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September 2013 Nuts & Bolts - Tech Questions

Posted in How To on August 13, 2013 Comment (0)
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Photographers: 4-Wheel & Off-Road archives

First Fabber
Q I have a ’91 Toyota truck that I really want to build into a rockcrawler. I have been saving my money to buy a welder and just purchased a used MIG machine with some help from my dad. He has promised to help me with a solid axle swap, but we both agreed to start with other upgrades first, like bumpers and rock sliders and then maybe a rollcage. I am looking for some input on how best to build a bumper. I want a winch but don’t think I can afford a good one just yet. (I’m steering clear of the imports; I’ve heard bad things about them from my dad’s buddies). Do you have any input for a kid looking to build his own bumper? I have a welder and a grinder of my own and have access to a torch and tube bender at a friend’s house.
Shane P.
Via nuts@4wheeloffroad.com

A You are on the right track, and that’s great to see. Building bumpers and sliders will get you good fabrication experience on components that would not be overly life-threatening if they failed, compared to a custom suspension or rollcage.

If you want a winch but cannot afford it, I recommend getting a winch mounting plate first and building your bumper around that. Most winch companies sell these to work with their winches, but double-check exactly what winches it fits. An 8,000- to 9,000-pound winch will be plenty for a Toyota mini truck. Most winch companies also list the dimensions of the winches on their website or catalogs, and you’ll want to be sure the winch will clear the rest of your bumper and grille and can be installed after the bumper is installed if you’re welding it directly to the frame.

Another recommendation I have is to make the bumper so it can bolt on and off, as this will allow you to remove it to better paint it and install the winch. Of course, many fabricators build bumpers that weld right to the frame, but just realize that you’ll probably destroy it if you ever try to remove it. With that size truck I think a tube bumper made of 13⁄4x0.120-wall tubing will look good and be relatively strong. Or you could use cardboard and design a flat plate steel bumper, but then you need to cut all those pieces out of plate with the torch, and I think you could make the bumper look better with tubing. I actually just built a super-simple front bumper, and you’ll see some of it next month in Cheap Truck Challenge.

Another item you may need is tabs and brackets for lights or to use as gussets for your bumper. I recently ordered up a Smith Pack from TMR Customs (www.tmrcustoms.com). This is a kit of various-sized tabs and brackets, and gussets and even light mounts and tube flanges, and it only costs $100 but gives you a variety of parts to start building with.

As a final note, remember to make your new bumper high enough not to hinder approach angle, tight enough to the body that you don’t just hit bumper when coming up to an obstacle, and strong enough that if you need to be pulled by it or run it into a rock it doesn’t crumple into your grille and smash your radiator or lights. Good luck!

Which 60?
Q I am building an ’87 Dodge Ramcharger and need help with my front axle. I found a Dana 60 out of an ’85 1-ton Dodge, and it has a center axle disconnect. I want to know who makes gears for this axle. I want to run 4.56 gears and 36-inch tires. Any help would be great.
Justin R.
Via nuts@4wheeloffroad.com

A You are looking for a set of low-pinion or standard-rotation Dana 60 gears. Just about any gear supplier can sell you these. However, I do not believe there was a center axle disconnect offered in the Dodge front 60 in 1985, but there was starting in 1994, so it may be a newer axle you are looking at. Most axles have a bill of material, or BOM, number stamped somewhere in the axletube for you to verify what that axle is from. As an aside, you can replace the center axle disconnect with a solid long side axle. Nitro Gear & Axle (www.nitro-gear.com) offers these axleshafts (PN AXN48215).

A-Arm Error
Q I have an ’02 Chevy Silverado 2500HD 4X4 and would like to level out the truck by raising the front about 11⁄2-2 inches. It appears that there is plenty of adjustment left in the torsion bar bolts (11⁄2 inches showing), but I can see that tightening them up causes the A-arms to point down more, and likely the ride will suffer. Looking at the torsion bar keys available on the market, it appears that they would do the same thing and just allow more adjustment range due to the reindexing of the position of the torsion bar relative to where the key arm and bolt is positioned. For the same amount of lift, wouldn›t the torsion bar key give the same A-arm angle and stiffness of the ride as adjusting the stock bolt inward? Or am I nuts and confused?
Duane H.
Via nuts@4wheeloffroad.com

A You are exactly correct. By adding more preload to your torsion bars you are in effect pushing down on the A-arms and raising the truck. The difference is that when you add a torsion bar key leveling kit such as those made by Daystar (daystarweb.com) can allow the torsion bar to be twisted more than a factory torsion bar key and in effect raise the vehicle more. The angle of the A-arms isn’t the main problem; it’s the angle of the axleshafts and whether you overextend the CV joint in these axles. That is why most IFS suspension lifts lower the center axlehousing so the angles are not so great on these joints.

Companies such as RCV Performance Products (www.rcvperformance.com) continue to develop axles that can take even more angle and power than stock units. Of course, the other problem is ball joints on the steering knuckles. Companies are addressing this problem as well, such as Synergy Suspension (synergysuspension.com), which offers a full line of upgraded ball joints for various 4x4s.

IFS, ands & Buggies
Q I’m trying to build a full independent four-wheel-drive, four-wheel-steer buggy. I need help on what to do about differentials and driveshafts. I’m looking to run 35-inch tires with a 4.3L V-6 and a five-speed.
Victor B.
Via nuts@4wheeloffroad.com

A 15 years ago I would have thought you were crazy, but the current trend with high-dollar racing 4x4 buggies is just about what you are planning. The idea of a full independent buggy isn’t new, but the technology is just getting better and better to build it. A lot of ideas have been tossed around by successful race teams in the Ultra4 series (ultra4racing.com) for building strong IFS vehicles.

