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June 2005 4x4 Tech Questions - Tech Questions

Willie Worthy | Writer
Posted June 1, 2005

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Four Wheeler
6420 Wilshire Blvd.
Los Angeles, CA 90048-5515.

All letters become the property of Four Wheeler, and we reserve the right to edit them for length, accuracy, and clarity. The editorial department also can be reached through the Web site at www.fourwheeler.com. Due to the volume of mail, electronic and otherwise, we cannot respond to every reader, but we do read everything.

Question: Over the years you have given me succinct advice on each new XJ that I have owned, including an '87, a '93 and the last of the line, my '01 Cherokee Sport.

For perspective, I sometimes pull a 2,000-pound trailer, don't get way off-road too much these days, but do some desert exploring here in Arizona. I do travel to the Colorado San Juans and took my '87 on an early Hole-In-The-Rock Jamboree (and survived!).

As Jeep vehicles become only "trail rated," the Cherokees have become history, and Grand Cherokees are next, bigger and heavier-again! Now we see an IFS and a switch to electro-diffs on the new bloated version.

One simple question now: Is owning an '01 Command-Trac auto Cherokee better than running out to buy one of the last '04 Grand Cherokees with the Vari-Lock 4x4? Please give me some good advice on which choice is the "keeper" for the next 10 years or so.
Steve Owen
Chandler, AZ

Editor: The Vari-Lock on the Grand Cherokee is a really great system for what it was designed for-street use in bad weather, like snow and rain, and some not-so-serious 'wheeling. OK, with those words, I am going to get a whole bunch of letters telling me just how great their Grands are. And I will agree. If I could afford one, I would be driving an '04 instead of my '96. But I also get letters telling me that there is just way too much wheelspin before the system locks up.

The benefits of the new Grand are a great new engine with lots of performance that would do a great job of pulling your trailer, along with ride and comfort levels way beyond anything you will ever experience in your Cherokee Sport. They also make pretty decent off-road vehicles.

Question: I have a '78 Scout II 4x4 which I would like to change into a 2x4 desert rig. My problem is that I can't decide whether to use a solid I-beam front end or a Ford twin I-beam front end. The twin would be more work to install, but it would make for a better ride on rough trails. Which setup do you think would be worth the time? Or do you have any other better ideas?
Brandt Dietz
via fourwheeler.com

Editor: First off, why would you want to use a Scout as a go-fast rig in the desert? No, I don't have anything against Scouts and even built one as a project vehicle for this magazine and have owned at least four IHs. It's just that they are very nose-heavy, due to the "truck" V-8 they use and its forward mounting location. The IH engine is a torquer, not a high revver, the last being something that is handy in high-speed desert running.

I assume that when you say a solid-beam front end, you intend to use leaf springs. Well, that would be the easiest swap, as there were two-wheel-drive IHs made with a solid front straight axle that used the same leaf-spring suspension as the four-wheel-drive versions. While you would lighten up the front end somewhat, as well as the over all weight without a driving axle and a transfer case, I doubt that you would see that much difference in the handling. The twin I-beam conversion (I am assuming would come from a Ford truck), would be quite a difficult conversion, partly due to the engine's forward location. Nothing is impossible, but it would be a major undertaking. Do keep in mind that the Ford's track is wider than that of the Scout, so modifications to the arms would have to be made, or wheels with quite a bit of backspacing could be used to keep the track the same as the rear.

If you really want to go fast, the answer is to copy some of the Unlimited Class race trucks and go with a long-arm true independent suspension along with coilover shock units. Again this would take some major design and modifications along with a large amount of money.

Any better ideas? Yep, keep the driving front axle, modify the leaf springs so that the shackles are now at the rear instead of at the front of the spring pack, and enjoy-especially so when your two-wheel-drive buddies are stuck and you just pull the transfer-case lever back and motor on by them.

Question: I'm 14 and have been off-roading since I was born. I was looking at "The 10 Monster Rigs for the TTC" (Oct. '04) and I saw the '94 Chevy Suburban with the Dodge Cummins engine under the hood. It's said to have 3,400 lb-ft of torque. How in the world would you get that much power? Not even my dad's semi has that much power, and we pull 48-foot trailers that weigh 32,000 pounds, and when loaded, their weight is 85,000 pounds. So my question is, if a Dodge engine can have more torque than a semi, what would you have to do to make a semi have that much torque-as in 3,400 lb-ft of torque-or can you just not do that to a semi?
Emery Andrus
via e-mail

Editor: Nice catch. Somehow, that either was a misprint or wishful thinking. However, I was at a recent dyno test where I saw several modified Dodge/Cummins engines make in excess of 800 lb-ft, and one made an almost unbelievable 921 lb-ft and 442 hp!

This particular engine, I believe, used two turbochargers and a nitrous system to make this kind of power. How long the engine will last is anyone's guess. In my opinion, there are only so many horsepower-hours in an engine. Keep in mind your dad's truck engine most likely will have to pull loads like you described for about one million miles before it's time for a rebuild.

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