Heat Exchanger Refurb Success

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Dennis Vogel
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Heat Exchanger Refurb Success

#1 Post by Dennis Vogel »

What level of success have folks had in trying to refurb heat exchangers?

Is it possible to do a reasonable job of media blast and paint with the exhaust pipe trapped inside the exchanger body?

Can anyone provide the correct length of the pipe from the exchanger body to end of pipe?

Mine are super worn. (Bad Super 90 joke intended). :) Dented. Lots of surface rust. Don't appear rusted through in any place. Not clear if the exhaust pipe has been shorted or not.
Image

Trying to determine if they are a lost cause. I don't mind putting some effort into them, but I don't want waste time particularly if their useful life will be short. I guess the same question would apply to any original used I would consider buying.

I realize reproductions are available from Stoddard, Dansk, etc.
1960 356 S90 Sunroof Coupe
1970 914-6
2014 Carrera S

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Greg Carter
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Re: Heat Exchanger Refurb Success

#2 Post by Greg Carter »

I was able to blast and paint mine.

After bead blasting I inspected them very well to make sure there are no holes of any kind on the actual J-pipe that runs through the exchanger (carbon monoxide risk).

After that, I painted them semi-gloss black (Dupont engine enamel paint) and gray (Stoddard high-temp exhaust paint) then reinstalled with RemFlex exhaust gaskets.

The cardboard tube that connects the heat exchanger to the flap / muffler assembly at the chassis can be purchased from Stoddard in correct pre-cut lengths.

Greg

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Phil Planck
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Re: Heat Exchanger Refurb Success

#3 Post by Phil Planck »

IM001645.jpg
I had to take mine apart to repair them
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Vic Skirmants
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Re: Heat Exchanger Refurb Success

#4 Post by Vic Skirmants »

Dennis; yours are not stock configuration. There is a piece missing.

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Phil Planck
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Re: Heat Exchanger Refurb Success

#5 Post by Phil Planck »

Vic

Aside from the hose tabs, what is missing?
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Vic Skirmants
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Re: Heat Exchanger Refurb Success

#6 Post by Vic Skirmants »

The bent down elbow; unless those are for a pre-A.

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Alan Hall
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Re: Heat Exchanger Refurb Success

#7 Post by Alan Hall »

Maybe 912?

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Phil Planck
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Re: Heat Exchanger Refurb Success

#8 Post by Phil Planck »

Ah, good eyes. Thanks Vic.
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Martin Benade
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Re: Heat Exchanger Refurb Success

#9 Post by Martin Benade »

I think they are regular 356, cut almost as short as a 912. I think that makes it easier to put in a VW too.
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Albert Tiedemann
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Re: Heat Exchanger Refurb Success

#10 Post by Albert Tiedemann »

Alan Hall wrote:Maybe 912?
No, the connective pipe for the flexible connecting tube to heat the cabin is larger in diameter, shorter and at a different angle,
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Albert Tiedemann
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Re: Heat Exchanger Refurb Success

#11 Post by Albert Tiedemann »

All:

In the initial post the following was asked

Can anyone provide the correct length of the pipe from the exchanger body to end of pipe?

A better dimension is the distance between the J pipe mounting flange/head interface and the end of the pipe.

Unfortunately, or by design, the dimension is different for each side. It is approximately the difference between the offset of the cylinder banks but not all measured "exactly" the same difference on a sample of genuine, NOS Porsche heat exchangers. I know there is a difference because I have repaired many of the rusted straight section of the J Pipe.

In my repair I have produced a fixture which mimics the interface and sets the new section at the received length prior to welding to produce an exit center at diameter .010" true position.
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Dennis Vogel
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Re: Heat Exchanger Refurb Success

#12 Post by Dennis Vogel »

Albert Tiedemann wrote:A better dimension is the distance between the J pipe mounting flange/head interface and the end of the pipe.
Thanks for sharing the insight. Do you know what that length normally is for each side? I'm really just trying to determine if mine have been chopped or not. Thank you.
1960 356 S90 Sunroof Coupe
1970 914-6
2014 Carrera S

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