The "Fuel Tank" Thread

Michael Mayben

IHPA Tech Moderator - Retired & No Longer Online
For general questions/discussion of fuel tank options for IH schnizz, let's park 'em here for now!
 
In this thread, Matt posed a question regarding fuel tank alternatives:

http://forums.IHPartsAmerica.com/IH-parts-america-product-questions/1110-33-gallon-gas-tank.html

So let's brainstorm on this...keep in mind Matt's rig is a Scout 800 which is considerably different in the rear frame/body configuration as compared to a Scout II.

I'm posting this information because I recently installed a heavily modded 30+ gallon tank inna Scout II and happen to have some pics so that folks can see what a "typical" install might entail. Unfortunately I did not gather any dimensional detail since this was a project that had lingered for more than a year and we simply wanted to get the rig finished and gone back to where it lives!

And the original source of the extended capacity tank shown in these pics is not known. At first, I thought it might be from the company eric reminded me of...northwest metal products. But due to the crude construction of this tank (but very robust!) it simply is not up to the quality of the products they produce.

About two years ago, the owner of this tank had the bottom replaced with diamond plate by a local welding shop in the portland area. That resulted in many porous welds and leaks when pressure tested. Consequently I spent several hours brazing over the porosity and pressure testing many times to insure we handled all the leakage before installation.

This first pic is a reference shot for Matt of the oem 19 gallon tank. This rig is a 1974 sii and has a completely intact evaporative emissions system which is functional. The oem tank is designed to "nest" into the space under the rear floor of an sii, between the frame rails. The top is contoured to fit adjacent to the rear floor and cross supports. The fuel feed to the fuel pump is from the sending unit mounted into the top surface of the tank, that follows standard practices in the automotive industry and is a major safety consideration.
 

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This shot shows the nest in the rear section of a typical sii where the oem fuel tank mounts. The floor support creates an issue where the top of the tank has to be contoured to provide clearance. And the frame intermediate crossmember dictates where the tank must sit in relation to the rearmost crossmember.

The filler neck nipple and all the "vent" (eecs system) nipples are located above the frame rail and many of ya know how difficult it is to deal with those connections when the connecting soft hose is old and rotten!
 

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This is a general shot of the modded aftermarket 30+ gallon tank with the "skid plate" bottom added. Ya can easily see the crappy weld job, looks like the shit welds I do with the mig!

Since this tank was fabbed from sheet goods, the top had to be contoured during fabrication to follow the oem tank contour. Also, this tank does have the "sub-tank"-type baffle inside which is part of the eecs design. That is located in the "step-up" portion of the tank.

On each side of the tank ya can see the two triangular tabs welded to the side walls. These tabs are "stops" that contact the frame rails on each side. When the mounting straps are pulled up snug, those stops prevent any movement of the tank in it's mounting arrangement.

This tank has also had a npt bung welded into the bottom on one side to serve as a drain. That point was a big leak that I had to repair!

For pressure testing, the tank was blown up to 15psi and douched with a liquid soap solution. Once we thought we'd repaired all the leaks, it was pressurized one last time and then allowed to sit for several hours watching for "leakdown". After the tank was installed it was finished off with flat black rattlecan and plumbed, then we added five gallons of alkeegazz. If any leakage had been noted the flat black paint would really "bloom" and show any minute leak point, none has been found to this point.

The top of the tank had been previously modded by the welder for installing a typical aftermarket fuel gauge sender (five hole pattern). The light line sender available for the IH option 33 gallon tank and available through IHPA worked perfectly. I did "adjust" the float rod slightly to take into account the amount of volume that had been removed from the tank when the bottom was replaced. And yes...that replacement sender is the correct "10ohm>78ohm" sender used on all IH light duty vehicle fuel gauge systems that incorporate the 5vdc constant voltage regulator instrument system. So that sender will work with the oem Scout 80, and the Scout 800 fuel gauges also. I added an insulated disconnect to the sender gauge feed to allow easy access if the tank ever needed to come back down. A separate ground wire was also installed under one of the sender mounting screws and run to a ground point on the frame.
 

