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1988 3-Day Jeep YJ For $3K

Posted in How To on September 6, 2013 Comment (0)
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A while back we began outlining a bunch of $3,000 buildups, first for ’97-’06 Wrangler TJs (“3-Day TJ For $3K,” April ’12), and then we built up an ’07 JK with a couple of alternative JK builds (“3-Day JK For $3K,” May ’12) and promised to follow up with similar treatments for the YJ Wrangler, XJ Cherokees, and maybe even a couple of CJs. Well, all our plans were put on hold when we acquired an ’88 YJ that needed more than a little work before we could feel safe driving or even get it registered for the road (“Number Two: Part 1,” May ’13; “Number Two: Part 2,” June ’13). Once again as part of the 3-Day 3K series, we cover only bolt-on parts and modifications that you can do yourself at home in three days or less.

Jeep enthusiasts have been modifying YJs since the first ’87 Wranglers rolled off Jeep dealer lots in 1986. Since then several different formulas have been used to get better off-road performance out of these Jeeps. We first dumped the temperamental computer-controlled Carter carburetor from our YJ’s 258ci in favor of a Motorcraft 2100 with a Trans-Dapt adapter, K&N air cleaner, and air filter from Summit Racing. We then bolted on a 4-inch lift kit from Rough Country. We added a set of Mickey Thompson 33x12.50R15 MTZs mounted on Mickey Thompson’s new heavy-duty steel wheels, and also tossed in a Rough Country 9,500-lb winch and winch plate for those occasional sticky situations. To cover up a dent and add tons of body protection we also bolted on a set of Rock Hard 4x4 Rocker Sliders. Lastly, we bolted on and hacked up some beat-up TJ flares to add tire coverage and looks to our YJ. The end result is a much better looking Jeep that works well off-road…until…well you’ll just have to follow along to see what happens to our pile of ’88 YJ Wrangler.

Our 3K Build
Description Part Number Source Price
Rough Country 9500lb Electric Winch RS9500 Rough Country $299.95
Rough Country Jeep TJ/YJ Winch Mounting Plate 1189 Rough Country $59.95
’87-’96 Jeep 4-in Suspension for YJ with power steering 620N2 Rough Country $449.95
’87-’96 YJ 1-in Rear Boomerang Lift Shackles RC0403 Rough Country $54.95
Mickey Thompson Baja Radial MTZ Tires, 33X12.50R15 5253 Mickey Thompson $985.00 ($246.25 each)
Mickey Thompson Metal MT-28 Series Black Wheels, 15x10 90000001685 Mickey Thompson $313.88 ($78.47 each)
Mount and balance N/A Discount Tire $80.00 ($20.00 per wheel/tire
Rock Hard YJ Rocker Sliders Powder Coated Black w/Side Tubing RH-3003-YJ Rock Hard 4x4 $344.95
Motorcraft 2100 1.08 venturi N/A ’78 Jeep J-10 $140
Beat up TJ fender flares N/A $80
Trans-Dapt Performance Carburetor Adapter 2086 Summit Racing $17.95
9-inch K&N Air Cleaner Assembly with filter KNN-60-1110 Summit Racing $78.95
Total $2905.53

