I'm in the progress of doing a frame-off build up of my 1984 Jeep CJ7. I had been putting it off for years. I finally got sick of staring at all the parts sitting collecting dust in the garage so I got to work.
This Jeep started off as a well used 1984 Jeep CJ7. The original drivetrain was a 150ci 4 cylinder
engine, 4 speed manual transmission, Dana 300 transfer case, front Dana 30 and rear AMC 20 axles.
Since I started working on it, things have changed a few times. I made a lot of progress with an SM465
and Atlas t-case but ran into trouble fitting a clutch so I decided to go with an engine and transmission
I already have in the garage. The plan now is to fit a Chevy 5.3 liter V8 with a 4L60E 4 speed automatic
and a Dana 300 transfer case. The axles remain a heavily modified Dana 44 axle in the front and a well
built Ford 9" in the rear. The front will have an Eaton Elocker with 5.38 gears while the rear has a
spool, both with 5.46 gears intending to drive 37-40" tires.
The suspension is going to be a custom build. In the front, I'm moving the spring shackles to the rear of the leaf spring and upgrading to wider Jeep Wrangler YJ leaf springs. I bought a kit from Mountain Off-Road Enterprises to do this. It comes with all of the brackets and hardware to make this swap as painless as possible. In the rear, I'm going to be using leaf springs from a Jeep Cherokee XJ. These springs are longer with an offset mounting position for the axle which will push the axle backwards and give me both a longer wheelbase and a better departure angle. I'm using a kit from Blue Torch Fab to set this up. They make a bracket that welds to the back of the frame to accomodate the longer leaf springs. Rather than use tall lift springs, I am doing a SOA (Spring Over Axle) conversion. All that means is that I'm putting the leaf spring on top of the axle rather than under it, giving me about 6" of lift to clear my tires.
I'll keep adding updates as I accomplish more on this build.
Update 08 May 2011:
Now that the engine is in, I decided to put the front clip together to make sure everything fit. Alos,
I'm going to need to get this Jeep ready to move. I've decided to accept a new job in a new town. I
have another week before I load up the Jeep on a trailer and get moved up to my new home. For the short
term, this project is going on hold. It will probably be a couple of months before anything significant
is done to this CJ again. Rest assured, I'm more motivated now to get it done than ever. I really want
to take this Jeep out for a spin and have fun on the trails.
Update 16 April 2011:
It was another fine day for working out in the garage. Mild temperatures and a light breeze. I started
by cleaning the firewall and prepping it for paint. While the engine is out for the last time, I figure
it's the best time to do it. I scrubbed and scraped and ground off a good 27 years of accumulated crud.
It was stubborn but power tools won the day. After I had cleaned and prepped the surface, I laid down a
couple coats of Rustoleum primer. After the primer, I used some "universal black" automotive paint and
laid down three coats. After that, I put on some clear coat in the hopes that it will make it easier to
clean the firewall in the future.
Once the paint had sufficient time to dry, I turned my attention to getting the engine mounts welded in. Of course, as I was putting the engine in, I put a good sized scratch in the paint on the firewall. It's a good thing this is a Jeep and not a show car or I would have been mad. Then again, I would have been more careful. I lined up the engine and verified my measurements 3 times. I took the engine out and welded on the frame mounts. Once they had cooled sufficiently, I slid the engine back in and all bolted up. I didn't think to snap any pictures of the mounts. Once I had the engine in, I started to install the grill to see how it would look as an actual Jeep with an engine. It looks good.
Update 09 April 2011:
As I was getting ready to put the new engine between the frame rails, it occurred to me that knowing
whether or not it would hit the body was important. So I took advantage of the very nice day today to
put the body tub on the frame. I got most of it with my engine hoist and a bit of chain but a good
neighbor did stop by to offer some much needed help at one point. After that long day I decided to clean
up the garage again so I could test fit the 5.3 between the frame rails. It looks like it's going to
fit just fine.
