MK1 single fuel filler at Le Mans 1966

Agostino

Supporter
Just a curiosity on MK1 race car specs and the single fuel filler system starting from Le Mans 1966.
Looking to some pictures of all the GT40 equipped with a single fuel filler, Gulf JWA chassis looks clearly having a crossover pipe in the cockpit for connecting the fuel tanks together. This system implies a lot of changes to the chassis central part, probably not a big issue on cars that were built with this system from the beginning but a significant change in an already existing car.
MKII SAE paper reports instead a completely different system, in my understanding the two tanks work as usual without a real fuel balancing, just a crossover pipe running behind the dashbord to allow to fill simultaneously the two tanks from one single fuel filler. This was probably the system used by MK II when entered at Le Mans 1966.
I saw a "recent" picture of 1040 (that partecipated to Le Mans 1966) with a system clearly resembling the one on the Gulf cars. However 1040 went completelly destroyed at Monza in 1967 and rebuilt later. Considering that the 6 MK1 entered at Le Mans 1966 were originally built with two fuel fillers and just converted for attending Le Mans (1017 seems still having the second filler at Spa 1966, just one month before Le Mans) the Gulf-like crossover looks to me an overkilling system and MKII approach would have definitely been a more effective, simpler and safer solution for the filler issue. Is there any other info on the system effectivelly adopted on race MK1 in 1966?
 
Hi Agostino,
your probably looking at the FAV plans and thinking the same thing I was. I spent a few weeks trying to find images and understand how it all works.

here is the thread.

Good luck with the Mono build.
regards Ryan.
 

Agostino

Supporter
Hi Ryan, yes, your thread actually triggered my curiosity too. In the picture you reported in the first post of 1040, the crossover pipe looks very similar to the Gulf one (I have in mind the 1076 recreation on the Gelscoe website for these details). This system in a standard MK1 requires a lot of changes: a complete change of the seats, a reinforcement added across the cockpit, the tunnel top opening, the crossover pipe installation and the re-routing of the coolant pipes to pass on top of the crossover pipe. MK2 system looks to me a much simpler solution on SAE paper. Is it possible that MK1 originally used the same system with just a crossover pipe running behind the dashboard to allow the simultaneous filling of both tanks? Why should they have uses a different system on MK1 and MK2 in the same race in 1966? May the lower crossover system been just a later specs as in JWA lightweight chassis?

Regards,

Agostino
 
I have never seen a photo of the system that ran through the top of the dash structure, only the diagram/drawings in the ford papers. I don't know how it would self level, or vent. by the time the fuel got high enough to flow through the cross over tube in the top of the dash it would have very little head height left and would have taken ages to fill. A mate has a fuel rig for his 24hrs of "lemons" race car that lifts his fuel can up about 3m and then dumps it in using a straight hose. there is a dry brake vent tube on the rear bumper that allows the air out so it doesn't need to come up the filler tube.

Wasn't there somewhere that was talking about a diverter in the filler neck on the early GT40s so that it started to split the fill to the other tank as it came in through the gas cap or am I thinking of something else, might have been in an interview with one of the mechanics/fabricators maybe a you tube vid?
 
This is the diagram I am thinking of
 

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Agostino

Supporter
Wow, I just spent five minutes looking to the picture for seeing what you mean! So both systems on MK1 and MK2 looks requiring a similar change in the chassis design to accommodate the lower crossover pipe and no need to think to something different.
Thanks,

Agostino
 
@GT40Graham , I had completely missed that lower cross link before.
it certainly explains the holes in the top of the foot box side panels that allow access into the structure behind the dash face.

Did the MK II have the cross tube in the dash as well? was this just a small breather tube to allow the air out as it filled from the single filler?

Fuel System P39Crop.png
 
@GT40Graham , I had completely missed that lower cross link before.
it certainly explains the holes in the top of the foot box side panels that allow access into the structure behind the dash face.

Did the MK II have the cross tube in the dash as well? was this just a small breather tube to allow the air out as it filled from the single filler?

View attachment 104414

The SAE drawing is the Mk.II set up so yes, it did have the cross tube.

Regards,

Graham.
 
From memory, all the drawings and photos I have for the fuel filler tubes under the scuttle only show two small vent tubes coming backwards and downwards towards the door opening. I haven't seen any photos that show a tube running across in the dash structure......
will have to go and look through the 1000s of photos I have saved again and see what I can see.

Ryan
 
From memory, all the drawings and photos I have for the fuel filler tubes under the scuttle only show two small vent tubes coming backwards and downwards towards the door opening. I haven't seen any photos that show a tube running across in the dash structure......
will have to go and look through the 1000s of photos I have saved again and see what I can see.

Ryan

I think you're mixing up the two systems - the Mk.II had the tube running behind the dash.

Regards,

Graham.
 
Hi, in the documentary “tomorrow this time” Le Mans 1966. In around 13min 40 you will see big filling pistol with extra rubber hose pipe fixed on the pistol....

in my young years in Flemish Belgium the fuel cans were named “jerry cans” as imported by the “Jerry’s” American soldiers in the ww2 .
 

Neil

Supporter
Paul, the 5 gallon "Jerry cans" were named by the American troops for the Germans, "Jerrys".
 
I think you're mixing up the two systems - the Mk.II had the tube running behind the dash.

Regards,

Graham.

I haven't had a chance to check as we had a local car club meeting last night. Would this explain why some cars have holes in the lower part of the rear door pillars (think its drawing 2035 from memory) while others don't. some seem to have 2 holes on the left side, 1 on the right, others have 1 and 1 while others have none. The real early cars, pre P numbers, seem to have just the one large oval hole in this area.
 
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