Exhaust fab questions

[bluebobtail]

Hi,
I have a stainless exhaust to put together for my car.
I've got all the bends mounts and straight pipe, the correct filler wire and everything else.
The question I have is, which is the best way to hold it together while your mocking it up. Its completely been made from scratch from the headers back over.
Is there a little trick?
I'm all ears

 

[brightspark]

Hi,
I have a stainless exhaust to put together for my car.
I've got all the bends mounts and straight pipe, the correct filler wire and everything else.
The question I have is, which is the best way to hold it together while your mocking it up. Its completely been made from scratch from the headers back over.
Is there a little trick?
I'm all ears

yup strips of metal and jubilee clips to hold them in position then when in position tack them up as u go along then take it off and fully weld

 

[bluebobtail]

That makes sense,
I wouldn't care i have done that before.
I'll try and get some photo's up as i'm doing it or when im finished.
Thanks

 

[chimpface]

Just used to use tank tape /gaffer tape and draw 2 opr 3 lines with a marker over joins so you can see alignment . then you can just tack one bit on to another [ if youved got a good fit up with no gaps et ] Then clean off with solvent before welding - let the solvent evaporate thouroughly before!!!

 

[Wallace]

I've used short pieces of tube with a section cut out down one side to slide over both parts so it keeps the tubes concentric. A piece of angle clamped on works well too.

 

[normspanners]

i've used 2 exhaust u bolts with 2 short bits of 25x3 with holes drilled at the ends,under the nuts, joining the clamps together, for each join, you can then bend the strips, if the cuts arent exact and twist the pipes etc and then by just nipping the nuts it makes it a solid unit, but then make sure you hang it on its rubbers to mock it up, on the car with thick welding wire or cable ties and put three tacks on each join, coz a1mm movement on a join as you take it from the car to the bench to fully weld it, can mean the exhaust being at least 50mm out at the other end.

 

[PhillipM]

I use aluminium foil tape to mock it all up, then just peel it back to tack up:

Bottom left, it's suprisingly sturdy if you put it on tight!

 

[normspanners]

what is the s2000 in ?

 

[langy]

I use wide Jubilee clips with 3 holes in them equidistant around the band, just tack through the holes, simple

 

[PhillipM]

what is the s2000 in ?

Safari race buggy.

 

[normspanners]

Do you own it? or just making ex manifold

 

[PhillipM]

Yeah, it's the weekend toy

 

[bluebobtail]

Thanks for all the replys,
Its from the manifold back over, hopefully weather permitting i'll be mocking it up this weekend then welding her all up.
Most of the joints will be slid together maybe like a normal exhaust, in that situation do i need to purge the back still?

 

[normspanners]

Yeah, it's the weekend toy

your primary's look very long---?
I built an escort with a s2000 on throttle bodies etc, we found after much dyno testing the standard honda ex manifold was near perfectly tuned but I did have to tweek it, and make secondaries, to get the steering columbe through the middle !

 

[hotrodder]

Most of the joints will be slid together maybe like a normal exhaust, in that situation do i need to purge the back still?

Yes and no (clear as mud? )... It's possible to do lap (and fillet) joints without sugaring/coking up the back of the weld, on thick stuff it's very easy (or very difficult to make a mess), thick to thin is pretty easy (flanges etc), when both pieces are 1.5mm wall it's a lot tougher- mostly autogenous with maybe some 1mm wire, or even some 0.8mm MIG wire, here and there would be a lot easier than trying to do it with 1.6mm

It won't fall apart if there's a bit of coking, effect on gas flow barely worth mentioning. I have seen, and repaired, manifolds that were welded without a purge/the purge didn't work properly and the welds had rusted/scaled- talking light surface rust not heavy pitting

The fitting/clamping thing has been done but FWIW http://www.icengineworks.com/icewtackingclamps.htm You don't wanna know what they cost but not exactly hard to make. They've been at the bottom of my things to do list for a while now- i've got various modified jubilee/mikalor type clips and yet still tend to use tape when mocking up and witness lines + holding them in one hand while tacking most of the time

 

[langy]

Thanks for all the replys,
Its from the manifold back over, hopefully weather permitting i'll be mocking it up this weekend then welding her all up.
Most of the joints will be slid together maybe like a normal exhaust, in that situation do i need to purge the back still?

I don't back purge any exhaust systems I make unless the customer asks for it to be done, it's not neccersary on a road car system

 

[PhillipM]

your primary's look very long---?
I built an escort with a s2000 on throttle bodies etc, we found after much dyno testing the standard honda ex manifold was near perfectly tuned but I did have to tweek it, and make secondaries, to get the steering columbe through the middle !

They are, they've been tuned for the first and second harmonics rather than the 3rd like the stock manifold.

 

[bluebobtail]

Thanks,
I'll post some pics up of the parts i'll be using.
I have some 1mm tungstens and some 1mm filler rods for the job.
The car is a range rover and as it will be generallly covered in mud looks dont really matter that much to be honest. As long as it sounds ok and passes a mot it will be fine for me.
No Cat just 1 silencer.
Manifolds are already made luckily.
She sounds sweet with only the manifolds but i get strange looks from my neighbours

 

[bluebobtail]

Langy
Where do you get your exhaust parts from?
i.e flanges, im after a flange to fit my headers or is it easier to get on cut specifically?

 

[Jiffers]

Just a couple of questions is the car going on road and having a mot if so what is the age of the car as you may need an option to fit a cat at time of mot
Jiff