rossman Posted June 11, 2009 Share Posted June 11, 2009 I purchased this used custom turbo header recently. The flange is bowed ~.030" at #2 & #5 and ~.060 at #1 & #6. The flange is .5" thick. What is the best way to flatten the flange? Would it be a good idea to cut the flange between 1&2, 2&3, 4&5 and 5&6 or is this asking for more trouble? Quote Link to comment Share on other sites More sharing options...
Challenger Posted June 11, 2009 Share Posted June 11, 2009 Arent most custom headers like this built from a flange of several pieces? Does this fit the stock S30? Quote Link to comment Share on other sites More sharing options...
rossman Posted June 11, 2009 Author Share Posted June 11, 2009 (edited) Arent most custom headers like this built from a flange of several pieces? Seems like I have seen them both ways. I'm afraid if I cut the flange that it might move around more. But it could go back to flat if it's the flange causing the bow. Is it the flange or the header pipes causing the bow? I dunno. Does this fit the stock S30? The down pipe will have to be custom but otherwise it looks like it fits. The wastegate pipe is about an inch from the motor mount bracket. Edited June 11, 2009 by rossman edited format Quote Link to comment Share on other sites More sharing options...
rossman Posted June 11, 2009 Author Share Posted June 11, 2009 FWIW, MSA and Stahl NA headers have one-piece flanges. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 11, 2009 Author Share Posted June 11, 2009 I've decided to have it machined flat but I can't find a local shop that can do it. I guess I need to find one in Houston. Anybody know a decent shop in Houston? Quote Link to comment Share on other sites More sharing options...
slown280z Posted June 12, 2009 Share Posted June 12, 2009 Does it really have to be machined? A local machine shop has this huge true belt sander that they true big flanges on. They've done 2 exhaust manifolds for me, maybe try asking if they can true the flange instead of "machining" it. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 12, 2009 Author Share Posted June 12, 2009 I use the term "machine" kinda loosely I guess. I'm open to whatever method gets it true and flat. One shop I talked to today offered to belt sand it until they realized it was 24.5" long. Their sander isn't long enough. They called another shop but they couldn't do it either. I'm going to check another "speed shop" tomorrow. Does it really have to be machined?A local machine shop has this huge true belt sander that they true big flanges on. They've done 2 exhaust manifolds for me, maybe try asking if they can true the flange instead of "machining" it. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 12, 2009 Author Share Posted June 12, 2009 I tried another two shops today. The first shop had a Bridge Port but they didn't want to take it on because they didn't know how to set it up. The second shop had a belt sander long enough but they won't touch it because they have to remove too much material. I'm at a loss now. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 12, 2009 Author Share Posted June 12, 2009 One guy recommended that I do it by hand with a disk sander and straight edge. Sounds kinda hokey to me. Quote Link to comment Share on other sites More sharing options...
dan5138 Posted June 12, 2009 Share Posted June 12, 2009 .060 is quite a bit of meat. Maybe buying a new flange and cutting tho old one off is an option? Just have to be carefull and find someone who can weld really well. Also if you do a bit of searching I'm sure someone knows of a vendor that sells header flanges. I imagine either route is less expensive than a complete new header. Quote Link to comment Share on other sites More sharing options...
MREDDLE Posted June 16, 2009 Share Posted June 16, 2009 If you can find some thick metal, you could heat it up (glowing red) then clamp it down to the metal and let it cool. This might help get it closer to bing stright. I have done this many of times and it does help. The large belt sander is the quickest, if someone has done one before. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 16, 2009 Author Share Posted June 16, 2009 Yes it was. I was not happy to discover the flange is warped as much as it is. I'm still negotiating with the seller to get a partial refund to cover the cost of straightening. He offered me a full refund but I still want the header because I think I can make it work. Was this the one out of JapanI was watching it and thinking about buying it myself Quote Link to comment Share on other sites More sharing options...
rossman Posted June 16, 2009 Author Share Posted June 16, 2009 Oh if it was my pipe i would put it in a elcetic furnace bolted to a head and heat it right up , of course not to hot so the head doesnt meltThen pull it out while its still hot and put it into a box of sand and shovel sand over it. This will make it cool very slowly and take most if not all of the warp out of it So this is basically a stress relieving process to take out weld shrinkage? Hmmm, If I only knew somebody who had an oven... 1 Quote Link to comment Share on other sites More sharing options...
rossman Posted June 17, 2009 Author Share Posted June 17, 2009 (edited) If you can find some thick metal, you could heat it up (glowing red) then clamp it down to the metal and let it cool. This might help get it closer to bing stright. I have done this many of times and it does help. The large belt sander is the quickest, if someone has done one before. You mean heat the header flange until it is glowing red then clamp it down? Do you think bolting it to a scrap head would work? How about heating while it is bolted to the scrap head? Edited June 17, 2009 by rossman formatting Quote Link to comment Share on other sites More sharing options...
rossman Posted June 17, 2009 Author Share Posted June 17, 2009 What causes headers like this to warp? Is it weld shrinkage? Is it heat cycling? Is it different cooling rates due to the flange being mounted to a large relatively cool heat sink (head) and the pipes are thin, only exposed to air and the relatively hot turbo flange. Quote Link to comment Share on other sites More sharing options...
DeleriousZ Posted June 17, 2009 Share Posted June 17, 2009 I would think welding can easily cause this. I warped my 3" downpipe circular flange welding on it, so I imagine something of that length would warp very easily if not bolted down to a jig when welding. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 18, 2009 Author Share Posted June 18, 2009 Yeah, I've seen many things warp from welding it's just something that has to be dealt with. I guess I was wondering why header flanges warp after they are used for some period of time. They start out straight then warp - what exactly causes this? I have read that a thick flange prevents warping but mine has a 1/2 inch thick flange and is still warped. If I straighten the flange by heating it up and cooling slowly as suggested in this thread, won't is just warp again? Quote Link to comment Share on other sites More sharing options...
MREDDLE Posted June 18, 2009 Share Posted June 18, 2009 If you have a spare head, then heating it up while it is bolted to it, would be easiest. Then you can have it sanded down on a large sander. Don't use a hand sander, I have never seen that work. Also, I have never seen a flange warp while bolted to a head. I would image that bing rare. a 1/2" flange is just fine. When I made my turbo manifold that is what I used, then sanded it down. Worked like a charm. Hope this helps. Quote Link to comment Share on other sites More sharing options...
rossman Posted June 26, 2009 Author Share Posted June 26, 2009 (edited) I purchased a 48" belt sander and got half of it flat but it became obvioius that I needed a longer belt. I did learn that 48" meant the length of the belt looped around the rollers NOT the distance between rollers. Stupid me. Today I took it to a shop with a big enough belt sander that said they can true it up for me. I got my fingers crossed. Edited June 26, 2009 by rossman spelling Quote Link to comment Share on other sites More sharing options...
rossman Posted July 4, 2009 Author Share Posted July 4, 2009 I got the header back from the shop yesterday. It looks good, nice and flat. Quote Link to comment Share on other sites More sharing options...
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