Here's something that still confounds me about A-bodies and I've been driving them off and on for all my adult life. How do you get them entirely full of gas? Every fall I fill up the tank on my '69 4-4-2 convertible as full as I can get it so as to ward off condensation over winter storage. And every fall, it spits back at me and overflows through the rear license plate-mounted filler, defeating the auto shutoff on the pump. I've tried running the pump so slowly that I'm only getting a dollar's worth per minute (still overflows, just more slowly) and I've tried filling from a jerry can (awkward angle and multiple funnels required resulted in spilling more than I got in the tank). This tank/filler design was not a triumph of engineering, so I'm at a loss to explain why they used it for so many years.

I need to come up with a solution -- 94 octane ethanol-free runs about six bucks a gallon around these parts, so I'd like to be pouring less of it on the pavement. Ideas?

 

I think this has more to do with California gas pumps than filler neck design.

 

The OP is in Canada.

To Mr. ragtop, you are WAY overthinking this. These fuel tanks were never designed to be filled to 100% capacity. There will ALWAYS be some airspace above the fuel in the tank.

Here's a gas tank for a '69 442. Look where the filler neck joins the tank. It's on the SIDE, not on the top the way the sending unit and outlet pipes are. Just looking at this photo, you can see that when there's enough gas to begin coming back out the filler pipe, there will still be perhaps an inch or two of air space above the liquid.






Just fill the tank as much as you can, put the car away, and don't worry about it. There is a little air space, and you will get some condensation of moisture into the gas. It can't be avoided. But the moisture-carrying capacity of cold air is very small, so the amount of water that will actually condense during the winter is negligible.

 

I saw the CA at a quick glance...

 

You're right, he lists both. I was trying to figure out where gas is $6 a gallon in this age of under $2/gallon regular, and I guess both Canada AND California could fit the bill.

 

I put 19 gallons by hand into my 72 last weekend. It was damn near empty, and now it is up the pipe full.

 

Maybe not, but it does eliminate a visible gas door in the side of the rear quarter panel like ALL new cars have, AND having the tank inlet positioned in the middle hidden behind the plate allows you to pull into a pump that is on either side and not have to stretch the hose across the paint like I see so many do at Costco. The reason it was used for so many years is probably because stylists were able to rule that roost until regulations prohibited this rear-entry fill location much later when rear-crash standards were elevated following the Pinto explosion fiascos.

Back in the '70s during the oil crisis(s), Dad installed a cone-shaped spring thingy that "threaded" into the filler neck to prevent thieves from sticking a hose in there to siphon gas. In theory, it was a great idea since its way more convenient than farting around with a locking gas cap (which was another popular anti-theft device back then). However, in practice it further restricts the flow of fuel when filling, I can't even get the nozzle to the first "click" to hold the valve open until its full. So I feel your pain for sure. There is no way to get that springy thingy out, I'd have to replace the tank to get rid of it.

 

I was trying to figure out where in CA he's was finding 94 octane non ethanol fuel.

 

There's a station near me and the pavement slopes downward right past the pump at the end of the row of pumps. If I pull in with the front wheels on the downward slope and run the pump until it automatically shuts off, the gas gauge reads way past FULL. Seems as if I can get an extra gallon or so in with the car in that orientation.

 

Yeah we get take it dry here in Canada, in Ontario the gas is $1.04 atm for a liter, so that's about $4.16 for a gallon, keep in mind that's regular gas, 87 Octane. you can get 94 Octane at Petro Canada but the premium gas will cost you probably 1.40 a liter costing $5.60 a gallon.

 

I had the same problem with my '72 Supreme. I've learned to keep my ears open and listen to the gas as it's going in. Once it's close to full, you'll hear the "rush" of the gas nearing the top. Once you hear that, stop pumping.

 

You're over thinking it. I've been putting in ethanol laced 93 octane and adding Stabil in the winter for 10 years without any problems.

