thinking about making my own headers/exhaust system and was thinking if their are any learned do's and don't do's.............(that I haven't learned) I've seen headers crack a few times (even factory, mostly inline 6's) I'm not going for performance or hi rpm operation, more concerned with clearances and long lasting. I've search and found some good threads, but one question I can't answer; why aren't gussets every used? just not needed or promote cracking from being to rigid? ideas/thoughts?
With the expansion and contraction of the hot header pipes adding gussets would only serve to create stress, adding a new place for cracks to develop.
If that's the case, why not just stay with cast manifolds. Will outlast headers every time, you don't care about performance so why do you really need headers? SPark
Good cast iron manifolds are OK for most street use. Headers are a means to get around things in the way after most engine swaps. If you have ever seen the cast manifolds used on the 425HP 409 Chevys or the flowing design Ford used on the 427 High Rise engines you know what the factory was capable of.
A friend of mine, who is an outstanding fabricator, use heavy gauge materials for the headers/manifolds he builds. To be clear, he is not doing typical hot and and muscle car headers, but has made several custom exhaust manifolds for older vehicles. He uses pipe fitter weld type elbows ("weld ells") for curved sections and the corresponding pipe for straight sections. I have seen him split a pipe lengthwise and shape it to the taper he wanted, weld the seam, and grind it smooth. All his welds joints are done with beveled edges for good penetration and ground smooth when finished. Works of art and very durable. Ray
I had a header on a Pinto back in the day. Cracked like crazy, welded it up and made a brace from the collector to the bell housing, never cracked again. V8s run smoother, so cracking isn't as much of a problem, but I always try to brace the collector to the engine someway.
thanks for replys, I want/need headers for clearance reasons, I tested a couple cast manifolds and they don't fit. I like this idea, i don't suppose you have a link or pictures of his work? i'm going to research "weld ells", that's what I was thinking, i suspect the same reason the header bolts like to come loose.....
Unfortunately, no, I do not have any photos. The weld ells and pipe are available at many plumbing suppliers. Just to clarify, this is material used for commercial/industrial plumbing, such as steam, and is not common water pipe. Ray
My T bucket has headers and long side pipes, so there's quite a bit of weight (and leverage) hanging on the flange welds. To avoid cracks, I supported the side pipes off the trans tailshaft housing. I used a horizontal support from the bottom bolt on the tailshaft housing to the pipe and a diagonal support from the top bolt to the pipe to create a triangle. The supports are bolted to a curved plate welded onto the back side of the pipe, so you don't really see it. The pipes are very rigid, I think you could jump up and down on them and they wouldn't move. No cracks in over 20,000 miles.
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