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Thanks for the insight into this fuel tank deal. I think my 2 most promising options, when the time comes, are probably measuring my rig to find what size tank will fit with the least amount of modification to fit that criteria, or to go with a fuel cell. In the past not only in our scouts, I've seen guys running fuel cells in their rig but more often than not, they look like a damn hack job. I'm all for utility, but I still like things to look well sorted and put together! Again, thanks for the information michael, keep it coming!!! :icon_smile:
 
This shot shows how not to arrange a fuel pump outlet from any motor vehicle fuel tank!!!!

This is a gravity feed that can allow fuel flow unimpeded in the event of a fuel line/plumbing failure. It'll simply allow fuel escape until the tank is empty.

The welder added a "guard" to the outlet, and the outlet is also well protected by the body from a road/trail debris hit, but this is not an accepted practice!!!! The only "offroad" service this rig sees is the rock parking lot at our shophouse!

The owner elected to retain this design, that was his choice.

So...I hope this sheds some light on a typical aftermarket fuel tank workaround. It does not directly address Matt's concerns but hopefully points out some considerations to look for when swappin' tanks around.

And keep in mind...a Scout 80 and Scout 800 platform is a completely different animal as compared to a Scout II!
 

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For the Scout 800 Matt, I could see a nicely done fuel cell recessed into the rear floor as long as the exhaust system doesn't pose any interference. And it could incorporate a three-way mechanical selector valve so that the oem "saddle" tanks can be used also, along with switching for the fuel tank senders.

I agree with ya about the "hack job" using fuel cells or aftermarket marine fuel tanks!

Let's keep brainstorming here about nice fuel system upgrades!
 
That is a great idea, I had not entertained that one yet, retaining the 2 stock tanks and installing a 3rd. Since the stock ones are what, 8gal.? Having a 33gal.± back there would probably be a difficult swap. But, retaining the stock ones, and using a 3rd tank, would be a good solution to the small stock capacity. To me, the exhaust is something that is so easy to change, it could be routed around something that is not as so easily changable, like a fuel tank/cell. I will have to try to search out a 3-way mechanical selector.... :smilewinkgrin:
 
The three-way valves are available from many parts sources, just a plain old weatherhead piece, I pay about $30 for 'em local. Absolutely identical to the 2nd gen brass two way valves that later Scout 80 used if equipped with duals. Here's a shot of my three way right after I did the mockup. The third port is plugged and is in the center of the "tee", ya can just barely see it.

I have a selector switch on the dash for each fuel gauge sender so the oem level gauge can read each tank separately.

The oem tanks were "rated" at 11 gallons if ya spill about two gallons on the ground when filling with them scruuball fillers! But we didn't givea shit when reglar gazz wuz only 19 centavos a gallon and we washed our shop clothes (and hands) in it! And spillin' petro on fire ants in tejas iz tha only way ta kill 'em!

With my highly modded oem tanks (filler necks are modernized), I can squeeze in about 9.75 gallons in each but if the temp comes up, one of 'em will puke through the vent which now runs to the ground and away from the exhaust pipe!!!

The original option dual tank kit for the s80 had no provision for switching, just a 1/4" "equalizer" tube connecting the two tanks, how stoopid can we be???? That way the fuel level gauge would read only after tha dam thang set for about 30 minutes while the fuel levels "equalized"!!! That was a typical "agricultural" deal since the Scout 80 was just an evolved manure spreader witha pump motor!
 

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Mike,

I've got some random pictures of fuel tanks laying around. Do you want me to shoot some pictures and post them up, just for reference. Off the top of my head I have Scout 80 saddle tanks, c-series under passenger's side tank, with fill neck and d-series under passenger's side tank with fill neck.
 
Carl,

although im not Mike, it probably would not be a bad idea just for reference sake. I'd say go ahead and post up so we can have somewhat of a god fuel tank database complete with photos. A other idea (running up the flagpole) would be to have some measurements on the tanks. This May help folks out in the future for custom fitment purposes? Just an idea... :sosp:
 
Any posts here of appropriate fuel tank alternatives for IH-related products would be welcomed! Most especially with basic dimensions and location of filler neck port, pickup/sender location, and any other penetrations.
 
Any IH related fuel system type questions okay here? The pyramid valve on my 73 1210 camper special just quit working on me and I was wondering if they can be taken apart and repaired. I found one at Travelall parts dot com but they want $395 for it. Yikes!

