Cracking headers

KB olds Blown alky engine. #1 and #7 crack every race around the bottom outside where they are welded to the flange. I have tried Bronze and mild steel filler. I have clamped the flange down while welding and tried without. Ground out the old cracked filler rod to get to closer to the flange material. (they have been welded a lot).
Got some slow mo video of the headers and they move a LOT when the cylinders fire. Not sure if I should try some gusset plates on the bottom I have seen that on some or if that will just give me another spot that will crack. Not sure I can even buy flanges for the old AJ alky olds heads? Anyone know of a weld up kit for this application? I have not called any header companies yet.

 

Try Smiley's

Single or double wall?

 

These are single wall.
thanks!

 

You mentioned they have been welded a lot. I suspect the parent material heat affected zone is beyond help. Maybe get some pipe & cut some dart pieces to weld as doublers around the top & bottom of the pipe. That would get your fresh weld onto a more virgin area of the tube as well as giving you more strength. The dart pieces would look similar to this:

Chad Head's Headers 2014

Chris Saulnier - Team Tigges
Mechanic Falls, Maine

 

They should hang in an art museum not on a car. Beautiful work.

 

Ok I was wondering about support plates.
Thanks for the help! Got some Cad drawings from AJ too so I can get some new flanges made.
Thanks!

 

Need to tig it with silicon bronze.. My smiley headers are 10 yrs.old and look new.. We put on our head man's this year to see if there is any performance difference

 

I started using .500 thick 4140 for header flanges did a set for a screw blown pro mod no cracks so far with the 5/16 thick mild steel had to weld them almost every race

 

Yep been using that Dave.

 

Any better results using Stainless? Turbo 69, Mild steel tubes with the 4140?

 

You might try normalizing your welds. Take a torch rose bud and heat the welded area untill dull red on weld and 1/2 in. on each side of the weld, then let cool slowly. It will draw tension away from weld bead.
-Dale

 

Dale I have been using the silicon bronze rod. Will the draw back process work on that too?

 

I don't know. Usually I've only seen it done on steel welds.
-Dale