David recently posted about vent valves on fuel caps, and I wondered if anyone can clear the fog around this.

My SVA manual is a coulel years old. It mentions nowt about fuel issues.

I have heard that a car must be submitted with a full tank of fuel so that it can be checked for leaks. There is nothing in my manual on these lines, but I can see the logic.

There also is nowt about specific fuel caps.

Traditional caps have an air hole for venting. More modern cars have some kinda valve in the cap.

COntrasting stangely with this is my wifes new megane, which has no cap as such.

There is a sprung 'gate' over the filler kneck. Its not air tight.

Thats it.

When you close the door over the filler, there is a really shabby looking 'plumbers plunger' kinda plasic thing that presses vaguely over the general area of the filler hole. I cant see how this prevents leaks on an inverted car.

So, as far as you guys know, what kinda fuel filler arrangements are compolsory?


atb

steve

Not really an answer for Steve, but might be useful to the rest of us builders:

Most of the big dealers like Demon Tweeks, etc. advertise a flush 'sort of aero' petrol filler cap for around £45 + VAT - but when you try to buy one they say that they're not available for a few weeks.

When speaking to Mocal today, it became apparent that they make these caps - and they sell them for £38 + VAT. The reason they're not shipping them is that they've changed the design from a plastic 'bung' to an aluminium one - and they're not quite ready. They call it the "Smarty" cap.

I've just bought one with a plastic bung (as shown on their website) for £38 including VAT - special price as it isn't the latest, and they didn't have the rubber gasket to go behind it (I can live without that).

If you're interested, have a look at their web site on

http://www.thinkauto.com/

You could try asking for Matthew - he said that they offer discounts for clubs (LocostBuilders Club? )

It's worth looking at their site, if only to see the mark-up that other dealers put on their products...

David

[Edited on 4/4/03 by David Jenkins]

Think automotive are just up the road from me in Isleworth,and yes it is worth looking at the prices.

They have been very helpfull.

no one using filler caps then.....gas powered cars?


atb

steve

Not got that far yet, still haven't got a fuel tamk to connect it to yet!

I have both!

However, I wanna make sure im not up for a certain fail with the filler I have.

At the end of the day, the default will be to use what I have. Im sure it wont be the only thing needing attention after SVA and I can always put something crappy and compliant on to pass, then put old one back.

atb

Steve

Try your local SVA Centre, or the SVA office in Wales. Manual not with me so can't supply number and name of the guy I've spoken to in Swansea. They can be quite helpful.

David

How big is the filler cap you bought from Mocal?
They list 1.75", 2" etc which I expect is the pipe diameter for connection to the tank, are all cap diameters the same?

Nick

quote:

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Originally posted by Nick Davison
David

How big is the filler cap you bought from Mocal?
They list 1.75", 2" etc which I expect is the pipe diameter for connection to the tank, are all cap diameters the same?

Nick

---

Steve, I read the same post with interest as I have heard nothing about vent valves on filler caps etc. My filler is within my boot space and received only a quick look from my SVA tester - Its a Spitfire, non locking, quick release unit of about 20 years vintage.

My understanding of the "full tank" is for weight purposes. Go to the section that covers weights etc at the back. They check your axle weights, then check your calcs you have submitted with your SVA application and from that work out your brake efficiency requirements ... Fuel leaks are obviously checked for at the tank and throughout the car.

quote:

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Originally posted by David Jenkins
I can give you the exact dimensions in the next day or so - waiting for delivery!

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quote:

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Originally posted by david walker
Steve, I read the same post with interest as I have heard nothing about vent valves on filler caps etc. My filler is within my boot space and received only a quick look from my SVA tester - Its a Spitfire, non locking, quick release unit of about 20 years vintage.

My understanding of the "full tank" is for weight purposes. Go to the section that covers weights etc at the back. They check your axle weights, then check your calcs you have submitted with your SVA application and from that work out your brake efficiency requirements ... Fuel leaks are obviously checked for at the tank and throughout the car.

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I've got a mocal screwcap in ally from thinkautomotive,i'm fitting a breather pipe on the tank as in my archive.
I've seen a car go through SVA with this set up,so thats the way i'm going.

If this fails rally design and merlin motorsport sell a non return valve at a price,so all is not lost.

It seems to be another grey area as the manual states the tank should not leak,just depends on which way up it is i suppose


[Edited on 7/4/03 by bob]

Has anyone tried a motorbike fuel cap? have been offered one from a suzuki bandit for a fiver, and guessing that its been blatting about on a bike for a couple of years, it should do the trick?

Cheers Chris

quote:

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Originally posted by bob
If this fails rally design and merlin motorsport sell a non return valve at a price,so all is not lost.

---

As promised...




