The Ultimate Stewart Warner Gas Heater Thread

[Ian]

I'm in Denver, so these things are still pretty common. A lot of people seem baffled by these things, so hopefully this encourages people to try and get some real heat in their VW. Please use this information at your own risk and remember that gasoline is flammable, so have a fire extinguisher near by.

Basically, Stewart Warner (Southwind) Gas Heaters are very typically found in old VW's. They have a stainless steel heat exchanger and safety switches. Nothing really dangerous about them unless your fuel lines are cracked or your safety switches are broken. When they are working, they work good, when they don't, they can be a real PITA to figure out.

A brief history from Wikipedia:

[Ian]

Steps to perform for basic troubleshooting if heater is still installed in vehicle:

1. Check all electrical. Black wires from motors go to ground, red wires are hot. There is one user controlled switch, it rotates to turn the electrical on and pulls to turn the heat up (thermostat cable). There is one wire going from the switch to the fuse box, constant hot fused. There is one wire that goes from the switch to the thermostat and usually tee's off to the blower motor and runs to the coil and the combustion motor. Anything more complicated than that, look it up in the technical manual for your specific model on page 13

2. Make sure your fuel line is in good condition. Cracked at the ends or unknown means replace. There should be a tee fitting under the gas tank for the heater fuel line. Got a spare fuel filter? Great. Hose clamps are recommended.

3. Make sure exhaust is intact and combustion fan can suck fresh air. Make sure combustion fan hoses are clamped tightly. Any debris should be removed from the blower fan.

4. Turn heater on and make a note of what happens. You should have the combustion fan blowing at 4,000rpm. The fuel pump should be clicking away, and the blower fan should be blowing increasingly warmer air.

Typical issues at this point would be a leaky fuel pump diaphragm or very smoky exhaust. Maybe one of the fans ist kaput. There is also a point gap and a spark plug gap. I'll discuss how to fix those problems and setup the gaps next.
_________________
All your Buses are belong to us.
Love and good roads!
IN LOVING MEMORY OF ROB CRESS 1968-2012

[tootype2crazy]

Neat thread. I am a gas heater enthusiast and I love seeing the 'other' gas heater found in VWs. I understand they are operationally similar to eberspachers, though not as advanced as some of the later models. Is it these ones that depend on a vacuum line from the engine?
_________________
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)

[Ian]

There is no vacuum line going from the heater to the motor, with either a S/W or an Eberspacher.

I really like the S/W heaters because they are much much simpler than an Eberspacher. They can also be had for very cheap because nobody wants to mess with them.
_________________
All your Buses are belong to us.
Love and good roads!
IN LOVING MEMORY OF ROB CRESS 1968-2012

[Ian]

These S/W heaters are very very simple. If there are issues here are some steps to help troubleshoot the problem.

1. Pull positive wire (red) off of ignition coil positive side.
2. Unclamp fuel line at combustion chamber and insert fuel pressure gauge.
3. Turn on heater and record fuel pressure. Pressure should be between 5.5 to 9.5 PSI while the heater is running...I have a valve that I can open on my tester to simulate the heater running, or you can just confirm that you have about 10psi to the gauge.

Disassemble combustion housing. You will see half of the spark plug. The grounding portion is attached internally to the metal cone that unscrews with 3 screws. Make sure the electrode isn't damaged or corroded, they usually are fine even after 50 years. There is a special tool like a bent coat hanger that goes inside the cone once it's bolted on, that measures the gap. Like I said, usually the sparkplug is not a problem.

In the center of the combustion housing is the fuel nozzle. Make sure it's tight in there, it's a 16mm. I built a test setup that had a 12v power supply and a low pressure 12v fuel pump. Put fuel pressure to the combustion nozzle circuit and check for leakage without energizing the fuel solenoid, there should be none. Now energize the solenoid, fuel should spray out of the center of the nozzle in a very smooth cone pattern. I like to use diesel to do these tests as it's less flammable.

Last thing are the points on the back of the fuel pump. The points operate like normal points, there is a cam that opens and closes them at 4000rpm constantly. These points are a replacement item and as such the instructions say to solder the screw permanently. Well, since parts aren't available what you can do is file the points down and unsolder the screw. That allows you to adjust them to the correct gap of .018". Once done, resolder the screw so it won't move. Put a little grease on the cam lobe and you're good to go.

If your gas heater doesn't work absolutely perfect now, you might have some other issues like a bad thermostat or the wrong nozzle, but those problems are very uncommon as usually nobody even messes with the nozzle.

I hope this helps and please post any questions you have regarding these heaters, I'll try to help out where I can.
_________________
All your Buses are belong to us.
Love and good roads!
IN LOVING MEMORY OF ROB CRESS 1968-2012

[tootype2crazy]

Ok now I have it straight. Old southwind heaters from the 40s and 50s for watercooled cars use a vacuum line off the manifold.

http://southwindheater.com/Home.html
_________________
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)

[Redlines]

I've got what could be a very good Stewart Warner South Wind model 781-B. Not your typical heater for a vw. Has anyone ever installed this model into a Bug? I've heard it can be done. Anyone with a game plan on this installation?

[highaltidude]

Got any source for new rubber in the fuel pump???
I've got a working SW heater in my DC, and two spare pumps in need of freshening up.......

Chuck
_________________
66 Double Cab
83 Vanagon Westfalia, Vanistan'd

[thomas.]

