Engine and Cam question

Discussion in 'Engine, Fuel and Exhaust' started by Ironman1962, Aug 30, 2012.

  1. Ironman1962

    Ironman1962 New Member

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    I have a 2008 heritage classic with a cvo 255 cam in it. If I put the 107 big bore kit on, do I need to change the cam or is it ok with the new set up?
     
  2. Jack Klarich

    Jack Klarich Expert Member

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  3. hogrotten

    hogrotten Junior Member

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    You should be OK with that cam as long as there isn't any dramatic change in compression ratio.
     
  4. dolt

    dolt Senior Member Contributor

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    Can you say "ping monster"? Yeah, you need to change cams.
     
  5. BUBBIE

    BUBBIE Well-Known Member

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    IF you run the 107 build and parts used Like head gasket @ .045
    and using stock Flat tops pistons. Then add the SE255 cams INTO the Big Boys Calc.

    You will see the compression at sea level is about 207#level OR what ever alitude you use.

    ME at 4400' in Az.,,, would welcome High compression UNTIL I drop down to sea-level.

    IF you go this route and have the SE255 alrerady in, YOU Might think of using the -4* gear (about 36$)to move the intake close from 25* to 29*. This will make a difference to lower compression to Not ping on pump high octane gas. From 207# to 204# at sea level.

    IF you already have the SE cams, I'd try them in First. Cams can always be changed out later.:D

    signed....BUBBIE
     
  6. dolt

    dolt Senior Member Contributor

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    Can't argue with what Bubbie says. However, it's JMHO but corrected CR is 9.8; I am betting it will ping or he will have to take so much timing out that it will be a turd. -4* will help but corrected CR just drops to 9.7; still high. IMHO, wrong cam for that application. There are too many better cam options and for another $300, why take the chance. :unsure
     
  7. hogrotten

    hogrotten Junior Member

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    According to the same calculator my corrected is at 9.93:1 and my bike pulls like a tractor! :D
     
  8. dolt

    dolt Senior Member Contributor

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    I don't believe I have seen a build with corrected CR that high. Most builders won't go higher than 9.6 and lower on touring bikes. Just curious, what is your static and CCP?
     
  9. hogrotten

    hogrotten Junior Member

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    Mind you I'm using the big boyz calculator and inputing my info it comes up with 198ccp.

    Here are my cam specs:

    Int. Exh. duration lift centerline tdc lift

    5˚/18˚ 58˚/24˚ 203˚ 262˚ .583" 96.5˚ 107˚ .113" .206
     
  10. dolt

    dolt Senior Member Contributor

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    Need more than the intake close to calculate; need chamber volume, head gasket thickness, deck height and piston dome volume. Not saying your numbers are wrong but what cam are you running with an 18* intake close?