Need ideas on reworking headers

[John Fitzpatrick]

My exhaust system is 40 years old and I recently bought a pair of replacement collectors. Unfortunately, the primary tubing ends that should slip into them have been expanded over the years to the point that they won’t fit into the new collectors. I’d prefer not to expand the collectors, but haven’t had any luck finding a tool that will compress a piece of tubing. Short of cutting off the ends and welding new stubs on or expanding the collectors, is there a way to fix this?
Thanks

[Bill Musarra]

John,
Just a suggestion. Find a lenght of tubing that is the correct size for the collector. Use a tubing expander at Harbour Freight or the like, and expand the primaries you have to slip fit over the tubes that fit into the collector. Then weld the two pipes together and then use whatever(fitting or weld) to join to the collector. May have to trim back the original pipe to get the correct length.

Bill

[Bob Stoeger]

John,
First are the headers stainless or mild steel, if stainless you can pack the ends of the headers in dry ice the slip the new collectors over them, but remember that once the headers expand again you mite not be able to take them apart again, kind of like a sweat fit.
good luck,
Bob

[Charlie M]

John,

How much smaller do the primary tubing ends need to be? If you're only talking 0.005/0.010" you might be able to use a single or double split shaft collar for a compression tool.

:: Dayton Superior Products ::

They're available in ID increments of 1/16"

Just a thought.

Charlie

[Bob I.]

You might consider cutting a slit or two up each expanded primary tube,
nothing that might show by keeping the slits under the collector tubes.(1.5"?)
I would think a few slits per pipe would allow for a bit of taper while still providing a good seal.

[John Fitzpatrick]

Thanks for all the suggestions guys-- I think I'll try carefully slitting the tube ends. Every 0.1" removed in the circumference by a slit should reduce the diameter by .032, right? So depending on how oversized they are and the thickness of the saw blade, one or two cuts on a band saw ought to do it.
Who was it said "Every project will take twice as long and cost three times as much as you thought."? Whoever, I think he was an optimist.