430 - Machined my headers flanges flat | FerrariChat

430 Machined my headers flanges flat

Discussion in '360/430' started by strongx, Jul 5, 2020.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. strongx

    strongx Karting

    Mar 20, 2009
    166
    Utah
    Full Name:
    Rock Thompson
    My F430 MK2 headers were leaking due to warped flanges. I machined them flat on a 4-axis horizontal machining center. The 4th axis was great as I only needed to get the flange perpendicular to the table, then I could dial it in with the rotary table. The two center flanges were close to planar with each other and the two outer flanges were warped away from the plane (convex). Getting them flat required milling .050-.060" off the center flanges and .010-.020" off the outer flanges.

    I also elongated the outer mounting holes because these had impressions of the stud threads. So now I have flat flanges, no leaks, no constraining OEM exhaust brackets and I hope they will last a long, long time. I like the stock sound and didn't want them louder, so that's why I did this as opposed to aftermarket headers.
    Image Unavailable, Please Login
     
  2. Danedingerson

    Danedingerson Karting
    Silver Subscribed

    Dec 26, 2011
    218
    Maui
    Full Name:
    Dane
    I like this approach. Do you think this can help with cracking along with removing the brackets? The bolts would put pressure on the manifold if the mounting surface was convex.
     
  3. strongx

    strongx Karting

    Mar 20, 2009
    166
    Utah
    Full Name:
    Rock Thompson
    If the manifold isn't under stress then they shouldn't crack. The flanges are now flat and the mounting holes elongated. Most important is to eliminate the high stress created when the exhaust system gets hot and tries to expand, but is prevented from doing so by the rigid mounting.

    Now there will still be some stress and movement just from the manifold itself going from cold to hot. But this will be a small fraction of what it was undergoing before.

    An interesting question is why did my flanges warp? Was it because of the rigid mounting forcing and bending them, or did they just warp from the high heat they were under for many cycles? There is a lot of welding on the headers. That itself induces stress and can cause warping. The header flange is a stainless casting. The side away from the engine is machined to accommodate the nuts and this is done before welding. Probably the flange face that goes against the engine is also machined before welding. Most welded flanges will not be flat to the standard they would be if they were machined after welding, but that's okay because the mounting nuts will clamp it mostly flat and the gasket (4 layers of thin steel) is forgiving of minor imperfection.

    My Mk2 headers were replaced under warranty and lasted about 4,000 miles. Then they started leaking at the ends of the flanges. I wish I had thrown the factory brackets away when the headers were changed; if I had I bet I wouldn't have had the problem.

    My advice is what others have said: If your headers are not cracked/leaking and you have the factory brackets, get rid of them now.
     
  4. carguy007

    carguy007 Formula Junior

    Apr 24, 2013
    839
    Are you talking about the brackets that mount it on the gearbox with the two dog ears to the side? Is this what you are saying to get rid of?
     
  5. Danedingerson

    Danedingerson Karting
    Silver Subscribed

    Dec 26, 2011
    218
    Maui
    Full Name:
    Dane
    Yes
     

Share This Page