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Screw on fuel cap

Steef74 - 28/6/25 at 12:30 PM

As I put a boot lid on my MK indy, I want to get rid of the feul filler with a lock on.
I am looking for a twist on cap, that will fit on this pipe.
The pipe is approx. M48x1.8 (measure 48 mm on the outside and 45 between the treats)

Feull filler pipe

voucht - 29/6/25 at 07:36 AM

Hello,
I'm not sure you can buy the cap alone.
Here you have the complete neck+cap :
https://www.thinkauto.com/acatalog/On_line_shop_Screw_filler_cap ___neck_319.html
Hope that will help

designer - 29/6/25 at 11:30 AM

Also Merlin:

Link

nick205 - 30/6/25 at 10:33 AM

quote:
Originally posted by designer
Also Merlin:

Link

This is what I used on my MK Indy.
I didn't want to make a hole in the rear tub.
So used this and opened my boot to fill with fuel.
Worked just fine, but you have to fill carefully to avoid overspill.

NOTE 1: For SVA this got round the lockable fuel filler bit because the boot was lockable.

NOTE 2: The screw on cap was not tethered to the the neck. The SVA tester didn't seem concerned (IVA rules may be different). This meant I could have driven off without putting the cap back on!

[Edited on 30-6-25 by nick205]

gremlin1234 - 30/6/25 at 11:22 AM

there are rules for iva, (though I notice OP may be in NL, and this retrofitted but...)

"Fuel tank filling points must not be in the passenger compartment,
luggage compartment or within an engine compartment. "

MikeR - 30/6/25 at 02:44 PM

Does the cap have a breather or does the tank have a breather? If you use a screw on cap without some way of the tank breathing you'll create a vacuum as you draw the fuel out, leading to running issues and the car stalling.

nick205 - 30/6/25 at 02:44 PM

quote:
Originally posted by gremlin1234
there are rules for iva, (though I notice OP may be in NL, and this retrofitted but...)

"Fuel tank filling points must not be in the passenger compartment,
luggage compartment or within an engine compartment. "

For me, I took the SVA test (forerunner to IVA).

1. Certainly not in passenger compartment.
2. In the boot, but no actual luggage storage provision so not a luggage compartment.
3. Certainly not in the engine compartment.

Mr Whippy - 30/6/25 at 05:50 PM

If you had a printer or knew someone who does you could always, 3D print one. Tinkercad has quite good thread generators for modelling.

gremlin1234 - 30/6/25 at 08:36 PM

quote:
Originally posted by Mr Whippy
If you had a printer or knew someone who does you could always, 3D print one. Tinkercad has quite good thread generators for modelling.

I would worry about what material to print it with.
I think petg should be ok, but nylon would be better.

nick205 - 1/7/25 at 07:04 AM

Back when I was building, 3D printing wasn't an option.
Ally bits of the shelf did just fine for me!