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10 Modifications to Make a Jeep CJ-6 Stand Out

Here are the hidden features of Christian Hazel’s 1971 CJ-6 Ultimate Adventure Jeep you may have missed

Christian HazelAuthor/PhotographyHarry WagnerPhotographyJerrod JonesVideography

It's no secret that almost every year the staff of Petersen's 4-Wheel & Off-Road builds a wild 4x4 to lead its super popular Ultimate Adventure event. For the 2017 event, the 4WOR staff of Christian Hazel and Verne Simons planned and executed one of the most unique Jeeps to grace the face of the earth. And given just how many Jeep builds there have been on this planet, that's saying a lot. The "UACJ6D" is the name we hung on this thing: UA for Ultimate Adventure, CJ6 because we started with a CJ-6, and D for diesel. But more on that in a bit.

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The Jeep CJ-6 ("UACJ6D") Backstory

Christian Hazel has always been into long-wheelbase early CJ Jeeps, having owned about five of them. What would eventually become the UACJ6D was purchased in June of 2012 as a non-running former US Border Patrol 1971 CJ-6 from a neighboring town in SoCal and dragged home. As Editor of Jp magazine at the time, Hazel got it running and then started prepping it to enter Four Wheeler's Top Truck Magazine by installing a pair of Rockwell 2.5-ton axles under it. But soon after the axles were installed, Hazel became Editor-in-Chief of Four Wheeler, thereby making him ineligible to enter Top Truck Challenge. The Jeep CJ-6 went into project hibernation mode, sleeping in Hazel's RV parking area until the stars aligned. After becoming Editor-in-Chief of Petersen's 4-Wheel & Off-Road, Hazel decided it was finally time to make something of the UACJ6D, loaded it onto a trailer, and dragged it to 4WOR Tech Editor and all-around creative genius, Verne Simons. Verne just has a different way of looking at things. Where most people see 10 as the sum of 5+5, Verne sees it as the square root of 100. Or something like that, we're not good at math. Point is, Christian told Verne what he wanted the project to be in broad strokes and Verne worked his unique combination of exceptional original thought and mechanical talent to make the ideas a reality. So here are some of the more unique features of the UACJ6D.

Cummins Turbodiesel Power

The UACJ6D's party piece is the Cummins R2.8 Turbo Diesel crate engine (cumminsrepower.com). One of the very first Cummins R2.8 Turbo Diesel Crate Engines to ship, 4WOR was one of the few outside Cummins to be part of the R2.8 Beta program and the R2.8 in the UACJ6D is one of the longest-serving R2.8 diesel engines in North America. With 161 horsepower and 310 lb-ft of torque, the R2.8 in the UACJ6D delivers plenty of power to move the 38-inch tires, exceptional on-trail fuel economy, and impressive highway mileage. Depending on the vehicle speed and grade, the UACJ6D gets about 17-21 mpg heading to the trail, which isn't bad for a 4,876-pound Jeep on 38-inch tires.

Five Gear Shifters!

Christian Hazel likes manual transmissions, so the drivetrain in the UACJ6D takes shifting gears to an extreme. Directly behind the Cummins R2.8 Turbo Diesel Crate Engine is a Ranger Torque Splitter gearbox from Advance Adapters (advanceadapters.com), which provides either a 1:1 direct-drive ratio or a 0.73:1 Overdrive. Since the Ranger Torque Splitter can be shifted in or out of any gear, it essentially doubles the number of forward and reverse gears in the UACJ6D. Behind the Ranger Torque Splitter is an original, unrebuilt SM420 four-speed transmission that Hazel bought used for $100. The SM420 features a super-low 7.05:1 First gear ratio which provides a really good crawl ratio by itself...but we're only on shifter Number Two, so you know it's not by itself. Behind the SM420 is an Offroad Design (offroaddesign.com) Magnum Box Planetary Underdrive that adds a 2.72:1 gear reduction into the mix when the little wrench welded onto the shift lever between the bucket seats is yanked. Yes, a wrench serves as a shifter. We told ya Verne was creative. The Magnum Box features some truly gargantuan parts, including a super fat output shaft that prevents gear reduction-induced shaft breakage in the NP205 T-case behind it. And yes, the final two shifters belong to an Offroad Design rebuilt and beefed Ford NP205 transfer case with ORD's super-sweet-shifting twin-stick package that allows independent shifting of the front or rear outputs. With the 1.96:1 Low of the NP205 in conjunction with the Magnum Box Planetary Underdrive, the Offroad Design Magnum/NP205 combo allows for low range ratios of 1.96, 2.72, or 5.33:1. But remember, any of those ratios can be reduced by 27 percent by engaging the Ranger Torque Splitter and obviously any of the SM420's four gears may be selected. So with this dizzying array of available gearing options, the UACJ6D can produce an engine and tire speed for pretty much any terrain.

