129 with Exhaust Issue

[TractorRick]

PO attached the exhaust manifold to the block with a single small spot weld so I assume the threads are damaged or worn. I really don’t want to have to get a new block and rebuild but the exhaust leaks allot but it runs great. I am not in a rush but can you Heli-Coil exhaust threads? When the time is right I will cut the weld and get a good look. Anyone have a like issue? Just looking for ideas. Rick

[mrfred54]

I have wrapped the threads with tin foil, like you would with pipe tape and smear the threads with exhaust cement, you can get at auto parts store. Clean the threads in the block good with a small wire wheel, and safety glasses. Maybe good idea to get a new elbow to if yours has bad threads. Has worked for me

[TractorRick]

Great idea! I was going tu use my wire wheel on Dremel and get a new manifold elbow anyways. I am hoping if I clean the threads it can get a bite on the pipe.

[ironman]

Originally Posted by TractorRick

Great idea! I was going tu use my wire wheel on Dremel and get a new manifold elbow anyways. I am hoping if I clean the threads it can get a bite on the pipe.

Unless you can find a good used exhaust elbow, make sure that you are sitting down when you look up the price of a new one.

[finsruskw]

Repair the one you have with a short threaded end from a nipple.

Buy a 6" nipple from a plumbing shop, preferably a double thickness one, plus coupling.

Screw your elbow into the coupling and note just how long a new threaded piece you will need.

Cut the damaged end off the elbow while screwed into the coupling in your chop or band saw utilizing the nipple to assure a 90* angle while doing so.

Cut one of the treaded ends off the new nipple, leaving the new piece a bit longer and tack weld the new piece onto your elbow.

Check for proper fit to make sure it will clear the governor arm when screwed into the block, adjust as needed for correct length and weld.

It would be a good idea to clean up the female threads in the block with a tap, The threads are tapered pipe thread.
I have done several this way, just be careful dressing the weld to make it look as nice as you can.

[kalebevans]

Yeah, if you can repair what you've got that's probably the way to go. Mine was rusted in and the machine shop said I needed to pull it, so I went another direction once I destroyed mine getting the nipple out. I found somehow that a VW Beetle manifold end was the right size, so I had the machine shop drill and thread a pair of holes when they machined the block .010 over for me. Not a factory look, but I don't mind it and it's easy to take off if needed. I used a muffler made for a TO-35 Ferguson, which fit under the hood but isn't particularly quiet.

[TractorRick]

That is a great idea, thanks