73 gas heater questions

[74 Thing]

I have a few questions about the 73 Thing gas heater:
1. Why are there two outlets for the fresh air intake for the combustion chamber (one in the upper inner fender well area an the other straight down by the rubber grommet for the gas tank breather line that runs back to the charcoal cannister)?
2. Where does the gas line come through the body to attach to the gas heater?
3. Is it necessary to have a "foot" on the exhaust pipe that exits through the fender and if so what are the consequences of running without the foot?
4. What is the gasket material made of for the exhaust pipe so it does not burn or damage the paint?

Thanks!

[[email protected]]

1. Why are there two outlets for the fresh air intake for the combustion chamber (one in the upper inner fender well area an the other straight down by the rubber grommet for the gas tank breather line that runs back to the charcoal cannister)?
one is a fresh air intake from outside fender
the other is a recirculation fresh air pipe
2. Where does the gas line come through the body to attach to the gas heater?
through small hole under exhaust pipe along with the wiring to gas heater fuel pump
3. Is it necessary to have a "foot" on the exhaust pipe that exits through the fender and if so what are the consequences of running without the foot?
probably a danger of re entering gas exhaust back into passenger compartment
vw engineers designed it this way for a good reason

4. What is the gasket material made of for the exhaust pipe so it does not burn or damage the paint?
its a special secret substance derivative unknown just kidding idk
original gas exhaust pipe was asbestos ring pipe to heater
_________________
Michael Basso
http://www.thingparts.com
New and Used VW Thing Parts Free advice
CALL 518 630 0173

[KAmes]

I have a few questions about the 73 Thing gas heater:
1. Why are there two outlets for the fresh air intake for the combustion chamber (one in the upper inner fender well area an the other straight down by the rubber grommet for the gas tank breather line that runs back to the charcoal cannister)?

I don't know the answer to that one.

2. Where does the gas line come through the body to attach to the gas heater?

On mine it comes through a hole along with the fuel pump wires under the heat shield and exhaust pipe.

3. Is it necessary to have a "foot" on the exhaust pipe that exits through the fender and if so what are the consequences of running without the foot?

I have the foot on my thing heater, I think it's to deflect from blowing on the tire. I also have a Webasto gas heater in my '74 beetle and it exits straight through without the foot, doesn't seem to bother anything. The Thing Shop sells the foot and the complete pipe.
https://www.thethingshop.com/GAS-HEATER-EXHAUST-PIPE-ELBOW-NOS/productinfo/181261145A/
https://www.thethingshop.com/HEATER-EXHAUST-PIPE-NEW/productinfo/181261603TTS/

4. What is the gasket material made of for the exhaust pipe so it does not burn or damage the paint?

It appears to be maybe some kind of silicone rubber. Thingparts.com has a used one.
https://www.thingparts.com/gas-heater-sealing-ring-exhaust-pipe-to-body/

Edit: I just saw that Mike from Thingparts.com posted above me

[mondshine]

I plan to install my BN4 sometime soon.

What are people using for "alcohol-safe" fuel line from tank to pump, and pump to heater?

What is the I.D. of these hoses?

Are there rubber mounts under the "mounting feet" of the heater body?

Probably more questions once I get into it. (My heater is still in a cardboard box.)

[74 Thing]

KAmes,

Can you post a photo of your Webasto install?

[KAmes]

[KAmes]

[mondshine]

[KAmes]

[mondshine]

I started playing around with my BN4 this afternoon.
I rigged up a test stand and fired it up. It works great with one caveat.

The run-on time is infinite; the blower will never turn off.
The workshop manual says the heater should run on for ~200 seconds, but mine will run on until the battery is dead.

The manual's troubleshooting chart says to replace the quartz rod.
WTF is the quartz rod? Is it internal to the flame switch? No adjustment of the flame switch has any effect, so I returned it to it's original position.

I will be grateful for help on this one.

Thanks, Mondshine

[KAmes]

The quartz rod is inside the rod below the thermo switch, I would imagine it's what does the expanding and contracting to work the switch.
https://germansupply.com/thermo-switch-bn2-bn4-gas-heater.html
Beats me if they actually have one to sell but it's that thing. I've replaced the top electric switch on mine but never had the rod out.

[KAmes]

https://www.thesamba.com/vw/classifieds/detail.php?id=2014696

[KAmes]

This one that Mike has looks like it might still have that part on it.
https://www.thingparts.com/gas-heater-blower-used-with-wires-and-relays/

[KAmes]

I was just thinking trying to remember what the deal with mine was. It was the opposite of yours, it was shutting the heater down early as if it wasn't heating up even though it was. It turned out it was just the switch itself not making contact not a problem with the rod, just thinking out loud.

[mondshine]

Thanks Kevin-

That's about what I was a'figurin'.

I will call Scott in Toronto tomorrow to see if he has a new one.

Worst case, I will take the risk on a used one.

Edit:
My lucky day. Scott in Toronto (German Supply) had a new flame switch for me, so with luck, I will get back to this heater in a week or so.

[doublecanister]

I know a broken timer switch (the one on the dashboard) will make it stay on too. Mine was broken when I got my 73 but the heater would work I just had to manually turn it off, after cool down it would completely go off. Replaced the timer switch eventually to fix.
_________________
****************************************
2020 - Mustang Eco Boost [High Performance]
1973 - Thing
1966 - Mustang GT- Fastback
1951 - Ford F1 pickup Flathead V8

[mondshine]

Thanks for that Double-

I don't intend to use the timer switch; no room for it on that dash panel with the transplanted gauges from the old car. I will just use a simple on/off switch, powered by the SU circuit (relay) so that the heater will operate only with the key in the ignition switch (like the radio, glove box light and garage door opener transmitter). This is a Summertime car; no real need for me to ever pre-heat it.

Now that I have a new flame switch ordered, I felt more comfortable about taking the old one apart. It is a simple SPDT microswitch (the switch itself is actually made in the USA) that is actuated by expansion of the quartz rod inside a steel tube.
Once I had it apart, the quartz rod (which looks like a glass rod maybe 1/8" diameter and 4" long) moves freely in the steel tube, and appears to be in perfect shape. The microswitch itself, when actuated by light finger pressure, works exactly as it should.
So now, I am in doubt about this whole deal until the new switch arrives.
Time will tell.

[doublecanister]

Hey Mondshine,

oh yeah I forgot that part (being a summer car).

Well, just to mention,
If mine sit too long without use, the heater fuel pump can stick,
also,
with the original dash timer, once on, got hot, then it timed out, it ran a "cool down" mode for "x" minutes depending on temp I believe.

Hope you can sort that out with your new method, I guess it was to be safe and not do a hard shutdown on a super hot heater.
That thing gets freakin hot too, when I run mine I dont run it at the hottest temp, you can cook marshmellows under the dash, make tea, etc.
It made my water bottle water hot!

Well Good luck with it man! I know you'll get it sorted out.

T
_________________
****************************************
2020 - Mustang Eco Boost [High Performance]
1973 - Thing
1966 - Mustang GT- Fastback
1951 - Ford F1 pickup Flathead V8

[KAmes]

I use a simple on/off switch with mine, it still runs the cool down cycle after shut off. I'm using a windshield wiper switch.

[Dougster43]

Mondshine - did the replacement flame switch fix your issue? My heater just started acting up and I think it may be a flame switch issue.