One of the first things we did with our YJ was get rid of the computer-controlled Carter carburetor. To do this we first bolted on a Trans-Dapt adapter (PN TRD-2086) from Summit Racing. The mounting flange on the stock YJ intake is very small, so to avoid vacuum leaks we had to make a thicker gasket out of some spare gasket material we had. As an added precaution, we filled the bolt mounting holes with a little silicon gasket maker. We then made a new upper gasket to ensure a leak-free seal around the adapter bolt holes. One of the first things we did with our YJ was get rid of the computer-controlled Carter carburetor. To do this we first bolted on a Trans-Dapt adapter (PN TRD-2086) from Summit Racing. The mounting flange on the stock YJ intake is very small, so to avoid vacuum leaks we had to make a thicker gasket out of some spare gasket material we had. As an added precaution, we filled the bolt mounting holes with a little silicon gasket maker. We then made a new upper gasket to ensure a leak-free seal around the adapter bolt holes.
The Motorcraft we used was the 1.08-inch venturi unit originally found on AMC V-8s and some smaller Ford V-8s and six-cylinders. Once tuned and the float set properly, the YJ now idles off-road almost as though it has fuel injection. To top it off, we added a 9-inch K&N air filter and housing (PN KNN-60-1110) from Summit Racing. The Motorcraft we used was the 1.08-inch venturi unit originally found on AMC V-8s and some smaller Ford V-8s and six-cylinders. Once tuned and the float set properly, the YJ now idles off-road almost as though it has fuel injection. To top it off, we added a 9-inch K&N air filter and housing (PN KNN-60-1110) from Summit Racing.
The Rough Country 4-inch suspension kit comes with everything necessary to lift your YJ including four full leaf packs, a dropped pitman arm, a T-case lowering kit, brake line extensions, bumpstop extensions, front sway bar links, U-bolts, track bar relocation brackets, and hardware. Installation is straightforward using the supplied instructions. With a little help from a friend, installing the lift kit will take a long day. The Rough Country 4-inch suspension kit comes with everything necessary to lift your YJ including four full leaf packs, a dropped pitman arm, a T-case lowering kit, brake line extensions, bumpstop extensions, front sway bar links, U-bolts, track bar relocation brackets, and hardware. Installation is straightforward using the supplied instructions. With a little help from a friend, installing the lift kit will take a long day.
We also ordered up a set of Rough Country’s boomerang shackles (PN RC0403) for the rear of our YJ. These add a touch of lift, but more importantly allow the slightly longer lift springs to stretch out better than the stock shackles would when the Jeep flexes. We also ordered up a set of Rough Country’s boomerang shackles (PN RC0403) for the rear of our YJ. These add a touch of lift, but more importantly allow the slightly longer lift springs to stretch out better than the stock shackles would when the Jeep flexes.
Bolting on the Rock Hard 4x4 Rocker Sliders is very easy. We used a floor jack with a large bumpstop to hold the sliders in place while we drilled out a few mounting holes with a 3⁄8-inch drill bit. Line up the rear edge of the rock slider with the front bottom edge of the stock fender flares. The rear-most bolt hole on the side and bottom of the rock sliders require the two longer bolts. These rockers add protection as well as cover up any rocker damage your YJ may have…like ours did. Bolting on the Rock Hard 4x4 Rocker Sliders is very easy. We used a floor jack with a large bumpstop to hold the sliders in place while we drilled out a few mounting holes with a 3⁄8-inch drill bit. Line up the rear edge of the rock slider with the front bottom edge of the stock fender flares. The rear-most bolt hole on the side and bottom of the rock sliders require the two longer bolts. These rockers add protection as well as cover up any rocker damage your YJ may have…like ours did.
Installing the winch is as easy as removing the plastic bumper cover and four bolts. Then bolt the winch to the winch plate, bolt the winch plate to the Jeep, mount the roller fairlead, make the electrical connections, zip-tie up the wires, and you are ready to make a pull if necessary. The winch plate is a universal piece that bolts to either TJ or YJ Wranglers. Unfortunately, it sticks out past the bumper on a YJ, slightly decreasing the approach angle—a small price to pay for having a winch. Installing the winch is as easy as removing the plastic bumper cover and four bolts. Then bolt the winch to the winch plate, bolt the winch plate to the Jeep, mount the roller fairlead, make the electrical connections, zip-tie up the wires, and you are ready to make a pull if necessary. The winch plate is a universal piece that bolts to either TJ or YJ Wranglers. Unfortunately, it sticks out past the bumper on a YJ, slightly decreasing the approach angle—a small price to pay for having a winch.
