TheSamba.com :: View topic

Fri Jul 22, 2016 2:10 pm

I picked up a merged stainless steel header the was reported as not welded correctly. The flanges weren't on right. ( it was new and real cheep). I've got the flanges clocked correctly now and it fit well. There is more stress than usual on the loops from exhaust #2 and #4 when it bolts up I'm sure some have run into this before.
Has anyone heated up the loops to relieve some of the stress? Oxy accetalene torch would be it with a big tip. Again its stainless steel. It's going to have to reach red hot. Any thoughts?

Fri Jul 22, 2016 2:23 pm

Yes you can.

After you heat and bend, you can clean and polish the stainless so it doesn't look as bad. After you heat it up it will have a nasty spot on it.

Fri Jul 22, 2016 3:53 pm

If it bolts up then just run it. The heat from running the engine 2-3 good 1/2 hour drives will do the job and relax the stress.

Fri Jul 22, 2016 4:02 pm

Do you think the heat from the exhaust would be hot enough?
I have turned and milled different stainless but not delt with tubing

Fri Jul 22, 2016 4:17 pm

chrswlsn wrote: Do you think the heat from the exhaust would be hot enough?
I have turned and milled different stainless but not delt with tubing

If you exhaust gets metal up to red heat, maybe yeah.... But I doubt it gets that hot...

Fri Jul 22, 2016 4:28 pm

The only way I know to make a header fit an engine is weld it together when it's bolted to an engine. I don't see how it can be under stress and yet also fits well, maybe that's contradictory, or maybe it isn't.
If the flanges are at the correct angle (parallel to flange surface) to the head when the header is forced into position then it will be ok.

Fri Jul 22, 2016 4:39 pm

The loops for pipe #2and #4 were off a bit. Again.......it was very cheep because of the flanges weren't clocked correctly I just don't like putting that stress on the exhaust studs on the heads. It looked like the factory or welder had some tubes backwards. I've always used a rubber mallet on the header sections and a couple whacks while tightening up the nuts on the studs
Has anyone heated up the loops with a torch to relieve some or the stress?

Fri Jul 22, 2016 4:48 pm

I don't care how much it cost.

If relieving the stress makes the flanges at the wrong angle then it will leak.
Make sure the flanges meet the head at the right angle.

Fri Jul 22, 2016 4:53 pm

That's what I did. Had to cut the flanges and reclock one of them to fit. It was way off. And , the loop from 2 and 4 were bent or rolled off a bit. That is where the stress or preasure is. I would like to relieve it. The torch seems to be an answer. Was hoping someone else has used this method before.

Fri Jul 22, 2016 4:55 pm

The header is currently mounted and flanges bolted on. Now would be the time to heat up the loops from 2 and 4 to relieve some of the preasure

Fri Jul 22, 2016 5:14 pm

if it was under such stress how did you hold it in place to weld the flange back on?? straps?

Fri Jul 22, 2016 5:15 pm

1000+F degree exhaust gasses aren't hot enough, you need to take a torch to it? :cry:

Fri Jul 22, 2016 5:21 pm

After you remove the bad positioned flanges and mill out the centers, you bolt the flanges on the heads and fit the whole header in place Run a strap around engine to hold it in place and tack the pipe to the flange with tig welder. Then remove and finish welling completely around. Simple.

Fri Jul 22, 2016 5:24 pm

Ok then your done. If you wanted to bend the pipes I feel you should have done that prior to welding the flanges. Don't worry it will work work fine, bolt on and go!

Fri Jul 22, 2016 7:21 pm

A few good 1/2 hour drives and the entire exhaust system will shift around and the stresses will relax themselves.

Drive it and it will fix itself.

Fri Jul 22, 2016 8:05 pm

I've seen this dozen of times. It's all you can do to get it bolted up, but when you take it off it will fit perfect. :-D

Fri Jul 22, 2016 8:31 pm

Recut at flanges only enough to relieve stress, bolt it all up with gaskets in place, tack weld in place. Remove header and finish weld.

Wed Jul 27, 2016 5:03 pm

I took a rosebud tip and heated up the large loops from 2 and 4 exhaust tubes.
It actually worked. And worked well. Fits like a glove now. Thanks for info all wrote in.

Keep the dirty side down.

Wed Jul 27, 2016 5:17 pm

I've heated up regular headers to relieve some stress, but like Dave says take it for a good long drive and it will find it's own happy place. This was the case on my big headers which were a bear to put on but came off easy like John said.

Take it for a good drive or 2 and then see how it comes off. If it's still off a bit heat it up with a rosebud tip, but I doubt you'll have to.

brad