GT Carrera-Style gas filler

Are you saying that the 4" tube is actually fitted thru the top of the tank and is extended into the tank 1" off the bottom or......... is it 1" extended into the tank from the top ? I would assume that air is displaced evenly no matter what....this is a unique problem.

If you don't have a quick resolution, I'll be installing the top, boot and side curtains on the speedster all of tomorrow...give me a call.

Alan

Bruce,
Does this happen even when you put the gas in slowly?
If it's happening when you're filling the tank, maybe you do need a breather.
If this happens when the cap is off, Can you put some holes or maybe a slot inside the 4" filler neck, below the top level of the tank.
That would vent the tank as you're filling it.

I don't think air is your problem.
Maybe you're trapping gas in the tube and it can't disperse to the tank. I think the level of fuel in the tank can't maintain the level of the gas in the filler tube (as fast) because the gas in the tube has to overcome the weight/pressure of the gas in the main part of the tank.

Greg.

Bruce ,

I think Greg is on to something , this is also my thoughts,

Greg: wrote "Maybe you're trapping gas in the tube..........."

Alan

Be careful......if it's trapping air as I think it is, you'll be potentially drilling into an air pocket (with diluted gasolene fumes).

Might be best to fill it as best you can with water, invert it or stand it on end so the drill space is down and has water behind it.....

It would be really cool if you could fit a dremel down the filler neck and cut it off, but you'd have the same problem with air space behind it (or a very wet dremel if you worked inverted).

Guys,

Thanks for your thoughts. Rest assured - if I do any drilling or dremmeling it will be with all the gas drained, the sensor/float removed and the tank completely filled with water.

I think once the gas rises above the bottom of the filler tube the tank around the tube becomes airtight and the air that is in there cannot compress, escape or be dispersed by fuel. At this point the only thing the gas can do is rise in the tube because the air on the tank has no where to go.

I was away last night and today so haven't done any work on it but have done alot of thinking. I may be able to remove the sensor/float, put the drill though the opening and drill a hole as high as possible in the tube this still will not let me fill the tank completely but will be better than what I have now.

Gordon,
I may be able to get the dremel down the tube and grind an opening, do those thin black dremel cutters create sparks?

Greg,
I like the breather idea. Do you know of anythign I can use to do this? I rummaged through the plumbing department today but could not find anything that would work.

Alan,
Yes the tube extends from the cap all the way doen into the tank and is 1 or 2 inches from the bottom and is welded where it meets the outside of the tank. BTW, I just checked and the level of the gas in the filler tube has not changed after 30+ hours. My guess is it will go down when I remove the sensor/float.

I agree , there is no place for the air in the tank to go. If you can safely drill a hole or two say 3/8 + as close to the top of the 4" pipe that you can get at. A single hole willl only allow for a very slow fill of the tank.

....An old trick I use when drilling an area where I don't want metal to get into is to put a good tab of axle bearing grease on the first inch of drill bit , you'll be surprised to see that most if not all of the metal shavings will adhere to the grease on the bit and not drop into the tank.

.... Option two, add some type of vent( That's a new one for me)
When filling a tank, there is a large volumn of air that needs to be displaced.It's kind of like having an attic/gable vent in your home. What the square inch volumn of the fan you may have, there is a need to have the same area at the oppposite end in the other gable to allow the air to move freely and unrestricted..Am I rambling here:~) ?


~Alan

Bruce,
look around at harbor tools.
What I had in mind was a cut off grinder, or a right angle drill.
The one shown here is less than 4" diamater and you can reach down the tube about 5".
The bad news is, anything you use to cut or grind will potentially cause sparks.
If you use one of these cutoff wheels, you will need to clean your tank thoroughly, as the cut off wheels are abrasive and turn to powdered grit as you use it. It will cause real grief if it gets in your motor via the fuel.
Whatever you end up doing, It would be a good Idea even after you flush the tank, to run Multiple filters. I use one at the tank outlet and one in the engine compartment filtering again before the fuel gets to the carbs.

www.harborfreight.com/cpi/ctaf/Category.taf?CategoryID=331&pricetype=

Greg

If you decide to install a breather, visit your local motorcycle accessory shop(s) that deal with motorcross bikes. You can get an ACERBIS-brand check valve ($5) which will allow air to enter the tank but will not allow gasoline to flow out.

KABOOOM!!! Well, no there was not an explosion because I decided not to drill into the gas tank as described above. After taking another look I loosened one of the sender screws and ...Whoosh!....air rushed out of the tank and the gas drained down into the rest of the tank. Okay, that confirmed what we originally thought - air was being trapped in the tank around the filler tube.

