Rewelding header advice needed

[Silver Fox]

I finally got my driver's side header off to reweld it. I have a friend who is a professional welder (for aircraft) who is going to take care of it Monday (12 June) for me. I think he is going to TIG weld with stainless steel rod.

Does anyone who has done this have any good tips/advice so I will not have to do this again in a year or two?

I am also wondering about the factory heat shield on the header. Should I just leave this off after we weld it? I do not believe I need to put this back on after taking it off to reweld the crack.

Also, does the header have to be bolted to something to keep it from warping during the welding process?

And as far as reinstalling the header, I have been advised by a fellow board member to just use some copper based RTV on the header flange (where it bolts up to the head), and it should seal up okay.

Thanks in advance for the help.

Rob

 

[Turbo1dr]

After welding the crack, I've welded a brace between #3 and #5 header tubes trying to help on the expansion and cracking. I also left the shield off.

 

[turbodave231]

I've had very good success rewelding these headers and very low reoccurance of cracks. A few things that I do:

Remove the shield and glass bead the whole manifold
Stop drill the cracks with a small drill bit
TIG weld the cracks using stainless filler rod
Weld in a reinforcement made of a 1/4" SS bar in the Vee between the #3 and #5 legs.
Reweld the heat shield (you need it to protect other components from direct heat)

This seems to fix the problems. Lots of guys will tell you they can't be fixed, but I don't think they pay attention to the detail. If your friend is involved with aircraft, he'll know about stop drilling cracks and will do a lasting repair.

Good luck with the repair
Dave

 

[Dans SS]

what does it mean when you stop drill crack? how do you do it.

 

[suicide six]

The ends of the cracks are drilled with say a 1/8 inch drill bit or somewhat bigger to relieve the stress area.The crack is then welded along with drilled holes.

 

[Silver Fox]

Okay,

I got the header welded today. The crack was pretty large to say the least. We got it fill in very good, although the inside of the weld is a bit rough. We smoothed this out as best as we could with a small grinder. (I'm sure this roughness will be in the back of my mind and convince me to buy headers at some point.)

Due to work/night school/kid issues, I won't get around to reinstalling the header until Thursday morning.

Thanks for the tips on the rewelding. I'm anxious to see how much better the car will run with the header leak being fixed.

Oh yes, not only was it leaking at the crack in the header, but one of the welded on nuts at the header/downpipe flange was loose from the flange (weld busted) allowing for an exhaust leak at the flange too. It made it interesting getting the bolt out, as the nut has a square head on it (a 19mm twelve point socket works best - after a bit of trial and error - including an 18 mm socket which got stuck on the nut and wouldn't come off very easily.)

I guess I'll have to keep on eye on the boost gauge when I get it back together to make sure I am not overboosting.