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September 2009 Your Jeep

Posted in How To on September 1, 2009
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Flattie Follies
I've read your magazine for a few years now and love it. I just decided to part ways with my '03 TJ. I'm currently active duty in the Army and just returned from a 12-month tour in Afghanistan and am currently serving another 12-month tour in Egypt. While over here I just found a '46 CJ-2A for $500. So, with a few quick emails to my dad and buddies it's being picked up this weekend.

I haven't had much contact with the guy I'm getting the flattie from so I don't have as much info as I'd like. Apparently the engine is in pieces in the garage, yadda, yadda, yadda. So it looks like I'm not getting the stock 134 L-head with the Jeep, but the rest of the original drivetrain (as far as I know) is intact. I've been looking online and can't seem to find hardly any L134s for sale, so I've been looking into engine swaps.

I've settled on a GM 4.3L V-6 as my main option. I would like to keep the flattie very simple and as close to stock as possible. Is this an easy swap that can be accomplished with few modifications? I would also like to drive the Jeep every now and then on the road, so I'm assuming the old Go Devil would have had a tough time keeping up anyhow.

Also what would you recommend upgrading drivetrain-wise? I would like to keep the original axles, but I'm looking at using maybe 33-35-inch tires and doing a 1-2-inch suspension lift with a spring-over.Chad Burnumvia e-mail

Sounds like you're planning a pretty smart little buildup. A 4.3L will be a great engine for a flattie. There are plenty of aftermarket motor mount kits available through Advance Adapters ( and Novak Adapters ( for starters, as well as conversion bellhousings and parts to mate the V-6 engine to the stock T-90 tranny and exhaust headers if you need them. However, I'd recommend using the stock 4.3L exhaust manifolds. Depending on which 4.3L you go with, you'll have some options as far as injection and wiring. The simplest method will be to nab a 3.8L (the smaller version of 4.3L, nearly as good, came in early '80s GM cars) or an early 4.3L with a carburetor and just slap it in there. If you go injected, steer clear of the later Vortec engines with the distributorless ignition and the coil-on-plug setup because the aftermarket support for these engines isn't as strong as the earlier Vortec V-6 engines.

The only other bummer you'll have with the 4.3L would be a little bit of distributor-to-firewall interference if you keep the stock large-cap HEI distributor. However, you can make it work with a hammer, or just swap to an aftermarket small-cap electronic distributor (Accell, Mallory, MSD, etc), as long as you're not running a computer-controlled ignition.

As for the drivetrain, I'd stick with the stock T-90 tranny. At least for a while. It'll hold up if you keep it moderately sane. The same is true for the Spicer 18 T-case. I'd think about eventually adding a Warn, Saturn, or ATV Mfg. overdrive. Check out all three at Herm Tillford offers a lot of early flattie stuff and does a great job rebuilding gearboxes. It's a good company to know about if you're building a vintage Jeep.

Axles I'd keep stock as well. You've got 5.38 gears in the Dana 25 front and Dana 44 rear. Lockers? I wouldn't. As soon as you lock up these axles, they start chucking their guts unless you upgrade the shafts, which can be costly. At the very most, I'd add a locker to the rear Dana 44 and would whip up some sort of full-floater conversion kit that replaced the stock 10-spline shafts with later 19-spline or aftermarket 30-spline shafts. Again, I think Herm has something on his site at for this.

As for tires, I think you're making a mistake trying to go all the way to 35s. That is, unless you want a full gonzo trail killer. Put that on the back burner and focus on having fun with the Jeep first. I'd suggest a simple spring-under suspension. Check around as there are lots of bolt-on kits. Replace the factory C-shackles with later ones if it hasn't already been done. As for tires, you can fit 32s with a 2-inch lift and you won't have any driveshaft issues. When or if you do finally pull the trigger on bigger tires and a spring-over, keep in mind that using 1-2-inch springs on a spring-over will be circus-wagon tall. Stock YJ leaf springs will give you plenty of room in a spring-over, but you'll have bad axlewrap and the springs will be in the way of the steering components.

I think a better long-term suspension plan would be to convert to YJ spring perches and then run a 3.5-4.5-inch YJ spring-under suspension. That way your steering is kept simple, you won't have any axlewrap issues, and you'll still have as much flex as you would with a spring-over and stock springs. It's a way better setup.

Goin' Postal
I've got a '70 DJ-5 and am having a surprisingly tough time finding a Dana 30 front axle, but what I did find was a '52 Willys pickup in my local junkyard. It has the front Dana 25 and the spring perches are almost exactly the same width as my DJ. I think it might be off by like 1/4- to 1/2-inch. I know the Dana 25 has a few weaknesses, but I'm not planning on doing any crazy rock crawling, just some fire trails. Can you see any major problems with this setup?Josh Biggsvia e-mail

If you're cool with the increased width (the pickup axle is something like 10 inches wider than the Jeep axle) and you're able to cut and weld the spring perches to match your Jeep's, then go for it.