The filler came with the hose pushed on (they used the assembly to hold the screws, keys, etc.). I would have taken it off for the pictures - but it didn't want to come off! It seemed a good idea to leave it where it was and simply fix it with a jubilee clip. You'll just have to imagine the 1.5" of ali tube under the rubber hose...

Total diameter is 85mm, hole diameter is 57mm (a generous 2.25", and it takes 52mm/2" hose. It sits about 3mm about the surface of the body skin (which is why I'm not stressed about the non-rounded edges - it has to be 5mm+ to warrant the proper radiused edge).

BTW - that rubber hose is EXPENSIVE! About £1 per inch, and that was the cheapest I found.

Final photo - I also bought a tank vent from Think, their model "6JIC in line", which by very good fortune screws straight into my PTM tank's vent hole! Lucky, or what! It's the shiny red thing in the photo - the bit on the top is a screw-on hose adaptor.



Hope this helps,

David

JIC fittings are US mitilary designations, commonly used in aircraft and high end motorsport fittings.
They're just UNF threads with a taper seat nose, and are sized by "dash" numbers:
- 4 is 7/16" UNF (20 TPI)
-6 is 9/16" UNF (18 TPI)
-8 is 3/4" UNF (16 TPI) et. etc.
You can also get bolt-in tank valves, ones with a barb at each end, and also with just about any pipe thread imaginable.
Do fit one.

I've just got the screw on hose adaptor as a vent with a piece of pipe up and over the side of tank,i think i'll change it now i've seen yours and visit matthew at think auto again.

How much of my hard earned will i have release from the very very thin wallet i now have ?

[Edited on 9/4/03 by bob]

The official price is £38 + VAT, but they seem very open to discounting!

For example, I bought the set with the old plastic plug instead of the new ali one they're waiting for, and paid £38 including VAT. He also gave me a big discount on all the other bits & pieces I bought.

He said that they give discounts to club members - "LocostBuilders", "MK Owners" - the choice is yours!

cheers,

DJ

What?.....nearly spent your 250 already Bob?....

£250x4x4 more like,and i seem to be that amount worse off in the last tax year.


DAVID
yes they do like to keep the cutomer happy at think auto,i also like going therte as chaters the motoring book people are a short walk away too.

Thanks to Bob, I've just bought a lovely Mocal solid ali screw-on filler cap with a 6in straight piece of hose and stainless clips for about £23 inc. from Think Auto. I didn't want it through the bodywork, just straight up inside the chassis - easier filling with a jerry can at track days.

Nice chaps and a lovely piece of kit.

Just in case people are still looking for the aero style fuel filler caps I've just got one from Demon Tweeks at about £60 all in. The product code in their catalogue is CAP3ZF but they know it as MOCCAP3ZF so I'm assuming it's a Mocal one. Also they don't have it on their website but they know about it if you phone the order through.

Pictures on my photo archive... filler1, 2 & 3.

My filler cap is from a mini, I used the neck from a mini tank welded to my home made tank with the filler inside the lockable boot. The full tank of petrol at SVA is for the all up weight Steve, not for leaks. The tester never asked for the boot to be opened as he could see from underneath.

yours, Pete.

thanks for that peteff.

If mine fails cos its external edges, then im gonna mount it in the boot and refit it outside after SVA!

Plenty of time to worry about that tho!

atb

steve

Just bought an SVA compliant, locking, Aero style Smarty Cap (part no CAP3ZF) from Think Auto for £37.60 inc vat and postage. This represents a 25% discount off list.

82mm (3 1/4 inch) overall diameter with a built in 2 inch flange to connect direct to my PTM tank via some 2 inch hose.

I've not seen better anywhere.

Thanks for all the pointers.

quote:

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Originally posted by MK7
Just bought an SVA compliant, locking, Aero style Smarty Cap...

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Andy,

It's not turned up yet but I suspect it looks very much like that. An earlier post in this thread said they'd be replacing the plastic centre with an aluminium one, as yours has.

The Smart cap is around 85% of the way down the following page

http://www.thinkauto.com/acatalog/intro.html

and is 5 items below the standard aero caps.

How much did you pay for yours inc VAT and P&P?

I particularly like this one cos it's nice and small and therefore provides more choice as to where I mount it.

Russell

Russell,

I paid about £60 all in from DT!

I suspect it is the same as DT didn't have any for quite a while and then suddenly had them in stock. I assume that this was because Mocal were changing to the all ally version. DT even use the same ref as you've got from Think, CAP3ZF!

A LOT of DT's stuff comes from Mocal/Think Auto!

I strongly recommend that anyone likely to buy a lot of bits & pieces gets a catalogue from Mocal before you start.

The difference between their prices and those in other catalogues is remarkable (and they give good discounts when you buy a lot of stuff).

David

Andy,

mine looks like this

Looks kinda familiar eh?, I'd see about getting a refund...

Russell

[Edited on 30/7/03 by MK7]
Rescued attachment Fuel cap.jpg