Farmall H Exhaust pipe

FWB in SK · Dec 3, 2020

The exhaust pipe on the manifold is rusted out and the threads are damaged in the manifold. Need to repair before installing new pipe. What kind of treads are they. what size threader would be needed. Pipe or ?? any other ideas. Also put in Farmall forum..

shaun wallace · Dec 3, 2020

Manifold is 2 inch 11 1/2 fnpt. That is a big tap and not cheap for 1 use.

SDE · Dec 3, 2020

You might get more information about how to clean up the threads by googling it. What many of our patrons will tell you, is to cut a groove in the pipe threads, on a pipe and use that to clean the rust and crap out on the threads in your manifold. It has worked for some of them. Pipe taps have flutes to allow the chips to move out of the way of the cutting edge of the tap. You are going to try and re create that same affect with the pipe that you have cut the groove into. Maybe even grind some of the thread away from in front of the groove to allow it to clean out the threads better.

roy prins · Dec 4, 2020

Take the manifold of and bring it to Your local machine shop --have him hog out the old threaded area to the size of the out side of a pipe connecter cut the pipe connecter to about one and a half inches and braze it in -- walla ! new threads for a new pipe -- then have the manifold planed on the head side --- now you have a better than what You can buy manifold-- Roy

the tractor vet · Dec 4, 2020

2 inch NPT . I have had good luck retapping with a good tap and a new 2 inch pipe . once you have chased the threads as best ya can then heat the manifold up to around 500 degrees and screw the new pipe in .

rustyfarmall · Dec 4, 2020

It helps to use a torch down inside the threaded area. It will burn out a lot of the carbon buildup. Don't use it as a cutting torch, just use the heat.

Ellis Kinney · Dec 4, 2020

You can make your own tap by buying the pipe nipple and modifying it. I did this a few years ago with success. Start with a 5 or 6 inch long nipple. Saw down through the threads every 90 degrees. Then take a rawhide or plastic mallet and gently hammer the threads in slightly. This will help it get started. Stuff a rag in the hole to keep stuff from falling in the manifold. Use a little tap magic or other cutting oil and work your new tap back and forth. I also used a small cold chisel and a centre punch to remove some of the carbon build-up. Hope this helps. Ellis

504 · Dec 4, 2020

I used a pipe tap to chase the threads, worked fine. There is a big machine shop here in town that will loan a tap,you just leave them a deposit equal to the price of the tap. Break it you buy it.

FWB in SK · Dec 4, 2020

Thanks for all replies. Threads are really bad so will take all ideas into consideration..

Pete in Holland MI · Dec 4, 2020

If ya can't borrow a tap, maybe find a shop that has one and bring the manifold/tractor to them and let them do it.

Either way, your manifold needs its threads chased for the new nipple to have a chance of staying put.

Over the years, I've accumulated used taps up to 2-1/2" NPT for purposes like this.

Good luck !

Farmall H Exhaust pipe

FWB in SK

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shaun wallace

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SDE

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roy prins

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the tractor vet

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rustyfarmall

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Ellis Kinney

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504

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FWB in SK

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Pete in Holland MI

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