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Shrink fit question?

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  • Shrink fit question?

    I have a small off road buggy that I want to put a spark arrestor muffler on I have the muffler and clamp for the muffler it fits a 2" pipe the buggy has a 1.5" pipe I have a piece of seemless 2" pipe .250 wall that fits the inside of the muffler and has an ID of just under 1.5" like 1.484" I checked it in the dark last night so it maybe a little different.

    I am wondering if I heat this piece of seemless pipe .250" wall cherry red how much expansion should I see. I can turn the sleeve to what ever size I need it to be I would like it to shrink fit tight on the 1.5" pipe so I don't get any exhaust leaking around it. I plan on putting a set screw in the sleeve just so it really locks on good but I am not sure how much expansion I should expect anybody know? I could weld the sleeve but I may want to take it off later when I add a turbo and redo the exhaust to 2". If I can just heat up the sleeve and put it on the cold exhaust pipe with the idea of when it cools it being locked on the pipe that would make the job short and sweet.

    I am not sure what the sleeves are made of but my guess is Chromolly. This is some high dollar looking seemless pipe that I bought as scrap in small pieces.
    Last edited by gundog; 10-09-2008, 03:49 PM.

  • #2
    A standard for sweating and shrink fits for steel is . 000007" per degree F.


    • #3
      Even knowing the exact material that the sleeve is made from the amount of expansion that you get will vary with the temperature of the ring when you heat it... I think you should get enough expansion to get it to slide onto the cold pipe...and have a good chance of getting a good tight fit... since it is a scrap piece, go ahead and give it a try--you have nothing to lose and wont damage the pipe you are trying to put it on! You should drill your setscrew holes and thread them before you heat it and put it on... Good Luck!


      • #4
        Machine each to a nice smooth surface.
        Make one about +0.0025" on either the bore or od
        Heat up one, the other in a freezer.
        Put them together quickly.
        please visit my webpage:


        • #5
          And just how are you anticipating gettin it apart "when you re-do"
          the system???


          • #6
            Actually If I redo the system this part will get chucked into the trash. I could weld it but the pipe is rather thin and chrome so it seems faster to sweat on a sleeve than to grind off the chrome and try to weld the very thin pipe to a .250" sleeve plus the possible damage to the ECU from welding or the subseqent work to remove the leads. The only part that I need to reuse is the muffler and it will just be clamped on to the sleeve.
            Last edited by gundog; 10-09-2008, 06:49 PM.


            • #7
              Well I ended up not doing what I originally planned when I cut the exhaust pipe to install the muffler it was pipe inside another pipe. The material they used was really thick too. The pipe was really small inside right at 1" ID. I decided it needed a bigger exhaust so I took the whole pipe off and ran it to a muffler shop the guy coppied the old pipe and made the new one 2". I just finished putting it all together. I did have to make some parts on the lathe a new exhaust donut to fit the 2" pipe and a new flange. What started to be a small job ended up taking me most of the day. The 2" exhaust will be better if I later decide to turbo it.