The 2020 Ultimate Adventure Long Range Jeep #UA2020
Part 2: Steering, control arms, and mounting the drivetrain.
In part one of these more in-depth and detailed articles on the 2020 Ultimate Adventure Long Range Jeep we introduced you, the reader, to the source material for the theme of the build. Namely the WWII SAS-piloted Jeeps that helped win the war for the Allies in North Africa. We also introduced the drivetrain components and gave you a rough idea of how all these parts would be assembled to power the UA LRJ. This time we will take that a bit further by showing you how we mounted the drivetrain in the vehicle.
That means we'll show you and tell you how we built motor mounts to secure the Cummins R2.8 and a stout center crossmember to hold the transmission and transfer cases. From there we will dig deeper into the control arms and control arm mounts that locate the Dana Ultimate Dana 60 axles. This, of course, will take some custom work since the chassis under the UA LRJ is a lengthened TJ (1997-2006) Jeep Wrangler, and our control arms are from Skyjacker and intended for a Jeep JK (2007-2018).
With the engine and axles held in place fabricating a steering system becomes important, so we will also dig deep into all the parts that make the 2020 UA LRJ steer down the road and trail. That includes a ram assist system and ported box from West Texas Offroad, Steering shaft from Borgeson, and huge heavy-duty tie rod and drag link with their unique tie-rod ends from Rare Parts. Mix all these bits together with some elbow grease, thread locking compound, and a few hours of labor, and things begin to take shape.
Quick Draw Brand Adapters sells a complete motor mount installation kit for the Cummins R2.8 to be swapped into a TJ or LJ chassis like the one we are using. Using the parts that they designed would have been easy, but we wanted to control where the engine ended up. That meant using the engine side motor mounts from Quick Draw Brands but building our own frame side engine mounts. To do this we got the engine right were we wanted it, offset about 3 inches to the passenger side of the vehicle, and used CAD (cardboard aided design) to first build the passenger-side frame side engine mount you see here.
With one side of the engine held in place, we duplicated our methods to build a driver-side frame side engine mount. We used 3 x 3/16 (or 0.188) steel plate to construct both sides of our frame side engine mounts. These mounts started life as boxes open to the bottom so the rubber motor mount isolator could be accessed for removal and replacement. Both frame side engine mounts will receive triangulated gusseting to strengthen them as the build progresses.
With the engine suspended between the framerails we could focus on building a transmission and transfer case crossmember. It will end up being made of two major components. One spans the gap between the right and left framerails and is mostly made of 2 x 5 x 0.188-wall rectangular steel tubing. The second part is hard-mounted to the transmission and transfer case. This part is then isolated from the first part of the transmission and transfer case crossmember using some polyurethane pucks supplied with the Magnum Underdrive and Ford NP205 from Offroad Design.
Here you can see one of the bolts (there are two, one per side) that hold the two pieces of the crossmember together and two of the polyurethane pucks that isolate the two pieces from each other. Between this and the motor mounts the engine, transmission and transfer cases are held firmly in place, but can move and vibrate, to some extent, independently of the vehicles frame.
Jeep Wranglers with coil springs and link suspensions have evolved over the past 23 years since the introduction of the TJ Wrangler in 1997. TJs, from the factory, ride pretty darn well, but JKs and JLs (the two Wrangler models that followed the TJ) ride even better. That's for a few reasons, one of which is longer control arms and better suspension geometry. While we want this Jeep to, without doubt, be a Jeep, we want it to ride well, both on-road and off-. To that end we had Skyjacker Suspensions send us a set of long arm control arms for a JK. They would fit the Ultimate Dana 60s no problem, but we'd have to further customize our lengthened TJ frame to accept the frame side of these control arms. For the front lower control arms, we used these simple control arm mounts and set the front axle about 1.5 inches ahead of the stock front axle location on a factory TJ.
Out back we used part of a Skyjacker supplied control arm mount (again, intended for a JK) to locate the front end of the Skyjacker Suspensions JK long arm control arm, and an aftermarket upper control arm mount for the Skyjacker JK upper rear control arm. The multiple mounting positions of the frame side rear upper control arm mount allows us to fine-tune how the vehicle climbs on the trail. Our intention is to copy the rear control arm geometry that our friend Chris Durham of Chris Durham Motorsports uses, namely geometry that helps in climbing situations. Chris is well known for one-shotting climbing obstacles all over the country on UA and while he competed in rock-crawling competitions.
The rear suspension of a JK isn't perfect, and nothing is. For one, most folks prefer a true four-link with triangulated uppers or lowers over the four-link with a track bar that JKs use from the factory. We agree, but hey, a JK's rear suspension works pretty darn well, and as with any project, we had to make compromises because we didn't have all the time in the world to fine-tune triangulated upper control arms. We may change this in the future, but for now we are going with the factory JK rear upper control arm placement using Skyjacker control arms mounted to our rear Ultimate Dana 60 axle housing. We'll talk more about the springs in a future installment of this build, but you can see we moved the rear coilover spring mount out about as far as we could with the shown tabs. As we said, we'll elaborate more on this later, but this helps keep the rig stable on sidehills.
