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Thread: Exhaust header stud reinstallation issue

  1. #1
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    Exhaust header stud reinstallation issue

    Hello Mafia, for those of you who have replaced their exhaust manifolds with catless headers, how did you reinstall the header studs? I've seen many forum posts about how to get them out of the block, but not many posts on reinstalling. I just got my second set of headers in place (first set had bad welds), including new OEM gaskets, nuts, and studs, but am having a difficult time getting the headers bolted to the block.

    My issue is that the header studs do not want to stay in the block while I tighten the nuts. They are backing out as I tighten each bolt. Some of them I can get in about 50% of the way or so and get the nut tightened to spec. I can't reinstall the studs without the headers in place, because the space is so tight I can't slip the headers over them. Double nutting proved ineffective. I might try that again though.

    I'm almost thinking about JB-Welding the nut and stud together in the right place so that the stud can't travel backwards and screw the whole thing in like that. Bad idea?
    2005 Jet Black ZHP Sedan "Adriana" || TunedByDaniel || BMW Alarm + Fuel Lock || ORION V4s || Eagle Eyes || 435i Coupe Sport Seats || Perforated Leather X5 M-Sport Wheel || FLOW Designs Lip

  2. #2
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    Yeah, it's a bitch. I think I put my studs in with loctite and let them sit for 24+ hrs before installing the headers. Either way, I said to hell with the standard studs and used these N54 studs that were recommended in a lot of the header threads. Made install much easier.

    https://www.fcpeuro.com/products/bmw...ud-11127593376

  3. #3
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    Quote Originally Posted by ZHPizza View Post
    Yeah, it's a bitch. I think I put my studs in with loctite and let them sit for 24+ hrs before installing the headers. Either way, I said to hell with the standard studs and used these N54 studs that were recommended in a lot of the header threads. Made install much easier.

    https://www.fcpeuro.com/products/bmw...ud-11127593376
    I saw those but was afraid they weren’t going to fit properly. But if they worked for you, I’m tempted to throw all these troublesome ones out and go for those. Why can’t all the studs look like that?!
    2005 Jet Black ZHP Sedan "Adriana" || TunedByDaniel || BMW Alarm + Fuel Lock || ORION V4s || Eagle Eyes || 435i Coupe Sport Seats || Perforated Leather X5 M-Sport Wheel || FLOW Designs Lip

  4. #4
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    Quote Originally Posted by usinjin View Post
    I saw those but was afraid they werenít going to fit properly. But if they worked for you, Iím tempted to throw all these troublesome ones out and go for those. Why canít all the studs look like that?!
    Worked for me and dozens of others. Definitely use them if you can wait. One of those little updates that were made on the e90 production run to help the line build these things faster.

  5. #5
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    Quote Originally Posted by ZHPizza View Post
    Worked for me and dozens of others. Definitely use them if you can wait. One of those little updates that were made on the e90 production run to help the line build these things faster.
    Done. Seems to be a far better solution than trying to mess with loctite. Thanks for your advice!
    2005 Jet Black ZHP Sedan "Adriana" || TunedByDaniel || BMW Alarm + Fuel Lock || ORION V4s || Eagle Eyes || 435i Coupe Sport Seats || Perforated Leather X5 M-Sport Wheel || FLOW Designs Lip

  6. #6
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    Quote Originally Posted by ZHPizza View Post
    Worked for me and dozens of others. Definitely use them if you can wait. One of those little updates that were made on the e90 production run to help the line build these things faster.
    Hmm. After maybe 10 hours of tedious wrenching, the new and improved header studs are in. Now, I am unable to tighten the nuts sufficiently. None of them get tight. They screw on up to the flange, but will not tighten against it. The nut strips, or the stud begins stripping out the block. Not fun at all. Nothing seems to be cross threaded; nothing is going on at a weird angle, and everything is hand-tightened before wrenching. Any ideas? This one has me stumped.
    2005 Jet Black ZHP Sedan "Adriana" || TunedByDaniel || BMW Alarm + Fuel Lock || ORION V4s || Eagle Eyes || 435i Coupe Sport Seats || Perforated Leather X5 M-Sport Wheel || FLOW Designs Lip

