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header tips.
I'm in the process of making headers for my 3500 Fiero swap, and thought I might share a few tips I've learned along the way.
When I was done welding my primaries, I built a pressure tester that I could hook up to my air compressor to test my welds, it cost less than $20 to make, and has worked great so far,
I made it out of an 1 1/4" PVC repair coupling, a 2" PVC cap, a air line coupling, some epoxy, and a rubber expansion plug.
drill a 5/8" hole in the 2" cap, and epoxy the air line coupling in, the epoxy the 2" cap to the repair coupling.
The repair coupling's threaded ring and washer will fit over a 1 5/8" primary that has been pressed into a "D" shape, and then you can tighten the coupling and it will seal against the outside of the pipe, the seal may not be perfect, but it doesn't have to be.
then get the rubber expansion plug, and tighten it into the other end of the primary you want to test.
now hook an airline up to the air coupling you epoxied to the cap, and apply pressure, I would not go past 25-30 PSI, you don't need to, and I don't trust the epoxy to that.
Brush a mixture of your favorite dishsoap and water over the welds and look for bubbles, if you see bubbles, you have leaks!!!
Some of the guys on the Fiero forum had a little to add.
The following only applies to Stainless Steel:
you have to be careful if you do the following and are not an experienced weldor, it makes it much easier to blow holes in the pipe, and create restrictions in the pipe.
- FITMENT FITMENT FITMENT! Pipe fiment is everything! if you want clean good looking headers inside and out, make sure the pipes fit perfect before you start welding. this means the primary tubes fit where you need them, and that there is no gap when you but them together where they will be welded. if they don't fit perfect, they are not ready to be welded!
- find a comfortable place to work. don't work sitting on concrete where you cant be upright and have full range of movement, it makes a big difference in the finished product!
- Check your machine before every weld!
IE: on my welder, the power switch is right next to one of the heat switches, if I'm not paying the utmost attention, I may inadvertently switch to high heat from low and start blowing holes instead of welding. - tack tack tack, then weld.
on each seam, start with for tack welds, do one at 12 o'clock, then 6, then 9, then 3, if you do one big seam, the pipe will warp and cause fitment issues. also don't weld the whole seam until you're sure it's where you want it, it's much easier to cut a few tacks than a whole seam. - Invest in a high quality welder that uses a shielding gas, or tack the pipes with your welder, and have a friend or welding shop do the final welding. the welds lay down much smoother, and will seal better than with flux cored wire. Of coarse this mainly applies to those of us who don't have a TIG or are not Oxy Acetylene welding our headers.
- Invest in a tubing cutter or any other tool that can cut the full width of your pipe in one pass.
it's much easier two weld to strait cuts than two crooked cuts, I picked up a pipe cutter for $20 at Lowe's (plumbing section) that will cut most header primaries no problem. funny, sounds like tip number 1 doesn't it?
The best tool I have found thus far was a $20 chopsaw I got off craigslist, that I put an abrasive wheel in to cut the pipe, works like a champ, and produces nice straight cuts, minor deburing is required, but takes less than 5 minutes on a bench grinder. total investment, $25.
- weld the flanges and colectors LAST.
it's easier to weld up the full length of your primaries when they aren't bunched together. - If you're using the TCE 3x00 D-forming tool, weld some "ears" to it so it will hold itself in the vise for you.
- PRACTICE PRACTICE PRACTICE. order enough materials so you can practice on the same size and thickness pipe, it will help you get a feel for your welder, and the materials you are working with.
I cut some straight pipe, and then keep welding and welding and welding until I find a technique and the settings that work best on my material.
When I was done welding my primaries, I built a pressure tester that I could hook up to my air compressor to test my welds, it cost less than $20 to make, and has worked great so far,
I made it out of an 1 1/4" PVC repair coupling, a 2" PVC cap, a air line coupling, some epoxy, and a rubber expansion plug.
drill a 5/8" hole in the 2" cap, and epoxy the air line coupling in, the epoxy the 2" cap to the repair coupling.
The repair coupling's threaded ring and washer will fit over a 1 5/8" primary that has been pressed into a "D" shape, and then you can tighten the coupling and it will seal against the outside of the pipe, the seal may not be perfect, but it doesn't have to be.
then get the rubber expansion plug, and tighten it into the other end of the primary you want to test.
now hook an airline up to the air coupling you epoxied to the cap, and apply pressure, I would not go past 25-30 PSI, you don't need to, and I don't trust the epoxy to that.
Brush a mixture of your favorite dishsoap and water over the welds and look for bubbles, if you see bubbles, you have leaks!!!
Some of the guys on the Fiero forum had a little to add.
Originally posted by Arns85GT:
The only thing I would add is that I used a common sink stopper and filled the tube with water to check my welds. This not only identifies holes but also when you have a thin weld which water oozes through. I wasn't satisfied until the tube was water tight.
Arn
The only thing I would add is that I used a common sink stopper and filled the tube with water to check my welds. This not only identifies holes but also when you have a thin weld which water oozes through. I wasn't satisfied until the tube was water tight.
Arn
Originally posted by gusshotrod:
When fitting the tubes, bolt the header flange to the heads with SAE washers between the heads and the header flange.
This will allow the tubes to go past the face of the flange and will give you some wiggle room. The tubes can then be ground flush with the flanges after fitting.
When fitting the tubes, bolt the header flange to the heads with SAE washers between the heads and the header flange.
This will allow the tubes to go past the face of the flange and will give you some wiggle room. The tubes can then be ground flush with the flanges after fitting.
Originally posted by Pete Matos:
You forgot one of the most important things....you gotta flood the tubes with shielding gas or you will get some serious sugar crystallizing on the inside of the tubing. It is not hard to do and you can just put a Y on your gas line pretty easy and make some plugs or use some rubber sink stoppers with a hole in them for the line input.
You forgot one of the most important things....you gotta flood the tubes with shielding gas or you will get some serious sugar crystallizing on the inside of the tubing. It is not hard to do and you can just put a Y on your gas line pretty easy and make some plugs or use some rubber sink stoppers with a hole in them for the line input.
Originally posted by Pete Matos:
Also make sure you bolt your flanges down before you weld the tubes to the flanges or they will warp all to hell no matter what you do. Would not be a bad idea to get an old blown head to work on building your headers with.
Also make sure you bolt your flanges down before you weld the tubes to the flanges or they will warp all to hell no matter what you do. Would not be a bad idea to get an old blown head to work on building your headers with.
Originally posted by Pete Matos:
Also I find a very small champfer on each tube end helps to get a good penetration and makes it easier to follow the seam for me. Just some ideas....peace
Also I find a very small champfer on each tube end helps to get a good penetration and makes it easier to follow the seam for me. Just some ideas....peace
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