If you're only looking to do some light cruising off-road, another thought would be to look for an early Dana 25 or Dana 27 closed-knuckle, drum-brake axle from a flatfender, CJ-5, or CJ-6 Jeep built from '41-'71. These will have the same spring perch width and overall WMS-WMS measurement as your Jeep. Your biggest hurdle with either will be getting the steering linkage hooked up, but I believe if you go with the narrower Dana 25 or Dana 27 you'll be able to use your 2WD steering linkage. As for the strength of the Dana 25 or Dana 27, I ran the stock '71 Dana 27 in my CJ-6 over the Rubicon with 31-inch tires and didn't have a lick of trouble.

Baby Steps
I know that you are going to make fun of me, because that is what you do to people who don't know what they are doing when it comes to off-road driving. I have been going to Moab for years now and have driven the easy trails as described in the book by Charles A. Wells. I have no interest in actual rock-crawling, but I have wanted to take in more scenery the next time I go and do the moderately-rated trails. I have this fear of getting stuck out there and spending the night in my 1999 stock XJ, never mind the enormous tow bill. My XJ is due for tires now and I'm wondering if it will need to be lifted? What other improvements, if any, should I make before attempting the moderately-rated trails?Pete WinklerKansas City, Missouri

We all gotta start somewhere. I really have no stomach for making fun of somebody just because they don't want to do hardcore trails. I'll leave that to the more childish web forums.

As for your questions, I took Jp's '99 XJ Sport out to Moab when it was stock and had a lot of fun with it. I had the little P225/75R15 tires on it with stock suspension and was able to do Hell's Revenge and a few of the other mild trails out there with no problems. I did drag the rear trailer hitch a bit, but that's to be expected given the steep climbs and drops of the terrain.

Whether or not you'll need to lift it really depends on what tire size you want to run. If you're honestly happy with the mild stuff, but want a little more clearance under the bumpers, transfer case, and for slightly larger tires, the Rubicon Express 2-inch budget lift (PN RE6165) comes with everything you need to lift your Jeep for under $300. That gets you front 1.75-inch spring spacers, rear blocks and U-bolts, longer braided steel brake lines, and four shocks. I ran the company's PN RE6160 kit on my '99. It's the same as the PN RE6165 only it uses add-a-leafs instead of the lift blocks. The add-a-leafs made the ride a little stiffer and it complicates the install a bit, so I think the blocks would probably be good for you. You won't need steering or driveshaft corrections for the 2-inch lift and it will let you go up to a P235/75R15 or 30x9.50R15 on the stock rims with no problems.

As for your fear of getting stuck, one of the best additions you can make to your rig in the name of self-reliance is a good winch. There are many good aftermarket front winch mount bumpers available for the XJ and nowadays there are at least half a dozen companies making 8,000lb winches in the $500-under price range.

One inherent weak spot on all XJs and TJs is the stock steering tie rod/drag link assembly. They usually bend on the passenger side (where the factory bend already is). I'd replace it with a Rugged Ridge Super Heavy-Duty Steering Linkage Kit, PN 1805082, since it can stand up to more abuse than the factory parts and it's not that expensive.

I'd also recommend a good limited slip for your rear Chrysler 8.25 rear axle. There are several out there, but I've had the best results with the Detroit Truetrac by Eaton. It has great manners on the street, but offers tremendous traction off-road.

As for which modifications to do first, I'd go with the winch first and then do the others in the following order as funds permit; Currie steering, lift, tires, then limited slip. I'd say with the setup I've outlined for you there would be very few places or situations that would leave you stranded in the middle of nowhere.

Not a Question
Rear disc brakes from a Crown Victoria from around '92-'96 will bolt right up to the axle tube of an '87 Dana 44 from a Jeep Cherokee. I think they will also fit a Dana 35 non-C-lip housing.

I did this conversion on my '89 Jeep Comanche. The backing plate bolt holes lined right up, although the backing plate thickness is a little different than the drum brake backing plate. You can mill a few thousands off or shim the rear axle bearings. The difference was about 0.050-inch, which is not a lot, but I think it needed to be dealt with.

The rear disc brakes have the cable-activated drum brakes in the hat of the rotor.Joel HetheringtonCalgary, Alberta

Thanks for a great, cheap tech tip, Joel.

