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oldtin
oldtin HalfDork
6/7/10 11:34 p.m.

Nothing off the shelf is going to fit the MG. Any tips for fabbing up a set? Was thinking of buying a box of bending mistakes from stahl and having at it.

oldeskewltoy
oldeskewltoy Reader
6/7/10 11:53 p.m.

http://www.centuryperformance.com/exhaust-header-sizing-and-tube-length-spg-137.html

mainlandboy
mainlandboy New Reader
6/8/10 12:52 a.m.

I built my own headers for my Locost. I used a 1/2" thick piece of flatbar for the flange, and used a holesaw to cut the ports (took forever to cut the 4 holes). I then bought a box of 90 degree elbows, cut them to fit, then joined them into a 4 into 1 collector.

There are some pics in my online build gallery here:

http://picasaweb.google.com/marktsui1975/MarkSLocost#

Hope this helps, Mark

erohslc
erohslc Reader
6/8/10 8:54 a.m.

GRM Tech Tips to the rescue! http://grassrootsmotorsports.com/tech-tips/58/ Mock them up first. Tack the bits together. Unless you are good, find a pro to do the final welds.

Carter

orphancars
orphancars Reader
6/8/10 9:45 a.m.

This guy has been helping folks build their own for almost 50 years -- call Ed up with a few questions, be prepared to spend 1 hour + on the phone. He has a packet that he sells for $25 that is loaded with info.

http://headersbyed.com/

z31maniac
z31maniac Dork
6/8/10 10:30 a.m.

Paging Keith.....

orphancars
orphancars Reader
6/8/10 10:41 a.m.
z31maniac wrote: Paging Keith.....

Oh yeah -- that prompted me to remember to add this:

http://www.icengineworks.com/

Model your headers in lego type thingies before cutting a single tube!

Keith showed them on a post a year or so ago -- FM uses (used?) them to model headers. They used to be VERY expensive but I assume ice engine works was getting less hits at ~$1k for the kit -- it is now $399. I think it'll pay for itself with just a couple uses....

Anyone want to go in on a set??

emodspitfire
emodspitfire New Reader
6/8/10 10:44 a.m.

Hey,

Try Britishv8.com for build tips/vendors.

Those guys have put just about every decent motor you can think of in Brit chassis.

Good luck!

Rog

Dr. Hess
Dr. Hess SuperDork
6/8/10 10:45 a.m.

My primary rule in making headers (I've made two) is that they have to fit the vehicle. I also use 304 Stainless. For a non-turbo application, I buy "sanitary tubing," used in chicken processing plants. It's polished inside and out, 16ga, and you can buy fabricated 90's that are formed perfectly round, not even "mandrel bent." I tack them up and then get the chicken plant manufacturer place to TIG them. And I get them to waterjet cut my flanges off my CAD work.

This one is sanitary tubing: The collector was made from a piece of restaurant counter top, cut and beat into shape around 4 short sections of tubing that I had expanded at the local muffler shop to slip fit on the runners.

This one has to support the turbo and half the rest of the exhaust system, so it's 1/2" plate for the flanges and Schedule 40 (140 wall) 304 for the runners:

4cylndrfury
4cylndrfury SuperDork
6/8/10 10:46 a.m.
mainlandboy wrote: I built my own headers for my Locost. I used a 1/2" thick piece of flatbar for the flange, and used a holesaw to cut the ports (took forever to cut the 4 holes). I then bought a box of 90 degree elbows, cut them to fit, then joined them into a 4 into 1 collector. There are some pics in my online build gallery here: http://picasaweb.google.com/marktsui1975/MarkSLocost# Hope this helps, Mark

awesome build...truly awesome. I hope one day to have a similar photoalbum. This deserves its own thread...hint hint

Keith
Keith SuperDork
6/8/10 11:43 a.m.

I've done three now - a Locost header that was pretty easy (there really aren't a lot of packaging problems with that when you get to go outside the body), the OTT one for the Targa car and a pair for the MG.

Locost (keep moving forward in the diary, it's interspersed with other aspects of the car)
Targa car
MG

I usually start by figuring out the general routing with pool hose cut to length. That tells me where the header can run.

I didn't have access to the "header lego" for the Locost header, but as I said they're easy to package in that chassis. I simply used aluminum welding rod cut to the appropriate length and left lots of room around it. The shape was then transferred to mandrel U bends, cut and welded. Even without the header lego, it turned out really well. The lengths and sizes for this one were based on measuring a Boig Racing header for the car. I then cut the ceramic coated Boig up for parts and proceeded to use it on all of my subsequent headers

The lego really does make life easy, and lets you make the total whack job stuff if you want. At $399 for a kit, it's an investment that would pay for itself really quickly. Don't stress about getting the perfect diameter - we have a 1 5/8" kit, and I've used it to make two 1 3/4" headers. It takes a bit of planning to use it correctly (it's easy to cheat and combine radii as well as put extra twists in the tube) but it's really really really helpful. One nice thing about it is that you can figure out ahead of time how many mandrel bends you need and of what radius so you can order the correct amount.

For the MG, I used a combination. The packaging of that car meant I couldn't do a tuned equal-length setup, I was just looking to make it fit and hopefully keep a decent flow. The pool hose wasn't used, I started with the lego instead. Just for fun, I built the second side of this one tube by tube instead of modeling it all in the lego. It worked out pretty much the same. Because I was building that one on the car instead of on the bench, I was actually able to get a slightly improved fit in the tight confines as I adjusted the angles on the car.