Real Wood Floorboards

Going back to the days of horse-drawn wagons and early automobiles, floors were made of wooden boards. That's where the term, floorboards comes from. So while we can't necessarily call using wood as the floor of the UACJ6D an original idea, what is original was using the wood from the crates that our Ultimate Dana 60 front and rear axles and Cummins Turbo Diesel Crate Engine came in. Verne added some varnish to help protect the Dana crate logos from heavy foot wear, but otherwise the floors on the UACJ6D are made of the engine and axle crates just as they were. Verne built them with enough room to expand when the weather is wet, and when the vehicle is run in super arid conditions the wood shrinks up so much that you can see the trail between the boards. It's pretty cool.

Modern Frame, Suspension, and Axles

Although the UACJ6D started out as a complete, running 1971 CJ-6, we decided to use a modern frame from a JK Unlimited that Verne had procured. Verne shortened the JK frame about 9 inches in the middle and lopped some of the rear overhang off to match the shorter body lines of the CJ-6, but otherwise most of the axles, suspension, and steering use bolt-on parts for a JK Wrangler. The steering is comprised of a hydraulic-assist PSC Motorsports (pscmotorsports.com) box, pump, and ram for a JK Wrangler. The suspension is a bolt-on Skyjacker Curt LeDuc Series coilover system (skyjacker.com) that allows excellent travel and control, yet fits on the factory JK frame with minimal effort as compared with trying to fabricate an entire coilover suspension on an early CJ frame. And finally, the axles are a pair of exceptional Ultimate Dana 60 bolt-in JK Wrangler crate axles from Dana (spicerparts.com) that offer better than 1-ton strength, huge brakes, incredibly beefy chromoly axleshafts and SPL70 U-joints, as well as your choice of gearing and lockers. For the UACJ6D's torquey Cummins we went with 4.88 gears and Eaton ELockers (eaton.com) front and rear for on-demand traction when we need it and tight turning when the lockers are off.

Classic Jeep Factory Parts

Although the temptation to replace every factory component with high-zoot aftermarket parts is strong when building a high-profile vehicle, we showed some restraint and kept many key pieces of factory hardware. The low-back bucket seats have been recovered with grayish-blue cloth some time in this vehicle's past, but the frames and cushions are the same stuff that left the factory in 1971. It's the same story with the huge, cracked steering wheel. And although rusted with almost 50 years of patina, the body, sheetmetal, and (most) of the paint was retained rather than replaced with aftermarket steel or aluminum panels and a fancy respray or vinyl wrap.

Chopped Windshields and Hot Rod Rake Rollcage

Christian likes hot rods, including early '50s styled T-buckets and Model A roadsters. Because of that, he asked Verne if he thought he could chop the windshield in a text one day while Verne was out in the shop working on the Jeep. The reply came 15 minutes later in the form of a texted picture of the windshield frame with about 3 inches taken out of it. The resulting windshield line left Verne a puzzle to solve regarding the rollcage design, but in the end Verne nailed it with the Hot Rod rake of the B- to A-pillar tubes. Hazel loves it. Adding those Hot Rod cues into the mix is the fact that Hazel wouldn't let Verne cut down the original SM420 shifter, which sits somewhat comically tall inside the cockpit, but evokes memories of early 1950s T-bucket ape hanger shifters.

