We have been Tig welding manifolds for years now and it seems we are on a trend of our head flanges warping out, can anyone add some insight?

 

Too much heat input can do that. It can also be caused by too large of gaps between the flange and tube...causing more shrinkage than before.

 

Like Engloid said, too much heat. Here's one of the jigs I made, it is made out of 3/8" aluminum. I tapped it to the bolt pattern of the stock manfolds and put in studs. I had stainless flanges and copper gaskets custom made for the exhaust. I just weld the flanges while they're bolted down to the plate and I don't have any problems with warping because the copper gaskets and aluminum plate transfer the heat away from the flanges.

 

You can also play with a slight amount of "pre-bow" in the opposite direction. If you prebow too far, it's really easy to just go over a couple welds and draw it back.

 

why not just machine the surface, kinda like decking a head??I've done a ton of j pipes for dsms and would get boost leaks,now i just use a belt sander and a steady hand, never had and issues after i started doing this.

 

we do get them resurfaced, but that isnt what we want to do each time, too much down time. We currently bolt the head flange to a duplicate flange to 'try' and keep it true, but after its all done and said, still warps slightly once its off.

Ill keep you all updated.

 

Either that or use a large Belt sander which is pretty comon to just hold it down on one until its flat. I personally use the mill or a boring bar.

 

make some kind of fixture that will help you bow them back straight. Something like what I made in the pic below to help the pipe from bowing would work fine. If necessary, you could put a few jack screws in there instead of just one.

Or maybe take that extra flange and bend it in the amount of prebow you want...then weld something on it to hold it bowed. Then all you'd have to do each time is just clamp the header flange to the one that's bowed...and weld it up.

edited to add the pic:



Modified by Engloid at 7:15 PM 1/9/2005

 

what pic below?

 

What about bolting it to an old cyl. head? It would keep it nice and flat AND the alum. would suck out a great deal of heat.

D.

 

^ i think that would work. sounds like a good idea. i guess that anything you can bolt the head flange down to and get it nice and tight would work to keep the flange from warping, correct?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wade &raquo;</TD></TR><TR><TD CLASS="quote">we do get them resurfaced, but that isnt what we want to do each time, too much down time. We currently bolt the head flange to a duplicate flange to 'try' and keep it true, but after its all done and said, still warps slightly once its off.

Ill keep you all updated.</TD></TR></TABLE>
honestly if it takes more than 5 min i would be shocked

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Masta &raquo;</TD></TR><TR><TD CLASS="quote">What about bolting it to an old cyl. head? It would keep it nice and flat AND the alum. would suck out a great deal of heat.

D.</TD></TR></TABLE>

thats how i do it. I weld 2/3 of it bolted down, then finish it off the head and they come out pretty close to perfect.

 

mine looks perfect, adam. no warpage from what i can tell.

 

Try and keep the heat out of course, but we just resurface ours on a 20" face grinder couple passes and wallaH! no leaky no more

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eLusive ek4 &raquo;</TD></TR><TR><TD CLASS="quote">Try and keep the heat out of course, but we just resurface ours on a 20" face grinder couple passes and wallaH! no leaky no more</TD></TR></TABLE>