BN4 Eberspacher Restoration and installation - 72-78

[notchboy]

Thanks a lot guys, Im glad you all enjoy this. Its been long in planning to get to this point where I could have fun playing with these!

The next on deck to shine will be a fairly nice original example. Pretty clean and looks like its ready to run. I wanted to clean, polish and service this one because of its shape. These first two pics show its top and bottom - it has typical rust spots starting to form on the side thats facing outside the engine bay and under the fresh air vent for the motor on the drivers side. So rain and dirt settle here - coupled with some down time no less in a junkyard for an undetermined amount of years - equals those "rust" age spots. Other than that looks pretty nice. I know the pump does not work and I suspect the points in the fan. So Ill tear this one down, clean it, service it and see how it goes? A coat of polish on that can will go far.

I want to stress the fact that these Later BN4s are out there. You can find a unit in the pic above fro anywhere between $20 to $400 - for the same condition unit! For some reason there does not seem to be solid education on pricing these anywhere. I know I personally like to stay below $100 for a nice complete can like you see above. Because that what you tend to see the most of - incomplete cans like you see above. Be careful when you do settle in on one - make sure it has all the bits on it, cover, all the wires, glow plug, cover and nut and not all beat to shit - rusty looking like its had some bad water damage. If you do find one of those, then price accordingly as its still a great parts source!

What bits will be missing?

Here is a spread of most the stuff you cant find or have trouble doing so. The best source is to find someone breaking a bus that has a complete unit - by all means pay extra to encourage the guy to collect up ALL the parts associated with the heater! Most of the stuff I have I made sure I was accommodating to the seller on the other end. A complete running restored unit is what we all want, right? How are you going to get that?

The hardest stuff to find seems to be the thermostat cable, silicone gaskets (real ones), Final ducting and the screen and catch for the return air snorkle. I plan on making some catches for the the snorkel out of metal - bend it up to make a box like the factory did - the original ones were welded to the body at the factory. Kinda hard to get if your lucky to find one at the wrecker.

Most of the stuff seen above in those pics are left on a bus that Im sure sits and finally gets crushed. I call those "mechanic items" You know those parts that end up with all your spare socks in that place no one can seem to find So if you have the chance to buy a fairly complete unit - with all these trimmings with it.........DO IT!


I just wanted to post up some of the external stuff these units need to be fitted to a late - 72-79 Bay Window bus. I will get back to that nice og unit over the weekend as well as post more of these bits as this thread moves along.

So for now stay warm with some Vintage Heat & Merry Christmas!



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[notchboy]

So I took some time this afternoon and serviced that nice OG unit I had. I tore it down, pulled the fan and cleaned her all up.

Here it is with all the bits off - stripped can and exposed combustion chamber with the fan still attached.

I like to mark where the fan housing lignes up with the combustion can before I remove it - that way I know it will go back to where it was - if you are not careful then you might have a fresh air intake not align with the hole in the can

Here it is - the fan. Inside there under the orange plastic fan and on the opposite side where the fire fan are lies the points. There are two sets. One that runs off a cam and closes every 10th rotation or so, and the other that closes every rotation. These work together to cause the power to be intermittent to the metering pump. By doing so gives the back and fourth pulse required to run the piston in the pump - delivering a squirt of fuel.

Out of the fresh air housing.

I then took off the covers to the points, cleaned and sanded them, reassembled after a touch of lube.

Points in action.....


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Back together and running strong - right out the gate!

Once the points were cleaned the heater fired right up after the pump primed. It blew out some old nasty smoke for a couple of minutes - ghosts of heatings past - then cleared up and runs strong. So what that make three runners now? I'm thinking I might just have to set one up in my 77 Westfalia
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[Alex6373]

Thank's for posting the videos of the action of these parts as you are doing more than one , it shows for me the normal operatiion of the units , I have never had mine running so it's nice to have a benchmark to compare , Alex .

Any chance of a meter pump clinic and adjustment video?

[notchboy]

Its funny you mention that. I just went out yesterday to get a new battery for my digital calipers for just this reason. The magic # is 16.5mm.

I have four pumps that need to be "fixed" if they can. At present they are not working, so next up is the pumps for sure. I also have one of the working heaters that belch some smoke while running - I suspect the pump is not set right.


Stay tuned.........

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[notchboy]

I wanted to point out that there is lots of PDF's out there on how to Service, Install and PN books on these heaters. Searching around here on the Samba and internet provides a wealth of information.

What I planned on doing in this thread - to reiterate - was to take that info and present it in a friendly maybe dumbed down (me understand mo better) version, hands on type stuff.