Update 03 April 2011:
I finally got the steering knuckles back from the machine shop. They were able to take the cast flat top
knuckles and set them up for the high steer arms. Getting the old knuckles off was a bit of a pain but
it was an excuse to hit things with big hammers and use power tools and that was gratifying. I did run
into a snafu when I was working on the axle. I thought it had 4.56 gears in it when in fact, it has
4.09 gears. So I decided as long as I had everything completely out, I will go ahead and swap the gears.
Now, since I decided to go to overdrive, the 4.56 gears aren't quite what I want for a rock crawler. I
want low wheel speed. So I have decided to just go ahead and swap in 5.38 gears in the front. I'm also
going to take out and sell the Detroit locker and replace it with an Eaton Elocker. The Detroit locker
is fine but since it's an automatic locker, it puts more stress on the drivetrain. The Elocker is
activated by a switch on the dash. When it's on, the locker is locked and says locked. When off, it's
open and it stays open. The Detroit springs open and closed on its own and that's harder on the parts.
I'm going to have to swap gears in the rear axle but they're not too expensive and the 9" is very easy to set up. I haven't been able to find any 5.38 gears for the rear but there are some 5.46 gears. They are within 1% of each other so they will work together fine. I also decided to swap out the u-joints in the front axle shafts while I'm in there. I'm not sure what brand of joints are in there now. They are fine and I will keep them as spares for the trail. But I put in some Spicer 5-760x joints. Spicer designed them to replace the older style 5-297x joints. They're stronger without costing a lot of money.
Sometime in the near future I will be pulling the 401 out and swapping in the 5.3. Some of the parts for my Dana 300 upgrade have come in. I'm still waiting on the 4:1 gear set but they told me it would be a little while before they shipped. I'm in no huge hurry on that though. There's plenty more to do on the Jeep before I need to install the transfer case. I also need to get some steering arms and get them bolted in. Right now I have the tie rod loosely in place on the factory steering arms. It's zip tied to keep it from falling off and that's about it.
Update 13 March 2011:
I've started to accumulate enough parts to start assembling the new drivetrain. So far, I have the
adapter kit to bolt the transfer case to the transmission. It's an
Advance Adapters 50-0432. The kit does
a couple of things. First, it adapts the input shaft of the transfer case and provides a compatible
bolt pattern to allow the transfer case to attch to the transmission. Second, and more importantly, it
provides a VSS (Vehicle Speed Sensor) signal to the computer. The transmission is controled entirely by
the computer. Without a VSS signal, the computer wouldn't know when to shift. Normally the VSS is
housed in the tail shaft of the transfer case and a signal is sent to tell the computer when the case is
in low range. However, with the different low range gearing, the calculations for when to shift would be
affected. Really, the computer just takes the low range signal and adds some arithmetic to factor out
the low range. So by taking low range out of the VSS signal, there is no need to tell the computer
that it's in low range. The only reason to worry about low range is if I was running a computer
controlled speedometer. I'm running the factory Jeep speedometer and using the mechanical speed sender
in the transfer case.
In the pictures, you can see first the reluctor ring. It's just a wheel with teeth. When the teeth go by the VSS sensor, they trip a magnetic swith that sends a signal to the computer. The computer just counts the number of signals over a period of time to figure out how fast the vehicle is going. In the second picture, you can see the front half of the adapter. It holds the VSS sensor. You can see it in the upper right hand of the adapter. It's black and a little hard to see in the picture. But it sticks in just about to where it touches the teeth of the reluctor ring. It also sticks out the side of the adapter so a factory plug can attach to it. The third picture has the back half of the adapter that the transfer case bolts to. Finally, I have attached the empty transfer case shell. I don't have all the parts yet so I don't have it back together. I just wanted to mock it up to see how it fit.
The gears for the transfer case are backordered until some time next month. So it will be a while until I get the transfer case together. I still have a lot to do until I need it. I should be getting my flat top steering knuckles back on Friday and I have to get the engine and transmission installed into the frame. I also need to repair some of the body mounts on the body tub so I can get a lot of that done before I need to put the finished t-case in.
