GOING THE DISTANCE

How to increase an Intermediate CJ-5's fuel capacity

- Verne Simons

Intermediate CJ-5s are a bit of a conundrum from a fuel capacity standpoint. The fuel-sipping 134ci I-4 that the original CJ-5s had was replaced with a thirsty AMC 304ci V-8 or similarly thirsty AMC I-6, but the fuel capacity of these early Jeeps did not grow on the same scale as the engine displacement. That was the situation with our '74 CJ-5. It didn't have great fuel economy and the factory fuel tank seemed to only hold 14-15 gallons. At 9-11 mpg the range was low, really low, making fuel stops frequent and inconvenient.

This problem is as old as Jeeps, and we've solved it to some extent by the addition of a 5-gallon jerrycan and mount. That seemed like a decent way to get about a third more fuel range, but we wanted more. So, we nearly doubled the fuel range using mostly factory replacement parts from Omix-ADA.

Truth is, we got this idea from our friend and longtime Jeep guy Mike Tarvin. The idea is pretty simple. Intermediate CJ-5s (and CJ-6s) have the same driver-side seat bracket as earlier CJ-5s with a gaping space underneath where in an early CJ-5 there would be the factory 10-gallon under-seat fuel tank. The recess for the fuel door is still stamped into the Intermediate body tub and the space is basically asking to be used. All one has to do is gather some factory new or used replacement parts, a fuel selector valve, some extra fuel hose, and do some trimming to get a 10-gallon under-seat tank added to an Intermediate CJ-5 (or CJ-6).

The first step is to remove the driver seat from the Jeep. That gives access to the space where the tank will live. Next, we had to cut a hole. To start the cut, we took the Omix-ADA fuel filler neck and held it in the factory-stamped location and traced it. Our cut line was about 1⁄2-inch inside this line.