R80/7 Fuel Tank

[shakyone]

I recently had my fuel tank stripped in an acid bath and relined with an epoxy liner. I then spent too many days priming, painting, clearcoating, pinstriping, clearcoating again and buffing. When I went to install the tank I realized that the fuel line connector threads were too badly damaged from acid washing to get a good connection to the fuel valves-The remaining threads crumbled.

I know that one option is to use fuelproof hose to connect the valves to the tank, but I wondered if anyone else has had this problem and came up with a better solution. Remember that welding or soldering is not possible due to the new paint and liner.

Also, does anyone know the thread size of the fuel line attachment on the tank?

Thanks,
Paul

P.S. Also posted this on the airheads list

[Major Softie]

I'd be searching through all the manufacturers for a larger petcock so I could re-cut those threads to fit.

[jagarra]

I would be checking out what thread pitches are available from Heli-coil and looking for a matching petcock.
There is also another possibility using nutserts, which provide a sturdy inserted thread into a thinner material.
I have attached a link to one style of these devises. There a many manufacturers and designs

http://avkfasteners.com/products.AR.php#benefits

Looks like these go only to a 10mm bolt diameter, possibly there are other manufacturers out there. The killer on these type of inserts may be the cost of the installation tools, sometimes they are specially designed. The ones I am using currently just require a long bolt and a spacing collar so the bolt grabs the threads and pulls the unit tight into the opening.

[esman100]

Can you post a pic of the damage?

[Major Softie]

A machine shop can do the insert for you, and that will save the cost of a kit or installation too. Just getting one done on something that is simple to carry into the shop might be cheaper than getting the kit. Just make sure you specify a liquid-tight insert when you are calling around, as some are and some are not.

[shakyone]

Here's an update.

I was able to tap the inside of the outlet bosses on the tank to 3/8-18NPT. This will allow me to use a wide variety of petcocks.
Thanks for all the advice.

Also, What would be good to use as a sealer on the new petcock threads. I need something fuelproof, but not permanent.

Thanks,

Paul

[Major Softie]

Teflon tape? It's designed to work with tapered pipe thread joints.

[shakyone]

Here's a pic of the finished repair:



Uploaded with ImageShack.us


Paul

[Major Softie]

Somewhere, some concourse restorer is spinning in the grave which he has not yet entered. But, hey, it works, and that's what it's all about.

Congratulations!

[ME 109]

That's a beautiful repair Paul, but I'm afraid it won't work.

Well, it will be fine at idle, but at speed the wind will prevent the fuel from falling into the fuel line. Well, unless the wind blows the fuel line back proportionately as well.

Perhaps a funnel?