Original fuel tank rollover vent valves

Elliot

Supporter
Hi guys,

Does anyone have any original or reproduction of original tank rollover vent valves for sale, or information on them. Most of the cars appeared to have these valves (first two photos), but some of the race cars appear to have had a different valve with a raised up middle, (last photo). Any for sale, in any condition, or information would be greatly appreciated.

Many thanks.
Elliot.
 

Attachments

Pedro

Guest
I have seen at least three different ones, original MKII, MKI and Gulf cars and perhaps more plus the aircraft type valves used on the engine compartments of some of the cars.
Check with Jay Cushman I know he made some of the original stile ones in the past, I got a set from him and they were very nice.

GT40 Fuel Vents.JPG
 

Elliot

Supporter
Wow! Thank you so much Pedro. That's most helpful. I will contact Jay. Much appreciated!

Best,
Elliot.
 
how do they work, what is inside them?
are these performing the same function as the small valves that superformance put in the engine bay behind the B pillar?
 

Elliot

Supporter
Hi Ryan,

I hope you're well.

Yes, there is a spring valve inside. The valve allows the tank to 'breath'. That is to say they allow airflow in both directions and prevent an overpressure or depression situation within the tanks,....and prevent fuel leakage in the event of rollover. And yes, currently Superformance fit their own version behind the left 'B' pillar in the engine compartment.

I have noticed that even some original cars racing in the historical races have had the valves removed. Perhaps race rules for fuel systems now outlaw a vintage style vent,...but I'm no expert and don't know for sure...
 
Hi Elliot,
Regarding current usage on cars these days, who knows?
New cars generally have a prescribed fuel filler neck diameter, with a spring loaded flap along with a charcoal canister for venting purposes all to avoid the petrol fume smell you used to get in the older cars and to reduce vapor emissions at petrol stations when filling up.

Anyway, getting back to originals, I have noticed on original MK I race cars that they tend to have a pipe running along the top of the sill, along the outer edge next to where the inner and outer sill covers are spot welded together, this then seems to go up through the a pillar towards the filler cap. This is often covered with a chrome plated or stainless cover on the top of the sill, but you can often see the pipe do an s bend before disappearing into one of the lower holes on the back of the b pillar below the dash face. I will need to go back and remind myself if its only on the race cars or if it was a feature of the street cars as well. Some of the chassis seem to have the holes for it, while others don’t. some even seem to have two holes in the place on the B pillar while some seem to have none.

I haven’t been able to work out what this is all for.

Regards Ryan
 

Elliot

Supporter
Yes I agree Ryan. Unfortunately I am in the dark like you. There is frustratingly very little information on these details of the fuel system. And also from where the components were sourced (off the shelf auto or aircraft parts?), or how they were made if specifically fabricated for the GT40.

Once again,....if anyone has any knowledge, diagrams, pictures, or component sources, it would be most gratefully recieved by us.

Many thanks again.
 

Brian Stewart
As far as we are aware, yes, the tube running along the sill is indeed a breather. On mine, local rules do not allow a fuel pipe in the cockpit, so we have run a dummy pipe on the passenger side and the cable release and feed to the extinguishers on the diver's side. The actual breather for mine is a flexible fuel hose that runs inside the sponson from the rear top of each tank to a fitting in the filler neck.

Feed.jpg
Tube.jpg
 

Pedro

Guest
The original valve is a very simple arrangement, when the valve is upside down the two perforated disks come in contact closing the valve; The pressure of the fuel and gravity keeps the valve closed, I will probably use something more modern myself.

Fuel Vent MKI-001.JPG
 

Charlie Farley

GT40s Sponsor
All of the broadly accepted MK1's from FAV were fitted with valves that did not operate with a ' perforated disc ' system. Nor did they look anything like any of the valves i have seen so far on this post. I have found that quite a sizeable number of chassis lost these over the years, i'm guessing due to a racing phase. Especially prevalent with the Road Cars.

They are available, but as with all these small scale, bespoke & hour hungry humint projects, at a price. But restorers & i guess ultimately the owners, appreciate the original fitments.
 

Randy V

Admin
Lifetime Supporter
All of the broadly accepted MK1's from FAV were fitted with valves that did not operate with a ' perforated disc ' system. Nor did they look anything like any of the valves i have seen so far on this post. I have found that quite a sizeable number of chassis lost these over the years, i'm guessing due to a racing phase. Especially prevalent with the Road Cars.

They are available, but as with all these small scale, bespoke & hour hungry humint projects, at a price. But restorers & i guess ultimately the owners, appreciate the original fitments.
Are you planning on showing us the “right” valves?
 

Pedro

Guest
Thank you for sharing the information Jimmy Mac, attached is a picture of the one used on 1075 (left hand tank)

GT40 1075.png
 
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