Eberspacher BN2 Rehab

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So, we recently got our hands on a BN2 in "good" condition for a decent price. Everything looks great from the outside, but there are some issues. First is that the fan rubs on the metal housing. I discovered this just by rotating the fan by hand. I'm not sure how anything could be misaligned inside, but it definitely rubs on the bottom.

I also checked out the fuel pump diaphragm and it's as hard as a rock with varnished gas evident inside the cap. I'm going to assume that the pressure regulator diaphragms are screwed as well.

It seems that a lot of the info that used to be available on these heaters disappeared along with Russ Wolfe's site. While there's some general stuff out there, most Samba posts seem to be more about installation than rehab. I found this in the classifieds (and reached out the seller)

http://www.thesamba.com/vw/classifieds/detail.php?id=489767

And this on the site

http://www.thesamba.com/vw/archives/manuals/ebersp...201991.pdf

But I'm not sure what the best next move is. Clearly, I need some material for rebuilding the diaphragms before testing out the heater with gas, but are there any other tests to run in the meantime on other parts?

For fun, here's the heater without the wiring cover and the pump removed

[sjbartnik]

Someone, maybe notchboy? has a good thread in the Bus forum about BN4 rehab, a lot of it might be applicable to yours.

So is your plan just to install this to replace the one your car has?
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

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I was looking around at some materials for diaphragms and Buna-N came up several times. Anyone have any experience with that stuff or know what thickness is best for making fuel pump and pressure regulator diaphragms?

https://www.zoro.com/buna-n-rubber-sheets/c/10299/

Also made some progress with the fuel pump. By pressing down on the metal center of the diaphragm, I was able to get it to move. It made crispy/crackly sounds as some of the old varnish cracked off but I was able to get the pump to run a bit off the car battery. It was finicky about where I held the alligator clip on the negative end. If I clipped it right onto the connector, nothing happened, but if I touched the connector in different spots with the alligator clip, I got a reaction like in the video. I wonder if something electrical further inside needs some cleaning up.


Link

[sjbartnik]

I still think you should get that BA4 up and running
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

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[sjbartnik]

Well you seem to take the engine out on a semi-regular basis, so you know, next time you have it out....
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1965 Volkswagen 1500 Variant S
2000 Kawasaki W650

[notchboy]

Russ was one of my first real information sources on the BN4. That ad for the BN4 info was one of the first I bought as well as emailing the Espar company that would send the same info out to you for free. Thats what you see on that link to my Eberspacher 101 page.

You have an early BN4 with all mechanical pumps and metering. The diaphragm in the pump can be easily fixed. The two in the top of the unit - not so much as they have weighted brass fittings pressed into them that can not be separated.

The BN4 just after this has a metering pump and a much simpler design - for a reason.

The BA4 is a much better design as well. Just didnt reach the popularity of the BA6 in the Bus and Vanagon.

My first heater ever was this kind that I installed in that Anthracite 62 I restored. I was lucky in that the metering diaphragm were semi playable.

I have a facebook page that has international connections on it. If you are serious about the BN4 then you will need to get past the metering diaphram issue. If you dont, then part this out and fix the better BA6.

https://www.facebook.com/groups/1029635500462666/

I have material that Russ Wolfe gave me. Since Ive gone to the metering pump type BN4 and BA6 I have little use for it.

Lots of my most recent vids on youtube are about Gas Heater and how they work. Here are some of the older relevant to this topic ones.


Link


Link


Link

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[neena]

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notchboy....thanks for your generous response!

I just paid what I think is a good price for uncommon VW parts in the NYC area for 3 BN2 cores. Hopefully, I can transfer parts b/w the BN4 and the BN2. If not, maybe I can build one good heater from the various BN2 cores.

http://www.thesamba.com/vw/classifieds/detail.php?id=2025918

I could only access one of the regulator diaphragms as the other one (under the regulator screw) seemed to require more muscle than I felt comfortable exerting. The accessible one looked like this.....the screw area was completely pliable but the raised center part was firm as hell. I don't know if this is b/c there's metal beneath or not. Here's a pic

Finally, is there a possibility that a metered fuel pump could be used with a mechanically regulated heater? I imagine that a metered pump would put out what an electrical pump and mechanical regulator would put out but I have no facts to base that on.

