Fuel fillers

Cobra Dude · #1 (**permalink**) 11-18-2007, 09:40 AM

I have the "typical" flip-style fuel filler on my car (see last photo here... http://narwani.net/neil/cars/cobra_photos.html), and I hate that I keep getting fuel splashed out when I fill up the car. Then I scurry to wipe it up before it runs into the cockpit, etc. I'm wondering how the fillers on "regular" modern cars work -- is there some way to use the mechanism from that on my filler cap, so I can just set the automatic stop on the pump handle and let it do it's thing? I know there's a sort of a flapper-door on them, and them some type of drain, but I'm sure there's more to the whole filler mechanism to keep it from spilling.

Anyone know if there's a solution to this?

Cheers,
-Neil.

vector1 · #2 (**permalink**) 11-18-2007, 11:54 AM

you need a smaller fuel filler inlet so the backwash enters the pump handle and shuts it off.

CHANMADD · #3 (**permalink**) 11-18-2007, 12:23 PM

Check this out,
http://www.finishlineaccessories.com...roducts_id=383

Cobra Dude · #4 (**permalink**) 11-18-2007, 02:27 PM

That's pretty much what I have, except it says roller latch which I don't see. Mine has the roller latch. But what about this specifically makes it prevent or reduce splashing?

Cobra Dude · #5 (**permalink**) 11-18-2007, 02:35 PM

Quote:

Originally Posted by vector1

you need a smaller fuel filler inlet so the backwash enters the pump handle and shuts it off.

Hmmm... is that how those things work? I've not found much about it thru google. Currently, I fill slowly and watch down the filler hose, and I do get some foaming well before it gets full, so I have to pause and let it settle, then continue. Of course the frequency and height of the foaming increases as it gets closer to full. I should be able to make an alum plate with a smaller hole as a test.... hmmm.... need to think about this carefully.

Cheers,
-Neil.

patrickt · #6 (**permalink**) 11-18-2007, 02:38 PM

CD -- Is this what your fuel cap looks like when open?

Cobra Dude · #7 (**permalink**) 11-18-2007, 04:32 PM

Nope -- this is mine...

Cobra Dude · #8 (**permalink**) 11-18-2007, 04:37 PM

So what is that thing in your filler cap? A separate cap that has to be removed for filling, or...???

jwd · #9 (**permalink**) 11-18-2007, 04:38 PM

How is your tank vented?

patrickt · #10 (**permalink**) 11-18-2007, 04:51 PM

Quote:

Originally Posted by Cobra Dude

So what is that thing in your filler cap? A separate cap that has to be removed for filling, or...???

Yes, that's exactly what it's for. It caps off the smaller tube running up to the filler cap and it also prevents leakage should you fail to keep the shiny side of the car up. I suppose you could fashion a separate tube to fit in yours and use a special epoxy (gas tank sealant type) to help seal it around (don't weld it

). Or you could just not fill your tank up past about 7/8's full.

Quote:

Originally Posted by jwd

How is your tank vented?

There are two vent tubes on the filler pipe below the flange visible in the pic. One goes in to the tank, one goes down to the bottom of the car, and they inter-connect through the top of the filler pipe. There is also a water drain line attached below the flange at the lowest point.

jwd · #11 (**permalink**) 11-18-2007, 05:13 PM

Quote:

Originally Posted by patrickt

There are two vent tubes on the filler pipe below the flange visible in the pic. One goes in to the tank, one goes down to the bottom of the car, and they inter-connect through the top of the filler pipe. There is also a water drain line attached below the flange at the lowest point.

That may be your problem. As you fill the tank, the displaced air has to be vented or you will get a bubble of air sealing the filler and gas will go everywhere. My vent is attached directly at the top of the tank itself and has a 3/8" hose that runs from there, up to a vent/rollover valve that is mounted approx. 12" above the top of the tank. I had the flip cap with the small cap inside like the first pic. I replaced it with the type in the second pic. because I thought it was kind of a cheesy set-up. I haven't had any problems filling with either cap.

patrickt · #12 (**permalink**) 11-18-2007, 05:20 PM

Quote:

Originally Posted by jwd

That may be your problem.

