12v BN4 for split bus 12v conversion

[1950split]

Hi,

I'm going to convert my 1965 SO-44 to 12v in a few days.

I'd like to keep an operational Eberspächer BN4 in the car.

Mine is 6v and from what I understood it is quite difficult to convert it to 12v (don't want to go the drop-a-volt way).

Is it possible to fit a bay 12v BN4 in the bus and if yes which one is the easiest to fit in terms of wiring, mods ?

Ideally it should be an early bay with the same light grey hammerite finish as the 6v unit but they seem to be pretty hard to find. I could have a unit from a 1971 (dark grey) for free but I'm not sure if the 1965 cabin switch would work.

Thanks for your help and hints,

Phil

[Major Woody]

I installed a 68/69 12V BN4 in my bus.
The stand was too short due to the different shape of the bay window bus in this area; had to lengthen it to align.

Here is the extended stand from the front

...and from the back. You can see where I extended it.

There is a sort of flange spotwelded to the duct where it passes next to the gas tank. It extends downward from the rectangular part of the duct and must be removed, as it hits the fuel tank "shelf" and interferes with the heater going fully forward as it should.
Pic of flange:

Mine has the old, diaphragm style of fuel pump, not the inline metering pump. I painted the whole unit Hammerite black, which is really a dark gray and as close to the original color of the heater as I could get.

I don't know if your switch would work. I believe it has a little tiny 6V bulb in it. It may also have circuitry in it that is not needed with the baywindow-era heaters because those use a separate relay to control some functions. I don't know much about that because mine did not come with a switch so I used an illuminated defroster switch from a beetle to turn my heater on and off.

[1950split]

Thanks for your help! Whats a clean engine bay

I got some information and apparently the original cabin switch with the bulb can be used after changing the bulb for a 12v. version.

[Cainepolo12]

Woody- did you rebuild the heater yourself? If so where did you find literature? If not, who did? I have the same bn4 and want to put it in my 67 but it needs to be rebuilt. It has the hardy e57 fuel pump and original dash switch so I think I'm in fairly good shape. Thanks.

[thomas.]

Hi, instead of starting a new thread I figured I'd add to this. You always read about starting something new on the same subject is taboo. On the other hand you read about butting in on someone's thread.So..I hope I'm not doing that.
Anyway on to the question. A guy took me up my offer for a BN4 because I think I was the only interested person. He said it was sitting for a while and never used. I figured he exaggerated about it being never used. But when I got it the only wear on the inside I can see is some dust. It has rust in some spots and it's missing some things. Not a bad deal I thought for a buck and a half plus he paid half of the shipping. I am wondering where this yellow wire goes from the fuel pump ? I'm guessing it goes to glow plug ? but didn't want to try it on a guess. I also was reading that it can be tested without a switch by connecting two wires but can't figure which 2 wires? It also looks like it's missing the relay. I have some old eber. parts and think I might have one but does it need connected for testing ?One more thing , If I can't get this to run, can a fuel metering pump be substituted for the older stuff on there. Any and all comments appreciated. picture quality not so good using phone. More in my gallery if interested.

[crofty]

The wire on the pump is routed to the fan. Every 33 revolutions it sends a pulse to the pump.

The other yellow wire in your pic that isn't connected could be a ground but they are usually brown. They are usually connected to the body, bolt on fuel pump and the heater body.

Wiring diagrams can be found in here.

http://www.thesamba.com/vw/archives/manuals/7_63_eberspacher.php
_________________
Your Vanagon sucks, Stop waving at me.

[thomas.]

On the pump the wire that's not connected is split off from another wire that is grounded to the body of the heater. Photos are crap but just got a new computer and it's not so user friendly with the digital camera. that's why I used the cell phone. Anyway thanks for the help . The wiring is latin to me in those and thought if someone knew right off...

[crofty]

[thomas.]

I figured my camera and comp. so got better photos. Here's another photo of the pump with the long wire. So this just grounds to the body? You can still see the inspectors green paint marks on these parts and the cable and knob looks brand new. Unfortunately a switch wasn't included. Do you know if this model had a relay ? I guess they all did right ?

[Ragman]

Yes, the long brown is a ground.

[thomas.]

Thanks guys. I'd hate to fry something after this thing has lasted so long. Both plugs are welded in with rust but I've been spraying blaster for the last few days. Hopefully have this running before spring.

[thomas.]

Update on my BN4 if anyone is interested. If anyone wants to comment feel free. I put 12 volts to the fuel pump and got absolutely nothing. So I pulled it off and took it apart. There was a powdery crap on the points I cleaned off. The faces of the points look flat and clean though. Tried voltage again and it clicked away like a machine gun. Cleaned the rust off the worst parts of the pump. I looked on u tube to see how others have hooked up without the switch. Also I mentioned that a relay wasn't included. Can you imagine that I would have this relay in my stash?? not one but two ! I put it back together and tried it dry without gas and lo and behold it worked.I haven't tried it with gas yet. My wife thinks these stink up the house or something so I'll have to test while she's out of house. Here's some photos of the pump. The rubber seems brand new. What about this cable do you think it N.O.S. or just a choke cable ?

[thomas.]

So I got some updates and questions if anyone wants to respond. My heater wasn't complete because in my neck of the woods it's tough even to find the heater alone. It didn't come with a filter but I have that covered. One of them I already had cleaned up but needed the fitting off the other so I got that on there and tried to fire it today. I did something I was sorry for though. I added a 4 foot long exhaust to it first running to my wood burner in the cellar. Dumb move.When I started it up it started to blowing visible smoke where the heat is suppose to exit. After removing the exhaust hose and opening the window (Ugh..I inhaled some of that shit) I started it back up. It cleared itself. Ran for about 10 min or so. Cycled on and off with the thermostat positioned about a 1/4 of the way open. No visible smoke either end. So when I was ready to turn it off I hadn't made a plan for that and didn't know what jumper to pull for the run on. So I pulled the one off the relay and it shut off 3 min. 15 seconds later. So as far as running it seems all good. I still haven't figured the bracket leg parts with the rubber shocks. My Westy originally had a S.Warner installed so there's some duct work still there. So I hope to install this soon. Feel free to comment. edit... the 2nd. to last photo shows when the heater was actually running.

[thomas.]

So , I installed the eberspacher the other day. About a month or so ago I was testing it again and it was blowing black smoke which I thought was from old gas but after testing with fresh gas it still did it. I then decided to check amount of fuel it was pushing from a test in the manual. I used a 3cc syringe to measure out 21cc in an empty aspirin bottle. My heater was putting out too much. I cut it back and measured a few times until it was right. No more smoke. I didn't have all the correct parts but just used what I had until I can get the right stuff. For instance, I needed the part that's under the back seat. The transition piece from rectangle to round. The guy wanted $100 for it. I have less than $200 in the whole thing. The one thing I might change is the front switch is wired to work only with the key turned on. I reused a switch wiring that was already there. It works real good though. The exhaust pipe still looks brand new. No smoke whatsoever .

Off the bn4 subject. I changed out the white heater knob in the center of the last photo to an ivory one with an new cable. Thanks for looking .
Tom