i have a 1986 ford f-150 longbed pickuptruck stock.
ford 1986 inline 6 4.9 liters 300 cubic inches
rear 2 wheel drive
carter yfa carburator



I currently have a 19 gallon midship tank.
i want to install a 16 gallon midship tank because i don't drive it nearly often enough and I dont want the gasoline to go bad in the 4-5 months I dont drive it.

is it possible to swap this::

with this::

i understand the 16 gallon was fitted to the extended cab shortbed trucks, and also the 4x4 trucks because the 19 gallon tank was too long and interfered with the transfer cases.

please help ( i am going to use fuel treatments to keep it stable, but 19 gallons is too huge of a tank for me and it would be empty half the time anyway.

 

You've asked a really tough question, which is why no one has responded. I've been looking through the catalog and there are so many variables. One is the engine - so what do you have? Once I know that I can post a few pages with which you may be able to answer your own question. I don't dare as I don't want to get it wrong.

 

It does not matter how much gallons a tank has for gas to go bad. I have lawn mowers gas tanks go bad after 2 months.

If there's nothing wrong with the tank now, why replace it and still have gas go bad no matter what size tank you have? 5 gallons is 5 gallons no matter the tank's size.

As for the swap, it will be bolt and go as many others have swapped out the smaller tank in favor of the larger one.

 

I think it would be smarter and definitely easier to just add "gas life extender" like Sta-Bil to your tank at each fill up. That's what I do. The gas will last for up to 12 months.

STA-BIL Brand Ethanol Treatment, Fuel Stabilizer, Small Engine Storage

 

4 to 5 months? Youd be lucky if the fuel is still good in 2 months.

Thing is with this Ethanol blend that is being used it goes bad a lot quicker than the old style of gasoline. We always rebuild carbs, and drain the fuel tank and drop it to inspect it if a car has been sitting for 2 months or more. Its not the size of the tank but the composition of the fuel.

We've had a '46 chevrolet truck that turned to varnish for sitting for half a year and that was just a 14 gallon tank. Also had a 85 F150 had fuel that went bad for sitting for two and a half months. You can tell if fuel is bad mainly by the smell.

Ironically my '56 which has fuel in it still from 1986, if you open the tank and take a smell, the fuel still smells good. Would I use it? Most likely not as I plan on dropping the 18 gallon tank to check it for rust.

 

updated with pictures... it seems that the 16 gallon does has slightly different support positions as the 19 gallons.. could be wrong

 

Right, i posted a comparison, and it seems the the 16 gallon has different distance for support bracings.

ford 1986 inline 6 4.9 liters 300 cubic inches
rear 2 wheel drive
carter yfa carburator

thanks muchly if you could post those pages!

 

I agree, and I never ever want to change a gas tank on a car unless I need to. Look at the pictures I posted above!IWWOWOW pinhole leaks everwhere on top the ethanol destroyed the top of my tank

The swap bolt and go? but it seems the support brackets are in very different spots?

 

I agree about the sta-bil ethanol treatment. I am curious does it work as good as they claim? has anyone here used it?

I plan on using it from now on, i will report back!

 

MMMMM the smell? I must have a weaker nose than you because I don't want to use it as a gasoline sensor!!! seriously! dont do it it can't be good for you..

Yes, I have also rebuilt carburators on lawnmowers maybe 40-50 times due to ethanol contaminations. I also got some of these lawnmower gasoline filters for my lawnmowers from ebay. works good

ford 1986 inline 6 4.9 liters 300 cubic inches
rear 2 wheel drive
carter yfa carburator




I've even rebuilt/cleaned the UNBELIEVABLE amount of gunk in my carter yfa carburator. After looking at my gas tank, and cleaning what appears to be tar caked with rust from within it, I should have though to clean out the fuel tank around the 4th or 5th time I rebuilt my carter yfa 1bbl.

This ethanol garbage really loves absorbing water out of the atmosphere. My thoughts on the smaller tank was that there would be less air space and therefore less chance of the ethanol absorbing all the humidity out of the hot and humid Louisiana air

 

Ethanol did not put pinholes anywhere in the top of your tank.

When E10/15 fuel absorbs enough moisture from the air, the alcohol & water mixture sinks to the bottom.
Phase separation occurs when about 4 oz. of water per gallon are present. (at STP)
Having less gasoline will only reduce the amount of moisture needed for "water bottom"

Latent humidity/condensation in the volume above the fuel level can cause problems but is unlikely to cause rust through unless you never fill your tank.

Of course the best solution is to keep the tank full of fresh fuel all the time, but that is unlikely to happen.

If you have a venting gas cap get rid of it.
Make sure all vapor recovery lines are intact and the valves or solenoids controlling the system are functional.
Air volume in the tank is never enough to introduce ~4oz. of water per gallon to your existing fuel -BUT- having it 'breathe' every time it cools down at night certainly is.

 

look at this

http://oi59.tinypic.com/xe0wlc.jpg

 

Yes, I saw your photographs.
Condensation on metal is a problem, but the ethanol is NOT the cause.

Use some cold galvanizing spray on the outside of your new tank and hose the road grime off more often.
That is what's causing it to rust.

Do you live near salt mines or the open water?

 

Sta-bil can make all the claims they want.
Ethanol is hygroscopic.
Additives will not change physics.

They do make a good product for keeping aromatics from evaporating during storage.

 

I live in Louisiana where there is water water everywhere! Also I haven't driven it in a loooong time more and it previously sat for a few years. A few years ago I used an aftermarket locking gas cap, that I am sure never fully sealed. If I had to guess, it was a combination of many factors.

Thanks for the tip, I will do exactly as you say and spray with cold galvanizing spray on the top of the new tank before I install. I am probably going with the 19 gallon because I can't risk the 16 gallon not fitting correctly and causing problems down the road.