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CJ-8 Engine swap... a question of approach..

5K views 14 replies 6 participants last post by  Pathkiller 
#1 ·
Howdy...

When I was in college, I rebuilt a 77 CJ-7 258 - T-130. Tubbed it with a 4WD Hardware tub with the tailgate opening and got it running and had a ball. A few years after that build I sold it.

I got the bug again and just bought a CJ-8, and I am having it delivered via flatbed today. The body is nice and straight and it has all parts except the original engine and drive train, which is not an issue as I wanted to do the 4.0 EFI swap anyway.

The fella who began this project had already purchased a salvaged 4.0 EFI engine, transfer case and auto transmission from a 1998 Cherokee. That stuff is "sitting" in the CJ-8 now. As far as I know, the engine has not turned over in 2 years.

Here is my dilemma. I want a 5 speed (AX-15) in this Scrambler:

I can hunt down all of the parts and try to convert this existing 4.0 setup to a Manual transmission. Don't know what all I would need to do this yet. (And the engine is still and unknown quantity)

OR, I can buy a whole 1996 Cherokee Sport - 4x4 TC - 4.0 - 5 speed, from a buddy for $800. It needs clutch work, but I would want to rebuild the engine, transmission, and TC anyway.

I have a feeling that the $800 Cherokee is the way to go, but was curious about the approach others who have walked in my footsteps have taken.
It seems like this could be cheaper and easier than collecting individual parts...

I am aware that there are issues that make different generations of electronics more or less friendly to work with, but I don't know what years the different generations existed. Are the 1996 engine electronics a "good year"? What is a good source for this type of model year info?

I can always keep my eyes peeled for an earlier year Cherokee that also has the desired engine if an earlier model year would be the easier route.

Any thoughts / input would be most appreciated.

Cheers, and Thanks!
 
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#2 ·
If you want a 5speed for that 4.0 I'd look for a NV3550, its slightly stronger than the AX15 and shouldnt be too hard to find as it was factory mated to the 4.0L. What are you going to do for a transfer case? The cherokee TCase will be a drivers side drop and the scramblers front axle will be a passenger side drop. I'd try and source a good Dana 300 somewhere and get the novak (or AA) adapter to the tranny.

That would be a pretty good combo for a scrambler!
 
#10 ·
Nv3550

Good advice. After much reading, I think that the NV3550 is the way to go. Now I am searching for one. The PO had a Dana 300 with a clock ring on it already, I just need to check the part number of the adapter and see if it's the right part. It was previously mated to an automatic transmission.

I am about to start my build thread. The hard part is choosing the parts. I don't mind hunting for them.. It's the initial decision making.... So many options. Gotta love it though. The 8 is about 2-3 weeks from being completely torn down so I better get a move on!

Thanks for pointing me in the right direction. Much appreciated.
 
#3 ·
Right.... more options... and... more questions :)
But now: I have to go meet the flatbed and bring the new baby 4x4 home.

I will think about what you said and drop you a note back later.

Thanks for taking the time to read about my project Kickingprop, and give me some feedback.

I will post an image of the "project" later tonight or tomorrow.

Cheers.

KC
 
#4 ·
personally, I would dig into the motor that comes with the 8 for right now. For 800, buy some 258 internals and build a stroker motor as long as the block isn't trashed. For all you know, everything COULD still be in great shape...you never know. Every now and then, the Jeep Gods smile upon someone. I got mine last week with my new bumper I won in a raffle. I'm just sayin....
 
#11 ·
Stroker...

The engine is in the stand and I am about to do exactly that. Stroke it! I have the number of a good engine shop that can help me with the machine work. A few buddies have used these guys, so I have some confidence in their work.

I am spending much time on this guy's site (Dino Savva) as he did quite the job of documenting the parts and the process of his stroker conversion.......

From Junker to Stroker

Overall the engine looks good so far. Fingers crossed. That said, this is gonna be one hella shopping list I can tell. I have rebuild Jeep frames and bodies, never done an engine before.

I will document in my build thread to be started this weekend. I have about 2 months of images I have to get up.

