PA Jeeps
The Garage => Work In Progress => Topic started by: Mike DeChristopher on June 17, 2015, 09:39:17 pm
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I recently "finished" my second jeep build project and thought I would share some of the experience to drum up some forum activity, share lessons learned, and generally open myself up to rig building critism.
Starting platform:
1994 YJ, 4.0L, 5sp 166K, SOA with 2.5" BSD springs, shackle reversal, high steering kit, 4:56, Super 35 with a Detroit, trashed Dana 30 and ARB, 36 x 12.50 Swampers, on board air, optima, ragged soft top, bestop seats, no frame or body rust.
Goals:
Seating for 7,
+100 crawl ratio
Skid plates on all sides
Flat belly
DVD player
Wife drivable
Fun
to be continued....
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Cool can't wait to see some pics
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Cool can't wait to see some pics
I like pictures to.
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Step 1: How long do we need?
After some reading and measuring of seats we determined pretty quickly that a scrambler length is perfect. However we didn't think the scrambler was a good fit because the extra length is all reduced width (between the fenders). Also I was concerned about the rear overhang. We decided the better route was to cut a YJ just infront of the rear axle and add to create the scrambler length. The added length would be full width and you could pass between the seats to get to the third row. After reading the bestop manual for a scrambler top, we determined the magic number to be 23.25".
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https://goo.gl/photos/AV5BkmazUtSEDpkJ8
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A YJ frame is a rectangular tube 4" x 2.5". There is a short straight section just in front of the rear axle front spring hanger. This is where I've seen most others have stretched the frame. I bought the same size rectangular tube for my patch. I wanted my extension to be undetectable so I chose to make a long tappered wedge cut for my butt joint. The long wedge increases the weld length significantly and should result in less stress concentration. I can always add more metal later if needed. I carefully jigged up the sections and welded it together. I added another factory looking body mount and some rustoleum and you can hardly tell that its not original.
https://goo.gl/photos/XgUinET8vcPgYwcF9
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Drive line:
The YJ I bought had a 4.0L to an AX-15 with a 231 t-case with 4:56 rears. My yellow CJ has a 90:1 crawl ratio which I really enjoy, so my goal was to at least match that. I considered the following combinations:
AX-15 + NP231 with 4:1 kit gives me 70:1 for $1400
NP 235 + NP 231 gives me 82.5 for $750
NP235 + NP231 with 4:1 kit gives me 122.2 for $2000
SM420 + NP231 gives me 86.6 for $700
SM420 + NP231 with 4:1 kit gives me 128.2 for $2000
AX-15 + Atlas 2 gives me 87:1 for $2400
AX-15 + Atlas 4 gives me 204:1 for $3500
NP 235 + Dana 300 with 4:1 gives me 122.2 for $1900
AX-15 + NP231 + NP231 (doubler) gives me 127:1 for $800
AX-15 + NP205 + NP231 (doubler) gives me 92:1 for $1000
Prices are approximate but include buying used gearbox from craigslist etc (except I already have an SM420) and all new kits/adapters from AA or Novak.
Based on this matrix, I chose the NP231 doubler from Behemoth Drivetrain. The "strong box" mounts between the AX-15 and NP231. It uses the input shaft, bearing and planetary gear set from a donor NP231. It's a little over 8" long and is indexable. I rotated my t-case clock-wise until I achieved a flat belly.
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With the frame stretch, addition of the t-case double, and tucking the drivetrain up I needed to cut and reweld the spring perches for both rears. The rear axle needed a 31" driveshaft and a CV joint. This was a perfect application for a Cherokee front driveshaft (no length adjustment required). For the front shaft, I needed 51". This length requires a 3" tube. I shopped around and landed on Tom's Wood. MShar was the same price but Tom's offered a 4" slip yoke. Because I have the shackle reversal I was happy to have the added travel.
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Putting body back together. I ended up using all of a 4 x 8 sheet of steel to build the floor and sides. The floor is supported by 1" square tube and angle.
https://goo.gl/photos/JrXefiP6TDA4z36F9
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Did you get any inspiration from someone else's buildup, or is this all your own concept? Good luck with it, sounds like it'll be a real attention-getter when it's done.
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I've seen a lot of jeeps over the last 13 years.
After the body work was finished I moved on to fenders. I had about 6" of tire extending beyond the existing fenders. I had a set of plastic flares but my experience has been that they get damaged/ripped off. I knew that with the extra length turning would be a challenge so I wanted to be able to slide along rocks or trees on the fenders. For the front I made an 1 1/2 pipe hoop attached to the frame that goes over the fan. Then i punched holes in the fenders for 1" pipe that would tie to the flare. I borrowed a tubing notcher which worked awesome. I also borrowed HF pipe bender which also worked well for forminh. The flares are capped with 3/16" plate that I formed with c-clamps and a dead blow hammer.
For rock rails I used 4" x 4" x .25 angle. The rear fenders are the same concept. I bend sections of the 4" angle for rear body corner protection. The fender flares and rock rails bolt on thru the body and between the body and the body mounts on the frame.
https://goo.gl/photos/RHDPjVAh1Uwbs8B28
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Since the tube fenders turned out pretty sweet (IMO). I figured I would jump right into the roll bar. I used the same tube notcher and pipe bender to fab three main hoops and 8 spreader bars. The hole saws in the tube notcher held up really well. I used the same two cutters for the whole project (+50 notches). The roll cage ties into the 4" rock rail and the body. While I was at it I added mounting plates for 6 speakers, the CB radio, and the fold down DVD player monitor. The scrambler top I bought on CL was a great fit. I only problem was that it didn't fit through the garage door! I ended up making a telescopic mount for the main bow of the soft top with pull pins that allow the bow to drop so I can fit through the door.
https://goo.gl/photos/FJeHE3QDJV9bhp8A6
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I also bent and welded up an exo-cage. A couple years ago I made one for my CJ and fell in love with the luxury of not worring about my soft top. The upper hoop for the YJ is 20 ft long. The front bolts to the roll cage around the door.