Update 14 February 2011:
After a long hiatus with this project, I have started again. Since there was no way to make a clutch
fit under the bellhousing with an AMC 401 flywheel, I decided to abandon the drivetrain I was going to
use in favor of another I already had most of. The transmission and t-case I had are sold and the
proceeds have been used to fund the new transfer case.
I am focusing on getting the new drivetrain set up. I already have the engine and transmission. They were taken from a 2003 Chevy Tahoe that had been wrecked in transit to a dealership. The original D300 that came with my CJ is long gone but I was able to acquire a replacement fairly easily. I spent the weekend tearing it down in anticipation of doing some significant upgrades. I already have an adapter kit on the way from Advance Adapters. It has a replacement input shaft for the transfer case as well as a tail housing for the transmission that will let me run a VSS sensor to tell the factory computer how fast we're going. This allows the computer to shift the transmission at the right time. I am also in the process of ordering the internal parts for the transfer case. I will be ordering several things from JB Conversions, Inc. In addition to their LoMax 4:1 low range gear kit, they sell upgraded front and rear output shafts and other miscelaneous parts to use in a rebuild. The 4:1 low range will give me better rock crawling ability while the upgraded shafts take care of the few weaknesses in the factory case. I'm also going to be installing a twin stick conversion which will let me shift the front and rear outputs independently.
Update 24 November 2010:
This update has changed a little since the transmission and engine I was intending to use have changed.
I haven't dropped in the new drivetrain yet but I will see if I can reuse this transmission mount. If I
can, great. If I have to modify it a little, I can. If I have to start over, I'll build another one a
lot like this one.
I used a bit of the 2"x3" rectangular tubing I had laying around to build it. I cut one piece length wise along opposite corners to form the wings that bolt to the frame rail. As I was fitting the wings, I had to notch the tubing to fit around the bracket for the parking brake. I used the captive nuts in the bottom of the frame that held the original skid plate. Once I had them bolted in place, I placed a section of tubing across, under the transmission mount. Naturally, the tubing landed right on top of one of the bolt holes in the frame. I had to taper the end of the tube to clear the nut. I also decided to taper the bottom of the tube on either end as well.
In order to secure the transmission, I built some bolt holes into the tubing. I drilled a few holes in the tubing and slid a piece of metal tubing into the holes. These will help keep the bolt from crushing the tube under stress. As I was finish welding the bottom bar to the wings, I decided to reinforce it a little. I used the scrap pieces from what I cut out to taper the tubing as gussets. They were close enough to the right size and fit perfectly. The crossmember hangs down a couple of inches but it shouldn't be a big deal. I'll be building a removable skid plate that will cover both the transmission and crossmember to protect them.
Update 14 November 2010:
I finished up getting the suspension and axles in place. The CJ is now sitting on 4 tires. At this
point I still had the old engine and transmission in place and used it to build the crossmember. I still
need to get the new drivetrain in so I can measure for driveshafts and set the pinion angle on the rear
axle. I found the box with the new body bushings and discovered a purchase date in July of 2004. I know
I bought these bushings after I tore the Jeep apart so that means it's been over 6 years since I started
this project. It's hard to believe that it's taken so long to get this project on track. But now that I
have momentum, I hope to have this Jeep ready for next spring. (Or summer? Maybe fall?)
Update 07 November 2010:
I've been making steady progress on the Jeep. I tapped a couple of the bolt holes in the frame for the
front suspension and steering brackets. I installed the front springs and set them on an axle with tires
on it. I'm waiting on bushings for the rear springs so I can get that in place. I bolted up the HD
steering box mount and attached the PSC power steering gear
box. The first engine I intended to use is in these pictures but it will be replaced by another one
some time in the future.
Update 24 October 2010:
I took advantage of the mild weather to mostly finish the frame. I still need to weld on some gussets to
strengthen the rear spring hangers but I have all of the other welding done. I covered most of the frame
with spray on bedliner since it's a little more durable than paint. I have the frame set up where I can
now start mocking up the engine and transmission. From there I figure out all the measurements I need to
build the transmission crossmember. And once that's in I can measure for driveshafts and get those
ordered. I also have wheels that I can mount some used tires on so I can actually roll the Jeep around
in the shop. It will be nice to have a real rolling chassis.
