Diesel ZJ

The last year or so I have neglected the CJ5 and Jeepster to build a diesel Grand Cherokee. It is getting close to finished and hope to have on the road before winter.

The engine is a 6.2l GM diesel, trans is a 700R4 , and TC is a 241. They are all mounted and fit pretty good. Real close on the PS pump and exhaust manifolds, about 1/2" clearance here, and 1/2" clearance there...I wanted to use mostly what I had "laying around" if I could.

I had to massage the firewall a bit to get it where I wanted. I would have liked it a bit more 1/2" or so to the passenger side, as the stock engine is offset that way. It ended up pretty close to the centerline of the vehicle. Some custom exhaust manifolds might have made this a little easier.

Interferences I had to deal with included the firewall, steering gearbox, and the control arms. The front differential moves to the passenger side as it comes up. The way I have it now the driver side control arm is very close to the exhaust manifold on full compression, I intend to either extend the bump stop or add a budget boost. It is also close to the oil pan, I think if I hit a large bump it would leave a mark.

The motor mounts were the hardest part. The 5.2l engine has mounts at the front of the engine. I made some flat plates welded to square tube which mounted to the engine and the frame mounts. The frame mounts were out of the pickup I took the engine from. I trimmed them and flipped them over to fit the Jeep.

I replaced the manual fuel pump with a GM diesel electric pump from a 1993, can always share parts with the K3500. The manual pump was in the way of the engine mounts. I could put plates on front of the engine like a drag car, but I am trying to use what I have.

The fittings from the diesel PS pump worked with the ZJ PS box, with some rebending and fitting. I used a hydro-brake booster from a diesel van, and got rid of the ZJs ABS. I had to make a mount to make the hydro-boost and master cylinder fit. Made some new brake lines and adapted them to the stock lines at the point where they came out of the ABS block.

I was able to use the TC linkage with a little modification, I had some linkages off a Cherokee that bolted to the TC and worked with the ZJs shifter, what luck! It appears to work OK.

I added a deep trans pan, added trans shifter linkage, a B&M shift cable modified with a marine ball joint on the cable which clips to the stock shifter. The stock shifters for the transmission and TC are used. I also mounted an engine and additional trans oil cooler and ran custom hoses and lines. Had to run the engine oil cooler lines up the back of the engine and over the top around the radiator and AC condenser. Added some cooling holes to the bumper (150!) and front fascia.

I used the fan that came with the engine, had to make a custom shroud and will have to make a small scoop on top of the hood for clearance. I used the stock driveshaft with the 241 yoke. Had to get a U-joint with the two different sized cups. Hoping I can do the same for the front shaft, have not tried it yet as I need to repair the front differential's pinion gear.

The next items to deal with will be the wiring and finishing the cooling system. Also need to fix the front differential, and bleed the brake system. Thinking about installing 3.07 gears, along with 215/85/r16 tires.

I have a rough write up with photos on the web about my Diesel Jeep here.

 

Have not done much since August, back to work full time and working at the second job also. Been playing around with the wiring. Bought a converter from Dakota Digital to convert the signal from the flywheel to the signal the computer is expecting, 8p/rev. Bought a sensor that will count the teeth on the flywheel, send the signal to the Dakota Digital box and then to the Jeep computer. Decided to mount the batteries in the rear and run the battery cables along the frame rail up under the wheel well into the battery box.

I picked up some great used Firestone tires 215/85R16 and mounted them on Ford 16" Aluminum rims. Looks like I will have to trim the front bumper slightly. I also picked up some 3:07 gears for the rear Dana 35, Thanks Anders!

My hope is to get this fired up and running before winter, but working the two jobs and some freelance work is making it tough.

 

Any updates?

 

Sorry, been working too much, winter is my busy time. Had to fix the daily driver, and the plow truck with all the snow we have, and had to find my wife a new vehicle because she totaled her 99 Grand Cherokee. Did some brake work and I took the front axle shafts and gears out because the gears are bad, and installed some stub shafts temporarily. I will be back on it in the spring, with the new goal to have it on the road by summer.

 

I'm bringing this to the top for you Hans. Give me a call when your ready to start getting things finished up on this thing.

Anders

 

didn't you post this on Nagca.com too? There was someone over there doing the same swap, and it assume its pretty uncommon.

 

Yes, posted on NAGCA, uncommon...Why? Have not been to the NAGCA site in a while.

Anders, I'll call you when I need some help. Got to get on the road before summer. I have plenty of time now, unless job #2 has a bunch of work for me.

