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August 2011 Your Jeep

Posted in How To on August 1, 2011
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Idiots on Parade
A buddy of mine showed me your magazine to read the article “Engine Swaptions” in your June ’11 issue. As long as the small block Ford has been around, with as much information that has been written about it, and as easy as it should be to check specifications you incorrectly state that the 5.0L is a 60-degree engine. Idiots!

Then you go on to say that installing a factory HO Mustang cam in an SUV engine will bump horsepower up to 300 easily. When a Mustang only had 225hp? Yeah, right.

That’s about all I could stand to read. I’d be afraid to take anything else in your publication seriously. Stick with playing with your toys in the mud.
Jerry Olson
Via email

First, the SUV had the GT-40 heads (well, actually GT-40P) and Cobra intake. The GT-40 or (GT-40P) heads and Cobra intake flow much, much better than the Mustang 5.0L stuff. However, the lame-duck camshaft Ford stuck in the SUV engine for a glass-smooth idle and low-speed civility killed the potential of these parts. That’s why running the rowdier Mustang cam in the SUV engine gets you 300hp. You’re the idiot on that one.

As for calling the Ford a 60-degree engine, I’m definitely the idiot. It may actually have been an honest mistake on my part hitting the “6” on the keyboard number pad instead of the “9” and then not catching my mistake during the editing process. However, when I was a teenager my friend had an ’84 Mustang with the carbed 302. He always used the excuse of it being a 60-degree engine that didn’t make much torque as to why he always lost to my Olds when we drag raced. I knew the 5.0L was 90-degree, but perhaps I wrote 60-degree unconsciously from those long-ago arguments with my friend. Either way, my bad. Sorry.

Memorial Build
Love your magazine. My son got me interested in Jeeps. I got him a ’95 Cherokee two-door when he went to college. We had planned to modify it for primarily street use. I know that’s a sin in your mind; to not use a Jeep off-road. Sorry. We built a 4.6L stroker, which is in my shop. Due to his untimely death, the project was never completed. I’ve decided to finish the car similar to what he had in mind. I have purchased every NOS and reproduction part I could find from Team Cherokee in Kenosha, Wisconsin. I need advice on a couple issues.

First, I’d like to update the axles with Dana 44 hardware. Dynatrac seems like a logical place to start. I think I want a limited-slip rather than a locker for street use. I also want big brakes. I’m considering AEV’s kit that uses Dodge Ram front rotors. Since I’m switching axles I’ll go to a 5x5 bolt pattern. I will need rear discs too. I went to visit Novak Conversions in Utah. You should really do an article on them. They’ve got quite an operation there. They will fix me up with a 6.2L Gen III GM engine and an upgraded automatic transmission and transfer case. Plus, a modified wire harnesses and everything needed to make the A/C and cruise control work. I’m looking for 500 horsepower. Will the forced induction hardware from Edelbrock or the Corvette ZR1 engine fit under the stock hood? I think it’s taller than the stock ’Vette induction system, but I don’t know by how much. What about underhood heat? Any advice on my project would be helpful, as I’m just about ready to start. This hopefully will be just like my son would’ve liked it.
Kerry O’Connor
Via email

As a dad myself, you have my most sincere condolences. By all means, finish the Jeep for whatever purpose you see fit: street, off-road, whatever. I’m always of the opinion that as long as you’re building it for what you want to do with it, there’s no wrong way to use a Jeep. They’re tools.

Front Axle: If you’re not off-roading it, then the stock Dana 30 front axle should be more than sufficient. The ’95 model year was the first year the Dana 30 got the larger 760X (formerly known as 297X)-sized U-joints that came in the Dana 44 axles. Previously, they were a smaller 260X-size U-joint in the front axles. The inner shafts are still a somewhat-small 27-spline, but again – if you’re not off-roading it, the stock Dana 30 and shafts should hold up fine. If you’re looking for 500hp, upgrading the brakes to larger rotors/calipers with the AEV parts would definitely be a good idea.

Rear Axle: I’m of the opinion that Dynatrac is simply the finest axle builder on the planet. I think a “Trail Series 44” Dana 44 rear axle would be a good choice for you. Since you’re not off-roading you won’t need the high-clearance of the more-expensive ProRock 44 centersection. The Trail Series 44 uses the new generation ring and pinion from the JK Wrangler Rubicon, which is larger and stronger than the previous “old school” Dana 44 components. It also comes with 12.0-inch disc brakes, an electronically-selectable locker (open/spool), and 32-spline axleshafts. The larger shaft size is an advantage, as it will resist rolling and snapping when you launch that XJ with 500hp.

