Header Flange Gap?

[krazy86t]

DS header had a pretty large crack on #5 tube. A friend fixed it with his TIG using nickel filler (he stated that nickel is ductile and would relieve stress from the weld better than some other wire choices). he also welded a brace between 3 & 5 tubes as suggested by multiple other posts.

Checking flatness of the header flange on a machinist stone, there is a 0.025" gap on the surface to #5. This gap can be shifted to #1 by rocking the flange over the high spot in middle. the surface is not twisted, but bent back at #5 (or #1).

I've seen a lot of comments stating that the flange surface should be milled flat (<0.005"), but it seems like bolting these to the heads (which are on the car so I have no idea how true cylinder head surfaces are) would pull together the 0.025" gap i'm seeing on header #5. Maybe some high temp RTV for insurance?

 

[BadAssGN]

I would have no trouble bolting that on. Use some rtv
Copper and it will not be a problem.

The stock flange is not thick enough to prevent the bolts
From pulling it in.

 

[blackdeathtrap]

cut the flange bettewen each pipe problem solved thats what i did and now i have a perfect seal with the copper leak proff gasquet set

 

[lrayzer]

You can flatten the flange by doing a figure 8 with it on flat concrete, poor mans mill.....may have to find sidewalk curb

 

[pacecarta]

thats what happens when you dont bolt the flange down to make repairs

pipe will shrink toward the weld area once it cools so you have to secure it and even better is to just cut it and weld it on all sides of the tube to even out the shrink even if it didnt crack there


bolt it up making sure 5 is the last to be bolted down (work the bolts a little at a time )
when it gets hot (cherry red) from boost it will destress

 

[bison]

Inconel rod works best.