Asking for advice here as I can't get onto the Farmall site but I am sure some here can answer this for me.
On one of my Farmall cubs someone in the past ran the verticle exhaust into a tree or something and bent it over. Apparently they later needed to work on the motor and couldn't remove the hood due to the bent pipe so the sawed it off flush instead of removing the manifold. The manifold has a threaded hole in the center of the top and they later welded (I use that term loosely because I broke it loose with a pipe wrench) the pipe back on.
I have a new manifold and have removed the old one. I will put the new one back on tonight or tomorrow but would like to fix the old one rather than toss it. As I said, the old pipe is cut off flush and there is no weld holding it in place. How can I remove about an inch of threaded pipe out of the cast manifold? I don't know if there is enough room to try to sawz-all down inside and if that would ruin the threads, don't know if a torch would cut it away without again ruining the threads and there isn't anywhere to get a punch on the stub. This is my "back up" tractor for snow removal and I have time this weekend to get it back running.
Dremel tool with a cutter disc.Cut a groove into the pipe on several sides.Use a small pointed punch to get started peeling the old pipe from around the top of the hole.As you progress you will see the threads in the manifold,and you can keep working it out.
I would say to,heat with a torch till it is red and let it cool a couple times,then cut the grooves I am speaking of.I do this to old Briggs engines that the exhaust has been broke off up in the hole.You may leave a little "scar" inside the manifold but it aint gona hurt it.
I agree with Mack, If you heat the piece red then let it cool down and as it gets to the stage that you can spray penetrating oil on, it might come out with out sawing. Sometimes this works for me, if not go with the dremel. KB
If you cut just one groove like Mack suggests, even if you destroy some threads, it should collapse enough to come right out. Heat it up like Keith suggests if it is still stubborn. Heat around the outside on the manifold only to expand it.
Cutting into the threads in one spot only will not be too bad. If you cut two grooves straight across from each other you should be able to knock each piece inward with a good sharp punch.
Take your time whatever you do, but let us know how it came out.
Don't forget to soak it a while with a mixture of ATF and acetone or MEK. That stuff is too often ignored and goes too often without being tried.
50% ATF, 50% acetone.
You gotta shake hell out of it before each use.
I had a similar situation recently with a drain pipe that was rusted out and broke off in the flange of a cast iron elbow in the wall. I used a small pointed punch and chisel to separate the remains of the pipe from the threads in the flange. You might damage a very small area of the first one or two threads, but as you start a separation drive it toward the center. It will pull out of the threads and shrink at the same time. Then if it doesn't fall out, you can grab it with pliers and pull it out. I only damaged the very top thread the diameter of the punch point which I could easily clean up.
Tim, if all of the weld is cut through and not a factor, just heat the inside of the remains of the threaded portion red hot and let it cool. It will most likely screw out with your fingers. Dave
Many times, if I have a piece of steel in a piece of cast iron I just torch it out. Proven, if you have 2 pieces of steel or anything you want to torch cut, you can only cut one at a time. This is because no matter how tight or rusted or welded the two are, there is an air gap between the two and this insulates the second piece from the extreme heat of the torch. I remove broken head studs and small bolts like this all the time. Another thing, steel melts at a much lower temperature than cast iron so, it will blow out easily with the acetylene torch.
Thanks all, I haven't gotten to it yet but did get the new manifold on and ready to plow snow (supposed to be 63 today in central Michigan!). I wanted to play around with it Saturday but spent the day with a buddy working on his snow mobile--made him 2 auger holders for ice fishing.
I am a pack rat and just don't want to throw away a manifold that can be fixed (the new one was $95).