'74 Argosy 20' Motorhome restoration/rebuild

[bkahler]

My one concern about buying a new tank was the lack of a generator tap on the new replacement tanks. Last night I tried to remove the generator tap and found the screws were turning but not coming loose. Using an inspection mirror I and found that there are nuts on the inside of the tank! I was expecting some sort of welded on mounting boss, not nuts!

Apparently Airstream just bored a hole in the top of the tank and mounted the generator tap using screws and nuts. The sending unit opening is to small for me to get my hand inside to hold the nuts so I'm going to have to cut the heads off the screws. Airstream must have found someone with small hands to install the tap originally!


My initial external inspection of the main tank seemed to indicate it was in good condition. Last night using a flashlight I took a peek inside and found what appears to be a tank repair of some sort.

So, considering the tank has a prior repair and the generator tap is nothing more than screws and nuts I'm going just order a new tank. I'll have the repair shop (radiator shop) weld a mounting boss for the generator tap which would negate the need for nuts on the inside of the tank. I'll also have the new tank lined inside to help prevent future corrosion.

Brad

[Danec020]

I am sure having the extra fuel is quite nice but I would be careful about dropping it down further. If I am seeing things right it looks like it sits on the rear of the Argosy in that enclosure? My concern would be if you are coming off of an incline, say a steep curb or driveway, you will want that extra clearance so it doesn't bottom out. I would be afraid of denting it or putting a hole in it eventually if it sat too low.

-Dane

[bkahler]

Dane,

Even after dropping the tank several inches or more it won't be hanging down any more than is found on the later Classic models. Also it will be closer to the diff than the larger rigs with more overhang. The tank is only about 25" front to back and sits between the generator enclosure and the differential. I think that's a pretty protected area.

Here's an example of one of the later Classic coaches showing just how far the fuel tank hangs below the frame.


All things considered I think I'll be ok in dropping a few inches.

[Danec020]

I thought it mounted by the back bumper for some reason but I can see now that you are totally correct. Sorry about the bad advice . I am still looking for a 20ft Argosy for myself to tinker with so I didn't have a reference to compare to. I have just been stalking these threads trying to learn what others are doing.

Good luck with the tanks!
-Dane

[bkahler]

No problem! It's always good to have decisions like this be second guessed. I'd rather have a problem be caught early rather than later. Especially if money is involved!

Brad

[bkahler]

Ran into somewhat of a stumbling block on the gas tank sending unit. After many hours of googling I haven't managed to come up with a replacement sending unit. Most sending units being sold seem to be for 80s and later models and there seems to be about 13 billion different configurations available!



The original unit has two ports one for suction and one for return. Most replacement units have 3 or more. I'm ok with that as I could probably use a 3rd port as the generator tap. The bigger issue will be finding one that is the right depth and has the right flange diameter.

The only issue with mine is the variable resistor seems to be bad. It might be possible to retrofit an newer resistor to mine but I would prefer to save that as a last resort. Besides, any solution that I come with will likely be what Martin will have to use on his tank replacement so it would be nice find an off the shelf solution.

If anyone has any ideas I'm definitely open to suggestions.

[martin300662]

What about this one Brad?

https://www.millsupply.com/sending-u...75.php?p=47439

[bkahler]

That looks very promising. The three main points are depth which in our case needs to be about 11 to 11-1/2", flange diameter is 3.600" and it needs to be in the 0-90 ohm range.

There is some good info about GM fuel sending units at this site. The one you listed from Mill Supply is for 81-86 which falls in the range of years for the 0-90 ohm sending units.

[bkahler]

Got it!

Here's the correct tank and the correct sending unit. The sending unit has an extra port that is supposed to be plugged.

[jm2]

ISSPRO makes a pretty good product, and their sending units are built with a tubular style like this RA9512-ISS - ISSPRO Inc. ,

or the traditional style like this R8926 - ISSPRO Inc.

if I were having a 'custom' sized tank like Martin, the tubular style length can be specced to match the depth of the tank.

one of the previous owner's of our coach removed the mechanical fuel pump, and installed an external, electric fuel pump.

my other thought and question, if I were dropping or replacing my own custom (supposed to be 45 gallons) tank, is it worth installing an in the tank electric pump?

best,

[bkahler]

Originally Posted by jm2

ISSPRO makes a pretty good product, and their sending units are built with a tubular style like this RA9512-ISS - ISSPRO Inc. ,

or the traditional style like this R8926 - ISSPRO Inc.

if I were having a 'custom' sized tank like Martin, the tubular style length can be specced to match the depth of the tank.

The problem with the after market senders is the GM sending unit is a combined unit with the suction and return pipes as well as the sending unit. If I use one of the aftermarket senders then there is no way to get fuel out of the tank!

one of the previous owner's of our coach removed the mechanical fuel pump, and installed an external, electric fuel pump.

