Having some time on my hands and not being able to work outside due to the inclement weather, I began my aux fuel tank project. The hardest part I figured would be the dual filler neck. Thankfully, others had paved the way for me.
I had considered a simpler approach. It involved using an electric fuel pump to pump fuel from the main tank to the auxiliary, and then reverse the pump flow to get fuel from the aux back into the main. The biggest problem is getting a reasonably priced, waterproof high GPM pump to do the job. I like the dependability of Holley electric pumps and have a Holley Blue pump in hand. But even with a 110 GPH pump, I am looking at 12 or more mins to fill a 20 gallon aux tank from the main tank. While that is not an issue when driving your vehicle and refilling from the aux tank, it is a problem spending 15 mins at the gas station pumping into the main tank and waiting to fill the aux tank - hope that makes sense.
So, I perused the ih8mud 80s and 60s forum to see what others had done.
To my rescue comes the article called
poor man auxiliary tank installation by goranvolvo, where he covers in enough detail how to do your own installation.
I had already got a tank from the local recycle yard for $100. No holes in it and it is sound. It looks like it came out of a 4 door Suzuki Sidekick and is around 18 gallons. I got all the connectors but the fuel pump was removed a while ago. There is minimal rust on the outside and the inside is clean.
Next is a dual inlet fuel filler pipe.
Following the link above, I got a 90 degree piece of 1-1/2 " electrical pipe and cut according to his pictures. My ends were not as smooth as could be plus they were at an angle. So I placed them in the milling machine a got the fit I was after. A grinder could have also done the job.
There is zero gap between the pipes when they are fitted together and the pipes are different length on purpose. For my referencing.
With the pipes taken care of, I turned to the filler neck.
Looking down the filler neck, I could see the unleaded fuel only restrictor plate plus other bits of metal running down the filler pipe. Unable to find any information on what was down there, and unsure what I would find, I cut the pipe at the weld. I can always join it back together once I have things sorted out.
Next was to remove the restrictor nozzle plate. I placed the bit of filler pipe in the lathe and using a Dremel, cut a grove into the side of the plate holding the restrictor - it seens to be a crimped/press fit. I only have one filler, so no experimenting. Then off to the vise with the Dremel and cut-off blades and follow the grove. When I thought all was well, I tried gently hammering the plate assembly out and it moved.
And hammered out with a drift punch
Next step is to fit everything together.
I am considering brazing everything together with a combination of brass and steel rod with an oxy-acetylene torch. I like that I can heat the metal enough the the brass will flow into the joints for a strong and
waterproof fuel proof joint. Can't do that with MIG or stick. Brass will be used for the lip highlighted by the red arrows above. Steel rod for rejoining the tubes together. More to follow.