Update 03 October 2010:
I was able to spend two solid days working on the Jeep this weekend. I gave my grinder and welder a
pretty good workout. I ground what seems like half the primer off the frame to get good metal to provide
a good foundation for the MORE frame reinforcement plates. They were pretty close in shape to the sides
of the frame but not 100% exact. Fortunately, they did get all of the holes in the front plate lined up
pretty well. The holes for the shackle reversal mounts in the front line up well along with all 6 holes
on each side for the motor mounts. I did have to do a little customization of the front plates. They
weren't cut for the shackle mount that I had to drill for the shackle reversal but that wasn't so hard.
They also run well past the first body mount. After an email to the MORE team, they said I could cut off
the body mounts and reattach them or just cut the plate. I chose the latter since there is nothing wrong
with the body mounts. I gave myself a small gap between the plate and the body mount so I could weld a
solid seam at that point.
Once I got the four main plates on, I flipped the frame to tackle the bottom of each plate. The rear plates also came with some reinforcement caps for the bottom of the frame to give the factory shackle mount a little more strength. Even though I'm not using the factory shackle mounts, I decided to weld them on to have a stronger attachment point for the BTF bracket. Once those plates were on, I started attaching the BTF bracket and spring hangers. The bottom of the Jeep frame has an uneven surface since the boxed frame seam overlaps there. I was able to scavenge some 3/16" plate to even out the surface for the spring mounts. I still have some work to do to reinforce the spring hangers and I have to weld the top of the BTF bracket into place. But it's been a long two days of hard labor for a desk jockey. I'll get more done in a couple of weeks since more parts are set to arrive soon.
Update 09 September 2010:
The rear suspension build started with a bare frame. As near as I can tell by the dealer sticker on the
body tub, the Jeep had been in Florida for some time. Being in all that salt air and humidity means
rust. And there is a lot of it on this Jeep. The rear crossmember on the frame was rusted very badly
and I had to cut it off and start over.
The first thing I did was to get some 2"x3" 0.120" wall rectangular tubing. I cut it to fit and notched it to slip over the frame. I spent a fair amount of time grinding off the primer and rust to have clean metal for welding. Once I got the crossmember cut and shaped to fit, I welded it in place. To be sure, I weld it pretty thoroughly along every place the two pieces make contact. It will be further reinforced by welding on the BTF rear shackle bracket and the MORE frame reinforcement plates when they go on.
Update 07 September 2010:
Since I'm working second shift this week, I took advantage of the opportunity to run a few important
errands. I took the flat top knuckles down to the machine shop to have them do their thing. The work
on them needs to be precise beyond what I am capable of doing. They have the tools and the training to
get them set up properly. The other very important thing I did was to stop by the store and pick up
the tubing I need. I'm going to be fabricating several pieces on this Jeep and having the right metal
to do that with is important. I bought some rectangular tubing for the crossmember and transmission
mount. I also bought quite a bit of round tubing for building rock sliders and shock mounts.
Update 21 August 2010:
Parts have arrived. The rear suspension pieces from Blue Torch
Fab have arrived, along with a used set of XJ springs. The brackets are pretty heavy duty and should
hold up just fine, assuming I don't mess up welding them on. I'll be picking up the raw metal I need to
fabricate a couple of crossmembers and a skid plate pretty soon. I'm also going to be getting some
wheels for some old tires I still have so that I will be able to roll the Jeep around. In the pictures,
you can see the difference in length of the springs and you can see how the pin in the springs is offset
when I turn the springs in the opposite direction.
Update 24 July 2010:
I got motivated to make a little more progress. I moved the axles around in the garage and set them
roughly in place. For fun, I decided to put the engine, transmission and transfer case in line.
There's almost enough there for me to sit and make some "vroom vroom" engine noises and pretend to be
driving it. I'll be ordering the rear suspension pieces now that I have my welder here and can get
that built up. Once that's done I'll start getting the drivetrain in there permanently so I can get
the body tub in place and start the full assembly.
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