Other misc:
I swapped tail lights for flush mounted LEDs including side markers
I added a homemade truss and anti-spring wrap bar to the Dana 35.
The hoops and spreaders of the roll cage were drilled before welding so that the roll cage is my air tank.
I swapped the front shafts for ones with 297 U joints. The passenger side is now one piece. I replaced the blown ARB with a lock rite.
Added a conical K&N air filter.
Added homemade differential and gas tank skid plates.
Replaced the exhaust manifold with one with flex sections.
https://goo.gl/photos/UQHGdEvjesz9sdg28
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Mike, That is going to be one awesome rig. I was wondering how you were going to keep the family together as they grew. This should do it. With this wheel base, you'll be keeping the front wheels planted on some of those uphill rocky climbs. I'm thinking about the time you had the front end off the ground numberous times and you finally handed the kids out before trying again. That was a great day and you put on a heck of a show.
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For the seats, I installed a fold and flip bench in the rear. I had to move it back 3" for leg room. For the middle row, I used the two Bestop front seats that came with the jeep. For the front I used two Wrangler front seats that I bought on CL. The seventh seat is a child seat that's mounted between the two front seats. The front passenger seat still has room to flip forward.
I welded up a small heater box and fan setup for under the right middle row seat to provide a boost to the heating system. Its plumbed in parallel with the stock heater core. For under the other middle row seat, I built a wooden box that has a 10" subwoofer.
https://goo.gl/photos/2EFWtoCrDLfNJifCA
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When that 10" subwoofer is cranked up, it'll feel like you're sitting on massage chairs!
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One gallon of herculiner, lots of rustoleum and undercoating, all new fluids, an assortment of seals and gaskets, new 2.5" stainless custom welded exhaust from Red Run and that about wraps it up. I've put about 300 miles on it to date and made a trip to aoaa and RC with the club last month with no issues and tons of fun.
https://goo.gl/photos/sUqwLageWuxeah3n7
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So after wheeling my rig quite a bit I decided it was time for an axle upgrade. Early on I had decided not to mess with the axles right away due to the time and cost. I feel like I did pretty well with the Dana 30 and 35 since I only broke 2 front U-joints over the past ~1.5 years with 36" swampers.
My goal in the swap was to be able to jump to 38" swampers, keep 4.56 gear ratio, maintain my existing ground clearance & track width, and minimize cost.
Thankfully there's a bounty of info on the web for 1 ton axle swaps.
For my swap, I chose an '88 Ford F350 front axle and a mid-80's cab and chassis 14 bolt.
The 14 bolt comes in 2 widths: 63" and 67". I found a 63" rear with 4:56 gears on CL for around $100. It had huge drum brakes and was an oily rusty mess.
The Dana 60 is much wider at 69.25". The 85-91.5 axle uses kingpins (desirable) and the spring pads are located 3.5" offset compared to the sought after 78-79 version. In a strange coincidence, the location of the driver's side spring perch on the '88 Dana 60 was an exact match to enable a ~63" track width on a YJ! This means that I would only need to shorten the passenger side.
I found a Dana 60 on CL with 4:56 gears for under $1000.
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The 14 bolt is very robust. It boasts a 10.5" ring rear. Unfortunately the result is a housing that hangs very low. I elected to reduce the diameter of the ring gear and shave the bottom of the housing. I completely disassembled the rear and took the housing and ring gear to work.
I used a conventional lathe and carbide inserts to reduce the diameter of the ring gear from 10.5" to 10.0". I took my time and the result was awesome. There are those who say the gear is too hard to be cut with carbide but that's not true. I did need to sharpen the carbide frequently. The intermittent cut across the teeth does cause the carbide to chip once in a while.
I made a fixture to hold the housing on the bed mill. It supported the axle at the tubes so I could rotate the housing to the desired angle. I milled 1.5 inches off the bottom of the housing. I chose to mill parallel to the ground (I already knew my pinion angle). Others chose to mill parallel to the pinion but this results in more housing material removed without any increased ground clearance IMO.
After I shaved the housing, I machined a pocket into the base to receive a 1/2" thick flat steel plate. I then machined the plate to fit the pocket added a groove in the center to clear the gear. There's about 0.125" clearance between the plate and the gear.
I took everything home and welded the plate. Prior to welding I used a grinder and added a healthy bevel to the weld joint. There's a lot of differing opinions on how to weld the plate. I chose to preheat the housing and use nickel rod in my stick welder. I used a Mr. Heater on a 20# tank and some aluminum foil to heat the housing. It worked really well (and fast) and I was able to hold the housing at 400F with good consistency. I made multiple passes on the outside as well as the inside. It welded like butter. I recommend the nickel rods. They're expensive but it made the job seem easy.
After the plate was welded I allowed the housing to cool very slowly. I turned the heater down over the course of a couple hours and eventually turned it off. I ground the weld flat and took the housing back to the machine shop to face off the plate flush with the differential cover mounting surface.
https://drive.google.com/open?id=0B5rIHifrzBStZFJ0Z3Y0SjdUN1U