You mean CD's problem (mine fills up fine). It kind of looks like filling his tank is similar to filling up a separate portable gas can (like for lawn mowers or the like). You have to be careful with those that they don't over-flow, but I think the automatic "click-off" seems to work on them when I fill them, so maybe his venting could be the problem.

jwd · #13 (**permalink**) 11-18-2007, 05:28 PM

Sorry patrickt. I got confused on who was answering what. The bottom line is, if you don't vent an equal amount of air to the amount of gas being put in, you'll have problems.

patrickt · #14 (**permalink**) 11-18-2007, 05:30 PM

Quote:

Originally Posted by jwd

Sorry patrickt. I got confused on who was answering what. The bottom line is, if you don't vent an equal amount of air to the amount of gas being put in, you'll have problems.

I'll take responsibility for the confusion when I answered your first question about venting. I was reading with one eye while the other eye was watching the Redskins give away another one and kiss their playoff chances goodbye.

Roscoe · #15 (**permalink**) 11-19-2007, 07:33 AM

Do like they did in the old days. Works great. Been using it for years.

Cobra Dude · #16 (**permalink**) 11-19-2007, 09:22 AM

I think we've hit upon something here -- my tank is vented through the filler cap itself -- you'll see the two small holes on the inside disc on the cap. During driving it works well, but for filling, there is no separate vent.

My filler is made up of basically 3 pieces -- (1) a flat round plate (~4.5") with the filler tube (~2" dia) welded to it, (2) a base piece which has the mount holes and the threaded ring, and (3) the filler cap assembly (the whole piece with the ring (inner threads), hinge, latch, cap, etc.

I'm thinking that perhaps I can re-make that round plate with the filler tube, but I'd also add another small hole with a vent tube, then route that to the vent on the tank (which is currently sealed off). I don't need to vent my tank since I'm EFI'ed (return-style fuel flow). Here's what I'm thinking...

Now, I've added a third drain tube that drains to the floor below the vehicle, in case of overflow during filling, but I'm thinking that if I orient the new vent tube towards the lowest part of that base plate, then I won't need a drain. And yes, I would make this with new metal so I don't have to weld on anything that has previously touched fuel.

Thoughts?

Cheers,
-Neil.

patrickt · #17 (**permalink**) 11-19-2007, 11:31 AM

That's similar to the ERA design except the two venting tubes connect via the top of the fill tube, as opposed to the base plate. I can't see how that would make much of a difference though.

Cobra Dude · #18 (**permalink**) 11-19-2007, 02:47 PM

Actually, I've come up with a simpler way, that will save me from having to find an aluminum welder -- I can just remove and drill my baseplate, into which I'll attach a bulkhead pipe fitting. the bottom of the bulkhead fitting will have NPT female threads, onto which I'll connect a barb, hose, etc to the fuel tank.

I'll post my results.

Cheers,
-Neil.

Cobra Dude · #19 (**permalink**) 11-20-2007, 07:05 AM

Thinking more about this, it seems that the vent routed to the top of the fill tube (rather than the baseplate), would have the advantage of definitely routing any overflow (thru the vent line) during filling back into the tank. With the vent on the baseplate as I've drawn, it could run elsewhere and I'm sure the filler cap assembly is not hermetically sealed to the baseplate. Of course, placing the vent on the fill tube is not as easy as on the baseplate, if a bulkhead-type fitting is being used.

Cheers,
-Neil.

patrickt · #20 (**permalink**) 11-20-2007, 07:41 AM

Quote:

Originally Posted by Cobra Dude

Thinking more about this, it seems that the vent routed to the top of the fill tube (rather than the baseplate), would have the advantage of definitely routing any overflow (thru the vent line) during filling back into the tank.

No, it just pukes it to the ground. The tube going back to the tank has a higher pressure than the tube going out to the atmosphere. If it were me doing it, I wouldn't worry about venting it to the top of the fill tube; that would be more trouble than it would be worth. Venting from the tank to the base plate and from the base plate down to the ground should be sufficient coupled with the ol' tennis ball trick.