Fuel Cap and Neck

[cabrioman]

Help

Can anyone provide guidance on what they used here.

Where I am now.

I found a source for a brand new filler neck that has the unleaded insert needed for SVA (from the number kindly supplied by Peter Morris, thanks Peter). Then it got complicated.

The knurled edge caps painted to match the car are apparently only available to fit the old style neck without the insert (according to the Ford dealer who have stock of the later neck).

Most of the locking caps I have seen on Ebay for the late Sierra are either small in diameter because they were designed to be behind the fuel flap on the Sierra or are grained plastic which can't be painted.

Has anyone managed to find a source for the early style cap, knurled at the edges and capable of being sprayed that fits the later unleaded neck. Or a Chrome locking cap that fits the diameter of the body cut out and fits the later style neck or used one of the new style aluminium filler necks which fits the cut out on the body and has the SVA restrictor for unleaded.

Any help appreciated because this very minor job is becomming a pain in the proverbial!!

Regards

John

[paul]

Re: Fuel Cap and Neck

John,
I got my Marlin through her SVA in April. During the build there were a couple of simple jobs that took a wholly disproportionate time. The filler cap was one.

As you say there are two versions of the filler on the Sierra the early ones had a lockable filler flush with the outside of the car the later ones had a cover with an internal release by the drivers seat. The plastic mouldings for the latter are slightly shorter and are not so bent.

The fuel tank in my car had the filler neck in the correct position for the early type. Only the later type is now available. I suspect you could search the scrap yards and find an early filler but as you say it will be of a leaded type.

In the end I decided to fork out for an aero type filler. These are expensive and you still have to make up an unleaded restrictor. They are also sealed so you need to make up an air vent of some sort. I botched one together out of parts from a Mondeo or something (they all look the same in the scrap yard). This is not very satisfactory and is on the list of things to improve during the winter months. The tank take off is too low down and if the tank is ftb (full to brim) fuel can be pushed out of the vent. You should also have tank take off on one side of the car and have vent piping higher than the filler and venting on the other side of the car to prevent fuel leaking when you corner. In modern cars the tank is vented into the engine with a myriad of pipes, valves and charcoal filters used to prevent any fumes escaping.

Paul

[cabrioman]

Re: Fuel Cap and Neck

Hi Paul

Thanks for the reply, yep this does take up a whole more time than it should.

Can you expand on your comments regards the venting. I have the marlin deluxe tank in the car which as the vent directly infront of the fuel neck inlet to the tank when viewed from the rear. I thought the Sierra had a vented cap and the small diameter apeture on the marlin tank just connected into the filler neck just below the body line. Why do you get fuel leaks when cornering if its connected like this?

Cheers

John

[paul]

Re: Fuel Cap and Neck

Hi John,
The principle problem with my fuel filler system is my own ignorance. I am glad you have given me the opportunity to air this in public.

As you mention the Sierra filler cap has a small hole and this allows air, and fumes to escape when the tank warms up. It also allows air in to replace the fuel as it is used. A vent is also provided to allow air to escape as the tank is filled. This is a tube of about 10 mm bore that vents near the top of the filler tube.

The Sierra method is by far the easiest and I planned to use that method. The problem I faced was that I could not get an early version of the filler. I also think that while expensive an aero cap does look classier.

The problem with the aero cap is that it is sealed, presumably to allow aeroplanes to fly upside-down. This leaves the constructor to make separate venting provision.

I spoke to several builders and a couple told me they had problems with splash back when filling because they had omitted the thick filler. This was fairly easy to implement using rubber fuel hose and an existing vent connection. I did have to turn up a connector for the filler end. I can see this working when I fuel the car as splashes of petrol shoot out of it when nearly full. To be honest she still does not fuel well mainly due to the sudden bend immediately under the nozzle.

The fuel breather I robbed from another Ford. This had a thin plastic tube, about 4 mm bore, and a valve that allows air in unimpeded but restricts the air out to avoid petrol fumes escaping. I am also told this device will stop fuel escaping in the unlikely event of it getting turned upside down. It should also have a carbon canister but unfortunately I did not rescue that from the vehicle, perhaps next time I am there I will. The theory is that the canister will absorb any fumes if the fuel expands enough to force its way past the restrictor. Since the airflow is generally in the fumes will be released from the filter and drawn back into the tank. The valve should be situated above the filler cap, not so easy with the position of the Marlin filler.