And how drastically different are the various metered pumps? I found an ad for 221 261 467 A but according to germansupply.com my BA4 wants a 221 261 467 AU......is there a big difference b/w A and AU?

http://www.thesamba.com/vw/classifieds/detail.php?id=1728107

[notchboy]

Very few of these parts swap between the old mechanical type and the later metering pump.

The single biggest reason is the fan in the later units aso drive the metering pump with a contact point system. These type you have here the pump runs itself as you started to see with your test vid. Completely different animals.

Maybe you'll either find a solution to the diaphragms or get a usable one in the parts.

Of all my years into type 3s Ive wanted to have a nose mounted East West config Eberspacher in my notch. The biggest reason I never did was these problems Im describing. I was going to put a later BN2 in - but would have to figure out the 12v deal first.
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This morning, we picked up the 3 heaters I mentioned buying the other day. Got them home and got 2 good diaphragms (one better than the other) for the pressure regulator, so at least I'll be able to test the thing out. I also did a little more digging around for rebuilding the diaphragms and ran across this old thread on shoptalk....

http://www.shoptalkforums.com/viewtopic.php?f=1&t=1970&start=15

14 posts down, a guy claims:

Went to a Gasket builder , got a bunch of "diaphragm" stock (they gave it for FREE!)
and promptly replaced all diaphragms: in Fuel pump and the Pressiure regulator. Was able to reuse all the riveted assemblies.. just don't be an oaf when dissasembling:-)
Entire process took about 1 1/2hours.

I'm not really seeing how it's possible to separate the halves of the brass parts and notchboy says they're inseparable but this guy suggests otherwise. I'd PM him on shoptalk but he was last active there in 2003 so that's a dead end.

[raygreenwood]

Show me pictures both sides of the diaphrams. I can tell you how they are put together and how they will come apart.

The rubber material you will need for fuel is either viton or another fluoroelastomer.
Buna-n....which is Nitryl....is not suitable.
Some purpose made diaphragm sheets are using either a nylon or polyester scrim cloth that is impregnated with a heat cured polyester resin. You see this reddish material in items like accelerator pump diaphragms etc.

The assembly method for most diaphragms is similar to what you see in a vacuum advance diaphram. Ray

[notchboy]

The pump is super easy. Get the diaphragm separated from the body then just pin it out like a nut.

I also have plenty of gasket material Russ Wolfe sent me that I can pass some on to you. As well as copies of the manuals he scanned.



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[neena]

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It's a snow day in NYC, so I figured I'd poke around the heaters a bit and see what I could discover. From the used parts I picked up over the weekend, I at least have a working glow plug, 2 good fans, and the 2 good diaphragms for the regulator I mentioned the other day. I don't have the knowhow yet for testing the rest of the parts, but I feel pretty good that I didn't get hosed on the deal.

As for the heater I started this thread out with, the fan definitely works. Problem is, I can't get the heater halves to separate. It seems to be on account of this rubber boot that is very very firmly attached to the intake inside the heater b/c this is the sticking point when I try to pry the halves apart. It seems strange to me that this would be the hold up as the boot is clearly connected to something on the bottom half of the heater. All screws connecting the halves are out, fuel lines are off, etc. I don't want to pull a gorilla move and just yank this boot off and tear it. The other heaters I got just had a remnant of paper/aluminum hose in this location, not this fancy boot. Any tips?

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Okay, nevermind, a little more wiggling did the trick!!

Hey, Ray, if you're out there, what do you think about getting those diaphragms apart? I can't tell if that small nipple in the middle is the end of the rivet or if the slightly larger circle is also part of it.

[raygreenwood]

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