Trimming and mounting the TJ fender flares took a fair amount of time. We started by trimming the lip off the back of the TJ flares with a box cutter. We then trimmed the front fender flares just above the TJ’s stock turn signal lights so we could trim the front of our slightly dented YJ fenders. We used a cutoff wheel on a Dremel tool to cut the flares and then carefully used a 41⁄2-inch grinder with a flap wheel to clean up the edges. Installation involved clamping the flare in place, marking the mounting holes, and drilling. The TJ flares allow you to trim about 11⁄2-inch of sheetmetal from the rear wheelwells for larger tires or more flex. Trimming and mounting the TJ fender flares took a fair amount of time. We started by trimming the lip off the back of the TJ flares with a box cutter. We then trimmed the front fender flares just above the TJ’s stock turn signal lights so we could trim the front of our slightly dented YJ fenders. We used a cutoff wheel on a Dremel tool to cut the flares and then carefully used a 41⁄2-inch grinder with a flap wheel to clean up the edges. Installation involved clamping the flare in place, marking the mounting holes, and drilling. The TJ flares allow you to trim about 11⁄2-inch of sheetmetal from the rear wheelwells for larger tires or more flex.
We used an air saw to trim off the front of our YJ fenders. They had been dented at some point in the past and were just ugly. The TJ flares add a little more modern look to the Jeep and also allow for larger tires than the stock YJ flares did. We were able to trim a little more than an inch off the back of the rear wheel tubs where the tire tucks when flexed. We used an air saw to trim off the front of our YJ fenders. They had been dented at some point in the past and were just ugly. The TJ flares add a little more modern look to the Jeep and also allow for larger tires than the stock YJ flares did. We were able to trim a little more than an inch off the back of the rear wheel tubs where the tire tucks when flexed.
We took our four Mickey Thompson 33x12.50R15 tires and 15x10 Mickey Thompson Steel wheels to Discount Tire to get them mounted and balanced. Discount Tire had the tires and wheels balanced and ready to go amazingly fast. With the tires aired down to 8 psi, we crawled around on Arizona rocks as well as could be expected in an open diff’d, under-geared Jeep. We took our four Mickey Thompson 33x12.50R15 tires and 15x10 Mickey Thompson Steel wheels to Discount Tire to get them mounted and balanced. Discount Tire had the tires and wheels balanced and ready to go amazingly fast. With the tires aired down to 8 psi, we crawled around on Arizona rocks as well as could be expected in an open diff’d, under-geared Jeep.
Once off-road, we pulled one of the Rough Country front swaybar links for extra flex. We were happily amazed by the soft ride and flex afforded by the 4-inch Rough Country suspension. The Rough Country N2.0 shocks did a good job of dampening the bumps without being overly harsh as some nitrogen charged shocks can be. We’re going to mercilessly beat on this suspension and will come back with a long-term report in a future issue. Once off-road, we pulled one of the Rough Country front swaybar links for extra flex. We were happily amazed by the soft ride and flex afforded by the 4-inch Rough Country suspension. The Rough Country N2.0 shocks did a good job of dampening the bumps without being overly harsh as some nitrogen charged shocks can be. We’re going to mercilessly beat on this suspension and will come back with a long-term report in a future issue.
The Rough Country 9500 winch (PN RS9500) is pretty sweet for the price. The geartrain sounds like it’s lubricated with marbles, but so far it seems to be working well despite the rattley noises. Also, the winch came with a wireless remote control that seems to afford spotty-at-best control. Honestly, the wireless remote is scary. We’ll stick to the old-fashion wired remote that allows more positive control of the 5⁄16-inch steel cable. The Rough Country 9500 winch (PN RS9500) is pretty sweet for the price. The geartrain sounds like it’s lubricated with marbles, but so far it seems to be working well despite the rattley noises. Also, the winch came with a wireless remote control that seems to afford spotty-at-best control. Honestly, the wireless remote is scary. We’ll stick to the old-fashion wired remote that allows more positive control of the 5⁄16-inch steel cable.
Simons is quickly developing a reputation as an effective destructive product tester. He whaled the Rock Hard 4x4 Rocker Sliders on some rocks, and while he was able to mar the nicely hammered powdercoating, the side tubes did their job and kept the rocks from damaging more sheetmetal. The rock sliders did their job well even when the Jeep was practically laid on its side. Simons is quickly developing a reputation as an effective destructive product tester. He whaled the Rock Hard 4x4 Rocker Sliders on some rocks, and while he was able to mar the nicely hammered powdercoating, the side tubes did their job and kept the rocks from damaging more sheetmetal. The rock sliders did their job well even when the Jeep was practically laid on its side.
1988 jeep yj and a pile of parts

