Welding exhaust manifolds, need advice/help

admin

Hello, Matt here,I have been tig welding for a couple years, and have been producing some pretty simple turbo exhaust manifolds for 4 cylinders. I want to try and take them to the next level and try some more complicated designs.My main concern is basically I'm confused how you actually get the tig torch in certain places to even make a weld. I know for the collectors people generally weld those first, like this: Though how do you get the weld down there in that tight of a spot? Do you just have the tig tungsten sticking way far out from the cup to get down there?So after you make the collector, you then later weld the 4 runners to the top of those 4 ports on the collectors, and this is mainly where my question comes in. It seems that there are inexessable spots that need to be welded, but I just don't see how to get the tig torch in there to weld, here are some examples:That one is really tight, most of them are more like this:So mainly seeing if anyone can give me any pointers, even such as cup sizes, gas lense?, and tungsten combos that I should use, or how far out I should have the tungsten, etc. Any help is greatly appreaciated, thanks!Oh P.S. I am doing this in 304 stainless steel. I am using ER308 filler rods to weld stainless to stainless, and ER309 to weld stainless to mild, does this sound right?
Reply:You need to plan ahead and weld what you can ahead of time before welding on the rest of the tubes or tying into the merge collectors.  You can use a gas lens with extra stickout in some places, micro head torches in others.
Reply:PPPPPPprior planning prevents piss poor performance.The tube runners are all tacked to the header flange and to the collector and proven to be all in the correct position. Then they are cut some at the the collector some at the flange or some in a joint in the middle of the run (that would be assessable with the whole thing assembled). Then all the component parts are welded then reassembled and final welding is completed.
Reply:So even though the entire thing is tacked together like so:They will then break apart some of the tacks and then weld it in different areas, rather than doing all of the welds as is? By the way what are some of the cups and tungstens you guys use for stuff like this?
Reply:when i weld up my manifolds i just use a standard 17 torch with a 8 cup on a med gas lens. 3/32nd red tungsten btw.also when trying to weld in tight spots pulling your tungsten out of the cup about an inch or more may be necessary to complete the job. also i have needed to bend the tungsten 45-90* to get in some places. and have set up an external purging hose to get proper gas coverage.
Reply:And this is how to bend tungston..http://weldingweb.com/vbb/showthread.php...ghlight=copper...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Thats awesome I never thought to do something like that, that looks like a good way to get into some hard to reach places for sure, thanks!
Reply:Originally Posted by zapsterAnd this is how to bend tungston..http://weldingweb.com/vbb/showthread.php...ghlight=copper...zap!
Reply:Originally Posted by zapsterAnd this is how to bend tungston..http://weldingweb.com/vbb/showthread.php...ghlight=copper...zap!
Reply:Originally Posted by MahonroySo even though the entire thing is tacked together like so:They will then break apart some of the tacks and then weld it in different areas, rather than doing all of the welds as is? By the way what are some of the cups and tungstens you guys use for stuff like this?
Reply:Make sure the flanges are bolted down flat to something. I have seen to many manifolds in the trash because someone warped the flange past the point of no return.
Reply:I had one final question, wasn't sure where to ask so thought I would just toss it in here:Anyways, I use autocad to make the head flanges, and I have seen on a lot of flanges that the edges are kind of rounded and look a lot nicer, such as this:Do you know what kind of tool is used for this? Thanks again for all of the help!
Reply:They are machined on a CNC mill, the edges are "chamfered" with a 45 degree cutter after the profile has been cut.
Reply:Originally Posted by LenMannThey are machined on a CNC mill, the edges are "chamfered" with a 45 degree cutter after the profile has been cut.
Reply:Ok last question lol.What do you guys do on the manifolds to give them a nice finish? For example do you use something like a flapper wheel on all of the manifold parts, before welding them all together (just being careful not to ding/scratch it?). Or do you throw the whole manifold into a tumbler for a while? Or some other method? I'm trying to avoid having to sit there for countless hours sanding and buffing. Thanks again!
Reply:i use scotch brite pads before the fit up and i make sure to use the smoothest table possible to prevent scratching....hope this helps
Reply:before you begin  any work on your exhaust manifold, make sure you have some welding gloves, i would recommend matching up the ports  and then polish them with a small flapper wheel.
Reply:Originally Posted by MahonroyHello, Matt here,I have been tig welding for a couple years, and have been producing some pretty simple turbo exhaust manifolds for 4 cylinders. I want to try and take them to the next level and try some more complicated designs.My main concern is basically I'm confused how you actually get the tig torch in certain places to even make a weld. I know for the collectors people generally weld those first, like this: Though how do you get the weld down there in that tight of a spot? Do you just have the tig tungsten sticking way far out from the cup to get down there?So after you make the collector, you then later weld the 4 runners to the top of those 4 ports on the collectors, and this is mainly where my question comes in. It seems that there are inexessable spots that need to be welded, but I just don't see how to get the tig torch in there to weld, here are some examples:That one is really tight, most of them are more like this:So mainly seeing if anyone can give me any pointers, even such as cup sizes, gas lense?, and tungsten combos that I should use, or how far out I should have the tungsten, etc. Any help is greatly appreaciated, thanks!Oh P.S. I am doing this in 304 stainless steel. I am using ER308 filler rods to weld stainless to stainless, and ER309 to weld stainless to mild, does this sound right?