 

She drives under her own power! Took the ZJ for a lap around the driveway last week. Still have exhaust to do, and some wiring. Redid the oil pan tonight, small leak in the back. Seems to be burning a little rich, may be gunked up injectors or just old worn out injectors, would have been easier to change when the engine was out.

 

Wtg

 

Changed out the fuel injectors, but have not run it yet to see if it runs less rich. Ran out of time last week.

Ran some exhaust from the manifolds to the muffler. Still need to do two tail pipes. Used 2.25" and 2.5" pipe and a Dynomax muffler with two 2.5" inlets and outlets.

Also hooked up a solenoid with a momentary switch for the glow plugs.

More info and new photos on my Diesel Jeep page.

 

Some more updates on this project. Cleaned up the wiring, with some zip ties and loom. Used a Dakota Digital signal converter to get a marine tach working and the speedometer working. Installed some relays to power the lift pump, and the shut off solenoid. Fixed the fuel level sender, had to bend the float slightly as it was hitting on the pick up line I installed in the tank.

The hood is installed and does not hit anything. I thought I would have to install a slight bump to make it fit. Hopefully the accelerator cable will be OK. It appears to be the only thing touching the hood.

Need to still find a wheel to match the other 3, and some lug nut that are all the same. Tie down the battery and make a cover. I am going to run it a bit and then change out the fuel filters.

 

Had a chance to do more work on this last fall and this spring. Took the Jeep down the road, but would not shift out of second gear, so the DZJ sat all winter. Talked to my trans build this spring and he gave me some ideas to get it working and it works great now.

Still have quite a few minor things to do including
clean up wiring better
find rattle -exhaust??
calibrate speedo & tach
install some 3.07 gears
install a WVO system
find parts and install AC

But all in all I think I can drive it. Good to see the light at the end of the tunnel.

But today the CJ5 gets my attention. Nice weather and needs to be cleaned up from sitting all winter.

 

Been a while since I updated this. Time seems to have gotten away from me. Too much to do...work, school, weather has been a bitch . Barn roof partially collapsed in Feb when we had 18" of snow. ...but I have done some more work on the Grand.

We changed the gears to 3:07s. Took it out for a test ride. Drives great....except the front brakes are getting hot. Changed to a master cylinder for a 1/2 ton truck because the van one was leaking anyway and made the pedal real hard. Better pedal, but no improvement with front brakes. Think I found the problem, the shaft going to the hydroboost was rubbing slightly because of the angle to the pedal. Lowered the hydro boost and master and the shaft does not bind. Front brakes seem to be on the warm side, but not smoking now.

Next problem crops up with a few more miles of testing. I am out for a test drive to put some miles on it and I get the death wobble. First I changed the lower control arms and increase the caster, but still had the problem. Next, I changed out the right side ball joints (very little play), track bar (very little play in one end), and steering stabilizer. I am running the 215/85/r16 LT tires at 40 psi. All appears good now, no death wobble on last test rides.
Plan to drive around more in the next couple weeks, and work out any more gremlins.....

Now on to fix the K3500.....and the barn roof will be priority the next couple months.

 

Good to see an update, I hate front end wobble, seems like once it shows up you fight it a long time or are worried about it constantly even if you do fix it......

Hope you report more as you get some miles on it.

 

How time flys. Replaced the trusses and roof on my barn last November. Did some small things on the Grand last spring, new calipers on the front brakes, and wiring. Still has some electrical gremlins, but the Jeep is drivable. Found out the gas gauge reads about 1/8 when it runs out of fuel At least it was in the driveway close to the barn. The info center will not keep time, and date, but will keep mile to service. But I have been driving the Grand around and have put about 3000 miles on it. If my speedo and odo are right I am getting 22 - 22.5 mpg, not bad for a V8 SUV. Plan to drive on a regular basis for now. Got to watch the speed, I tend to drive it faster than the full size truck or the CJs.

 

Well this is a pretty interesting build. How is the get up and go with that 6.2? Got any present pictures? Nice job at building something different!

 

Like I said, I tend to speed in it. It goes pretty good, and we geared it up to 3.07. It ripped really good with the 3.73 gears. I was hoping for a little better fuel mileage. May have to move the injection pump a little. The pump I used was from a 1 ton van, because it was available in my storage. I'll see if I can find or take some current photos.

 

Filled up today...24.75mpg! not bad for a Grand Cherokee.

 

Last three tanks...

24.9 mpg
25.1mpg
25.9 mpg

So I'm averaging just over 25 mpg in an SUV that used to get something like 12 mpg.

 

Nice man.. Love the ingenuity.. Not an easy transplant for sure!