Heat Exchangers, Are the weldable? Options

[bandjoey]

The heat box around the exhaust pipes rattles and is loose at the front end on the pipes. Any reason not to take it to the muffler shop and have it welded back down tight? (IMG:style_emoticons/default/welder.gif)

[partwerks]

On the factory heat exchangers I had before, what I did was cut some sheet metal that was the approximate gauge equal to the gap between the box and the pipe and maybe cut them about a 1/4" wide and then basically make two 1/2 circles and tap them just under the edge where the gap is and I would then just tack weld the shim to the sheet metal only and not the pipes themselves. That way it would fill some of the cracks and the box and the pipes could expand and contract separately.

[Prospectfarms]

On the factory heat exchangers I had before, what I did was cut some sheet metal that was the approximate gauge equal to the gap between the box and the pipe and maybe cut them about a 1/4" wide and then basically make two 1/2 circles and tap them just under the edge where the gap is and I would then just tack weld the shim to the sheet metal only and not the pipes themselves. That way it would fill some of the cracks and the box and the pipes could expand and contract separately.

Were you patching fissures in the HE shell or gasketing the junction between it and the exhaust pipe, or both?

If it is the HE shell that's rattling against the pipe, you could try alumina oxide (refractory) tape, either as a gasket between the two or a wrap around the whole assembly. Not much room up there, however.

I suspect that the exhaust pipe expands quite a bit more than the HE shell in operation, closing a small gap.