Exhaust Manifold Repair

[Friartuck]

Pictured is an exhaust manifold that has rusted out near the flanges. Looking for suggestions on how to repair it. My first thought was to roll & contour sheet metal larger than the holes, mount in the inside and mig it in. The material is 16 Gauge stamped steel. The outside is covered with heat fabric so appearance is not a real factor. Finding a replacement is not really an option as these usually rust out in the same areas.

[Peter J.Heizmann]

Hi, Chris...good to hear from you.

Knowing you are one to venture into "new" methods of repair, or, recreation of old car parts, I must advise negatively on the manifold.

As you mentioned, replacement is out of the question. I have no knowledge of that.

Ask yourself:

--Beside the holes in the photo, how thick is this obviously oxidized casting further into the part?

--To weld, how thick is the part beyond the holes to withstand the welding?

--How much use of the part do you plan based upon your approach to form 16 gauge steel to patch it?

--If the Mig weld has leaks, where are the exhaust fumes going?

These are my concerns based upon what you presented, Chris. That manifold is spent in my opinion. The radii where the flange meets the body is called a "hot spot" in molding. The flange cannot be too stable structurally to the integrity of the overall manifold.

If you could blast it in a tumble-blast, I would bet more holes would appear quickly based upon only one area in the photo.

Take care,

Peter J. <img src="http://forums.aaca.org/images/graemlins/grin.gif" alt="" />

[nearchoclatetown]

Friartuck, your picture appears to show a tube header which could eaily be repaired the way you suggest. But if it were mine I would use a tig welder instead of a mig, because heat could be controlled much better. What is this for and why can't you replace it?

[Guest]

reguardless of what stories you might have hear, JB weld will not work.

[Friartuck]

Here is what the whole manifold looks like, before the heat fabric was removed. Water or moisture seems to collect under the material and rots out the steel at the flanges. It's two 16 Gauge stamped halves that are welded together along the edges, the flanges being the last to be welded. If I were to find another it would probably be rotted in about the same spots. There is enough material to weld past the holes and these are the only ones, albeit there are a few thin spots that I also plan on mig welding.

Maybe, just maybe this will be the excuse to go out and buy the TIG I always wanted. I guess I'll have to chance it with the MIG.

[leon]

last year i was at a praxair open house and one of the reps was demoing a powder

like substance that was applied with a gas welder (special type of torch) to weld manifolds and fill holes. dont know how well it works but the demo was very

interesting to watch. hope this helps

[Guest Silverghost]

Can't you have a good exhaust-pipe muffler shop bend you some new steel or stainless pipe bends then re-use the flanges using Mig or Tig welder??? After you re-wrap the pipes WHO will ever know??? Very similar to tube hedders!!!

Just an idea???!!!

[Guest PRR]

> <span style="font-style: italic">manifold that has rusted out near the flanges.</span>

It's "just" a tube header (albeit made of stampings), not even a complicated one.

For the effort needed to properly clean and patch it, any header-dude could knock-out a new one, possibly of better material or better-looking. If I read the size right, it could be done in exhaust-quality Stainless Steel without huge expense. Even if you still cover it up, the right kinds of SS will last a lot longer than carbon steels in exhaust duty. Or if the heatwrap is not essential, you could do a sexy Chrome Zoomie.

Take it to chopper motorcycle and hotrod shops, they know good tube-knockers.

If the application is slightly popular (what the heck IS it? not a VW? Piper/Cessna?), send a photo and hasty sketch to Hedman Hedders and a couple other mass-market manifold vendors. Maybe they would borrow it, copy it for you, and add the pattern to their catalog. The big benders have computer controlled machines, and buy tube in bulk: they can do low-demand models at a good price with a profit, even if they only sell a couple a year.

Uh, if this IS an aircraft part, there are Rules about aircraft engine repairs. I know nothing about that (except flying friends complain about it).

I'm not trying to talk you out of buying the TIG. But I suspect, if authenticity is not needed, a well-built replacement will serve better than a patch.

[jaxops]

Friartuck,

I ran into that on my 56 Cadillac as well. The replacement manifold was just as bad as the original one, so I am getting it welded and machined as was described in earlier replies.