There we were, cleaning out former Jp Editor John Cappa’s office. Amongst the toenail clippings, jars of formaldehyde-soaked amphibians, and the entire Meatballs movie quadrilogy on Betamax, we came across the tech sheet and photos of Brian Boyd’s ’82 Scrambler. Unlike the toenail clippings, we were stoked about the feature, which Cappa shot during his last month at Jp during a trail ride in Cowan, Tennessee. Check out the story “Southern Spin,” (Oct ’11) for more info on the trails.
Brian’s Scrambler typifies most of the characteristics we expect to see in a vehicle built to tackle the snot-slick trails of the Southeast: big tires, big axles, big power, and big wheelbase. For southern wheeling, you gotta pick your line and stay committed no matter how gnarly the action gets, ’cause the mud-covered rocks won’t give you a second chance to back down and try again. Starting to bounce? Stay in the throttle? Getting pitched sideways? Stay in the throttle. Front tires four-feet off the ground? Stay in the throttle. You just gotta build the rest of the Jeep to cope with the violence and resist rolling over backwards. Hence the heavy stuff, like Rockwell axles, 44-inch tires, and longer wheelbases. We mean, when was the last time you saw anybody stretching the wheelbase of a Scrambler? Yeah, we thought so.
Chassis
Brian took a perfectly clean, collectible Scrambler and did this to it. Yep, in a lot of ways he made it better. At least for what he wanted to do with the Jeep, which was take his family out on the local trails without having to worry about breakage. First, we’ll start with the factory frame, which is somewhere else. We don’t know where, because Brian ditched it to build his own out of 2x4-inch, 0.188-wall rectangular tubing.
Once the rails were laid out, Brian got to work building his own front and rear triangulated four-link with high ground clearance in mind. Since there are a lot of big ledges to climb in the terrain Brian frequents, the rear lower control arms were designed for maximum rear tire approach angle coming into ledges. The rear lower control arms are fabricated out of multiple pieces 1¾-inch, 0.188-wall tubing and the rear uppers are 2-inch, 0.250-wall. Up front, both the upper and lower control arms are 2-inch, 0.250-wall DOM; Currie 2.5-inch Johnny Joints are used at each end of all the control arms.
After the control arms that stretch the wheelbase out to 135 inches were wrapped up, Brian got to work building the mounts for his 14-inch-travel ORI ST struts. The ORI struts allowed Brian to forgo coil or coilover springs and have lots of high-tech features like internal bumpstops, adjustable rebound damping, and very lightweight construction. Despite the internal bumpstops, Brian mounted a quartet of Fox hydraulic bumpstops (3-inch-travel in the front and 2-inch-travel in the rear) because lots of time, and those ORI struts ain’t cheap.
Drivetrain
Let’s talk about the elephant in the room—or in this case, the pair of elephants. A couple 2.5-ton Rockwell steering axles from mid-’80s military M35A2 trucks were sourced and the double-reduction centersections stuffed with Detroit Lockers. You can probably tell by the wide stance that the hubs are flipped out. While the axles were apart, Brian chopped the “bowls” off the bottoms of the housings and welded in a “Mohawk.” In case you’re not up on your Rockwell terminology, what we mean is that he shaved the bottom of the housings nearly flat with the exception of the bull gear protrusion. The 6.72 gears and axleshafts were left stock, but the gargantuan drum brakes were pitched for some custom pinion brakes. For the rotors, Brian used cross-drilled parts from the rear of an ’87 Mazda B2000 pickup truck that were fitted to the yoke with some custom machining. Then, he hung some ’89 Toyota Tacoma calipers on some custom mounts. Pinion brakes have the advantage of multiplying the braking power by the ratio of the axle gearing, so as long as both axleshafts don’t bust in the front or rear, Brian has 6.72:1 times better clamping per caliper than a stock Toyota pickup. Additionally, Brian runs a custom Wilwood master cylinder setup that allows him the ability to run only the rear brakes (for cutting turns we presume), or both the front and rear brakes at the same time.
Moving up from the axles, Brian built himself a pair of super-heavy-duty 1410 driveshafts. The rear runs 3-inch, 0.188-wall tubing and the front has an extra-long slip spline and custom end yokes. The shafts connect to an Atlas II T-case with a 3.0:1 low range and a TH400 transmission was built to withstand hardcore assaults with beefed internals, a Transgo shift kit, a 2,200 rpm TCI stall converter, and a B&M pan for an extra 2-quart capacity. A B&M Hi-Tek tranny cooler keeps it from roasting itself in the rocks.