1948 CJ-2A Gas Tank Upgrade - 4-Wheel & Off-Road Magazine

Rick Péwé Editor-in-Chief, 4Wheel & Off-Road Photographers: Rick Péwé

Gasoline is one fine petroleum product, but let it sit around and it quickly degrades. Sure, it will still burn, but modern gas is extremely unstable in a storage environment, and an old gas tank in an unused 4x4 is probably the worst scenario. Condensation inside the tank can cause corrosion right off the bat, eating away metal parts and leaving tiny bits of rust to work through the fuel system, eventually clogging it up. The old cruddy gas itself turns into a sort of gummy varnish, hence the term "gumming up the works." And fuel starvation is a bad thing when you are in the middle of some exotic 4x4 maneuver, in a mud pit, on a cliff, or on the freeway.

1948 Cj2a Gas Tank Upgrade new Tank Photo 28432477

Of course the smart thing to do is to keep a fresh tank of fuel in your ride and drive it all the time with good filters. But for us, that rarely happens. In fact, we regale in getting a 30-year-old rig fired and driving on its own power with '80s-era gas, but eventually we're mired down on the roadside cleaning filters, jets, and fuel lines.

1948 Cj2a Gas Tank Upgrade rust Tarnish Photo 28432480 The old gas tank was full of rust and varnish from sitting for 20 years. While we nursed the Jeep along for years after, cleaning the tank would have been an alternate solution. Notice the rust and gummy varnish nearly plugging the fuel pickup tube. We figured that replacing the tank was far better than cleaning it out.

To combat this recurring plague on Pete's Jeep, our '48 CJ-2A flattie project, we called Omix-Ada for a replacement fuel tank and the associated bits and pieces. O-A sells its wares through a variety of 4x4 shops and offers most anything for almost any year or style of Jeep. We decided that since we would be replacing the fuel sending unit and matching dash gauge, a refresh on all the gauges would be in order. And since nothing is easy on any old rig, we figured redoing the floor and associated brackets might be a good idea as well. A month of wrenching and quite a few busted knuckles later, we can now cruise down the road or trail without running on vapors, and we can even tell how much gas we have left!

Keep Your Gas Fresh
Since gasoline typically starts to degrade after 30-60 days, our internal combustion engine collection is constantly having fuel issues. From motorhomes with dual tanks to weedwhackers and chainsaws only used once a year, the fuel left in the tank simply "gums up the works." Our solution to the problem is Sta-Bil, a fuel additive formulated to keep fuel fresh for up to a year or more. It also helps fight corrosion from water being absorbed by the ethanol in our modern fuels and helps fight the rust in steel tanks. Make sure you also rotate your stored fuel; we mark every container with a fill date and keep a list of where every container is squirreled away.

1948 Cj2a Gas Tank Upgrade fuel Stabilizer Fluid Photo 32621412 PhotosView Slideshow Our old tired Sun electrical gauges were pretty sad. The temp gauge was erratic as all get-out, the fuel gauge lied most of the time, and oil pressure was usually there. Plenty of amps and a Nippon Seiki speedo were our only true friends, but we decide they all needed a rehash for a more modern (or retro) look. Because this Jeep was converted to a 12V electrical system from the original 6V, we ordered a matching 12V sending unit and gauge from Omix-Ada. The sender has 5 screw holes in an offset pattern to match the tank. We prefer the Permatex No. 2 sealer on both sides of the cork gasket for a leak-proof seal.
Because of the extensive floorboard modifications done to this Jeep over its life, the factory strap hooks and holes were not available. We used a strap kit from Omix-Ada to reproduce the hold-down system closely to the original. The strap came a bit close to the sending unit terminal, so we made sure it was well insulated and then ran the sending unit wire to the gauge on the dash.
PhotosView Slideshow Originally the water temperature and oil pressure gauges were mechanically actuated with a 270-degree needle sweep, or full-face sweep. The fuel level and ammeter were electrically actuated and feature the half-face sweep. While either way works, and the mechanical is available in a half-sweep face, we like the original look along with black bezels, not chrome.
The mechanical engine temperature gauge works without electricity but rather with an integral bourdon tube that screws into a coolant passage of the engine block. This eliminates one more wire in the nest under the dash. Our Chevy 4.3L V-6 has multiple locations in the block and heads we could have used, but we stuck the probe in the intake manifold.
The original oil gauge comes with a standard fitting to mate to a ferrule with a 1/4-inch copper tube. This is a bit uncommon nowadays, and our local parts store only had a 1/8 tube that runs to a fitting in the oil galley of the engine. Fortunately, we know how to solder copper, so short work was made of this situation.
PhotosView Slideshow We ran a new line for the gas tank, as using the old line was asking for trouble. All the old steel and rubber lines were replaced, since crap would continue to be washed out and plug up more filters and carb parts. Yes, we changed filters and cleaned the carb as well.
Original Jeeps came with an ammeter to monitor electrical flow. Because we also installed a Premier Power Welder (page 82), a voltmeter to measure electrical pressure was used. We ordered the voltmeter from Omix-Ada for a '79 CJ-7, since we know it would work and look similar to the fuel gauge. Of course, we had to remove the bezel off it and the speedo to paint them to match the other gauges.
The gas tank now resides firmly under the driver's seat in full 10-gallon fashion. A new chrome gas cap and rubber grommet finishes off the Omix-Ada replacement installation. The custom seat bracket crosses the length of the Jeep and provides a safe mount for the Bestop low-back seats we installed years ago. Now we can wheel or drive with confidence that the fuel system won't be the next problem we encounter.