanup in the bowl area (there are some threads on this forum)

    Yes there are some good single LS style springs (PSI in my opinion) and I’ve got a mate with a set on a Holden V8, but they were not a direct drop on fit, minor machining required so they sat perfectly.

    The last Holden V8 that I fitted a SFT Cam was the Camtech version of a 280 Crane. Same duration but a bit more lift and I fitted Crane 99893-16 dual springs with positive seals, head place did seat job (standard Holden valves) and I cleaned up the bowls etc. It’s still going and my brother punishes it and puts a big smile on his dial.

    Food for thought.

  9. #9
    Do you ever leave? EH179's Avatar
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    The Crane 280 cam will require a spring to be set with installed height of 1.85" and be able to handle .580" lift before lash, on the ex lobe.
    .351.4" lobe lift X 1.65 rocker = .580" - .026" lash = .554" lift.

    Most single springs will only go around .550" lift @ 1.75" installed height.

    Crane recommend the 99893 springs and that's what i use.

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    Do you ever leave? paulzig's Avatar
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    Quote Originally Posted by EH179 View Post
    The Crane 280 cam will require a spring to be set with installed height of 1.85" and be able to handle .580" lift before lash, on the ex lobe.
    .351.4" lobe lift X 1.65 rocker = .580" - .026" lash = .554" lift.

    Most single springs will only go around .550" lift @ 1.75" installed height.

    Crane recommend the 99893 springs and that's what i use.
    You could probably set that 99893 spring to a 1.75" installed height you'll have a bit more seat pressure thats all ... But you'd have to check each spring for actual coil bind.. With around .560" lift you have room way before bind

  11. #11
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    OP what is the problem with machining the seats? It takes only a few minutes. & you'll have the heads disassembled anyway, Then you can run the spring the cam designer recommends

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    Another option to machining the seats is to use a spring locator, if you have enough installed height. The locators are usually 0.060" thick. You can also juggle installed heights with + 050 & - 050 keepers.

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    to be honest to run a spring on it limits is asking for trouble, theres nothing worse than a dropped valve because you tried to save on valve springs

  14. #14
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    Thanks for the feedback guys.

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    I don't like + 0.050" keepers. I would much rather run a + number retainer. Locaters and shims though imo are a legitimate fix

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