Here is one big issue: The differential that is closest to your engine—front if you’re going front engine, or rear if you’re going mid/rear engine—is going to have some severe driveshaft angles since you want the independent differential as close to the center of the chassis as possible and that means the driveshaft must come from the transfer case and wrap around the engine up to the diff. Most of the IFS rock-racing buggies have the engine in the rear and then use a solid rear axle with the differential pushed over towards one side or the other, but I think you could make it work with proper driveshaft angle with some work.

I think the most economical way to build a vehicle like this would be to use the independent axles and portal boxes from a surplus military Hummer H1. These are not designed with rear steering, but they look pretty easy to adapt to rear steer. I know Pat Gremillion from Premier Power Welder (premierpower welder.com) has built a very cool full independent Jeep CJ buggy with the Hummer differentials and portal box. This gave him a suspension with very flat A-arms helping the CV joints last, and the portals reduce the stress on the axleshafts. These parts are not impossible to find; you’ll just have to start hunting through the many government surplus yards to find them.

There are many other IFS differentials that you could build off of, but most are offset to one side or the other. A final option is to look into the many independent differentials that companies like Spidertrax Off-Road (www.spidertrax.com), Currie Enterprises (currieenterprises.com), and Dynatrac (dynatrac.com) have been developing.

Nuts, I’m Confused
A Lower High, Please
Q I have an ’83 Bronco on38-inch TSLs, with 4.56:1 gears and Detroits in a 9-inch rear and TTB44 front, with a failing NP208 case. I want deeper gearing and want to know if (and this is a challenge, here, to all aftermarket transfer case manufacturers) a transfer case could be built with, say, a 1.5:1 high range and the 4:1 low range. Could a planetary-type gear-reduction set be integrated into the input shaft to reduce the high-range ratio (possibly requiring the input shaft housing to be lengthened to provide ample space)? The idea here may allow a person to only acquire a replacement transfer case when installing taller tires and wanting a deeper low range, rather than gearing down the axles and acquiring a case. One product would then accomplish two purposes and possibly save time and money.
Josh A.
Madison, MN

A What you’re asking for isn’t impossible, but there are a few issues to consider. First, it is my opinion that you want a large portion of your low gearing closer to the tires. This is because then there are fewer components to run that torque multiplication through. By lowering your high range you are in effect increasing the torque against your driveshafts and their joints, where if you put that lower gearing in your axles the torque only has to go through the axleshafts. I have always been a fan of portal boxes or planetary axle hubs because that gets the gearing right down at the wheel ends, but this adds weight and cost issues.

The next issue is that any gearing lower than 1:1 is going to be less efficient because it will have to go through the gearing change versus having a direct drive. This can mean a depreciation of fuel economy, though that isn’t really a deciding factor for most 4x4 builders adding big tires.

Finally, there actually are a few transfer cases exactly like what you want. They’re found in some older Land Rovers and Suzuki Samurais. These cases allow lower high-range gears to help with running larger tires in high range, such as on the street. One problem is that all of these cases have an offset rear output with the rear differential offset to the passenger side and in line with the front differential. This is possible because the drive force comes into the transfer case and then goes through gears before coming out, while with a standard-centered transfer case the drive force goes straight through the case in high range.

I think your idea has merit. For this reason I picked your letter as the Nuts, I’m Confused letter of the month. But here is the kicker: Not many companies make aftermarket transfer cases, and I think this would require a complete redesign to achieve. Could they make a 1.5:1 high-range transfer case? Yes, anything is possible, but I don’t believe there is the market for it to cover the cost of R&D.

In our position at the magazine we get a ton of great ideas like this from off-roaders and readers, and we love hearing them. The problem is that there is always the issue of whether the demand can support the cost of development. Take for example the small diesel 4x4 truck everyone asks for. The U.S. market has learned that more buyers want a big truck than a small truck, but many of us off-roaders want a small truck. Over the past few years small truck sales have dropped off and many OEMs have discontinued them altogether. However, opinions change, and I think demand for a small fuel-efficient truck will rebound again and they’ll be back. There is almost always a market for a cool product; the question is, is the market big enough for someone to make the product? And in the case of the lower high-range transfer case, I think the market isn’t as strong as the market for lower axle gears and the preexisting transfer case design.

Since I like your question I’m going to award you one of this year’s Ultimate Adventure T-shirts. Oh, and by the way, have you heard of the Advance Adapters (www.advanceadapters.com) four-speed Atlas transfer case? There is a little rumor running around that Advance Adapters is developing a four-speed transfer case with a 1:1 high range, a 1.5:1 high-mid range, a 2.72:1 low-mid range, and a 4.08:1 low range. If that rumor becomes reality then your idea will come to fruition. I hope someone will soon invent the adjustable Allen wrench I’ve been waiting for.

Submission Information
Confused? Email your questions about trucks, 4x4s, and off-roading tech using “Nuts, I’m confused” as the subject and include a picture (if it’s applicable). Digital photos must measure no less than 1600 x 1200 pixels (or two megapixels) and be saved as a TIFF, an EPS, or a maximum-quality JPEG file. Also, I’ll be checking the forums on our website (www.4wheeloffroad.com), and if I see a question that I think more of you might want to have answered, I’ll print that as well. Otherwise drop it old-school style with the envelope addressed to the address below. Letters published in this magazine reflect the opinions of the writers, and we reserve the right to edit letters for clarity, brevity, or other purposes.
Write to: Nuts & Bolts, 4-Wheel & Off-Road, 831 S. Douglas St., El Segundo, CA 90245 fax to: 310.531.9368 Email to: nuts@4wheeloffroad.com

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