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Project 86 4.0 Ho


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Just really starting my project now. Here is my first major fix. Rust and lots of it. Having fun with the rubber sealer used on the seams.

 

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Drivers side is much worse than other but I still went out and got two new pans. 

IMG_5758.JPGIt was fun but I managed to remove all the wiring and clean  out the under hood area pretty well. Once I finish the floor, I will move to the firewall.

I have a 1998 XJ that will be the donor for most of this project. Will be slow going, but I think the 4.0 will be worth it. Toyed with building a stroker, but I decided the stock motor will be fine and not be as big of a pain to get running.  My only planned mods to the motor are, small cam, HV oil pump and polish/port head with header. For a daily driver, it should be plenty peppy.  

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  • 1 month later...

Well after much trial and error, I finally found the best method to remove the old floorpan. The spot weld cutter tool is sweet (as long as you can see the welds) but where the rust is bad, I finally went with a metal cutting blade on a 4 inch side grinder and a air hammer with a chisel. IMG_5786.JPG

After I finally got the old pans up, I spent the next few weekends prepping. IMG_5775.JPG

Then I was ready to start installing the new pans. This has also been fun. IMG_5785.JPG

Once I had the new pan marked, I drilled holes in it for the new spot welds. I also used 1/4 inch sheet metal screws to hold every thing in place when I started tack welding. IMG_5792.JPG

Screws worked great

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Notice my BFH fine adjustment tool. Its a must have to get the new pan to follow the the curve of the frame correctly. 

Now that I have one side, I have to do the other and then the rockers. I went the easy way on the front finders and just got replacement ones. 

I start pulling the motor and tranny out of the Cherokee next week. This is where it gets fun! 

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I do have a question for the folks with more experience at this than me. I have two Cherokees one has a 5 Speed standard (1992) and the other has a  automatic(1998). Now my truck came with an auto, I kind of want to go with the standard, how much trouble is it to mount the clutch pedal and all associated stuff in a truck not set up for it?

Will it be too much trouble? Should I just go back with the auto, its a solid tranny, no problems with it.

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I do have a question for the folks with more experience at this than me. I have two Cherokees one has a 5 Speed standard (1992) and the other has a  automatic(1998). Now my truck came with an auto, I kind of want to go with the standard, how much trouble is it to mount the clutch pedal and all associated stuff in a truck not set up for it?

Will it be too much trouble? Should I just go back with the auto, its a solid tranny, no problems with it.

I swapped my pedal set up from standard to auto and it was a piece of cake. Just had to twist your body all up to get a view of it under the dash.

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Tried to install the tranny today. Will not fit. Seems the stock xj tranny mount pushes it way to foward into the engine bay. The old mount from the original tranny will not fit. (NP 207 v/s NP 213) so, who has overcome this little bump? I am looking through the forums but if anyone can point me in the right direction it would be great.

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  • 9 months later...

Boy, this has taken awhile!! I finally made the transmission mount work, used the cross member from the XJ and the mount from the Comanche then added just a touch of finesse with a hand drill. So the motor and transmission are in, then I started working on the clutch master cylinder. I wound up putting the hole in the firewall about 1/4 inch too high, That was a beast to fix but I managed to figure it out. 

 

I put a 4.0 from a 92 XJ into my 86 that came with the 2.8, so I had to move the firewall back. To do this I cut the firewall out of the XJ and welded it into the Comanche. Even with this done I was really tight for room but it fit. I have her purring like a kitten now, BTW, I found a inline electric fuel pump from Auto Zone for 89.99 (MSD 2225) that kept me from having to replace or mod my old tank. All I did was add the power wire from the XJ harness into the existing wires from the Comanche that went to the tank, pulled it off at the tank connector and wired the pump in. Worked like a charm. Mounted the pump, inside the "frame" just in front of the tank, re-used the old steel lines and replaced the rubber lines with high presser ones.  I am now working on the tail lights. Oh my answer to converting the XJ engine and cab/dash harness to work with the Comanche rear harness was the tail lite converter kit you can pick up from Wal-mart for 20.00. I wired it in under the dash and my rear lights work as they should and no new wired were pulled. 

 

It is my tail lights themselves that are of issue, it seems they lived a hard life and are cracked and broken in various places. I may try and repair them with fiberglass and epoxy, but at this moment, I am looking at modifying the XL rear lenses to fit the Comanche. If anyone else has ever done this, please don't let me re-invent the wheel!!!

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I take it that the frame of the 86 doesn't have the holes for it? but the ealier engine/trans use the crossmember further forward than the later/4.0L/ The later models I believe have all the holes/nutserts in the frame.

There are basically 3 sets of holes. Glad you got it figured out. 

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I did take pics as I was working on the thing, as soon as I figure out where I put them I will post them. Basically I cut the XJ firewall out from the seam at the top of the firewall down to where the transmission opening started. And from about one inch shy of the AC opening for the fan all the way over to about 6 inches shy of the master cylinder Then I did the same to the MJ but on a smaller scale, then custom fitted the XJ part with a air grinder and the used sheet metal screws to hold it in place and mig'ed it from the inside (Left a service port for the Crankshaft sensor because it was all so tight.  Found some! If you look you can see where I used the AC unit bolts to line everything up. You can see the sheet metal screws too if you look. I should of removed those but didn't think about it until I had the dash back in and I was not taking that back out. 

 

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You can see how close things were, even with the XJ firewall. I built custom mounts for the radiator (2006 Wrangler) 

 

So far I haven't had any over heating issues, other than the first thermostat I put in was defective. Once I get it out on the highway I will know if this configuration will work. I have a 3000 CFM electric fan in front, pushing air through the radiator. Everything about this truck has been tight, If I had known how tight this was going to be, I would of just put a small block Chevy in it. There is 1.25 inches between the end of the fan mounting bolts and the radiator and the motor is only 3/4 of an inch off the firewall in the back. I know this is a very early production 86, I have wondered if the first few months may of had a bit shorter front clip than the rest of the trucks. 

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Here are a few more of the firewall as I was fitting everything. At this point, the motor was sitting on wooden blocks in the position I wanted to make it be. I had the front off the truck and would just push it up to the motor or pull it back for room to work. Just had to watch the front axle. I was fab'ing up my motor mounts as well as the firewall. 

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