rocker box mods.

Discussion in 'Harley Davidson Extreme Modification' started by 2006FXDCI, Aug 17, 2009.

  1. 2006FXDCI

    2006FXDCI Active Member

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    I am having roller rockers installed in my engine and have seen in several articles about having to clearance your stock harley rocker covers for the roller rockers. Has anyone done this them selves or have some pics of before and after. I have a bridgeport mill where I work and can probably do it myself and save some money. Thanks
     
  2. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    I doubt your will need a miller. Usually you can do any clearancing with a dremel and a grinding stone. Not taking off much. In fact, are you adding any higher lift cams or something the would cause the rockers to interfere with the covers? Double check your instructions, and definitely use clay to ensure the grinding is necessary.

    TQ
     
  3. 2006FXDCI

    2006FXDCI Active Member

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    Yes I am adding a set of .650 lift woods cams
     
  4. TQuentin1

    TQuentin1 Well-Known Member Staff Member Moderator

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    Ahhh. Well there ya go. Will very likely need to relieve the cover 20K-30K thou. I suggest clay. Glider has a post in Self-Help somewhere about all that.

    TQ
     
  5. kemo

    kemo R.I.P

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    Or you can get a set of aftermarket boxes from TP engineering that will work for you. They are a nice addition, milled from billet and the rocker shaft stancions are milled into the lower box, instead of bolted in. They are sealed with "O" rings and have a chimney built into the center for decompression valves
     
  6. glider

    glider Veteran Member

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    Valve Noises - Harley Davidson Community
     
  7. dolt

    dolt Senior Member Contributor

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    Its not the rollers, its the cam lift. The diagram linked to the previous post is self explanatory and you can do it with a dremel tool. The diagram doesn't show the removal of the internal cover webbing at the center bolt on the opposite side of the side where the two corners are clearanced but the pushrods can and will hit there with .650" lift cams. If using beehive springs, you are probably OK at the corners but mock up the top end and turn the engine through to be sure. If the springs aren't beehives, the corners will have to be clearanced and you could use your mill there.

    If you are using late model heads with the 7mm valves, you have another problem that occurs when the pushrod is at it’s lowest and highest points, especially with high lift cams; it's called geometry. There are potential contact points between pushrod and tube that is exagerrated with high lift cams. Additionally, the roller rocker tip will try to roll off the forward edge of the tip of the valve stem as well. This problem is eliminated with modified rocker supports that moves the pushrod out .030" away and towards center of the pushrod tube and provides an additional .030" in motion to help mitigate the roller tip action. I am sure Bobby Woods would be happy to sell you a couple.

    People think that roller rockers are quieter than stockers and that may be the case if cam lift does not exceed .500 and normal valve train geometry is maintained. Once you get in the .570 range, valve train geometry is altered and the valve train gets noisy and the closer you get to .650", the more the geometry is altered and the noisier they get. Centering the lower rocker boxes when installing is also important. It will help in with cams in the .570" range but offset rocker arm supports are sometimes the only way to address the problem with cam lifts over .600".
     
  8. vtbikers

    vtbikers Active Member

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    I would not use a milling machine.