 

My problem isn't what to use -- as stated, we have access to 94 non-ethanol here (Canada, that is, sorry I wasn't clearer), so I'm happy about that -- rather, it's how to get it into the rear-fill tank without spilling it all aver the pavement. I would happily live with the surface of my quarter panel being marred by cutlines for a filler door if it meant I could get the damn tank full.

Anyway, what I'm reading here is: "Do your best and don't worry about it," which is probably excellent advice.

Thanks, guys.

 

what I meant is there’s no reason to get it as full as you’re trying to get it. What I’m saying is I never fill it all the way and I use ethanol gas (with stabil over the winter) and I’ve never had a problem.

 

Got it. Thanks!

 

From your post 69442ragtop I can't determine if you are more disappointed the tank is not purged of air after your fill, or the overflow event, For me, it is the overflow event that drives me nuts. When I fill my Tundra, the automatic overflow mechanism works perfectly, do the same fill on my '57 Tbird or '70 W30 using the very same fuel pump, and I better be prepared for a gush of gasoline coming back at me if I don't stand there and listen for the gasoline backing up in the neck. I always thought this was due to the unvented fuel systems with the two cars, but maybe not. Anyway, it's annoying and I wish the automatic cutoff worked, but it does not in my particular situation. Glad to know I’m not alone with regards to this phenomenon.

 

I would say that I am equally annoyed in either case.

 

Much as this Toyota engineer appreciates the endorsement of our products, the giant Tundra pickup has a lot more potential energy to play with over the Bird or the 442 since the fill mouth is much higher, relative to the tank so it is not fair contest.

 

Koda, just as I suspected....a phenomenon is involved

 

Well, you guys are all to young to know this, except for maybe jaunty. The nozzles that go into the neck now, are like 1/2 the size of the nozzles on the pumps back in the 60's and 70's. There was less air space around the nozzle for gas to shoot out, and they seemed to shut off quicker. I think the pumps pump faster now, too. Back then I was working pumping gas after HS, and they didn't spit back like they do now.

 

I’m guessing the fuel backing up and spraying out is simply the design of modern fuel nozzles. I have seen this same issue with every car with the fuel fill neck low in the tank, I can’t imagine every one of those cars are defective with the same issue. And I don’t recall have that problem years ago with any old iron. The only thing that has changed is the gas pumps.

Unfortunately, we old iron owners are a tiny majority.
I don’t think I have ever been able to put more than 17-18 gallons in my car during any normal fill up. To be honest, I wonder if the rated 20 gallon capacity includes the air space, or if it’s MAXIMUM total capacity is 20 gallons. Either way, your never going to be able to completely fill the tank.

When I did the EFI conversion a couple years ago, I used a factory replacement style tank with internal fuel pump. I wanted to ensure the fuel gauge worked correctly. I disabled the fuel pump and verified the fuel gauge reads empty. I then used a small electric pump to transfer fuel from 5 gallon gas cans into the car fuel tank, while watching the fuel gauge slowly rise. I don’t recall how many gallons it took, but the electric transfer pump was slow enough that fuel would trickle out of the fuel tank vent. I’m sure the car being slightly elevated in the back was a major contributing cause, and not a concern in everyday life.

To make a long story short, fill the tank (without worrying about how much fuel it really takes) add some fuel stabilizer if it makes you sleep better, winterize the car, and relax. Unless your storing the car for an extended period of time, I seriously doubt any condensation accumulates.

 

As mentioned, keeping the front of the car lower than the rear helps, but, also as mentioned, those CA fume recovery pumps complicate the matter.

 

I filled up at Costco this past week and apparently they just got all new equipment. These pumps have a new vapor recovery system, with a round "gasket" or flange that fits over the end of the vehicle's filler neck opening and I had to maintain moderate pressure against it or the pump would shut off. They're not like the old ones that just had a rubber gasket to contain vapors - these have some sort of mechanism that has to be compressed for the pump to turn on. No more stick the nozzle in, lock it open for full flow, and let it fill the tank. I had to squat down and maintain nozzle pressure against the filler neck.