If you like to build your own headers here is a tech project you can do to to finish off your headers with a good looking, period correct, and efficient header collector. All that is required is a way to roll a cone and a press. Slip rolls are the most common way to roll cones, and a hydraulic press is the most universal way to bend stock, although a mechanical Dake press would do too. Header collectors run the gamut from a low tech tin can type affair to the later style "merge collectors" in common use today. Merge collectors are a little too techie to be period correct, so I am going to show a way to build good looking collectors. Making collectors is often problematic for a number of reasons. Lots of variables here to consider: primary pipe size, number of primary pipes, secondary (outlet) size, collector length, flange type and material. For these reasons I have found it necessary to make my own collector to get all those factors correct. I have made many combinations - everything from 2-into-1, 4-into-1, up to 6-into-1. The picture below of my nostalgia comp roadster has a 6-into-1 header I fabbed. The 2-into-1 stainless jobbie is one I recently made for my Attic Anglia project and was the inspiration for me to do this tech post. So if you want to see how I made them welcome to my world. Enjoy View attachment 6032071 EDIT: The picture of my nostalgia comp roadster "gattling gun" header got deleted, no doubt because the '23T altered was not on topic. Mea culpa! So I cropped the pic to show only the salient collector. Maybe it will p*** muster? Enjoy
Once you have determined the factors above - primary pipe size, number of primary pipes, secondary (outlet) size, collector length, flange type and material - the first step necessary is to fab the cones needed. Making cones is somewhat straightforward and can be seen on YouTube videos or in sheet metal fab handbooks, so I will skip over the process to get on with the steps specific to turning cones into collectors. I will say this about the calculations for constructing the cones: plan on allowing for enough material on the big end of the cone to include approximately 75% of the circunference of each individual primary pipe. Taking that into account, the pattern for the 2-into-1 cone is shown below. In this example I am using stainless steel for a long lasting piece. The section of material marked "overlap" was needeed to get a consistent curve on the cone going through the slip rollers and subsequently gets cut off prior to welding the cone. Now to address the special forming tools needed. Two parts - the hinged press die and the tapered round support mandrel. The die has some special features. The pivot point is offset. That is needed so pressure is applied unevenly, more on the big end where the most deformation will be needed, and less on the small (outlet) end, where a round outlet must be maintained. Another feature is the edge of the die starts with a sharp edge at the primary side for a nice looking well defined crease and it gradually transitions to a rounded blunt edge so the crease gradually diminishes. The tapered support mandrel is made from solid bar stock with a small plate welded to each end to position the bar stock, but small enough to allow the collector to be slipped over the mandrel before pressure is applied. My bar stock is 1" in diameter.
The process of making the crease is a little squisshy. By that I mean it may require a little bit of trial-and-error so start slowly to determing where the best place to apply pressure is. Note that the big end of the cone is placed over the side of the mandrels that are widely spaced apart so as to distribute the creasing force over a broader area of the cone. The outlet side, where no deformation is needed is placed over the narrow side. I suppose the mandrel could be improved by slicing the bar stock on a bias to pinch the small end even more tightly together, but that would entail a lot more fab work with little bang for the buck. Some reshaping of each end by hand hammering will be necessary so that both ends are round to accept the primary pipes and the collector extension(s) or tail pipe(s) if required. My Anglia will be getting a full exhaust downstream of this collector.
Timely for me. I need 4 similar 2 to 1 thingies to make tri-Y headers. And you know what that means. Plaigerizer to the garage...
Scroll back up to the top of the page. In small print near the right side are two icons - "Thread Tools" and "Watch Thread". Click on the "Watch Thread" and then hit the confirm box. done
In case you may have missed my EDIT in the first post where I reposted the shot of the 6-into-1 collector without all that O/T race car here it is.
You can also go to your profile page and select Alert Settings. Check the first box and you will get notifications of any threads you have created or replied to.
Well done, Thanks for showing how it's done. I like to make dies and use my press to form parts from sheet metal too.
At this point you may be thinking, "Sure, Flyer, you skipped right over making the cone. What if you have no slip roller? How can a cone be made?" I was faced with that issue when I did my avatar champ car because the collector was too long to fit in my smaller slip rolls. I took a low tech approach and formed the cone around a tapered table leg using a combination of pipe clamp, chain clamp, broken connecting rod, and flanges, slowly squeezing the piece into a cone. Another HAMBer @Dave G in Gansevoort mentioned you can start with a piece of large diameter tubing and pie-cut some away. Where there's a will there's a way.
@THE FRENCHTOWN FLYER, when doing this, how about spring back? Do you tighten past the 2 edges being flush, heat it while clamped, or ?
I generally don't use heat. I may put a tiny bit of over bend into the cone because there will be spring back, just to make it easier to hold while welding. Then I space a series of tack welds along the seam and remove the clamps to finish weld. I also weld the inside of the seam about a half inch into the cone so the creasing process and subsequent tapping does not induce a crack along the end of the seam.
I made a couple of stub pipes. They will join the original six dual exhausts (with some mods to fit the tube ch***is) to the collector. I made a simple template jig to hold the stub pipes at 3" on center, same as the head pipes.
My wife and I made a guy that builds headers,... little bit of a wait but 20 years p***ed by quick...he finished welding school top of the cl*** and has been building me headers for 10 yrs now...
Subbed, but with a question... For a simple 2-into-1 setup would it be any easier to use 2 pieces of tubing cut at a narrow angle along their length? Would need to flatten/open up the merge area a bit to get the larger diameter, then weld along the seams. Something like how "X" pipes are made from 2 elbows, but without the bends. (Don't have much in the way of sheet metal forming equipment) Thanks!
nice That looks really cl***y. Thanks for the post. That would certainly be one way to do it. I think I'd wrap the tubes in pattern paper first to determine precisely where the cuts need to be. Once you start bending and shaping, the cut lines can deform.
That's how I did mine. All four of them were different shapes. I used a strip of manila folder for a measuring device. They were made from two pieces of primary diameter tubing. Measured around a primary tube from weld to weld for the length of the top cut. I cut it a hair long because I was going to overlap the primaries. The bottom cut is is cut to the length of 1/2 the diameter of the secondary tube. To know where to place the cuts in relation to each other on the ends of your reducer you kind of have to know where the secondary is going to be. The second half is measured off the first piece. I used sockets to spread reducer halves. My top is spread to just overlap the primary tube and the bottom is spread to the diameter of the secondary tube Helps to have 3/4" sockets for the secondary end. Same process from the secondary tubes to the collector. The collector flange is a cut off from a 2 1/2" stepped collector reducer from Speedway
The Jalopy Journal