This I have connected up. The problem is that because the pipe bore is small the fuel will travel quickly down it. So when I go round left corners and the fuel tank is full enough that fuel sits in the filler neck some will force its way down the pipe. I have also found a few drips on the floor of the garage also when ftb.

I found a web site for Robin hoods that discusses this problem at some length. The solution suggested is to take the pipe from the offside to the nearside thence to the outside world. So when taking left corners the fuel may come someway down the pipe but not far enough to escape. On right-handers the fuel is forced away from vents tank connection.

I thoroughly recommend you do not search the web for additional information. It will only frighten you. One manufacturer caused the car to leak fuel through the vent onto a hot exhaust ? disastrous in hot climates.

With luck a photo attached.

Paul

[paul]

Re: Fuel Cap and Neck

I wish it would say the photo is too big before you send the append!

Disgruntled of Hants.

[amalgamated users from prior forum]

Re: Fuel Cap and Neck

Message originally posted by: Mike Woodley
Hi John,
Have used the same tank on my Cabrio with the Seirra neck and venting system with no petrol leaks or fumes.I had the later neck but without the restrictor as i have an early Rover V8 fitted, and this combination was allowed by SVA.If the knurled cap is still available through Ford it might be worth risking a few pounds to see if it can be modified to fit. I shall certainly be investigating this myself as mine was lost by the sprayers!
I have included a couple of photos showing my installation, including an replacement plastic cap.
I hope this is of some use to you. I am at the Exeter show on Sunday 20th Nov. if you would like to see the installation for yourself.

Regards Mike

[paul]

Re: Fuel Cap and Neck

Mike,
That certainly looks much neater than mine. The fuel tank filler connection is much further forward to suit the newer Sierra fillers. It must fill much more easily too.

Is the thing on the left of the filler an expansion valve? I can?t see a pipe coming out of it.

Attached (fingers crossed) is a photo of the two filler styles for comparison.

Paul

[amalgamated users from prior forum]

Re: Fuel Cap and Neck

Message originally posted by: Your Editor in a bit of a mood
Dear disgruntled of Hants

Please see below where it states that photos should be 600x600 pixels and no larger than 64k. It also states that the pics should be jpeg.

Irritated of Hornchurch

[cabrioman]

Re: Fuel Cap and Neck

Hi Mike

Thanks for the info, I think I will go with the later neck and see if I can make the knurled edge cap fit (if I can find one). Have a source for the neck, if you come across a source for the knurled cap can youlet me know. Sorry I can't be at Exeter, a bit of a long trek from Leeds.

Also interested to know what the canister thingy is on the left or your fuel neck.


Cheers

John

[paul]

Re: Fuel Cap and Neck

Dear Irritated of Hornchurch,

You are right to point out the rules are plain, simple and easily understood.

But here?s the rub: I need to check the size and format myself. Being a lazy sorta bod I need the computer to do it for me. It must check the size at some point, as it doesn?t try to attach errant pictures. Could the test be made before the append is appended giving me the chance to revise the size?

Slothful in Hants.

[amalgamated users from prior forum]

Re: Fuel Cap and Neck

Message originally posted by: Mike Woodley
Hi John,
Taken a photo of another fuel filler neck, as it was when i removed it from a second Seirra i was given.The canister is in the vent line to relieve pressure, i think it contains charcoal and its purpose is to take out petrol fumes.The second vent pipe allows air into the tank as the fuel leaves.
Hope this helps.
Regards Mike.

P.S.Have tried to attach second photo of filler cap.

[amalgamated users from prior forum]

Re: Fuel Cap and Neck

Message originally posted by: Your Editor , not in a mood
Dear Slothful

I will ask my webmaster if it is possible to check the size of the photo that you are trying to attach but, by the time it checks it, it is at the point of trying to attach it so by then you will know that it can't attach because it just won't! If that makes sense. You need to check it your end first, so to speak.

Benevolent of Hornchurch

[paul]

Re: Fuel Cap and Neck

Dear Benevolent,
Thanks for considering my suggestion. I promise to take more care inspecting my end in the future.

Happy in Hants

[pdm_engineer]

Re: Fuel Cap and Neck

guys
You seem to be making a meal of this subject when the answer is simple. Use all the sierra bits as shown in photo.The only difference is in the way the vent is connected. Because there is only 1 tank vent, I used a "T" piece to connect to the anti spill valve then fed the output of this valve under the car via a thin plastic tube.
Ref aero type caps and unleaded you can now buy an unleaded restrictor for SVA to fit inside the filer housing from EUROPA specialist spares.

Peter