For the first two jobs, I got the header flanges by cutting up a stock manifold. It's a bit of work, but easier than starting from scratch! For the most recent one on the LS-powered MG, I used a set of GM header flanges that were pretty inexpensive. The collectors for the first two were slip-on units such as the inexpensive Edelbrock merge collector. The last set was done with a cheap "weld-on" unit that was really just a clover-shaped piece of pipe. This obviously required more fabrication as I had to close it up, but it actually helped when I needed to cheat and angle the collector to one side to make it fit.

It's all kind of fun, actually. But I wouldn't want to do it more than once a year or so.

oldtin
oldtin HalfDork
6/8/10 3:22 p.m.

Now that I see it, I remember the pool hose pic or similar in the locost book. I'll have to hit the local home depot for hose and great stuff. I did scrounge one header that works. I just have the driver's side to deal with now.

Dr. Hess, that's some creative sourcing - hopefully the tubes don't arrive full of crap or that you end up with chickensh** headers. Actually I bet the internal polishing is nice for flow.

Dr. Hess
Dr. Hess SuperDork
6/8/10 4:16 p.m.

I buy them brand new from the stainless suppliers. Near as I can tell, they pump chicken guts and parts through them at the processing plants. Probably enough to put you off of pot pies for life. Being a vegetarian, I don't care, but my dogs like chicken.

That Esprit header took about 6 weeks of all my spare time. All the stock ones crack at the same place. One large will get you a NOS piece that will crack in the same place as your old one. Mine's holding up fine. It weighs the same as the English cast iron piece.

Keith
Keith SuperDork
6/8/10 6:15 p.m.

What's the bend radius of the chicken pipes? Can you get different sizes? I've found that 3" seems to be the most useful size for my builds.

44Dwarf
44Dwarf HalfDork
6/8/10 7:28 p.m.

wow that lego kit is cool! I've used pool hose before and filled it with "great stuff" foam spray tape it in place let it set up overnight then take the now hard tubes down to midas and have them bend'em up. Most of the time i just start with one that fits the motor and cut it up and weld as needed.

44

MrJoshua
MrJoshua SuperDork
6/8/10 7:51 p.m.

Sand bending always sounded like a cool way to make really good flowing headers, anyone here done it?

Keith
Keith SuperDork
6/8/10 8:08 p.m.

I haven't tried it, but I've seen a header that was made that way. In that particular case, it did not turn out well. An exhaust shop pipe bender would have worked better.

MrJoshua
MrJoshua SuperDork
6/8/10 8:40 p.m.

In reply to Keith:

Was it the fault of the concept of sand bending or just a failure in the execution? In theory it sounds like you could get intricate bends with beautiful flow because of the single bent tube design, but the fact that I never see it done has me wondering.

Dr. Hess
Dr. Hess SuperDork
6/8/10 8:48 p.m.

You can get the sanitary tubing bends in different radii. I think I used 3" or so on the one on my Locost. It comes in different ID's too. I bought a 3" 90 for a turn out after the muffler. You can kinda see it in front of the rear tire. The store-bought bends are not cheap.

I experimented with sand bending. It is my conclusion that it can work and make some really good bends. However, I would personally have to ruin about $10K worth of stainless tubing to get good enough to do it.

Teh E36 M3
Teh E36 M3 Reader
6/8/10 9:15 p.m.

Do you have a source for the chicken tube?

Keith
Keith SuperDork
6/8/10 9:25 p.m.
MrJoshua wrote: In reply to Keith: Was it the fault of the concept of sand bending or just a failure in the execution?

I don't know. That's why I said it didn't work in that particular case. I only saw the final product, not the actual procedure.

For pricing, I usually pay around $15-18 for a mild steel U bend from Summit or my local muffler shop. The MG headers took the following:
1x 2.5" radius
1x 2" radius
4x 3" radius

Add a couple of cheap collectors ($32/pair, I think) to that. The Targa header was more expensive, but I think I still have less money in it than buying a $400 Racing Beat header for that car.

stuart in mn
stuart in mn SuperDork
6/8/10 9:35 p.m.
orphancars wrote: This guy has been helping folks build their own for almost 50 years -- call Ed up with a few questions, be prepared to spend 1 hour + on the phone. He has a packet that he sells for $25 that is loaded with info. http://headersbyed.com/

Eddie Henneman lives a couple miles from me, he will talk your leg off. He does know his stuff. He ported a set of Pontiac heads for me years ago, they worked very well.

Dr. Hess
Dr. Hess SuperDork
6/9/10 7:29 p.m.
Teh E36 M3 wrote: Do you have a source for the chicken tube?

I buy it local from a place in Springdale, AR. Just google up "sanitary tubing" and look for someone local.

a401cj
a401cj New Reader
6/9/10 10:11 p.m.
mainlandboy wrote: I built my own headers for my Locost. I used a 1/2" thick piece of flatbar for the flange, and used a holesaw to cut the ports (took forever to cut the 4 holes). I then bought a box of 90 degree elbows, cut them to fit, then joined them into a 4 into 1 collector. There are some pics in my online build gallery here: http://picasaweb.google.com/marktsui1975/MarkSLocost# Hope this helps, Mark

1/2"? One-Half of an inch? yeah...I see you did. That flange must weigh more than the whole rest of the car! WTF?

foxtrapper
foxtrapper SuperDork
6/10/10 5:12 a.m.
MrJoshua wrote: Sand bending always sounded like a cool way to make really good flowing headers, anyone here done it?

There was a really great military aircraft article about sand bending exhaust pipes on the web many years ago. It was from and about the guys who did this decades ago, and who still do it.

It works well, but is frequently poorly executed. You've got to ram the sand tight, you've got to get the pipe bright red hot, the sand must be dry. People fail to do these things quite routinely, and get poor results.

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