My heat exchanger restoration project updated 10-1-11

[tootype2crazy]

Ok so I got some more work done. (It's going very slowly as I have umpteen other projects going on.) I made some semi-circles out of metal and then brazed them on around where the manifold pipes enter the heat exchanger, this thing should be leak proof now! And best of all, since the brazing metal is brass, it won't rust! Perhaps it's even better than VW made it in the first place.

So here's some pics:

Brazing is not very pretty, but it sure works! It's great for situations like this where the metal is far too thin to weld.

Here you can see the brazing detail. The rust hole went up onto the tube for the pipe so I made this piece a little longer to cover it up.

Some of you might be thinking that the pipe may get too hot for that brass. Ratwell's site showed that the pipe temperature after a long drive on the highway was right around 700 degrees. That brass doesn't melt until it is 1100 degrees, so I think it should be OK.
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air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[SGKent]

you should be Ok. Once it is painted it will look nice.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[tootype2crazy]

Ok, I finished the heat exchanger. I gave it an acid dip in phosphoric acid overnight. Phosphoric acid is very gentle to the intact metal, and turns all the rust black. It also has the benefit of protecting the metal from further rusting if it is not washed off. So the inside of the exchanger should be a little better protected than if it were just bare metal. The phosphoric acid can be picked up at Home Depot for $15 a gallon in the paint aisle. It can be diluted up to 1:3 with water if necessary.

So after I dipped it I painted it with VHT flameproof black paint. Gave that a bake in the oven and here's the result:

The underside looks different, because on the last bake (which I did with the self cleaning cycle on my oven, because it requires 650 degrees) flames popped out of it. It seems there was some left over oil inside that I could not get out that ignited and burned off. No harm was done though, the oven was fine and the flameproof paint lives up to its name. The smoke, however, did stink the house up to high heaven. I'll probably rethink that next time. Luckily the wife was out shopping all day; at least I think luckily (I haven't seen what she spent yet!)

_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[pittwagen]

tootype2crazy wrote:

[tootype2crazy]

Actually my wife is really great about such things. She enjoys the VWs as much as I. On our first date my pertronix electronic ignition broke rendering the bus totally immobile. She knew what it was all about right then and there. Fortunately, love is a very strong and sometimes unreasonable emotion, allowing one to see through the faults and eccentricities of others.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[Desertbusman]

Yep, big time odors when you bake it in the oven. Stinks the house real well. But that's the best way to get a good long lasting cure. The outgassing of the vapors and stink ends when the paint has completed curing.
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71 Superbug
71 Westy

[tootype2crazy]

Yeah, this wasn't the first time I baked exhaust parts. It was, however, the first time oil was in them, which significantly augments the obnoxious odors. Not to mention the burning oil smell hangs around for a long, long time. If I ever do this again, I will heat the whole thing up with a blow torch before painting to burn out those nasties.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[914guy]

My son painted our carb intakes with a high temperature paint. He waited until my wife was gone before he cured the paint in the oven. Fortunately, I was not involved in any of this so I got no blame for this.

[vw76westy]

[tootype2crazy]

Phosphoric acid is as easy on aluminum as it is on steel. It etches the surface slightly, but does nothing more than that. It is commonly used on aluminum to prepare for painting, it textures the surface just a little. To be more precise, the acid reacts with the aluminum to form aluminum oxide. This occurs only at the top layer of the aluminum. The oxide then serves to protect the underlying metal. It's a crude form of anodizing at a very basic level. Ask any radiator shop and they can tell you phosphoric acid is the one to use on aluminum. That's why I chose it over sulphuric or muriatic acid, which work much faster on steel and destroy aluminum. Sulphuric and muriatic acid also set off a chain reaction in steel to cause further rusting if all the acid is not neutralized. Phosphoric acid leaves a layer of ferric oxide on the steel, thus preventing corrosion.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[Wildthings]

[Malokin Martin]

[tootype2crazy]

Actually my wife knows and is fine with it. In fact she said she is looking forward to having good heat. I trust the asbestos pad, if there is one, is completely soaked in oil, as my exchangers were chock full of engine oil leaking prodigiously into the fan shroud. Oil was actually running out of the inside when I took them off. Acid has no affect on oil, and therefore would not have touched the pad. Also asbestos is known for being a fireproof material and 600 degrees would have no affect on it other than heating it up.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[Wildthings]

[tootype2crazy]

My thoughts exactly, if heating it up were a problem, all of us bus drivers would be in big trouble with our heaters on!
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[Malokin Martin]

[tootype2crazy]

I got the heat exchangers installed just in time for winter. I also sealed and insulated every single bit of duct that I could. And I restored my flapper boxes with a dip in the phosphoric acid and some new springs and a new paint job. What a difference!

First of all the volume of air that now comes out of the vents is truly amazing. In all my other buses I could barely feel it moving, but now I can actually feel a good push of air coming out of there. And I installed a booster fan under the front floor. So my bus now has 'low' and 'high' heat.

Then there is the temperature. On a 30 degree day the heat will get warm at an idle in about 2 minutes. Once I am driving around town it will heat up to about 110 degrees. When I get on the highway and get those constant high revs going, it will hit about 125-130 degrees. Might as well be a water-cooled car.

Lastly, the smell. There is none. When I first installed them there was a little paint smell probably from the fresh paint. But now there is absolutely zero smell. My passengers couldn't be happier. In fact, one of them actually asked me to turn down the heat the other day because she was getting too hot. That is the greatest compliment I could get.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)

[alikatcraig]

I'm not into the Type 4 motors myself, but if someone would pony up the money then Dansk will supply you the 2 halves for the heater boxes. I have done this for the Type 1, and I believe the order was for either enough to make 50 units or 50 pairs. The flanges are the fold over style, and you can get a fitting for an air chisel to fold it quickly, or a manual tool and a mallet. I don't know if Dansk would make them in stainless to order- but I believe a high nickel content is required to make it easily bendable. Could be a nice little business venture for someone!
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1967 Ghia
1971 Deluxe Microbus
1974 Convertible Bug
1973 Standard Bug
1998 Mexican Bug

[Stuartzickefoose]

Very Cool! ill have to look into brazing...i need to do this badly!
_________________
Stuart Zickefoose

2011 Jetta Sportwagen TDi 6 speed manual

206-841-7324
[email protected]

[tootype2crazy]

Brazing is easy Stuart. If you have ever sweated copper pipes for plumbing it's much like that only hotter. Not as hot as welding though.
_________________
air-cooled or nothing for me
1978 Sunroof Deluxe Bus (daily driver)
1978 Transporter (mom's, making into a camper)
1970 Single Cab 2.1 turbo/EFI 6 Rib, 78 front beam, vanagon backing plates on rear (project)
2001 GTI VR6 (wife's)