ACR valves

Discussion in 'Dyna Models' started by Tarheelrider, Mar 30, 2011.

  1. Tarheelrider

    Tarheelrider Member

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    At what point would acr valves be a good idea with modified engines?

    I'm running edelbrock performer heads and a screaming eagle cam. Don't know the cam number as it was put in by previous owner.

    I ask this because I have noticed the starter has a hard time turning over the engine and it kicks back against the starter occasionally.

    This setup loves to eat starters and batteries.


    Assuming the acr would be a good idea what brand of valve would be recommended?

    The bike is a 98 wide glide.

    Thanks in advance for the help.
     
  2. glider

    glider Veteran Member

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    Usually when you pass the 10/1 compression ratio or compression pressures up around 180-190+ the starter would get a workout.
     
  3. Tarheelrider

    Tarheelrider Member

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    Assuming that I determine I'm over the 10:1 ratio, which relief valves would you recommend.

    Thanks,
     
  4. Jack Klarich

    Jack Klarich Expert Member

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    Last edited by a moderator: Apr 5, 2011
  5. Tarheelrider

    Tarheelrider Member

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  6. texas tom

    texas tom Active Member

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    You could go with the manual releases, thats what I use there pretty simple dont know if they can be installed with heads on the bike,sure opinons are coming...
     
  7. Tarheelrider

    Tarheelrider Member

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    I have looked into my compression ratio and it looks like I'm at about 10.5:1.

    I was looking at two different valves: JIMS Manual Compression Release Valves and Vulcan Automatic Compression Release.

    Can anyone give me some idea of which would be best?

    Thanks again for the help guys,
     
  8. texas tom

    texas tom Active Member

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    Jims would be the easiest to install ,then again the question becomes do you need to remove the heads? If you do the automatics might be best then you can just forget about them,another option might be the new S&S easy start cams,saw a demo for em up in sturgis they have a ramp that holds the exhaust valve open until centrifugal force closes them ,dont know of anyone using them so no real time info on em but seemed a neat idea..
     
  9. Tarheelrider

    Tarheelrider Member

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    The heads will have to come off. They need to be machined for the valves. For the cost of pulling the heads and machining I thought about just putting in some flat top pistons to reduce the compression but my local mechanic bore scoped the engine and it still has the stock flat top pistons. I was working under the assumption the pistons were replaced with the heads, cam and carb by previous owner.

    Not sure which direction to go now..
     
  10. Jack Klarich

    Jack Klarich Expert Member

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    You could find some Stroker plates to lower your compression tho you may need to change the intake manifold and push rods as well. We did this on strokers in the past to get the compression down:s
     
    Last edited: Apr 8, 2011