I don't know about Martin's but mine had an electric pump right beside the tank and just forward of the switching valve that selected front or rear tank. I plan on installing a replacement pump in the same location.

my other thought and question, if I were dropping or replacing my own custom (supposed to be 45 gallons) tank, is it worth installing an in the tank electric pump?

best,

My front tank is the OEM 30 gallon tank. I don't have any plans on upgrading that tank. I believe Martin has the same thoughts but I'm not certain about that.

I think the only reason to have a pump in the tank is if you're planning on installing EFI which I am not. I've already spent way to much on this rig and I don't think the cost of EFI could be justified considering I've got a new engine with new performance manifold and carburetor. EFI would be nice though wouldn't it!

Brad

[martin300662]

Originally Posted by bkahler

I don't know about Martin's but mine had an electric pump right beside the tank and just forward of the switching valve that selected front or rear tank. I plan on installing a replacement pump in the same location.

Brad

Hmmm.....fuel pump, that's another subject.

Currently I have the original mechanical pump (with the bypass/return) which certainly doesn't help getting Bella started if I haven't run the engine for a few days. Coupled with the tank leaks and a large capacity separator filter in-line equals lots of cranking when starting.

[PeterH-350LE]

Originally Posted by bkahler

...

I think the only reason to have a pump in the tank is if you're planning on installing EFI which I am not. I've already spent way to much on this rig and I don't think the cost of EFI could be justified considering I've got a new engine with new performance manifold and carburetor. EFI would be nice though wouldn't it!

Brad

But why in the tank for EFI. My EFI system has a low pressure pump just outside of the tank for easy accessibility. After dropping these tanks a few times, you get kinda tired of it, especially the 80 gal ones
The high pressure electric pump is located just on the engine side of a heavy duty collector tank.

[bkahler]

Martin, I would definitely install an electric fuel pump somewhere near the fuel tank. That will help push fuel up to the carburetor.

On the longer coaches Airstream installed fuel pumps close to the tank to help get fuel up to the carburetor and to also overcome vapor lock issues.

Not that expensive or difficult to do.

Brad

[PeterH-350LE]

Originally Posted by martin300662

Hmmm.....fuel pump, that's another subject.

Currently I have the original mechanical pump (with the bypass/return) which certainly doesn't help getting Bella started if I haven't run the engine for a few days. Coupled with the tank leaks and a large capacity separator filter in-line equals lots of cranking when starting.

I am 100% with Brad on the inexpensive addition of a rear electric fuel pump.
I added a dash switch on my 79 28', only to use the pump prior to starting and on long inclines.
Once, when climbing a 10k' pass, the engine started to sputter. One flip of the switch "zoomed" me up the pass.

[bkahler]

On the 310 that I had the rear electric fuel pump was connected to the ignition switch so it ran anytime the switch was turned on. I know it never starved for fuel on grades with a 14' trailer and we climbed a lot of grades with it!

[bkahler]

Well bummer. I took my two fuel tanks over to the radiator shop to have them dipped and after looking over the OEM main tank he said it's shot and nothing he could do for it

So that means I need to figure out what combination of tank and sender that I want to buy to replace it.

As for the custom made rear tank it's to big to fit in his tank for cleaning

He suggested pouring in a couple gallons of Muriatic acid, sealing the openings and rolling the tank around to get the acid to clean out the inside. He's apparently used this procedure before on some tanks with success. After that's done I would need to take it back to him so he can seal the inside with sealer.

I'm not exactly looking forward to dealing with a tank that has a couple of gallons of acid in it but it would probably be cheaper than having a custom tank made. However I still might look into that alternative just so I have a price comparison to work with.

Oh well, back to looking at tanks and senders

Brad

[Danec020]

That is a bummer! If he is suggesting Muriatic Acid I am assuming it was rusting on the inside? As for dealing with the acid I believe Baking Soda will neutralize it so all you would need is a bucket with a box or two of baking soda to pour the mixture into when done.

If you know the dimensions off the top of your head of the propane tank, I can help search the web or even some local shops around here for some possible replacements.

-Dane

[bkahler]

Dane, this tank is my rear gasoline fuel tank.

It is rusty on the inside, however the tank is made from some fairly thick sheet metal so if I can eliminate the rust I should be able to salvage the tank.

Barring that I'll possibly check into a custom made tank although I'm leery of the cost for one. But I really would like having the extra fuel on board for long trips.

I have found several marine fuel tanks that are somewhat close in size but I don't know if they will work or not as the filler neck is always in the wrong location.

Thanks!

Brad

[Danec020]

Doh! I was reading Elisa's thread about her propane tank and then switched to this one after and my brain didn't switch over. Sorry about that, I remember you've been hunting the right sending unit down and contemplating on what to do with the tank for a little while now. Ignore my scattered brain.

-Dane