Hop Head
I had a question about the electrical system of the 4.0L. I know about the distributor and wires and stuff, but mine doesn't have that. It's an '03 and it's got a rail that goes to the spark plugs. Is that the ignition coil or is it somewhere else? Also just wondering if there were any performance parts for it? I can't seem to find them. Any information would be appreciated.Jered Wrightvia e-mail

Beginning in '00, Jeep went to a coil-on-plug ignition for the 4.0L. Those little boxes on the rail above your spark plugs are the actual ignition coils. If you look, you'll notice your Jeep doesn't have a distributor, rather it's got a small plug where the distributor would normally be. The ignition coils are fired via the ECU from signals taken off the crank position sensor on the flywheel/flexplate or where the distributor normally would be.

There really aren't any ignition hop-ups for your '03 and honestly, it really doesn't need any. You can use a Hypertech or similar programmer to hop up the spark output and bump up the timing, but you'll see better performance gains from bolt-on parts like a cold-air intake, header, after-cat exhaust, and a 62mm throttle body.

Spring Whing Ding
I have an '01 XJ Cherokee that's bone-stock. I'm looking to cheaply lift it enough to put 16-inch Rubicon wheels and tires under it. One of your tech tips suggests putting Grand Cherokee coils up front. Would those need to be from a V-8 vehicle or does it matter? Any other suggestions would be appreciated.Mark WalkerValparaiso, Indiana

The ZJ coils will really only net you about 3/4-1-inch of lift. It's a better plan of attack to use a Rough Country or Rubicon Express 2-inch budget lift. Both kits use coil spacers up front and either a lift block or add-a-leaf in the rear. Both can be had for under $300 and neither requires steering or driveshaft corrections.

Although a 30x9.50 will fit more cleanly, the 2-inch budget boost should get you enough clearance to run the 31x10.50-sized 245/75-15 Rubicon tires and wheels since they're a bit narrower than a regular 31x10.50R15 tire.

Popper Power
In Christian Hazel's ongoing article "The $1,035 YJ" he mentions General Grabber AT2 tires in the April '09 issue. I have a bone-stock '91 YJ with the same four-bagger in it. I run 215/75R15 LT tires. What is his opinion of running 235/75R15 tires with the four-cylinder engine? Also, do you have any other comments on the tires?Skip SteinSugarloaf, California

Not having had anything smaller than 235/75R15 on my Jeep I can't comment on the performance difference between the 235s and your smaller 215s, but I can say I was pleased with the acceleration and highway performance of my '89 TBI 2.5L with the 235 tires. I have noticed with the larger 31x11.50s I'm currently running that the engine can't hold highway speeds in headwinds or up grades with the 4.10 gears, but with the 235/75-15s I was always able to cruise the freeway in Fifth gear and had little trouble negotiating mountain roads without losing speed. Keep in mind my YJ is pretty light (no carpet, console, etc.), but I don't think you'll be disappointed if you go for the larger size.

I do think that a 235/75R15 or even a 30x9.50 is the maximum size you can run with the factory 4.10 gears and still have anything resembling acceptable performance on road. Even with the smaller 31s I've found the need to step up to 4.88s. Check out the story, "Gearing Four Power" in this issue for more on this subject.

Weld On
I am currently underway with my first Jeep buildup and am a do-it-yourselfer. My '91 Wrangler's stock tranny blew out some gears (missing teeth like most of the residents in my town), so I pulled it. In its place I swapped in a Ford NP435 mated to a NP205 and now I can reap the benefits of a granny-low First gear and a nearly bulletproof tranny. I also took the front Dana 44 from the donor Bronco and fitted it with West Coast Differential 4.88s and a Detroit Locker. The rear has a Superior Super 35 kit with Detroit Locker for now.

Now I need to fab up a new skidplate, axles trusses, roll cage, and some other miscellaneous items. I don't have a welder, but I'm looking for some references on a cheap MIG welder to get the job done. I have done some stick welding in the past, but am in no way an experienced welder. Money is tight for me being that keeping the kids fed and the wife happy comes first, but I always sacrifice any spare time I have to this build and would like to get going on the welding side of things.

Can you explain the differences between different MIG Welders and their numbers? I'm guessing the numbers are ratings for more power/thicker metal to weld.Nick S.Cool, California

MIG welding is by far the easiest welding process you can do. Pull the trigger and just concentrate on your puddle. I've already covered a lot of the basics in selecting a MIG welder in the story, "Affordable Fab Tools" which you can find on our web site at

I know the prices may seem a little steep at $700 or so, but when you consider you're buying a tool you'll never outgrow for the life of your hobby and that will most likely last your entire life, it's a bargain. Don't buy a 110-volt welder that plugs into a standard household socket. The 220-volt models offer much better performance and higher duty cycles. You can weld longer without waiting for a cool-down period. If you've got an electric dryer, you've already got the outlet socket. If not, a qualified electrician shouldn't charge more than about $250 to run a new 220-volt circuit off your electrical panel into your garage.

Got a tech question you're just itching to get answered? Send it on in to Jp magazine, Your Jeep, 6420 Wilshire Blvd., Los Angeles, CA 90048, or e-mail

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