Super Low, Wide, and Stable

Christian wanted the Jeep to sit as low and wide as possible. In addition to running a slightly shorter coil than what the factory Skyjacker Curt LeDuc Series JK suspension system calls for, during the buildup Christian asked Verne if he thought he might be able to channel the body down on top of the frame. In usual Verne fashion, the reply came about 30 minutes later in the form of a texted photo showing the UACJ6D tub on its side with the floor completely cut out. Verne built a pair of tubular rocker guards out of heavy-wall 2-inch DOM tubing, stitch-welded them to the rocker panels, and then attached them to the frame with runners. The rocker tubes are just about even with the bottom of the JK frame. The rest of the body mounts were custom-built by Verne and then once the body was attached to the frame, Verne went about building the floor and drivetrain tunnels to (more or less) close things up. Additionally, Christian wanted the inside of the tire sidewalls to be even with the outside of the body tub, so after doing some math to figure wheel backspacing requirements to achieve that with the 69-inch-wide Ultimate Dana 60 axles, Hazel ordered the 17x8.5 TrailReady beadlocks (trbeadlocks.com) with a 4-inch backspacing which put the 38x13.50R17 Falken Wildpeak M/T sidewalls right where he wanted them.

Different Headlights and No Symmetry

If you notice, the Warn 8274 winch (warn.com) is also offset to the passenger side just slightly to create clearance for the steering system. For the past 20 years Christian has been building his 4x4s with the mantra, "symmetry is for chumps." Really, when form follows function you have to be willing to let go of silly things like making sure stuff looks equal side-to-side. To that end, when Verne told Christian the huge intercooler that Axis Industries (axisindustriesusa.com) built for the R2.8 wouldn't fit behind the grille without blocking one of the headlight buckets, Christian just said, "well, we'll only have one headlight then." But on the final day of the build, as the entire Ultimate Adventure 2017 cronie crew were feverously helping to get the vehicle wrapped up in time for the official start of UA2017, our buddy and fervent early Jeep collector, Mike Travin, said "I think I got something for that" and ran off to his house. Mike returned a few minutes later with a tattered and abused early CJ-5 bikini top and a single Per Lux off-road light. While Chris Durham installed the bikini top to keep Christian from frying like bacon in the 126-degree Arizona sun that baked UA2017, Verne welded a little tab to a piece of tubing holding the intercooler in place and the lamp bolted right on with the vintage bracket that was still attached to it - just like it'd been planned all along. In truth, the Per Lux light is one of Christian's favorite parts of the build, partially because of how it looks, but also because it exemplifies the helpful and selfless nature of the Jeeping 4x4 community.

Radiator Overflow Cocktails

If there's one comment we get from people seeing the UACJ6D for the first time more than any other it's, "why is there an urn on the front bumper?" A lot of people think it's the ashes of a dearly departed family member or even a pet, but the answer is, it's not an urn. It's a martini shaker! It was literally five minutes from departure time to kick off Ultimate Adventure 2017 and somebody noticed the UACJ6D didn't have a radiator overflow catch can. Normally we'd just zip tie a soda can to the grille and hit the trail, but Verne said, "hold on" and ran into his garage. He came back to his backyard 40x40 shop holding an old martini shaker, which after drilling a hole for the radiator overflow tube, he tack-welded to the driver-side front framerail. In the middle of the Arizona desert while on UA2017 Christian found a beautifully patina'd propane bottle that somebody discarded that he's almost swapped out several times, but in the end just can't bring himself to part with the grandma urn martini shaker. By now it's become too ingrained with the whimsical character of this Jeep.

Road Runner

While many hardcore off-road rigs travel to and from the trail on a trailer, the UACJ6D is street-driven almost everywhere. The first rule of Ultimate Adventure is "No Whining". The second is "No Trailers". The UACJ6D upholds that tradition. The Cummins R2.8 engine loves the open road and the Ranger Torque Splitter effectively reduces the 4.88 axle ratio to 3.56s. When coupled with the 38-inch tires, the engine speed is a very sane 2,400 rpm at 75 mph. And because the suspension, steering and axles are all modern Wrangler parts, the UACJ6D tracks straight and true down the road at speeds (where legal) at 80 mph. We definitely get some weird looks as we blast past motorists in a Jeep with no top and doors that looks like it was just dug up from the bottom of a lake, but for every look of confusion we receive, we get three or four smiles, waves, and thumbs up. And that's what having a Jeep is all about: making you and others happy.

10 Modifications to Make a Jeep CJ-6 Stand Out

  • Cummins turbodiesel power
  • 5 gear shifters
  • Real wood floorboards
  • Modern frame, suspension, and axles
  • Classic Jeep factory parts
  • Chopped windshields and hot rod rake rollcage
  • Super low, wide, and stable
  • Different headlights and no symmetry
  • Radiator overflow cocktails
  • Drive it on the street