Technical Articles Relating To Off-Road Vehicle Development

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1985 CJ-7



Centech Wiring


Off Your Rocker Panels

1985 CJ-7

Old CJ7 TubThis started out as a 1985 CJ7, and over the past five years we’ve rebuilt it several times. This is the newest version of our Jeep, and it’s easy to see that there is hardly anything left of the original CJ7 besides the grill-shell and tailgate.

258 Engine360 EngineThis build-up started when the 5th head gasket blew out from between the 4.0L Clifford head and the 4.2L bottom end. The Clifford motor had been built to a point beyond reliability and I was tired of fixing broken parts. I started shopping for a V8 that was suitable to swap in and was happy to find something in the Mopar lineage. I found that the mid-90’s and newer Dodge Ram 3500’s came equipped with exactly what I was looking for. The Magnum 360 is a roller cam version of the Dodge small blocks from the 60’s and it comes in the 3500’s backed by the ultimate manual transmission. We bought a new 360 Magnum crate motor long block and then found all of the drive accessories, brackets and the bell housing in the salvage yards.

Holley Fuel InjectionThe stock fuel injection was ditched in favor of a Holley Performance, Commander 950 Multi-port fuel injection system. This is mounted on top of a Mopar M1 single plane intake manifold made especially for multi-port injection engines. Rance Fuel Injection made the custom fuel rails that are fed by a Holley pump and fuel regulator. Earls Performance hoses and fittings were used throughout the vehicle. MSD is responsible for the billet mechanical advance distributor, 6 Off Road series ignition box and coil: sending spark to NGK plugs through Holley Annihilator plug wires. Hooker’s Super Competition, block hugger style headers pass exhaust gasses to a single FlowMaster two chamber Delta Flow muffler. Air has to come in before it can go out and K&N keeps it all clean and unrestricted. Airflow is also important in keeping the engine cool and a Spal electric fan pulls air past the Be Cool aluminum radiator that is held in place by a custom grill shell made by TLT.

Mopar 360 on hoistThe NV4500 transmission is a heavy hitter, with a cast iron main case and is sought after by crawlers because of it’s 5.61:1 first gear ratio and 27% fifth gear overdrive. It can be adapted to any number of motors and transfer cases, but consider that for less than the price of a transmission and the adapters to bolt it up behind a Chevy 350, a person can buy a complete fuel injected 360 Magnum motor with the wiring harness, transmission and bell housing from a salvage yard. The NV4500 housing and output shaft also bolt right up to the Dana 300 or an Atlas transfer case. We bought a new NV4500 and put a Dana 300 behind it, using Down East Off Road’s Flip Kit and TeraLow’s 4:1 gears inside. TeraLow’s 32 spline HD rear output shaft should eliminate any transfer case failures.

Kevlar TubRollcage Rear ViewYou can’t fake a frame-up when that’s all you start with. We ordered a new AFW replacement CJ7 frame to build upon. We added a Kevlar CJ7 tub and hood from Fibertech and then fabricated an intricate roll cage with the help of Hanson Enterprise using 1.5” and 2”x .095” and .120” DOM tubing to tie all of the components together. The roll cage was designed and built to triangulate and brace the entire vehicle from bumper to bumper, while being as unobtrusive as possible. Hanson Enterprises is also responsible for the front and rear bumpers as well as the rocker panel guards used on the Jeep. Off Your Rockers was enlisted to bend up an extra heavy pair of 3/16” steel corner panel guards to keep as much of the body as possible out of the rocks.

InteriorInside, Beard Ultra seats and Simpson Camlock 4 point harnesses keep occupants comfortable and safe. Autometer gauges are used to monitor the engine and air supply, housed in the custom dash made by TLT. Ignition and electrical controls are locked safely away in the stereo compartment of a Tuffy Security console for convenient keyless ignition on the trail. Tuffy Security boxes provide additional storage space throughout the vehicle. A Bestop Supertop stays on the Jeep year-round and as the weather changes, just goes up or down. It’s never in the way and by also keeping a pair of Bestop soft doors in the bed; we always have a fully enclosed vehicle when it’s needed.

We ordered a custom wiring harness from Centech Wiring. These harnesses will accommodate just about any conceivable drive-train configuration and they use top quality wires and connections. Wrangler NW is the company we went to for our dual battery management system and for all of our misc. wiring and electrical needs. Two Optima Deep Cycle (yellow top) batteries are held to the passenger side firewall by a custom tray and Wrangler tie-downs. LED blackout taillights from a military HMMVEE are recessed into the tub using components from Kascar.

Steering Close UpSteering starts at the Ididit steel tilt steering column and then passes through a Borgeson intermediate shaft to an AGR Super Box II. An AGR Super Pump feeds the ram assist cylinder by way of Earls Performance hoses and fittings. All that leverage is provided by way of 1.5”x.25” thick DOM tie rods and 3/4” chromoly Heim joints to the Currie modified hi-steer knuckles.

Sway-A-Way ShockSuspension is simplistic by recent standards set in competition, but the 1.5” spring-over YJ leaf springs from Deaver give this Jeep as much stability, traction and articulation as many of the well-designed, coilover suspended vehicles out on the trails. SwayAway 2.5” remote reservoir shocks provide dampening at each corner and are positioned to have 50% compression from ride height.

Swinging heavily from those leaf springs and shocks is a pair of reverse rotation Dana 60 axles prepared by Currie Enterprises. A new, 2000 Ford F450 unit was built for the front with 5.13’s, an ARB, 1.5” 35 spline inner shafts, 30 spline outer shafts and Warn Premium locking hubs. The rear high pinion Dana 60 was pulled from a 1979 F350 and now houses 5.13’s, a full spool and 1.5” 35 spline semi-floating axle shafts. Both axles are 63” wide WMS to WMS, giving the CJ just over 80” of track width. We use Wilwood disc brakes at all four corners in the forms of Dynalite four piston calipers and 12” rotors.

A 1350 series CV driveshaft from South Bay Driveline handles the severe angles and still allows plenty of slip. The front axle’s shackle reversal and articulation posed a problem that South Bay solved by using a triangular driveshaft with an amount of slip travel equal to almost its entire 38.5” length.

Maintaining traction and keeping the rest of the Jeep up and out of the rocks is what those 39.5” Super Swamper TSL tires do very well. They allow for just over 12” of ground clearance at the lowest point of the un-shaved Dana 60 differentials. Those tires are wrapped around a set of Mickey Thompson Classic II rims in a 15”x10” size with 3.5” of backspacing and a 5 on 5.5” lug pattern. We do not usually carry a replica watches spare tire due to the prohibitive size and weight, but rely instead on the ability to patch flats, sew up torn sidewalls and most importantly; the fact that those tires will support the weight of the Jeep on a trail even at zero psi.

For a purpose-built trail vehicle this CJ7 still retains a lot of the characteristics that make it a Jeep, and we went to a lot of trouble to ensure that it would still be something that we could drive on the highway.