Fuel Tank Vents

**Veek** · 09-03-04, 01:56 PM

I am trying to kill the gasoline smell on my CAV and it would be great if any of you have pictures or solutions to the venting. The LeMans cap spring had very little tension so I think that was part of the problem but I haven't figured how that tank vents.
Also, does anyone know where there may be access to MTA electronics in the US? I need to replace one of my fuse blocks.

V/R,
Veek

Frank Catt · 09-03-04, 03:51 PM

Veek, we found that CAV had a pretty poor idea of tank venting - they just vented to the inside of the sills at the front of the tank, filling the voids with vapour. The sills also contain a lot of electrics !!!!!!!!!!. I modified the tank vents and ran them out into the front wheel arches, with a special cover plate to prevent road dirt from blocking the end of the vent pipe. Photos available if required, Frank

DC · 09-03-04, 05:42 PM

Veek, I also had trouble with fuel smells in my GTD.

I now have sealed (lockable) filler caps inside my traditional 40 caps. At the rear inside corner of the each tank I have a tank vent (from Think Automotive in the UK) which stops fule leakin if the car is inverted. Normally these act as simple vents. Fuel hose runs from these up and across the car just below the engine bay window. A tee piece then runs down to below the floor pan.

The idea is that in normal running air can enter via the vent below floor level to either tank. If I ever (God forbid) overturn the car fuel can still not escape.

The vents are at the rear because if you park on a hot day on a slope with the nose lower than the rear the trapped air in the rear of the tank pushes fuel up an out of the fillers! This did happen to me (no more) and more than one other person I know. The vents should ideally be at the rear.

**Veek** · 09-03-04, 06:17 PM

Thanks Frank, could you provide a picture? Hopefully, I can re-create it with AN fittings.
I'd also be concerned about a rear fuel vent near the engine heat.

Thanks to all. I've fixed 7 of my gremlins and have about 18 to go. The short in the right license plate light was a nightmare to track down but it no longer burns fuses. [img]/ubbthreads/images/graemlins/grin.gif[/img]

V/R,
Veek

Frank Catt · 09-04-04, 04:05 AM

Veek, this was just one of 37 items we found necessary to change on the CAV, mostly for safety reasons. I will E mail you pictures as requested, Frank

Bigend · 09-04-04, 04:37 AM

If you are using your vehicle in any form of competition you MUST have non return valves on your fuel tank vents which allow air in to compensate for used fuel, but do not allow fuel to escape if the car is inverted. Not a bad idea for everyday use too.

Tom_Hughes · 09-04-04, 10:30 AM

Veek,

Please send me a copy of te pictures when you get them from Frank please!

Thanks,
Tom

**Veek** · 09-04-04, 01:08 PM

Tom, you have mail.

Regards,
Veek

BenL · 09-07-04, 01:35 AM

You can find a picture of an original-style vent at: http://racingicons.com/gt/details.htm (Figure 3)

PATGT40 · 09-07-04, 08:41 PM

Veek,
Could you please copy me on the pictures of the vent system? Sounds like your car is getting "sorted".

Gary Gibbs · 09-07-04, 09:18 PM

I have installed a vent system in my blue car. I have a new racing style cap under the lemans cap with a vent installed in the cap. The vent is inertia based and shuts duriing braking vents otherwise.

Bill Musarra · 09-08-04, 05:33 PM

Here is one of the best sites I have found on vents, fuel cells, fillers, bladders, blackboxes and high pressure fuel pumps.
http://www.atlinc.com/racing/page20.htm

It has the largest aray of parts. They even have fuel tanks for the GT40(I think the originals). I'm trying to find out if they have a surge tank for the angled (GT40) tanks. If you wanted to really clean up your engine bay and get rid of a lot of hoses, swirl pots etc., they have an in tank surge tank with trap doors, high pressure pump, regulator and return line to that tank. Then all you need is a switch to change tanks and a couple of one way valves to end worrys of over fill.
Bill