Stainless steel headers fabrication

[DaxV8Cleveland]

Hi

Hope someone can point me in the right direction . What tools would I need to make up headers and work with stainless steel. I am looking at putting a small workshop of DIY use together .So far looked at the following

1) TIG welder approx £300 -£400 & Photo cell mask.

2) Saw cut-off for pipe cutting up to 4 inch pipe . Or will a normal mitre saw do with the correct metal wheel cutter? Do I need a dedicated cut off saw?

3) Polishing . Bench grinder 8 inch with buffer wheels .

Whats the easy way to grind and polish out welds?

Cheers John

[Grease Monkey]

I'm guessing you'd need something to bend the pipes with/around.

I've got a funky pipe bender for brake/fuel lines that gives a steady radius without the danger of kinking the pipe, doesn't quite go up to exhaust sizes though...

[chesterak]

If you can weld ss you may want to weld aluminium so you may want to consider ac/dc tig. Bending thin wall stainless is difficult - you need a mandrel bender that costs circ. £10K - so you need to buy ss bends. They can be dairy tube at 1/1/2" and other imperial sizes, the next I think is 2". You can get other bends from Daves mate in Stoke (ABC Metals ? - I've used them) that are 13/4". They also have stored in Autocad a RV8 ss individual manifold plate that can be pressure cut - this will suit any RV8 head, this was designed to take the larger id tube. SS is dificult to cut as its very hard and will blunt any blade quickly - the best is dedicated blades and/or dedicated to ss thin cutting discs. Oh, and a lot of shed time to make them up!

[DaxV8Cleveland]

Hi Thank Guys for the info.

The header fabrication will be using 90 deg bends cut and welded polished.
I am running a 2V cleveland ported heads so will have to get some flanges made . The pipe size is presently 1 1/2" which is restictive above 4,000 rpm . So the next pipe up is metric bends/pipe stainless steel 316 o/d 43 mm wall 1.5 or 44mm 2.0mm wall. This is used in the pulp and paper industry and most recently in the water industry (if anyone is looking for this size) . 43MM o/d comes out at 1.7 inch so will give me a better top end.

Searching for a supplier for small amounts is a promblem as most will sell only 6 metre straights.

Any one using zercomium cutting disks? See screw fix do some any good.

Cheers John

[mark]

hear some i did earlyer,you will need 13/4 headers.just take your time and you will be ok

regards mark (fat boy northern)

[CycleSi]

For engines producing up to a genuine 375 bhp use 1 5/8" or if over 375 bhp then use 1 3/4".
Also, the primary lengths are crucial to bhp and torque - somewhere between 28" and 32" is ideal; all equal length.
My engine lost almost 50 bhp on the dyno with the original headers before having some custom made. The difference was very noticeable !!!

[VinceGledhill]

Here's an old Article I wrote about just the same thing some time back. I made mine with no problems at all. Just take time.

After discussions with northern cobra club members on Sunday, and the recent post from Jesus in Spain, I thought I would explain how to manufacture your own exhaust manifolds from stainless steel. Or at least how I made mine.

Disclaimer..

These are not flow tested and will not give you every last bit of horse power. And if you've NEVER even seen a welder before then maybe you should think about paying for some.

As you all know I'm a tight git. That's not strictly true but I have had to watch the pennies because I have a wife, two kids, and a large mortgage to support. This made me think about ways which I could save money during the build. The manifolds are a very expensive item, and discussions with other cobra club members in the northern area made me understand that I could indeed save some money on my build by making these myself.

The engine you chose will dictate the size of pipes that you need to flow the exhaust gasses away. All I can tell you is that I used 1.5 inch (outside diameter) tubes on mine. (Rover 3.5 A friend of mine used 1.75 inch on his 5.7 chevvy)

The flanges themselves can be purchased from custom chrome. However, when I ordered mine they were out of stock for two weeks. I couldn’t wait any longer and decided to have a go at welding the mild steel flanges to the stainless tube. This worked very well indeed and would recommend saving another few bob by going down this route.

To start with, the body needs to be fitted to the chassis. Take one of your flanges and bolt it to the engine. I started with number 8 cylinder. The idea was that I needed to come out of the engine and then round in an S shape to where the collector would be. (this is where all four go into one)

It was clear that the pipe needed to come out and immediately bend towards the front of the car. For this I used a 1.5 inch O/D dairy bend. Dairy bends come like the diagram below, with a straight section at both ends of the bend. One of the straights needed to be cut off in order to meet the clearance requirements of the body. I then marked where the first welds needed to be. I then removed the two items and tacked the bend to the flange. Once they were tacked in place I replaced them loosely onto the manifold. I double checked that all was OK and then welded it all the way round.

The second bend within the S shape now needed to go on. Both straights on the two corresponding dairy bends were not enough for the distance that needed to be covered so a piece of flat tube was used as a “fill in”.

I continued in this manner, building up a jigsaw of dairy bends and straights until I had a set of manifolds like in the pictures below. They were bolted to an old rover manifold so that the stainless steel didn’t warp during the welding processes.

I used a “TIG” welder which is the ideal machine to weld stainless. I know what you are thinking… the price of the welder would make it not worthwhile…. However there are some reasonable welders available from Machine mart and this job will more than pay for your “TIG” set-up. I would recommend a TIG welder to anyone taking up this hobby. You can weld stainless or mild steel with it and it is much better than the cheaper MIG welders on the market.

Dairy bends are available from RS components but are much cheaper from specialist suppliers like Hygienic Process Equipment Ltd. Hillside works, Whitehall Road, Cleckheaton, West Yorks, BD19 4DW, Telephone 01274 852752 http://www.hpe.co.uk

To make a really neat job “weld good”. Alternatively if you are a learning welder like me, then use filler rod. Ensure that you have a proud joint. Then grind and sand out the welds later. Use successively finer grades of emery cloth then finally polish out with a polishing mop fitted to a bench grinder. One thing I will say about the polishing mop and bench grinder is to buy the best one that you can afford. There are about 5 different ones to chose from in machine mart. I bought the number 4 in terms of price (second to dearest) and thinking about it should have gone for the one with the most HP.

The job is a very long one indeed. It took me three full days to do mine. This “labour” is what you are paying for when you purchase them from custom chrome or one of the kit manufacturers.

The finished result will be in direct proportion to the time and effort you put into the job. I for one would definitely recommend the job to anyone who would like to save some money on their build and has the confidence to tackle the job. Let’s face it. If you believe you can do it, then you will find a way to make it happen.

[gwak76]

Hats off to anyone who makes their own headers, I spent 2 very long days producing mine and that was without any polishing, just dressing the welds. I am happy with the result as its unique, and my own work. If you go down the road of DIY make sure you take the advice of those who have tried before. Fit every component that my get in the way, brake servo, steering, pipes, oil filter etc. Then comes the fun of making equal length pipes avoiding all of these items. It takes planning but, the result is rewarding.

Enjoy