i bought a mugen header for $60. the problem is that the bottom two runners are dented pretty bad. how would i fix this? will post up pics later thanks.

 

Cut out the damaged area, buy some stainless tubing of the same diameter and cut out a patch from the new tube the same size as the damaged parts you cut out and weld it in.

 

Slide hammer then tig the holes closed

 

i'm with this guy

 

I know that a lot of dirtbike shops can cap off the ends and run compressed air into the header/tube and pop them out that way. I'm not sure how much psi it is but Im sure its a ridiculous amount. Also the tube thickness will come into play.

 

/\ You forgot about the part where they heat the smashed tube to a bright red color.

 

i always cut out the area and then beat the dents out of what i just cut out then weld it back in.
but thats just when theyre dented not if theyre scrapped to the point the metal is thin

 

is the header a 1 piece, or 2? if it is 2 and you have access from a straight section of pipe to the damaged area, you shouldn't need to cut and weld. we made a slide hammer tool to do the job nicely on a hytech header with the same damage.

 

[QUOTE=fastcody1;38363961]i always cut out the area and then beat the dents out of what i just cut out then weld it back in.
but thats just when theyre dented not if theyre scrapped to the point the metal is thin
[/QUOT

its a 4-1 and im plnning on using this method can i do it with a hand-electric or a dremo tool. any other pointer will be apriciated

 

at the minimum i would recommend a sawzall. i used a band saw but that was awkward and i almost cut my finger off, lol. im shure you could use a 4&1/2 in angle grinder and a 1/16 blade

 

It doesn't look too bad from the pics. If your using a dremel tool then good luck, those little discs are a pain.

 

id just leave it... its not like its effecting your performance

 

the pics make it look small but its alomost half way in. i cut out one of the dents the other ill do tomorow. heres another pic of the dents before. will post pics of the cuts tomorow. and yes the little discs are a pain.

 

Slide hammer. Tig the holes. Should take about 10 minutes. Cutting and welding would take a lot longer.

 

Anyone try the freezer and water method?

 

Not really. I could sawzall that damaged area off in the matter of a few seconds. Beat the dented area with a ball peen hammer, and weld it back on in the matter of a couple of minutes, if that. Slide hammer would take longer, because i'd have to use it in several areas of the damaged part. You'd spend more time trying to get the whole area pulled out, trying to make it look right, than you would if you'd just cut it off, hammer it back out, and re-weld it back on. Trust me on this. I used to work at a muffler shop. We used to do work like this all the time. Repairing f*cked up stuff like that, all the time.

 

yeah no question slide hammer is going to be alot faster than cutting AND welding AND beating ect LOL

 

Yeah. No.

I'd have the the whole thing done in less time than it would take to grind down the welds when you're done.

Plus you'd end up with a better finished product anyway. Do the cut out, pound out and weld, then put a boroscope down there and look at how the welds look from the inside--may not be a smooth as you'd think.

 

Use a stud gun and heavy duty studs. Weld them to the tubes and use a slide hammer to pop the dents back out.

 

okay here are the cuts i made and how i plan to weld it. suggentions are appriciated. thanks

 

here are the welds, and after some elbow grease. do you guys think i will still get good flow?

 

The problem with cutting it like you did is that you can't weld all the around the cut.And its gonna leak.

 

well not exactly, you can weld one side completly then go back and weld as much on the second. then put a big cap pass to cover the gap between the two.

won't look pretty but will work.

 

It doesn't leak
i started by welding the gap then i welded one side completely then i welded the tight side of the other one
and proceded around to finish the weld

 

Sorry for reviving such an old thread but after reading this post I decided to learn more about the water/freezer method an give it a try.

Unfortunately I did not expect this to work so I didn't bother to take a before pic, but I tried this on my vibrant 4-1 b series header where along the 2 bottom runners each had a 1.25" dent(diameter) pushed in about 1/4" on one runner and 1/8" on the other.

It took 5 days straight of freezing thawing and refreezing, and I was starting to loose hope as I was not seeing any progress, but this morning I was amazed to see that both dents are now almost flush.

So I just wanted to confirm that this method worked for me, although it did take about 6 tries before i noticed any difference.