Griff in Fairbanks wrote:
I'm not sure if your fuel tank would pass an inspection. Sometime between the '70s and today, laws or regulations were put into effect outlawing fuel tanks with openings below the top of the tank. I had to abandon the original tanks in my '73 RM350 because they had drain bungs/plugs in the bottom of the tank. Where your fill is located makes it questionable a legal perspective.
Idaho does not have an inspection program, so no worries there.
Griff in Fairbanks wrote:
As for your fill-up question, there are two vent fittings on top of the tank. These will prevent air pressure from causing back flow into the gas fill hose. (I'm assuming your gas fill fixture -- where you insert the gas pump nozzle -- is higher than the top of the tank.)
Makes perfect sense, now that I read what you wrote.
Griff in Fairbanks wrote:
One question -- does one or both of the vent hoses connect to the gas fill fixture? If not, I'd put small air filters on the vent hoses, to prevent grit from entering the tank.
Only one of those fixtures is for the vent. There is a hose that runs all the way up to the metal filler. No filter, but it's a great idea. The other fixture is the return. Monaco plugged the original return off at the sender...because of the extra capacity of the tank, it sits right up at the floor of the coach, so the fixtures have to bend 90° and the original return on the sender does not.
Griff in Fairbanks wrote:
You may experience some difficulties with automatic gas pump shut-off. The nozzles on modern gas pump use air pressure to detect when to shut off. Because you're dealing with an older tank, that doesn't conform to modern standards, the pump may shut off before the tank is approaching full. Likewise, the pump/nozzle may not detect full and cause gas to be spilled on the ground. (Gas stations can, and will, ban you for creating a HAZMAT incident.)
My 1976 AMC/Jeep CJ-5 does the same thing. I have to be banned from any of the service stations here.
Griff in Fairbanks wrote:
StingrayL82 - An option is to have the gas full inlet moved to the top of the tank.
This will be difficult because most welders won't go near a used gas tank, oil drum, etc., due to the risk of a fire or explosion. I'd look for the absolute best welder in your area. (If I was in your shoes, I'd be willing to travel 400 miles to find a reliable welder willing to do the job.)
My father-in-law is a retired master welder, did all of the chassis for Kit Travel Trailers here in Idaho for 30 years. He's done plenty of fuel tanks for friends and family with no problems.
Griff in Fairbanks wrote:
Even if the tank is complete emptied and purged, enough fumes remain to create a danger. In addition to completely draining and purging the tank, safe procedure involves filling the tank with water. Creating an airtight weld is very tricky due to the water drawing heat away from the weld. The tank also needs to be well vented because the water will boil, creating vapor pressure inside the tank.
I have had to weld on fuel tanks before and have always purged them with CO2 and have never had one single issue. I also insert an inert gas, when welding, to promote a better weld, especially with TIG.
Griff in Fairbanks wrote:
You should also plan on resealing the tank with epoxy fuel tank sealant.
The inside of this tank is immaculate, there is no rust whatsoever in it. The zinc is still visible, so no need to reseal it.
Griff in Fairbanks wrote:
(I really hate thinking of something I should have added to a post after I hit the send button.)
I know what you mean. I do it all the time. I really appreciate the responses. Forums are great for learning new things, as well as re-learning things forgotten.
