Heater Tube Replacement

[SGKent]

[Jason0115]

[orwell84]

I tested my heater blower again and it seems to work better than I first thought. I was expecting to get blown away by the amount of airflow it pushed. It doesn’t do that, but does push more air out the vents compared to the stock fan and the difference is noticeable when they are both running, at least at lower rpm. The fan draws interior air through the walk through vent. The idea is to use it when the bus has started to warm up, drawing some of the warm air from the gas heater outlet under the rear bench seat and pushing it up front.

It would all work better if I replaced the door and window seals, the slider is in especially bad shape. The stock heating system by itself will never cook you out if the bus in a really cold day, but it will make it bearable if you are wearing warm clothes. Years ago, I got very cold in the bus after 10 hours of highway driving on a cold day in late May in the northeast. I would have been fine with stock heat. It also does a great job of keeping the windshield clear. One of the hardest parts of the whole job was fitting new cables. At first, the lever was quite stiff, but has loosened up with use.

[orwell84]

I used the double walled chimney pipe to replace my center tube. It was a good fit. I was able to find the weird section that runs over the front beam. I cut it and sleeved it so I could install it without dropping the beam. I used flexible metal tubing in a couple places to connect it together. I welded up a few “adapters” in some places to improve the fit and wrapped the joints in a metallic clothe and foil tape. I used steel flex pipe in place of the accordion tubes which transmits a lot of engine noise up front. I will eventually replace them with some originals that need some work.

I tried to make a boost recirculating fan that draws fresh air from the walk through vent through miles of shop vac tube. It probably cools the air more than it heats it. I found that running it at idle (without the stock engine compartment fan) actually prevented the hot air from the heater boxes from reaching the vents. With the stock fan installed, it increased the output a little, but not enough to justify its existence. It might be a good place to mount a Chinese deisel heater, but I’m good for heat and may end up just ditching that part. The in line fan is still the best option IMO. Buy a new one every couple of years when it melts and chalk it up to the cost of doing business.

I found the floor vents to not do very much so it’s set to defrost. The whole thing might work better if I insulated all that tubing, but I think it would end up trapping moisture and I already have all the heat I need.

[alexbeatle]

[SGKent]

anything done to create a slightly negative pressure in the bus will help bring more heat forward. Going downhill an extended distance will lower heat coming in, and driving up a grade will increase it. Driving slow in ice and snow will result in less heat, and driving 65 mph on a dry night in the cold, one will find that the heat can cook them out of the bus. That said, it is now mid-April and the subject will soon turn to, "how do I air condition my bus," until next fall when this thread will start again.
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[mr matt]

[richparker]

[airschooled]

Drive with a late bus access hatch open even the tiniest bit and you'll see why recirculation isn't practical… If you had a Vanagon shroud things might be different; you could duct into the blower motor well enough.

VW designed all '71+ buses with a "flow through" ventilation system. Those little ducts in the doors are connected to the A-pillar door edges, which create suction while driving. It's easier for the stock heater system to pump air into a cabin under slight negative pressure; on a well-sealed bus you can feel the heat difference with the vents open and closed.

They're also well-designed, since the warm air from the ducts will then flow over your body instead of rising up through the dashboard.

Early bay owners can crack the front vent wings for best heat in mild cold.

Robbie
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[nemobuscaptain]

[busdaddy]

Later models switched to a flexible plastic tube, so no, the pipe is not structural.
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[alexbeatle]

Great projects folks! Thanks for sharing.

Just wanted to confirm something. Since many solutions do not involve the solid pipe welded to the frame any more like the original. Makes me wonder. Does the original pipe even do anything to the bus integrity?
I'm thinking of cutting my bus's pipe off and use the larger area space for the underbelly water tank.
Please help me understand.

[livingskies]

Before replacing the rusted out center section of the heater tube on the 1974 bus, this thread came up in my research. Both of the front and rear sections of the heater tube system are in excellent condition.

After completing the repair, here is a simple solution, for the record.

The tube is 3 1/2 inches O.D. The local muffler shop provided a four foot long piece of 3 1/2 inch O.D. exhaust pipe, which I cut to 37 inches in length. That is the exact distance between the front and rear connections.

The local hardware store provided 3 1/2" stainless steel muffler band clamps at a price lower than those at the muffler shop. Original support to crossmember refastened.

Pics below before installing the insulation over the pipe. Original piece of undamaged insulation reinstalled over the front part to the crossmember. May install foil back non-absorbent insulation over the main pipe.

Quick, neat, and uncomplicated.

[rsbadura]

[busdaddy]

X2, dirty leaky motors stink, well sealed clean ones don't, not only do you get to keep your oil in the engine where it does some good, sealing up the heat system gets all your cooling (or heating) air to where it matters.
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[richparker]

No, I do not smell any oil or exhaust fumes in my cabin. You need to make sure your engine is clean, has no oil leaks (or consistency clean it) and make sure your exhaust to heat exchanger joints are properly sealed. Just takes some maintenance.

I see all these posts using stove pipe piping to redo the center channel. The OP of this thread did it correctly. Just use 2 1/2” exhaust tubing and be done. It works great and it is much cleaner then all the other pictures I see in this thread.
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[1970Type2]

I have a question for everyone that uses the stock heating system in their bus.
I have been driving air-cooled VWs since I was a kid and I have owned a few.
My '70 Campmobile doesn't currently have the heater connected. I lived in California all the way through 2005 and it doesn't get that cold there so I blocked off my fan shroud but now that I'm in Texas, it can get cold during the Winter. I remember by past VWs having that smell of oil and exhaust when the heater was on and I'm pretty sure I remember getting headaches from it.

So the question is, do you guys smell fumes in the cabin? How hard is it to seal the engine well enough to where you don't smell enough exhaust to make you dizzy?
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[Wildthings]

[cmonSTART]

Any difference moving the bilge fan forward?
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[Wildthings]

This isn't the best picture of what I want to show, but this is my center duct, beta addition. The bilge fan is now gone, and now sits in the flexible duct near the front torsion bars, but the rest of the center tube is the same. It is a piece of fairly thin wall stove pipe with the crimp for the seam snipped off. I just fit the split pipe over the two "nipples" on either end of the span, use some band clamps to draw it tight and then use pop rivets to hold the seam together. I then wrapped the pipe with a couple of layer of foam insulation followed by covering the whole shebang with a split piece of thin wall pvc drain pipe held on by band clamps. This was done about 14 years ago and is still working well.