For thise wanting a good read on people before me - doing the samer thing in maybe a slightly (Thing BN4 based) manor:

http://www.thesamba.com/vw/forum/viewtopic.php?t=332848

The service manual Im going off of that gives you the points adjustment in the fan as well as the adjustments for the metering pump are in here:

http://www.thesamba.com/vw/archives/manuals/bn4tro...manual.pdf
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[notchboy]

So we've had the BN4 out, played with it a bit, looks like it may or may not fire - you find out the pump is not pumping - clicking while its on the heater in test mode 1) Now we've cleaned the points on the fan 2) Still wont click even when direct power is put to it by having the Neg on one tab and touching the other with Pos.

So maybe the pump is broke? Maybe its gummed up from old gas in and around its piston? More than likely its the later. Your pump is simple in design but very hearty and may just need a leg up to get it going. Pumps in this form are used to this day to fuel Espar and Eberspacher heaters. They can be had from Eberspacher/Espar or generically for less. Metering pumps are out there if you don't have one. It needs to be 12 volt but I don't think it matters if its diesel or gas - just as long as its adjustable!

These photos are for the guy that does have one and it does not want to click. I have seven original BN4 pumps. Of those I found four to be in non-working-state. They didn't want to click when power was applied. So I decided to take them apart, clean them, adjust them and see if that did the trick?

First I completely disassembled them. Soaked the big parts in carb cleaner for 24hrs. The little brass jets with O rings on them I decided to clean by had as the carb cleaner will swell the O rings and destroy them. I was fortunate enough that all the O rings were still usable, pliable. But if you need to - source new ones from your FLAPS.

The body of the pump houses a piston that when power is applied creates a magnet pulling the piston to one end. Power is shut off then the piston moves back. Repeat the process every second then you get a pumping action. This is why its important to clean the points in the fan as it creates this on and off effect of power to the pump as well as the spark plug

By soaking it in the carb cleaner we are trying to remove the gunk that may be around the piston. Once soaked for 24 hrs - I took the pump out, sprayed some carb cleaner directly into each end, took a small hammer and started to tap around the body and gently at each end. This may dislodge it if the cleaners haven't taken all the gunk out. After this I applied the 12 volts intermittently. The first one I tested - its started to click!

On the side - I had the jet portion hand cleaned and ready to go back in, but not before some pre adjustments per factory spec. As seen in the shot of the factory manual - nut to nut adjustment is 16.5 MM. This is a pre selection setting that should be close and get you going - but it is not the correct way to see if your pump is delivering the correct amount of fuel. I will cover that in a later post.

As seen in the pic the setting of 16.5 MM is met by using some cheap calipers. I then shot some WD40 into the pump body, all over the O rings and jets since I don't know if I will use this tomorrow or two years from now? So I want some kind of lube in there for the moment. The capture nut is tightened and the tit for the opposite side is snug as well. Little side note - the side opposite the jet is a small plastic filter with metal mesh basket. I sure as hell wasn't going to mess with it. It won't come out easy and I don't have any replacements. So I made sure it was there and clean - thats all.

If you notice - the bodies of the jets have corrosion marks about half way up them? This is indicative of the 16.5 MM setting mark used from the factory. When I get to the actual adjustment phase of the pump - I'm anticipating that the capture nut may only move a turn either way at the most. we shall see?

Of all the four pumps only one was hesitant to work - and its that best looking one there Figures But with some back and fourth applications of power and tapping it came loose.

I see lots of these that look like they were boat anchors, rusted and pitted. In the past I have taken these, used a bench grinder with wire wheel - cleaned them up, taken them apart and had them running. So don't let the external looks fool you. Take some time to see if it works. You may be a few buck the wiser.


Here is the factory settings to use as a pre set guide:

All apart, cleaned - mind both of those O rings! And put back together:

Shot of WD40 and put back together:

Pre set before Assembled back into the pump:

In closing - I do want to warn there are a couple different versions of this pump. I have two distinctly different versions that hold exactly the same part number - I mention this as the versions are known to have different PNs for the BN2, BN4, BA6 and maybe the BA4. But the overall idea of the function is still the same with variations on how the jet - if any and the setting mechanics are set up.

Of my seven pumps, five are the same - exactly and the two different ones are seen on the red towel at the top. All my same pumps look just like the exploded view in the service manual. I wager to guess it to be the most common? I will look into the the functions of the variants I have in the next post when I set for accuracy of fuel delivery.

Now go clean your pump!

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[Alex6373]

Very nicely written , thank you I'm off to start my pump service thx

[Stuartzickefoose]

Nice write up!
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Stuart Zickefoose

2011 Jetta Sportwagen TDi 6 speed manual

206-841-7324
[email protected]

[notchboy]

Today I took the unrestored BN4 I had that was puffing black smoke from the exhaust. I had serviced the points only and cleaned the rest up. When I initially ran it I suspected the pump when I saw black smoke puffing out. This prompted me to look into the pump setting and restoration side of things.

So I set up the OG unit and ran it with a "restored" pump. I took the liberty to improve the test stand a bit as well. I added a fuel tower - so the gas can prime the pump faster with gravity - the air in the line jumps out now. I also put that switch on the post where it belongs.