Thanks for your thoughts.. :cheers2:
 
#5 ·
So, I got the new vehicle home last night and we could not get it pushed up into the garage.... I had a plan to build a strong wall plate for the back of the garage so I could attach a chain and wench the jeep uphill and in.... I just had to accelerate that. 2 hours later, the plate was built, the wench was hooked up to the wall plate and the jeep, and it was finally inside and parked.

What I now know after talking to the old owner when I picked this jeep up. I have a 1991 4.0L out of a Cherokee, I have a Dana 300 TC, I have some sort of TC adapter to allow it to clock to the other (correct) dif side, and I have an auto transmission I want to take out.

So, stroker aside -for now- :) It sounds like perhaps the NV3550 might be the way to go. Which means my parts list will be a Transmission, Clutch Bell housing, Clutch assembly, Drive Shaft.

Any other thoughts / ideas..? I believe the 1991 engine was an OBD-I which from what I have been reading is easier to work with than the OBD-2.

KC
 
#6 ·
Here she is, being loaded onto the flatbed. Exciting.... :thumbsup:
I will need to start a build thread....

 
#8 ·
Ya won't get anything done on that Scrambler if you keep hanging with the wenches....
That's awesome!

I could fix the spelling, but last night when I was talking to my wife I was making the Winch / Wench joke.. so it stands! Thanks for the chuckle HackFab.
 
#13 ·
Good luck. Looks like a very clean Scrambler to start with. My Scrambler has a 4.6L stroker, AX-15 and D300. I really like this setup. Even running 33" tires with relatively high gears (3.31) it pulls hard and has no problem smoking the tires in second gear. There are lots of technical write-ups about swapping 4.XL motors into CJ's, but the CJ Offroad forum has probably the most comprehensive coverage of this issue in their 4.0L swap forum: CJOffroad.com - 4.0 Swap Information

The 91 model 4.0L is an OBD1 system, whereas mine is a 97 and is OBDII. OBDI is a lot simpler, and it boils down to basically 5 wires needed to fire (you'll hear the term 5 to fire frequently on the CJ Offroad forum).

Here's a pic of my engine when I bought it, I have cleaned up the wiring a lot since then, the PO was an idiot when it comes to wiring:
http://www.fyurl.com/rr.php?c=2&sit...://cjoffroad.com/forums/forum.asp?FORUM_ID=24


And here's how she looked in the PO's for sale ad:
http://www.fyurl.com/rr.php?c=2&sit...://cjoffroad.com/forums/forum.asp?FORUM_ID=24
 
#14 ·
Pathkiller. Nice Scrambler!

I am a little jealous, she is quite the looker. :drool: What a great place to start.
Thanks for the link to the CJ Forum info. I will kill some serious time over there today.

I see that your 8 came with a 4.0. Did you do the Stroker job or did the PO do it? If you did it, how did you decide on all of the bits and pieces. More of a mentality question.. like smoothness (heavier crank) etc.

I about about a week from buying parts. That will be a fun day.

After getting the engine out I could see the stamp on it, it's a '92.




KC
 
#15 ·
Thanks. It looks pretty good but still needs some attention. It's got some rust issues starting that I need to address ASAP. I just finished installing one piece rear axles and an ARB air locker, so it's coming along. The PO installed 3" Black Diamond springs with ProComp shocks and 33" BFG AT's.

The PO built the stroker and installed it. I bought it running but needed a lot of detail work. He was okay at doing bigger projects but sucked at paying attention to detail. The wiring was a mess, none of the lights or gauges worked, half the bolts had not be torqued, etc. I spent about 3 months fixing all of his mistakes. Which makes me wonder how well the engine was built, but it's running great so far and seems very tight.

Without knowing the full details of the build, I only know what he told me which was:
97 4.0L long block from an XJ bored and stroked to 4.6L
"dished pistons" (I don't know the specifics of what pistons he used)
Competition Cams Extreme 4x4 Cam 68-232-4
62mm throttle body with 1" spacer
Ford 24lb injectors.
Hedman header
Turbo City Rock-It air intake with K&N filter

It's running the stock 97 XJ wiring harness and computer which seems to be working okay. There are some issues with using a non-stock cam with a 4.0L, you will have to cut the ears off the distributor to allow you to index the distributor correctly. It's a bit of a pain in the butt, but there are several write-ups about it on the web.

 
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