Big Block Street

[patrickt]

Originally Posted by cobrakiwi

What did all the original csx 3k cars do with there filler caps as far as ground straps go?
Any of you original car owners out there have an answer to this one?
Thanks.

All the original fiberglass cars had them. Seriously, if the metal fuel inlet portion is securely fastened to an aluminum body, and the fuel tank itself is securely fastened to the frame via a conductor like aluminum and not leather straps, then the resistance of both those components are almost certain to be less than one ohm to the system ground. Glass cars like my ERA require a little more care.

[cobrakiwi]

I ment to ask what did all the Street csx 3k cars do with the fuel cap as far as ground straps?

[cobrakiwi]

Morris
I understand why your grounding the fuel thank but why the cap?
That car is a aluminum body right?

[Gaz64]

Originally Posted by cobrakiwi

Morris
I understand why your grounding the fuel thank but why the cap?
That car is a aluminum body right?

The filler neck needs to be grounded, because while it is not grounded it is a point of static electricity conduction. Placing a fuel hose into the neck creates the loop, and we have fuel vapour right at the point of the spark path.

All late model cars with plastic tanks have a ground strap at the filler neck.

Some cars I have worked on needed to have a strap added as a rework.

Gary

[cobrakiwi]

Hey Gary
So how does touching the fuel cap or the cap neck with the pump nozzle make any difference if the cap has a ground strap or not?

[patrickt]

Originally Posted by cobrakiwi

Hey Gary
So how does touching the fuel cap or the cap neck with the pump nozzle make any difference if the cap has a ground strap or not?

A cap with a wiggly hinge on it might not meet the "less than one ohm" test. If it doesn't, then touching it with your hands, after rubbing your butt on the leather seats while wearing wool pants, would be just like shuffling your feet across the carpet and then touching the doorknob on your wooden door. You can get a spark if the planets are aligned just right.

[patrickt]

FWIW, my tank and inlet are grounded, but my cap does not have a separate bond to ground. The ERA fuel inlet though, below the lemans cap, has a twist off gas cap below it, so fumes are presumably vented out below the car via the vent tubing.

[cobrakiwi]

Originally Posted by patrickt

A cap with a wiggly hinge on it might not meet the "less than one ohm" test. If it doesn't, then touching it with your hands, after rubbing your butt on the leather seats while wearing wool pants, would be just like shuffling your feet across the carpet and then touching the doorknob on your wooden door. You can get a spark if the planets are aligned just right.

Yes I agree with that, so what? You will touch the cap to open the cap to fill the car right, I still don't see how that is any different if the cap has a strap to any place on the car or not.

[Gaz64]

Originally Posted by cobrakiwi

Hey Gary
So how does touching the fuel cap or the cap neck with the pump nozzle make any difference if the cap has a ground strap or not?

It is the filler neck that needs to be grounded.
The filler neck metal is nearly always isolated from the car body/chassis.
The amount of volatility that occurs at pump delivery is higher and more likely to combust from a spark, as can be seen by that woman in the video above.

[cobrakiwi]

The video in post 95,
I think this shows the risk at the fuel pump, it makes no difference if your fuel neck is grounded to the cars ground side or not.