After taking another look around I decided the sending unit was the only safe place to drill so I removed it and took a look. There was enough room between the actual mechanics of the sender and the tank gasket to drill a small hole and install some sort of vent. After a few visits to hardware stores I decided on a 1/2-20 coarse thread NYLON hex head bolt. I drilled a 5/64" hole down the center of the nylon bolt and a 1/4" hole in the sending unit in a location where the head of the bolt would clear everything. Then I inserted a rubber washer and the bolt from the underside of the sender and fastened it on the topside with a rubber washer and nylon bolt - instant breather tube! A little sanding of the bolt threads with the dremel created a barb-like connection. Next was a length of hose "T'd"
into the other vent hose then mounted the "T" high on the firewall so the gas level would always be lower than the vent. We poured in a few more gallins of gas and the tank filled just fine. Done!

Thanks for your suggestions and thought. Now to see if the rain drain works....

Bruce,

Great job with the gas filler (and car in general) - you've inspired me to try and repeat your feat on my own car.

I've found a local supplier of the porsche cap you used (201-271-00) and already have a central fill on my tank, care of Chesil - albeit currently under the bonnet not through (photo below).

Hopefully this means I won't need to weld my tank further but can clamp a double walled extension tube over the existing inlet (will need to reduce internal diameter to 2" from what looks like 4").

Can you tell me how you finished the edges of the hole you cut in the bonnet and what you used as a gasket - looks like you got the finish good enough not to need to repaint the panel after?

Also how does the cap attach to the new filler cap?

Any other tips from what you learnt in the process of making this for your car?

I feel a winter of outlaw changes coming on :))

Cheers,

Simon

Simon,

It's great being able to fill-up and not have to pop the hood (bonnet)! I'm looking forward to following your mod. You can get a few more details about mine by reading through a thread called "Outlaws" found here: www.speedsterowners.com/forum/readmsg.asp?t=3184

I purchased one of the large 356 fuel caps for $30 from NLA Limited, disassembled it, used a hole saw the size of a VW fuel cap to cut a hole in the bottom of it, fit the VW cap up into the hole, spot welded the VW cap into the 356 cap and voila! I had a 356 cap that fits my VW fuel tank.

One of the toughest jobs of this mod is getting the angle of the filler neck right and hitting the hole in the hood correctly. First we cut a hole in the fuel tank for the fller neck. Once we had an idea of about where we wanted the hole in the hood, I used another hole saw the diameter of the 356 cap and drilled through the hood. Then the welder wedged the filler neck with the cap attached so it fit right into the hole in the hood when it closed. Once we were comfortable it was solid and where we wanted it, he tacked and finish welded the neck in place. All of this did take some time and perspiration.

The hood is actually hollow with the top and bottom sides being seperate pieces. Once we cut the hole I carefully cut and shaved pieces of hardwood to fill the openings, bonded them in place, finished the hole with 'glass filler, sanded and carefully fit the opening to a close tolerance around the cap using a Dremel tool and sand paper. Alot of painter's tape saved the finish around the opening. Since we were careful and knew where we wanted the hole I only have about 1/4" of primer around the opening. Be careful, the angle of the hood closing is a little misleading when you decide where to cut the hole. I cut the gasket out of some sheet rubber I purchased at a car show, plann on using the rest of it to glue inside the rear fenders to avoid getting star dings in the fiberglass.

I'm not sure how you will attach a 4" tube around your 2" tube without welding. We actually cut the 2" tube out of teh tank, cut the top off, welded it into the top of the 4" tube and welded the 4" tube into the tank.

I hope this is helpful. There are a couple of finished photos in my file that won't load here. Let me know if you have any questions and I'll provide more details. Remember: "Cut once, measure twice!"

By the way, I noticed the different color. Are you rebuilding your Speedster or is that a new one you're building?

Bruce,

Yes, that helps thanks. Any other photos you have from your modifications would be gratefully received though - especially the shape of the handle added to the 356 cap, and a view of the neck with the cap removed.

Is the ring visable around the hole on the outside of your hood the primer that you refer to?

The picture of my car is from before it was painted black - but it shows the tank oriented for the through hood filler (currently its fitted facing the other way, with the filler to the front).

The filler neck on my tank currently is a bayonet locking style from a (old) mini. Don't ask me why, its what Chesil welded the tank up for. Since I need to source an additional filler neck (as I don't want to weld a tank thats had fuel in it) I guess I may as well start with a new tank and cut the current neck off of that to reuse it. That way I can take my time and not have the car off the road - Was trying to make less work for myself but as you say it would get complicated clamping the 2" inlet to the existing tank neck without leaks and mechanically supporting the 4" tube without welding.

One of the captive threads for the sender is also dodgy on my current tank....he says justifying it to himself!

Bonnet straps arrived today also :)

Simon,
Attached below are a few more photos, I hope they are clear enough and helpful. The first one is the filler neck from the top (bonnet closed). The center is the VW neck, a plate was cut to surround it and seal to the inside of the 4" filler neck. In this way you can screw on the VW cap and make it look like the 356 cap is sealing the 4" tube. The depth has to allow the cap to screw on without hanging on the 4" tube.

The second photo is the drilled handle. I've seen some with four holes and five holes, not sure what is accurate but I like the look of five.