P.s. When ya makin yer way back here to see yer long lost cuzzins @ hill country binders? I really enjoyed yer last visit.

P.p.s. Fuel was $1.49 this weekend so I poured some on the fire ant hills by my drive way :)
 
Sorry I missed this trukker! Good ta hear from ya!

Yes, by all means the fullsize fuel tank selector valves are available inna "reconditioned" mode from IHPA! But ya won't find 'em in the online store, ya need ta ring the offishul landline to order!

Talk to Jeff about this and I can dropship ya one or ten! But we'll need yore core valve back so it can be rebuilt too!

Ain't makin' tha trip south this year, I'm still payin' the debt accumulated during last years trip! But hopefully sumtime in '09 we'll be back down home!

Litein' off that ant pile is even more fun...I luv ta hear them bastards squeal when incinerated! If ya use this e10 alkeegazz shit, it just makes 'em drunk if ya don't lite it off!

Yawl stay in touch!
 
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I have a 1973 Scout that I have a lot of trouble filling with gas at service stations. Some stations are for some reason easier than others but still a big pain. I have taken to filling a gas can and then fill my tank. Any thoughts at to what the problem might be? I live in CA, but don't need any emission stuff any longer for this year, so I can take anything off I want. Thanks.
 
Yeah man, you can pull off all that emissions garbage as far as getting the thing smogged. I dont think any of that stuff would make filling your tank difficult unless there was some weird vacuum but I think thats doubtful. What May be going on is larger and smaller diameter fuel nozzles at the different stations. Notice any difference with the halde pulled all the way back versus maybe 1/2 way? Any obstruction in your filler?
 
I have a Scout II 19 gal tank. I have pulled the tank cleaned and replaced all hoses and sender. I can only run the pump wide open when the tank is empty. Once its about 1/2 full the return air is pushing more that just air. I've pull the nossle back and you can see gas shooting out of the air return. Not much, but enough to mess up new style gas nossles. If there was a little plate covering the hole so the gas would not hit the nossle that might help. Maybe a screen or something. I just pull the nossle back about 1-2" and finish filling the tank.
 

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Hi all,

I'm in the planning stages of replacing my bed sill and center crossmember. Since I need to drop the tank, and because it has a large dent in it, I'm considering convertion to a 19 gal. Poly. Is there any obvious method to determine if I need a emissions or non-emissions tank? The only emissions related thing I can find is an evapoation canister under the hood. Pretty sure I'm pre-smog. Likely, I'll also replace the sending unit while I'm there.

I also notice my garage always smells of raw gasoline, so I'm assuming the vent lines etc. Are all trash.

Thanks for any tips.

-brett

1972 Scout II, 304 4 speed.
 
Brett...if you have the charcoal canister under the hood, then ya should have the so-called "condenser" up inside the driver-side rear fender that is also part of the evaporative emissions system. Those systems were used on many/all vehicles prior to the evolution of what we refer to around here as the "emissions motors", etc. You May be "pre-smog" as pertaining to your local/state regulations, but ya still have an eec system to deal with.

And...your tank will look very similar to the one I posted regarding an oem 19 gallon tank from that '73 sii that we converted to the 30+ gallon tank. All this guapo is covered in this current thread.

Look up behind the driver side rear wheel at the side of your fuel tank.. Determine how many hoses/fittings you can see and compare with the pics I posted.

Also, many sii came with a molded plastic filler neck that cracked/distorted after a few years of service. That will allow fuel to escape, as will a rotten connector coupling.

I'd pull the tank and all the associated plumbing out before ta start dealing with the floors/sills/rockers. Lay it all out and see whatcha got and then determine what to do about it. That pic Craig posted tells the whole story, very nice labeling job Craig!

I'm attaching again, a .pdf of the evaporative emissions system from an ihc service reference, first diagram izza sii. This illustrates the big picture.

I know what I'd do...but I won't discuss it here on the forum, email me privately for my "opinion"!

So is this gonna be the winter project once the snow is piled in front of the garage door and ya can't git the rides outside??? I've spent new years on the cape and in new hampshire on the same swing, so I know all about "winter projects" in yore kuntry! Ya got the antifreeze in tha matchless???
 

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