  7. #7
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    Quote Originally Posted by usinjin View Post
    Hmm. After maybe 10 hours of tedious wrenching, the new and improved header studs are in. Now, I am unable to tighten the nuts sufficiently. None of them get tight. They screw on up to the flange, but will not tighten against it. The nut strips, or the stud begins stripping out the block. Not fun at all. Nothing seems to be cross threaded; nothing is going on at a weird angle, and everything is hand-tightened before wrenching. Any ideas? This one has me stumped.
    Man I've just gone through all of my pictures from that project and didn't leave myself any clues as to what I did. Probably torqued the studs into the head with loctite, then came back 24+ hours later to mount the headers. You said the studs themselves torqued down ok, so the holes in the head aren't stripped right? That's bad news bears if so.

    The nuts themselves are stripping???

  8. #8
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    Quote Originally Posted by ZHPizza View Post
    Man I've just gone through all of my pictures from that project and didn't leave myself any clues as to what I did. Probably torqued the studs into the head with loctite, then came back 24+ hours later to mount the headers. You said the studs themselves torqued down ok, so the holes in the head aren't stripped right? That's bad news bears if so.

    The nuts themselves are stripping???
    It's so hard to tell what the issue is. My gut feeling is that the slightly crude fitment of the headers and construction is the root culprit.

    The first clue that something was off was that the studs were hard to get in. That made no sense. I examined them carefully and the threads are exactly the same as the stock studs. Only one of them would go in all the way. Again, started each by hand, made sure each one was going in straight. I thought they probably would still be fine, as they are in the block very tightly. None of them stripped at this point.

    With the headers on (the hole spacing seems fine, no pressure on the studs), I began tightening the nuts. Brand new, OEM, pert number 11721437202 which matches realoem, even for the newer studs. The first few turns were easy. Then, they got a little harder to turn, and getting closer to the flange, either the nut threads begin to strip, OR it began turning the stud that it's on. When that happens, it starts hurting the stud holes in the block. Yes, one is definitely damaged. Not gone, but not great either. Bad news bears indeed.

    So essentially I can't get the nuts very tight. When I try, it starts destroying everything. Wish I had an engine hoist. And a lift.
    2005 Jet Black ZHP Sedan "Adriana" || TunedByDaniel || BMW Alarm + Fuel Lock || ORION V4s || Eagle Eyes || 435i Coupe Sport Seats || Perforated Leather X5 M-Sport Wheel || FLOW Designs Lip

  9. #9
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    That sounds really odd... are you sure the stud isn't just turning into the block more when the nut catches onto it? Even if the studs aren't fully bottomed out, as long as you have them threaded in a decent amount they shouldn't strip.

    I've dealt with some pretty janky headers myself and a few other guys made up for a CBR600RR and we threaded in the studs as far as they would go by hand. With dirt and other crap blocking the threads, not all of them bottomed out but it tightened up and we sent it
    2004 BMW 330CI ZHP (well, technically ZAM)


  10. #10
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    Quote Originally Posted by t.er View Post
    That sounds really odd... are you sure the stud isn't just turning into the block more when the nut catches onto it? Even if the studs aren't fully bottomed out, as long as you have them threaded in a decent amount they shouldn't strip.

    I've dealt with some pretty janky headers myself and a few other guys made up for a CBR600RR and we threaded in the studs as far as they would go by hand. With dirt and other crap blocking the threads, not all of them bottomed out but it tightened up and we sent it
    That's what I thought too originally..but then I realized that while turning, the studs were not going in further. And then, one of them got much easier to turn. I carefully reversed it out and the threads on the stud were destroyed. And a bigger yikes when some of the block material came out with it. After blowing the hole out as best I could, I hand threaded in new clean stud. This time it stopped entering the block sooner and I could get it even less tight than before. At this point I stopped, because something is definitely wrong.

    The last headers were far easier to install, except the welding was so bad that they leaked right in the middle. I feel like the fitment of these might be too janky. I'm planning on taking it to the indy for a look.

    Maybe I should know better than to go for $150 headers.
    2005 Jet Black ZHP Sedan "Adriana" || TunedByDaniel || BMW Alarm + Fuel Lock || ORION V4s || Eagle Eyes || 435i Coupe Sport Seats || Perforated Leather X5 M-Sport Wheel || FLOW Designs Lip

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