Jeeping On Air: 1986 Jeep CJ-7Posted in Project Vehicles on November 1, 1998 Comment (0)
Bruce Bishop is a farmer in northwestern Ohio. A farmer divides his year between the growing season and the winter. In growing season, his days consist of long hours and backbreaking work with not much time for Jeep building or riding. Come winter, there's little time for a life other than the land. But in six years of winter "vacations," Bruce has managed to build a totally unique Jeep.
The first thing you need to know about Bruce is that he likes to go fast. This probably comes from putting 10,000 miles a year on a tractor that is only driven at three mph. To satisfy the need for speed, Bruce built a Chevy small-block that propels his fiberglass bodied '86 CJ-7 though the quarter-mile in 12.6 seconds. The puzzle for him was how to build a catapult-launch engine that wouldn't get an attitude problem with low-rpm trail work.
The 388ci stroker on Bruce's Jeep uses Keith Black hypereutectic pistons and Trick Flow aluminum heads that were further massaged by Nick Norris at Norris Racing in Findlay, Ohio. The valves are opened by a mild Competition Cams Magnum cam in concert with Crane roller rockers, and are driven by a Keith Black geardrive setup.
What gives the engine the combination of all-out power and low-end grunt is the Weiand Pro-Street supercharger. The mild 230-degree duration (at a .050-inch lift) Magnum cam is smooth and docile at low revs, but as rpm builds, the supercharger force-feeds the Chevy via a 750-cfm vacuum secondary Holley. Well-burned petroleum exits via Hooker headers and SuperTrapp mufflers. On the computer dyno program, this surprisingly docile engine produces 540 hp and 530 lb-ft of torque.
The engine hands off the power to a TCI-built TH-350 that's coupled to a Dana 300 with a Currie twin stick shifter. The Dana 300 transmits to a hefty Dana 60 rear axle that is beefed with 35-spline Moser axles, Ford 9-inch-style bearings, and a Detroit Locker. Up front a standard CJ-7-style Dana 30 with a Powr-Lok carries the load. Both axles are fitted with 4.56 cogs.
Now we come to the most interesting part of Bruce's Jeep: Using Firestone air springs at each corner, he fabricated a four-link setup at both ends that offers about a 6-inch range of driver-controlled up-and-down movement. An engine-driven compressor and a chassis-mounted tank provides the air supply, and Bruce controls the system from valves in the cockpit. He also built an air manifold and has separate gauges for the front and rear. Equalizing the gauges levels the Jeep.
Bruce fabricated the suspension pieces in his shop using the fabrication skills common in farmers that maintain their own equipment. It took a couple of tries to locate the Heim-jointed radius arms for best effect, but after a few years on the trail, the setup has proven itself reliable. While Bruce wishes for a bit more articulation, he's pretty happy with his unique Jeep. It's probably the only fully air-sprung CJ-7 in the world.