The third photo is the underside of the 356 cap with the VW cap welded into the inside of the larger 356 cap. Be careful with this and the drilled handle - very thin metal here. Not sure if MIG or TIG was used but one is better than the other for welding thin metals.

There is a fourth photo in my file, it shows the cap installed. I can't over emphasize the need for patience and care or you will end up with a too large hole in your hood, the neck at the wrong angle or the cap not flush wth the hood. Hope this helps.

Bruce,

They're excellent thanks.

My planning and research continues; Wondering about welding the porsche cap onto an aero filler cap (3" cap and 4.25" outer) - that way there is a readily available rubber spill catcher to sit under the bonnet and divert the rain/spilt fuel and i can choose between a custom ally tank, a new 5" steel tube with flat end to mount the flush filler in, or using the 4.25" to 2" funnel and running hose to my current inlet.... see the photo below for the parts available.

What is the diameter of the hole in your bonnet and of the Porsche cap? (Ordered my Porsche 356 cap today,

The cap is about 4-3/8" in diameter (sorry, not metric) and I have about a 1/16" gap all the way around between the cap and the bonnet. I'm not familiar with the aero cap but your description sounds like it might work.

It's finished. I completed installation today, poured in two gallons of gas, test drove it and am pleased with the way it looks. In the topside photo the cap actually fits better than it looks, there is a ring of grey primer around the cap so the opening appears larger than it actually is. That's the good news. The bad news is the welder installed the 4" tube about an inch or two off the bottom of the tank. I didn't think this would be a problem until I started adding the fifth gallon, then the gas started flowing out the little vent tube on the side of the filler neck. Here is what I think is happening, when the gas gets above a certain point air gets trapped in the front of the tank and because the tube extends down into the tank the air cannot escape. I would appreciate everyone's suggestions on how to resolve the problem.

I am thinking I need to add a vent to the front part of the tank so air can escape as gas is added. I am planning to drain the gas, fill the tank with water (to avoid problems with sparks), drill a hole where the old filler cap was welded shut and add a vent there. I don't know what kind of vent should be used, any ideas? Now that I have had gas in the tank welding or reweldng is no longer a option. Any ideas on other solutions?

Note: For some reason the two photos are not loading but you can see them under MDSPEEDSTER

Bruce can you take some pics of the under hood set-up of the filler.
This is a hot mod and I am thinking about doing it myself.

BTW your car looks great
MRDS

Dave,
Take a look at the photo in my file: P5140673(1).JPG It shows what everything looks like under the hood (a view not many see anymore). Ideally, I would have liked to have a rectangular 356-style tank fabricated but I didn't want to lose anymore space for roadtrips so I used the lower-profile VW tank.

Still weighing up the custom tank versus existing shape tank question.

The chesil tank sits quite far forward under the hood so I think that a thru-bonnet filler for this tank will have to be fed via a hose rather than welded to the top of the tank.

*** Does anyone know the "correct" distance from the centre/edge of the filler to the edge of the hood aperture? ***

A custom tank looks attractive in making room for a gas heater up front too (Obviously carefully segregated & shielded from the tank).

Some time ago, I saw a custom Speedster gas tank cover that was a replica of a Spyder tank ...Did that ever look great! It was done in an aluminum and covered over a standard VW gas tank

Here are pictures of the parts i've assembled so far, plus the design of the flange I plan to get made up at emachineshop.com - I'll also get handles for the filler cap laser cut.

Getting 5 made up costs me about the same as getting 1, so I may have a few available if anyone else takes this approach. Likely to be a few months out.

Ok.

I've just received back the handles that I had laser cut from 3mm steel by eMachineshop, and they're a great fit!

I had a batch made, so if anyone wants one they can have one for $15 (including posting to the US).

Just hope the filler neck adaptor to allow me to use a standard cap on the mounting flange of new fuel tank is as successful!

Simon

Simon,

The handle looks good, laser cutting was much easier than my method. And $15 is a great price. I believe there is a website that charges about $150 to install a similar handle when you send them your own cap. You're going to love filling up without lifting the hood/trunklid/bonnet.

Bruce,

The last component arrived yesterday - Well I said in July it was a few months out!!

I'm pleased to say it all fits together fantastically, and I just bought a 152mm holesaw, ready to make the hole in the outer skin of the bonnet, to put a collar of GRP in, prior to cutting right the way through!

Have a couple of CNC adaptors to sell - these aren't as cheap as the handles though as they are made from a lump of T6 aluminium, though I may make a couple of complete kits complete with finished caps.

Simon

very cool, I manufacture cnc aluminum ga caps for vw cabriolets, gti's and rabbits,I'm planning to do the sme for my speedsters

check it out they are the sport bike style
www.signsandgraphics.com/stevelangford/stevelangford.html

Simon,

Great looking products - both the adapter and the tank, Was the tank difficult or expensive to have made? A couple of the replica manufacturers mentioned an interest in carrera-style fillers, maybe you could go into the business. Outlaw 356's mightalso be interested.