Drivetrain: Novak builds great components. They offer all the conversion parts you need to run the L92 6.2L in your Jeep, but highlights will include a new radiator, motor mounts, fuel pump/regulator kit, and T-case adapter for the Chevy transmission. Your stock T-case should be fine and can be made to work with the Chevy transmission with a new input shaft to match the Chevy transmission’s output shaft. I would recommend adding a 32-spline slip yoke eliminator setup to the rear of your T-case to prevent snappage when you launch or get into the gas.

Engine: If you’re “only” looking for 500hp there’s really no need to run an expensive forced induction system on that 6.2L. The 6.2L L92 comes equipped with some of the best factory cylinder heads ever produced. It doesn’t take much to unlock the performance potential of these mills. Really, the only thing you’ll need to do to get into that ballpark is perform a cam and valve spring swap. From the factory, the L92 6.2L truck engine puts out 403hp/417lb-ft with a runty 198/209-degree duration cam with .500/.500-inch lift. Mast Motorsports (mastmotorsports.com) makes a nice complete package that bumps the L92’s power to 530hp. It includes a new cam, lifters, wiring harness, programmed ECU, and air filter. MAST can also sell you just the cam and lifters if you want to source the harness and computer through Novak, however you may need to have Novak do a bit of custom computer programming to nail your power goal. I’m not sure the taller truck intake will fit under the hood, but you can purchase an Australian Holden L76 intake manifold setup from GM Performance Parts at your local GM dealership. The intake will come with a 90mm throttle body, 39-lb injectors, and fuel rails. Or, you can run an aftermarket LS3-type intake for a lower profile. Either the LS3 or L76 39-lb/hr injectors will supply plenty of fuel at 60psi to support 500-550hp.

Best of luck to you as you complete you and your son’s project.

CEL Diet
I’m the Third registered owner of a ’00 Wrangler Sport with the 4.0L and five-speed manual transmission. I bought this Jeep 1½ years ago. About a week after I brought it home the check engine light came on. I replaced the coil packs, all the injectors and plugs, and ran carbon cleaner through the engine. I still get the check engine light from time to time. I bought a code reader and I get the same error code each time “number two cylinder misfire.” The engine runs fine and I get 16-17 mpg consistently. I clear the code with my reader and a week or so later the check engine light comes back on. It seems to happen at idle while I’m waiting in the fast food line. I tried avoiding fast food for a while and lost weight but didn’t lose the light. Any ideas on how to eliminate the problem besides removing the check engine light bulb?
Chris B Sodeman
Yakima, WA

I had a ’99 Cherokee that would inconsistently do the same thing, but mine did a “number three cylinder misfire.”

There’s a lot of scuttlebutt on the Internet about what causes it, but after trying just about everything on mine (different injectors, cleaning/replacing sensors, cleaning ECU connections) I’m almost convinced it’s because of worn valve springs. Sounds silly, but if the valve is bouncing off the seat when it closes the ECU could read the event as a cylinder misfire. That would especially be the case when the engine is operating at lower rpms and the fuel and spark events happen closer to top-dead center.

I sold my Cherokee before I could try it myself, but a new set of stock replacement valvesprings isn’t that expensive. Unlike the attached photo in which the cylinder head is off the vehicle, if you have an air compressor and a valvespring tool you can change them with the head still on the engine. Pop off the valve cover, rockers, and pull the pushrods (just so they don’t fall into the oil pan by accident). You can buy a spark plug fitting to run compressed air into the cylinder to hold the valves closed at any auto parts store. Bring each cylinder to the top of its stroke and charge it with compressed air as you pop off the intake and exhaust keepers/retainers for the intake/exhaust valve. Then, one-by-one run through the cylinders and change the springs. When you’re done, replace the pushrods, set the rockers to zero-lash, and button the valve cover back up. If you’re fast the whole process shouldn’t take much more than an hour or so start to finish.

E-CADs!
My YJ’s T-case clicks smoothly to all positions without any interference with the body or shifter boot. But when I slowly (just off idle) enter deep, sugary sand only the back tires are turning. If I blip the throttle (while spinning rear tires in low-range) I’ll hear something “grab” and then the fronts start pulling. If I shift the tranny to Reverse, I back up in, but only the rears are spinning. Blipping the throttle doesn’t work in Reverse. But if I shift back into First and “blip” to engage, I can sometimes go back into Reverse and have the 4x4 working properly. If you have any ideas I would be grateful to hear them. My family would be devastated if the ol’ girl had to be put down for repairs.

