Exhaust Issue...Insights?

[Richard Vollman]

I have a 129. One of it POs tack welded the exhaust to the block but left a large gap. I assume the threads in the block are gone? I was thinking to either cut off and file down the welds and maybe a heli coil or get the new 1100 degree JBWeld and just fill the gap. Anyone have other suggestions or experience?

 

[gary noblit]

Rick, just because it's been reengineered doesn't mean it can't be saved but it WILL take some time.The pipe showing is not in very far,maybe there is broken piece still inside the block.?If it were me...I'd cut pipe off and leave enough to grab,cut the jam nut off.If there is good metal there is hope.Grind weld off and carefully try some heat on pipe and use a small pipe wrench to try.I have done this..cut off close to block(leave a 1/4 in.) and used a file to cut thru threads of pipe then a punch to try to squeeze remainder together.Eventually it will bend some so you have a chance to start trying to remove.Use a smaller hammer than you want to because you're beating on a block also..The odds are good there are threads left inside so a tap might clean it up good (I believe 1 in npt).If the pipe is solid you could weld an adapter to it .I would go the removal route but it won't be fast or fun

 

[jregister]

If there is a piece of pipe in there, you might try dry ice to shrink it and help break it free.
To concentrate the effect on the pipe, I would pack something like paper, polystyrene foam or foam rubber in the exhaust port to keep the dry ice from getting to the block itself, and make a sleeve out of paper (or a PVC threaded adapter) to act as an insulator and reservoir for the dry ice chunks.
I tried this once when heat wasn't an option - trying to get a B&S taper arbor out of a milling machine. I used packing material to keep it around the arbor. There was a lot of mass in the arbor to cool down, but I was finally able to tap it loose. If you have a thin stub of pipe, it will probably take less time. I don't remember how long I waited - it has been quite a while. The one time I tried it, I had a 100% success rate. (If I try it three more times, it may go to 25%...)

I found my dry ice at a Harris Teeter grocery store. Bought a 1 pound block, I think. Have no idea what it costs nowadays.

 

[tkhoffman]

Id grind off that weld and get the muffler out of the way. See if there is any pipe left in the Block.
If there is pipe left, you could use a hacksaw and cut down toward the block. When you start hitting the threads on the block, Stop. That should leave you with a thin enough pipe that you can collapse the pipe it. Small chisel or you big ugly screwdriver. You may have to cut in two spots. Ive done this a few times on stuck pipe applications. Of course acetylene torches is always your friend.
If no pipe stuck in Block and no threads left. I'd grind down the POs mess and weld it correctly.

 

[-CӞ]

if sawdust is man glitter,
then grinders make man sparkles!

 

[Richard Vollman]

Thanks All! I will tear into it as soon as I use the loader to move a tree I cut up.

 

[rfunk]

Do some careful file or grinder work to verify if there are threaded bolt holes beside the exhaust port. If there are, this works well:

 

[dschwandt]

Huh???!!~

 

[rfunk]

Huh???!!~

Made a flange, welded pipe to flange, bolted flange to block with two layers of exhaust gasket. I can go back to stock, if I can figure out how to clean up the cross-threaded port. For now, works well.