Testing Failure
After our modifications, we did what any real off-road magazine staff would and went wheeling in one of our favorite local off-road areas. It was a blast, and the little YJ did really well all day until the last obstacle that we were gonna tackle. We attacked a stack of rocks on a hill, and with a bounce and a bang we lost most of our forward pull. Pretty quickly we were informed by our wheeling buddies that the rear driveshaft had fallen out. A closer look revealed that the rear driveshaft U-joint straps had failed massively during the hop. They may have been loose or maybe had hit a rock (although there was no scars on the shaft). Either way, they had failed. Since it was near the end of the day, we grabbed the driveshaft and what parts of the rear U-joint and straps we could find. We then rolled the Jeep to a flat spot so we could work on a plan to slow the flow of tranny fluid from the slip yoke of our NP231J.

We tried shoving a Gatorade bottle cap in the output of the T-case, but the splined shaft would not allow it to seat. Plan B was half of a water bottle duct-taped to the slip-yoke housing. With this plugged, we were able to limp off the trail and back home in front wheel drive. It worked…kind of. On the way home the T-case started making some sad crunchy noises, and for some reason we lost the clutch on the way home. The two red lights we encountered on the ride were interesting. The good news is we have a spare T-case and plans for a tranny swap. What are we gonna do? You’ll have to keep your eyes peeled on Jp in the future to see how we resurrect our YJ.

View Slideshow

What We Should Have Built
They say hindsight is 20/20. That’s true, and it turns out we should have added a slip-yoke eliminator and a double cardan driveshaft to the build sheet. That would have given us a much stronger and a little longer rear driveshaft. It also would have forced us to check the rear U-joint straps that may have been the weak link that failed us out in the desert. As it happens, we did not need the winch, so dropping the winch and adding a slip-yoke eliminator from Advance Adapters and a new rear driveshaft from Tom Wood’s Custom Drive Shafts helps us almost make our budget of $3,000.

Description Part Number Source Price
Advance Adapters Slip-Yoke Eliminator NP231-SYE Advance Adapters $199.00
Tom Wood’s driveshaft with a slip yoke N/A Tom Wood’s Custom Drive Shafts $314.99
’87-’96 Jeep 4-in Suspension for YJ with power steering 620N2 Rough Country $449.95
’87-’96 YJ 1-in Rear Boomerang Lift Shackles RC0403 Rough Country $54.95
Mickey Thompson Baja Radial MTZ Tires, 33X12.50R15 5253 Mickey Thompson $985.00 ($246.25 each)
Mickey Thompson Metal MT-28 Series Black Wheels, 15x10 90000001685 Mickey Thompson $313.88 ($78.47 each)
Mount and balance N/A Discount Tire $80.00 ($20.00 per wheel/tire
Rock Hard YJ Rocker Sliders Powder Coated Black w/Side Tubing RH-3003-YJ Rock Hard 4x4 $344.95
Motorcraft 2100 1.08 venturi N/A ’78 Jeep J-10 $140
Beat up TJ fender flares N/A $80
Trans-Dapt Performance Carburetor Adapters 2086 Summit Racing $17.95
9-inch K&N Air Cleaner Assembly with filter KNN-60-1110 Summit Racing $78.95
Total $3,059.62

A Back East Build for 4-cyl YJs or Those With the 4.0L HO
If your YJ is a ’91-’95 or if your YJ has the 2.5L then your Jeep has a much better fuel delivery system than our ’88 YJ did. If that’s you, you are lucky and you won’t need to go to the trouble of adding a Motorcraft 2100. That gives us about $331.37 to play with out of our $3,000 budget. Drop the winch and mounting plate and you have the cash to add a Bestop Supertop with upper soft doors and tinted windows from Summit Racing—cause it rains back East!

Description Part Number Source Price
Bestop Supertop 54600-37 Summit Racing $776.95
’87-’96 Jeep 4-in Suspension for YJ with Power Steering 620N2 Rough Country $449.95
’87-’96 YJ 1-in Rear Boomerang Lift Shackles RC0403 Rough Country $54.95
Mickey Thompson Baja Radial MTZ Tires, 33X12.50R15 5253 Mickey Thompson $985.00 ($246.25 each)
Mickey Thompson Metal MT-28 Series Black Wheels, 15x10 90000001685 Mickey Thompson $313.88 ($78.47 each)
Mount and balance N/A Discount Tire $80.00 ($20.00 per wheel/tire
Rock Hard YJ Rocker Sliders Powder Coated Black w/Side Tubing RH-3003-YJ Rock Hard 4x4 $344.95
Beat-up TJ fender flares N/A $80.00
Total $3,085.68

Sources

Summit Racing
Akron, OH
800-230-3030
SummitRacing.com
Advance Adapters
Paso Robles, CA 93446
800-350-2223
www.advanceadapters.com
Discount Tire
855-869-7914
http://www.discounttire.com
Rock Hard 4x4
N/A, AK
308-750-4690
www.rockhard4x4.com
Tom Woods Custom Driveshafts
877-495-6468
www.4xshaft.com
Rough Country
800-222-7023
www.roughcountry.com

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