By the way, loved the Sh!%box Derby! How did your back feel after jumping your Commando on that dune?
Tommy
Via email

The landing was on a sloping dune and wasn’t bad at all. It only seemed like it would be violent, but it wasn’t harsh.

Could be your CAD (central axle disconnect) vacuum motor or the switch on the T-case isn’t working properly. There’s a huge mess of vacuum lines that can crack and deteriorate under there. I could explain further on the CAD system, but just read this story and check it out on your Jeep (www.jpmagazine.com/techarticles/drivetrain/axletech/154_0904_dana_30_vacume_disconnect/index.html).

When your front isn’t pulling like you described, have a friend get on his knees at a safe distance away from your Jeep and observe the front driveshaft. If the driveshaft isn’t spinning, your problem is inside the T-case (anything from worn synchros to bent shift fork to who knows). If the driveshaft is spinning, chances are it’s gonna be the CAD motor or vacuum switch. Follow one of those procedures in the story as a fix.

Little Stuff That Kills Ya
I have an ’83 J-10 with the original 360 and TF727 tranny. I need better gas mileage. Will a TH700R4 bolt in? I can get a rebuilt one with a guarantee for about $500.

A transmission shop told me it won’t swap in and the electronic overdrive would be an issue. However, another tranny dealer said it will be a good swap, with the addition of an adapter to the fix the swap equation. I’m confused!

If it would make a good swap, what else would I need to consider?
Chris Franklin
Asheville, NC

You can put the TH700R4 in your FSJ, but it’ll cost more in adapters than what you’re going to pay for that $500 transmission.

Advance Adapters (advanceadapters.com) has an adapter plate (PN 716138) to mount the GM transmission to the back of an AMC I-6 or V-8 engine. You’ll use the GM torque converter, but you’ll need to run PN 716138-A flexplate with your ’83 360. The ’88-’91 360s require a different flex plate.

You’ll also need to find a way to mate the TH700R4 to your existing transfer case. Jeep last used the Quadra-Trac in 1979, so any ’80-up FSJ should have a T-case with the modern six-bolt pattern shared by most NP208, NP231, NP241, and so on T-cases. Although the pattern should be the same as your current T-case, the TH700R4 from a 4WD Chevy application should have a 27-spline output shaft. Your T-case is most likely a 23-spline input shaft, so they won’t mate. Hopefully you have the NP208 T-case and not the NP228 or NP229. If it’s the NP208, Advance should be able to source you a new 27-spline input gear to mate to the TH700R4. Otherwise, you can source a Chevy T-case with the appropriate drop for your front axle.

As far as the electric torque converter, transmission companies like B&M has this covered. Advance Adapters (notice a theme here?) should have all the parts to get the transmission shifting. Don’t forget, the TH700R4 uses a TV cable to control shifts. You’ll have to attach that to the carburetor linkage, as well as the kickdown electronics. I believe Advance uses components from B&M.

Don’t go into this swap hoping for better fuel mileage because when all is said and done you’ll be well above your $500 target by the time you get the adapters, electronics, kickdown components, new driveshafts (or modify your old driveshafts), and T-case stuff sorted. You’ll have to drive the Jeep for about 100 years to recoup your investment.

It’d almost be more cost-effective to look for a junkyard GM 5.3L engine, transmission, and T-case from a wrecked ’99-up Chevy pickup or SUV and drop that in since the GM engine will knock down significantly better mileage than your AMC engine while making lots more power. Just something to consider.

High Tech Name Change
What do you know about Treadwright tires? I’m thinking of running them on my ’07 JK. They’re almost half as cheap as new tires since they’re retreads. But I really don’t want to spend the cash on tires that may last half as long as regular tires.
Chris Beasley
Morgantown, IN

The company used to be called High Tech Retreads, but then changed its name to Treadwright. They’ve since changed the tread design a bit, but the tread adhesion retread process is the same.

Write Us!
Got a tech question you’re just itching to get answered? Send it on in to Jp magazine, Your Jeep, 831 S. Douglas St., El Segundo, CA 90245, or e-mail christian.hazel@jpmagazine.com.

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