Gas Cap Modification for B and B

[Wbulk]

Has anyone modified their gas cap by adding a regular gas cap inside the LeMans cap. I have seen this on other brands and it seems to have merit.
Wayne

[lnfletcher]

Just curious, what are the merits?

[Wbulk]

After I read some posts about the LeMans caps opening in roll overs it got me thinking about it. Some of the manufacturers have the inside cap as standard equipment. I have also read of problems with gas leaks with only the LeMans, but that may have been due to bad installation or maybe design, not sure. It would also allow me to be able to put in a locking gas cap so I wouldn't worry about unwanted things being put in the tank.

I think for me the most important issue is the higher risk of fire in accident situations. Yes the cars are basically unsafe as they are but there are some things that can be done to reduce risks. As a retired cop I can say from experience that accidents with a fire and trapped occupants is the worst.

[Clois Harlan]

Wayne,

The best reason is that should you be involved in an accident (particularly rollover) and the top of your passenger fender contacts the pavement (dirt) your lemans type gas cap could open. I used a regular twist on gas cap inside my lemans cap. I had to modify the spring but it works and I am much safer.

Clois

[Gunner]

ERAs have the inside cap. I didn't understand the reason for these until I installed an original GT-style flip-cap on my Mustang. It came with parts to use it as-is, or with an inner cap. I use the inner cap because almost any hard jolt can open the flip cap, which, facing to the rear, would spew fuel on acceleration. Or a moderate rear-end bash.

The LeMans caps are better designed but it's still the same principle. For safety (and also to meet many state requirements), I'll take a nice, tight, secure twist-on under the beauty cap.

[Wbulk]

Gunner, I agree! The twist in cap is more secure.

Cloise, could you send me a picture of how you did yours, please.

Wayne

[Wbulk]

I am now installing my gas tank and was reading the tank instructions. It said the vent valve is supposed to be installed above the filler neck. That's not possible. The filler cap is one of the highest parts of the body. I guess that's the reason most install it on the upper rear frame, but that's still about five inches lower than the filler.

In reading several old posts on the subject some complained when they fill up they smell gas fumes. That would makes sense, when you fill all the way up the fuel level would be about five inches or so higher than the vent, so the fuel would run out the vent.

I have an old CR manual, and they handled the issue by using a car filler tube with a vent tube line in the filler tube neck. Going this route would allow the use of a vented gas cap inside the Lemans cap that will vent the tank. The vent hose from the tank would then just be routed to the filler neck tube.

Possibly another option on cars using the existing vent valve would be to run the vent hose from the tank up high, higher than the filler, making a loop and then going down to the vent valve.

I think using a filler neck with a vent hose connection and a cap is the best of both worlds. Tomorrow, off to the wrecking yard.

[BeasleyRB]

The vent mounts on the 2X2 above and behind the 3rrd member. (Not in the trunk area but in the area the 3rd member is in.) It mounts above the fuel tank level. 5,000 miles on mine and never any problems. I can send you a picture but we are getting ready to leave town for Thanksgiving for a couple of days. I will try to put in on the message system on this site for you. Everyone builds their car differently but I don't think you need to run a vent tube to the top of the gas cap.

[lnfletcher]

I agree with BeasleyRB. I have mine mounted at the highest point above the rear diff and have had no problems.

[Wbulk]

I wanted to report of the progress of the fuel filler modification that was discussed. I had a hard time finding a filler neck that would work as two inch fillers are hard to find. I was able to find one out of a 79 Ford F150. This one had a 22 1/2 degree angle to it which looks like it will line up perfect with a straight tube right to the tank fill hole.

First I had to cut off the 1/16" flange that was on the neck. I decided to mount this setup from the bottom by adding a new wider flange that's made out of 1/8" plate that will be welded to the neck on the bottom side. On the top is a .050 piece of aluminum that will go just under the LeMans filler. This is just for looks. I didn't want to be looking at a painted surface around the neck. In the picture for some reason these pieces look yellow, but the thinner one is the aluminum piece. All three pieces will be held together with the six screws through the LeMans Cap. The hole in the body was only widened enough for the filler bung to slide up through the body.

The real thing that made this workable was I called Kirkhams and Tom said he would cut the two pieces out for me on his water jet. I went down this afternoon and Tom programmed it perfect with even the six holes for the LeMans cap to mount. This is the second time the Kirkhams have helped me out and the price was more than reasonable.

[Wbulk]

It isn't bolted up yet but this is what it will look like.

[lnfletcher]

Looks Good!