Dent gas cap question

[Stoner Dan]

Hey, does anyone know anything about when dual-tank Dents went from using a flush-mount gas cap door to a bare cap exposed in the recessed filler neck area?

I remember my dad's '73 F100 single-tank had the neat door, but my '73 F250 dual-tank and '74 F350's caps are exposed.

Any light to be shed on this?

 

[Mil1ion]

In 1977 the fuel doors showed up

 

[Stoner Dan]

Ah, that makes sense.

And I misspoke: my dad's truck had the flush-mount cap, not door.

Which leads me to the next question: are the filler neck diameters different among the '73-'75 years? If so, did it have something to do with the advent of unleaded fuel and their gas pumps? I've got a pair of neat, slightly beveled, locking caps that just won't fit on my truck. It's like the filler necks are too small in diameter for the cap to fit, but they're the perfect O/D to fit the recessed area around the neck.

 

[Alvin in AZ]

Which leads me to the next question: are the filler neck diameters different
among the '73-'75 years? If so, did it have something to do with the advent
of unleaded fuel and their gas pumps? I've got a pair of neat, slightly
beveled, locking caps that just won't fit on my truck. It's like the filler necks
are too small in diameter for the cap to fit, but they're the perfect O/D to fit
the recessed area around the neck.

There's a parts-fitting mess up concerning gas caps that went on during
that time. Me and Bill went over it before, way back on FTE, and nothing
was really settled because it's such a mess. The dealer couldn't get me
the right cap because the books are messed up too.

Of course their first response was "it didn't come that way the (stupid) PO
swapped out the tanks :/" "Ford Motor Company is the only (stupid) PO "
"oh well in that case, we can't help you then (you damned liar)"

Posted June of 2008 and these pictures hadn't had a use until now...
http://www.panix.com/~alvinj/file12/tank-aux.jpg
http://www.panix.com/~alvinj/file12/tank-aux1.jpg
http://www.panix.com/~alvinj/file12/tank-aux2.jpg
http://www.panix.com/~alvinj/file12/tank-aux3.jpg
http://www.panix.com/~alvinj/file12/tank-rear.jpg

The six 8-32 machine screws, is of course, my modification. LOL And I
decided to use two caps that looked alike. The original rear was stolen by
a gasoline thief.

And when the rubber washer goes bad just get a new one at the hardware
store instead of buying a whole new cap. Mentioned that to almost a dozen
guys over the years and not a single one thought it was a good idea. LOL
"too much trouble" followed but a reason why it was for them.

When Baby Bush's and Obammy's spending finally trickles down through the
system, I bet it won't be too much trouble then. LOL

Alvin in AZ

 

[Stoner Dan]

That at least clears some questions up for me! The fact that the Ford parts counter had bad intel actually makes alot of sense and I'll keep my eyes peeled for a pair of gennie caps for my '74 SCS.

But why are the filler necks different diameters between years?

 

[Alvin in AZ]

But why are the filler necks different diameters between years?

Just because.
"why?"
Because it's a Ford.
"why if it's a Ford?"
"Ford never learned how to make the same part twice " -Chevy buddies
"why?"
Don't know, maybe some of it was job security for middle management?

But...
Bill sez Ford et.al. made way more money on parts than on new car sales.
So redesigning parts was a way to make money?

And...
Stant doesn't have it figured out either, if I remember right.
Seems like I had to buy "the wrong one" to get it to fit mine right.

"stupid PO swapping parts around and all "

Alvin in AZ

 

[Mil1ion]

Then Bill sez..ask Dennis to post all the gas cap applications so people will know for sure we're not Fuelling around .

 

[Stoner Dan]

Well, I guess that makes sense--I had heard once that it had something to do with the new unleaded gas pumps of that era having a different size nozzle OD so that regular gas pump nozzles wouldn't fit in "unleaded only" vehicles with matching "unleaded only" pump filler necks. It made sense when I heard it, but does that make any sense? I was a little kid in those days, so I don't have any first-hand knowledge of it.

But it drives me crazy when I find original gas caps that I buy off ebay and then can't use--I've got a few of 'em now!

 

[Mil1ion]

What you said about UNleaded nozzles is absolute FACT

There are also vented and non-vented caps

1.5 million different fuel tanks and fill tubes.

Remember these parts are made by a seperate company that makes parts for all auto companies and they change design constantly as well.

 

[Alvin in AZ]

I had heard once that it had something to do with the new unleaded
gas pumps of that era having a different size nozzle OD so that regular
gas pump nozzles wouldn't fit in "unleaded only" vehicles with matching
"unleaded only" pump filler necks. It made sense when I heard it, but
does that make any sense?

Wow Dan, between what you said and what Dennis said about 'em being
contracted out, sounds like the puzzle is solved?

My F150 has leaded-gas-filler-pipes and caps, no nozzle-size-restricter
inside the filler pipe at all, it's wide-open. So somewhere along the line
the F150's got confused with the F100 half-ton stuff? Now I'm thinking
I've got what Ford would call '74 F100 stuff or '75 F250 stuff?

Alvin in AZ

 

[Stoner Dan]

Yeah, I think I'm more confused now than I was before I asked! And to add to the confusion, I just saw a '73 F350 with dual fuel doors--which goes against the doors showing up in '77!

Also, my last twin-tank '73 F250 had a recessed rear filler neck area and a non-recessed forward filler neck area...while my "new" '74 has recessed areas on both. I haven't tried my nice locking caps on this one yet, but I'm hoping they fit--that would be neat, since I couldn't use them on the '73...

 

[Alvin in AZ]

Stoner Dan wrote:
>And to add to the confusion, I just saw a '73 F350 with dual fuel
>doors--which goes against the doors showing up in '77!

If that's the case, then something has been swapped in for sure.
Like the whole bed or they just body-worked-in some doors.

>Also, my last twin-tank '73 F250 had a recessed rear filler neck
>area and a non-recessed forward filler neck area...

Sounds stock to me.
Sounds like my '75 and my father-in-law's '74 Camper Special that
he'd special ordered.

>...while my "new" '74 has recessed areas on both.

Something funny going on there, but not sure what it is. Check it
out underneath and see if it hasn't had some body-work done.

Alvin in AZ

 

[BKW]

That at least clears some questions up for me!

The fact that the Ford parts counter had bad intel actually makes alot of sense and I'll keep my eyes peeled for a pair of gennie caps for my '74 SCS.

But why are the filler necks different diameters between years?

Is the Ford parts counter at fault, or are you unclear on the concept?

1973/79 F100/350 Stylesides: There are different filler caps and fuel filler necks as it all depends on if the truck has the Evaporative Emission System or not.

The filler caps and filler necks used on 1973/76 Stylesides are different (because the caps are exposed) than on 1977/79 Stylesides, due to the fact these caps are located behind doors.

If your truck was sold new in CA, chances are it has Evap Emission. If the DSO code on the Warranty Plate is 71 (SoCal) or 72 (NorCal), it's an original CA vehicle.

Evap Emission uses different fuel cap(s) and filler neck(s) for use with UN-leaded fuel only.

With Evap Emission, there's a fuel vapor valve mounted into the top of the tank(s) and a charcoal cannister under the hood, mounted on the right (passenger) side frame rail adjacent to the alternator.

Fuel lines route from the vapor valve(s) to the charcoal cannister, a corrogated paper hose then routes from the valve on the cannister to a elbow on the air cleaner that is connected to a foam filter.