[Diy_efi] GM Fuel Pump / Tank Options

[Clair Davis]

Wow, this idea has got some legs, at least with respect to discussing the
options out there.  Great stuff!

To be honest, I hadn't considered welding on the plastic tank until adding a
fitting somewhere other than the stock filler location started to seem
reasonable.  I would like whatever changes I made to the tank to be
abso-friggin-lutely STUCK, and stay that way in case something strange or
unfortunate happened.  Plus, since I'll occasionally be racing this car in
autoX competitions, I don't want anything TOO strange to upset the tech
inspectors.  Clearly, I've got some homework ahead of me before I delve in
to welding any plastic bits to the tank.  It DOES have some handles attached
to it (nice idea) that appear to be the same material.  We'll see how this
goes.

With regards to the steel tank, I won't be modifying my existing tank.  It's
38 years old, and in decent shape for what it is, but it's not ideal for any
EFI setup.  Just cycling the fuel through the filters on a return system
tends to clog them after a few hours, so I know there is a rust problem in
the tank now.  It was pretty nice 6-7 years ago, though.  SO, I'd be getting
a brand new reproduction gas tank from Quanta or one of their resellers,
cost is in the $160-200 range.  These are nice pieces, and are stamped from
Ni-terne coated steel.  I'm ASSuming that this is the "tinning" that was
mentioned earlier, with the addition of a flash-coat of nickel to improve
the terne coating adhesion.  If soldering/tinning will do the trick, that
sounds better to me than welding - plastic OR steel.

I'll try to get my photos of the tanks uploaded to my web pages so y'all can
see what the two tanks look like.  That should help to see what I've got to
work with.

Clair


----- Original Message ----- 
From: "James Panter" <9jim30 at charter.net>
To: <diy_efi at diy-efi.org>
Sent: Wednesday, August 29, 2007 3:33 PM
Subject: Re: [Diy_efi] GM Fuel Pump / Tank Options


> This subject is going on and on.  If a sincere effort is being made to
weld
> plastic then it's a common practice with body shops and the information is
> readily available on the internet.  The varous families of
> plastics--Polyurethand, Polypropylend, Polyethylene, Polycarbonates,
Nylon,
> and ABS (Acrylonnitrile Butadiene Stryene) all have specific rods to weld
> the material.  Using the original parent material may not work because it
is
> not virgin material.  In some cases it will work but not in all cases.  To
> weld it properly, identify the material, get some new welding rod, and
melt
> it to the proper temperature.  Of course, all good welding practices
> apply---grooving, cleaning, etc.
> Jim
> ----- Original Message ----- 
> From: "Gregg Eshelman" <g_alan_e at yahoo.com>
> To: <diy_efi at diy-efi.org>
> Sent: Wednesday, August 29, 2007 3:09 PM
> Subject: Re: [Diy_efi] GM Fuel Pump / Tank Options
>
>
> > --- Clair Davis <clair.davis at charter.net> wrote:
> > <clip>
> >> Would it be possible, or even necessary, to do a bit
> >> of plastic welding on
> >> the poly fitting to make it that much of a tighter
> >> fit?
> >
> > Fittings on rotationally molded tanks are attached by
> > first cutting a hole then spin welding the fitting.
> >
> > The fitting is held in a chuck attached to a motor,
> > then pressed against the tank and spun until friction
> > melts a bit of the fitting and tank.
> >
> > Try some experiments on a junk tank to see what'll
> > work. A Yahoo search for spin welding plastic turnes
> > up lots of info.
> >
> >