At the time of this vid - i had tested two pumps. Both ran awesome and the heaters exhaust ran clean and smooth.



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[Xevin]

That's it. I'm inviting myself to your place and fixing my heater. Or I'm dragging you down south
How do you do it? This workshop fix it tutorial is awesome. Nicely done brother! You rule the wasteland

[Tcash]

Great job Jason.
Could you please put the videos in a playlist on Youtube? Then I can put a link to the playlist in the Youtube post.
Thank You
Tcash
P.S. with them on the stand is a good opportunity to perform failure scenarios. IE cut power to the fuel pump or put a piece of paper between points and show the results. Just a thought.
Good Luck on the new house!

[notchboy]

Thanks guys I appreciate the kind words.

But I do want to make one thing very clear. I haven't done one thing special here in the least. What I've maybe done is condense lots of information down to some septs of importance. Meat and Potatoes kind of thing. The big thanks go to the others before me. From the site hosting to those that have explained and shared all they know. I just paid attention

From the Eberspacher factory tech to the all the great guys and gals here on the Samba - all this information is out there at ones fingertips. This has been done one way or another in various threads. Some with intense nappy time pages of data to others that start cool with no follow through and everything in between


The over all hit list of information is right at your fingertips

http://www.thesamba.com/vw/archives/manuals/heater_ac.php

But here is one of the most important.

http://www.thesamba.com/vw/archives/manuals/bn4troubleshooting.php

I can show you how cool (hot) these heaters are, but I cant make you get off your ass and do it Read. I am a hands on guy. Show me once and I got it - usually - just ask the Mrs. Ive made many discoveries over the years after I took the time to read the manual on a car task I've done a million times before.

Ok, I won't brow beat it anymore Search, Read, Explore what's out there. Apply the basics and you will have a kick ass heater - Thats all Im shooting for.

Tcash I'll pool them.

Kevin - Im down maybe early Spring to have a BBQ at the new pad - but if you want to swing up earlier than that let me know. Get some of the guys here for a small bbq.

Not sure what to do next. The 74 is at the painter again so I cant "install" one.

Maybe we should have a on site tech session?
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[Tcash]

Tcash I'll pool them.
Thank yOu

Maybe we should have a on site tech session?
Maybe with something like Go To Meeting, you could. With Web Cam access it could be in real time.

[notchboy]

[notchboy]

Play List:

https://www.youtube.com/playlist?list=PLpQbcw5hpVpp2aZIAMUy-VyT-sh58FCX1
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[otiswesty]

I put a BN4 in my 1978 Westy back in 1999. I got a reconditioned complete pump from a guy named Ark Mirvis in New Jersey. It was great, the only thing that was missing was the piece of metal recirculating air ducting that comes off and down the drivers rear corner from the interior. I did find a bus in a yard in Salem that was Canadian vintage with a heater. I had to hack the piece out of the bus as it was spot welded in from the factory. Sanded it down and repainted with some Autobahn sage green touch up spray paint. I just pop rivited it into my bus in the stock location. The grille hides the rivets when mounted in front. It is in the back of the lowest storage cubby behind the closet.

To be honest, I haven't run it in years.
I'll see if I can get some pictures up.
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1978 Sage Green P22 Westfalia
1989 T3 Syncro Single cab

Just a regular guy

[notchboy]

So its in that same bus you put that cool ass jump seat in?
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[Alex6373]

Watching your videos were fantastic as they for me take the fear out of what use to be a very scary unit "the VW GasHeater".
i got mine to for the first time in five years to fire up and run , some blue then white smoke then clean exhaust ..... It cycled on and of and then shut down , now I feel the fear is gone and would gladly use it . Thanks

[notchboy]

[notchboy]

I did another vid of how the points work inside the fan. Better vid of how it works. This - off a unit that did not pulse the pump or plug. It will be cleaned and put back into service.


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I also want to point out an achilies tendon of the BN4 and any Eberspacher for that matter. Its important to pick out a heater that you can remove the micro switch from the can - if you intend to do a full restoration.

The combustion can is mostly made of stainless steel - mostly. The spark plug/gas inlet and the nipple for the micro switch are steel pressed onto the stainless can. The microswitch nut tends to rust onto its threads making removal tricky and may cause damage to the can as seen below. That can had water in it and around it fusing the nipple to the nut Lots of fun on a Saturday night but no bueno if you want to restore and use the can. If the eberspacher you want to fix up has water damage - or even one you are potentially buying - beware - it may be a pile of spare parts. Water getting inside makes the rod with the quartz element in it rusty and had to pull out of the can. So lots of oil and or patience will be needed.

Now your can is broke - pictured on the right is a nipple I pulled right off the can while try to remove the micro switch. This is after 24hrs of penetrating oil.

This one had a free nut, but the micro rod was rusty, crust and had to be negotiated out with lots of lube and muscle.

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