For the front upper control arms, we once again used an off-the-shelf part from Skyjacker Suspensions in the form of JK front upper control arms. We mounted the frame end of the control arms in the same horizontal plane as the stock TJ control arm mount, but just behind the factory TJ upper control arm mounts. To mount the arm to the frame, we used a hole saw to drill holes for a sleeve that would allow a bolt to run through the frame and then through the control arm before being capped by a double shear box. Here you can see the top and rear of this double-shear box and how we clearance it for the Cummins exhaust.
Up front we decided to build these axle end shock mounts. Again, they are far out on the axle, increasing the stability of the rig once the upper shock mounts are finished. We will cover that in detail in a future instalment of this build series, but this picture fits well here since we are talking about locating the axles. While it's nice to slice a build like this into multiple parts, you have to have a holistic idea of how everything will work together, rather than solely focusing on one aspect of the build. The control arm mounts have to work with the drivetrain and steering, allow space for the tires and driveshafts, and more.
Tack-welding major components in place and then cycling the suspension with as many parts in place as possible is part of this holistic approach to building a vehicle. Again, we are getting a little bit ahead of ourselves here, but you can see that we cycled the suspension multiple times throughout the build to make sure all the parts will clear once everything is in place.
West Texas Offroad offers high-quality ram assist parts at reasonable prices. The company often re-builds and ports factory steering boxes for their customers. We've used them for several of the recent Ultimate Adventure builds with great success, so as we have in the past, we called them up and asked what they would recommend for us. The last three years TJ and LJ wranglers were produced, Jeep used a Mercedes-sourced box that several companies shy away from. Despite this, West Texas Offroad has had pretty good luck with these boxes, and they know how to port them for hydraulic ram assist. So we started out with a freshly rebuilt and ported late-model TJ steering box, because at the time it seemed like running factory parts in the factory location would be the simplest route to take. We ended up redoing the Jeep's front framerails to allow for maximum uptravel of the front axle. That means we could have gone with a more standard Saginaw steering box, but we'll work with what we have and quality parts from manufacturers we trust.
Here are our new front framerails. They are made from 2 x 4 x 0.120-wall rectangular steel tubing that is frenched into the factory frame and plated with fish plates at the junction between new and old parts. It raises the steering box up about 2 inches, which helps us run a flat Pitman arm (which is stronger than a drop Pitman arm) and allows us to get all the uptravel we can without the axle housing sharing space with the frame and engine. The steel sleeves hold the steering box in place, come what may, and our winch mount/front bumper will help secure the two framerails together, forming a box.
Rare Parts makes some huge steering parts for Jeep JKs and more. We put our hand in the picture for scale, but even that doesn't do these parts justice. The shank on that tie-rod end is 1 1/4 inches in diameter; the standard for 1-ton tie-rod ends is 7/8-inch. That's 3/8 of an inch larger. On top of that, these tie-rod ends have removable, replaceable, and flappable tie-rod end cartages. These cartages thread into the tie-rod end forging and are massive like the rest of the parts.
With the steering components falling into place, the front of the UA LRJ begins to look like a Jeep again. Check out the 1 3/4-inch tie rod from Rare Parts in this picture. You can also see the extra ports on the side of the Redneck Ram/West Texas Offroad prepped steering box. We used a flat Pitman arm from Parts Mike and drilled it to match the TJ Pitman arm length. Different boxes rotate different amounts, so it's a good idea to verify the throw of the Pitman arm and the throw of the axle's steering knuckles before drilling the Pitman arm for the tie-rod end at the Pitman arm end of the drag link. You want the steering stops on the knuckles to bottom before the steering box runs out of throw. Over rotating the steering box can damage it.
We've used Borgeson steering parts on countless vehicle projects, and the quality of the parts is second to none. We were able to use factory replacement steering shafts for our 2003 TJ (PN:000873 for the upper steering shaft and PN: 000876 for the lower steering shaft). This transmits the steering input from the Jeep's steering column to the steering box. We also had to incorporate the factory pillow-block steering support over our custom driver-side frame side engine mount.
These are the parts needed to add West Texas/Redneck Ram ram assist to our JK-style Ultimate Dana 60 front axle and JK-style Rare Parts tie rod. West Texas Offroad includes tabs, bolts, washers, and high-pressure hydraulic hoses and a few 90-degree fittings to hook the ram up to your ported steering box.
Cummins, 800.286.6467, www.cummins.com/engines/repower
Dana, 800.621.8084, spicerparts.com/applications/crateaxle
Falken Tire, www.falkentire.com/
IH Parts America, 530.274.1795, www.ihpartsamerica.com/
Offroad Design, 970.945.7777, www.offroaddesign.com/
onX Offroad, onxmaps.com/offroad-app
Quick Draw Brand, 513.446.9654, quickdrawbrand.com/
Quigley Motor Company, 800.233.9358, quigley4x4.com/
Skyjacker Suspension, 318.388.0816, skyjacker.com/
VooDoo Offroad, 844.866.3661, www.voodoooffroad.com/
Warn Winch, 800.543.9276, www.warn.com/