What I did was rebuild the diaphragm part of the pump myself then ordered the brass valve plates . They sell the whole diaphragm part but it's like $150.crazy ! the brass valve plates were around $50 plus 10 to ship. I've rebuilt 2 of them and both work perfect. Just for the heck of it I installed a 6 volt electric fuel pump to my S.Warner to see if it would work.Just needed to add a relay.Worked fine.That's another option if you already have an elec.fuel pump laying around. Here's a link to most any maintenance part you need.They still make them for small airplanes.So they still sell the parts. You won't see the parts you need listed on their website but if you call and tell them what you want they have it.You might want to look up the name of the part you need and part number in the technical section on gas heaters before you call.It's what I did. Real good merchant.shipped that same day.Prices may have changed since I bought.They didn't take paypal back then either.


http://www.haroldhaskinsinc.com/

[highaltidude]

[thomas.]

I didn't check the pressure.I just used a low pressure 6 volt pump I bought off eBay. I just bought the cheapest one at the time. I'm on my c.phone now but I might have a photo on my computer. I'll post later & let you know how I wired. I remember I wired it to thermostat & it cycled off & on just like the regular fuel pump.

[vwtopia]

I posted this a couple years ago in another thread but thought I would add it here just in case it might help someone. They do have a website but I didn't look at very much. I still have the parts listed below, just would have to find them.

[thomas.]

O.K. I couldn't find any photos but here is how i wired to get it to work.In the photos the yellow wire is one of those double connectors you'll need or there are other ways to splice in.I disconnected the top female connection from the thermostat and reconnected to the yellow double connector ,then reconnected both wires back to thermostat.From there yellow wire to 85 on relay. 86 to ground. 87 to positive wire on fuel pump. Number 30 on relay goes to its own separate positive 6 volt connection or direct to battery.Preferably with its own fuse .87a isn't used. Also here is a link to the 6volt relays .Hope this helps and I made it understandable.I'm not the best artist, I notice in the drawing it looks like #30 on relay is going back to thermostat. Disregard that . Like I said #30 goes to its own source 6volt connector.Also...The second photo was just to show the connector I used. You can see I reused the filter from the elec. pump. I'm still debating on installing.I already have a B2 heater installed and running but it doesn't have the features the S.W. has.(Instant start,thermostat,more heat)

http://www.newark.com/te-connectivity-potter-brumf...dp/21M4888

[Unclebon]

I am glad this topic has finally started up. Here are some photos of a before and after of my SW. It took two for me to make one. Mine runs on 12v. I ended up using an electric fuel pump from Napa, since my mechanical one was pretty much shot. The heater works great, it pumps heat instantly and a lot of it. I have a toggle in the cab that turns on the blower, then i pull the cable that starts up the fresh air fan that also runs the points. I recently put in an additional toggle that starts the fuel pump. For some reason my fresh air fan turns slowly for a couple minutes before eventually kicking in full speed. Before adding the fuel pump toggle, i think gas would be pumped into the firing chamber and then once the fresh air fan finally kicked on to full speed and enough to cause spark i would hear a scary loud explosion. There is a question coming. Today i woke up to gasoline dripping out of the heat chamber where the spark plug is. I assumed it was the fuel pump and replaced it. After hooking up the replacement. Gasoline flows right through the new electric fuel pump. My question is: what keeps the gasoline from flowing through the electric fuel pump into the firing chamber when the fuel pump is not running? Now that i have it all taken apart and back together it no longer leaks, but now i don't know why it was leaking in the first place, if the new fuel pump free flows like the old one. Sorry for my long windedness. [url]

[/url]

some additional photos of my heater installed. Can i add some sort of check valve or electronic shut off between the outflow of the fuel pump and the firing
chamber?

[highaltidude]

[thomas.]

You shouldn't need to add an additional check valve, like Chuck was saying there's already one there in the end of the H.exchanger right where your fuel line ends.There's a metal valve that moves back and forth when electrically magnetized from the thermostat. I've never worked on one of the type 2 Bus S W heaters. I know they already have a relay installed from factory.It looks like you didn't need to add an extra relay for your fuel pump ? On mine the speed of the fans doesn't seem to change much. Did it or does it smoke much ? I have a spare heater that did the same thing as yours.Gas must have pooled in the chamber after shut down. Then when I restarted it the next day it sounded like a gun going off.Boom ! You seem to have it fixed. The good heater I have burns really clean though.No smoke that's visable. Nice restore.
Tom

[Unclebon]

[type11969]

Anyone have any install pics in a 69 Beetle - or any Beetle with the external gas door? The usual Southwind Beetle install seems to be on the right side of the car . . . right where the fuel hose passes in to the gas tank.

I've got a sweet 12V working SW heater and I'd love to drop it in my Beetle that has no heat because of the t4 engine.

-Chris
_________________
1969 VW Beetle - t4ed indeed
1971 Porsche 914 - jackstanded
1976 Westy - DD

[Unclebon]

[thomas.]

What about the smoke you were getting ? Has that been corrected with this other fix. It sounds like your intake air fan isn't right. Are you certain it's wired correct.I only say because it sounds like its cycling with the thermostat and both my fans run as long as there's power.I tried to make a video of mine to show as a compare (the exhaust smoke) but somehow I left the sound off and the video looks stupid without audio.