Jeep CJ7 Engine Swap… SUCCESS!!!!

RacerX

RacerX

Professional Knucklehead; aka Jeffncs / RacerX
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So I started to shift gears towards the 65 convertible, when my wife reminded me that the Jeep still has a sewing machine engine while the replacement sat on an engine stand for 2+ months. (Thanks again @SDIVER2006 !!!)

So… I decided to bump my 4.0 EFI swap ahead of turning the first wrench in the mustang.

Current state:
1982 Jeep CJ7 258ci/4.2l engine, 5 speed and 3.73 gears front and rear.
The is running a new Weber carb, leaks like a stuck pig and has ~200k miles. It can barely get out of its own way.
The previous owner installed a skid plate spacer kit to help the driveshaft angle, but makes accessing the rear balve cover bolt IMPOSSIBLE,

Future state:
4.0 with the EFI, computer, harness and ECM. Otherwise keeping the stock driveline.

Plan of attack:
External, electric fuel pump - 55gph sourced from Amazon
Harmonic balancer with Crank Position Sensor conversion from Hesco
Speedo cable adapter and Variable Speed Sensor for computer from Hesco
Throttle cable adapter also from Hesco
Stainless steel exhaust manifold - eBay

4.0l Engine condition:
~200k miles but ran strong, no oil burn
Stock, fresh engine rated at 190hp (vs 95hp for my 4.2l) - even if a little tired, I’ll still have a substantial power boost
Valve train clean with ZERO sludge
Oil pan spotless and remaining oil clean, healthy brown

Current state:
Stripped the long block and shot it with semi-gloss black engine paint
Replaced the valve cover gasket with a rubber Fel-Pro
Installed a new timing gear set (cracked the cover when installing the last bolt!!)
Pending a buddy to weld the cover
Have a new, rubber Fel-Pro oil pan gasket

I love this stuff!!
 
So…. I’m sitting here on Labor Day morning mustering my energy to finish the front end of the Jeep.

Friday - pulled the T5 and transfer case as a unit. Gravity is your friend here! Using the trans jack and a little balancing, the assembly slid right out.

Saturday - said goodbye to wife and 2/3 kids (they went to her parents for the holiday). A CNC4x4 friend cam over to help. We yanked the old engine and set it on a tire for safe keeping. We then promptly shifted gears to installing the replacement 4.0. Aside from some minor obstacles, the job went smoothly.

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Sunday - A different married couple from CNC4x4 stopped by to help install the trans and transfer case. After fighting the pilot nose clearing the engine swap pilot bushing, I pulled it all apart for the 3rd time. This time I opened the bushing center using my Dremel with a stone wheel. Quick check and things cleared nicely. We decided to divorce the trans and transfer case to cut the weight. Things went together nicely from that point forward! We also ran the fuel lines and I installed the external fuel pump.

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Monday (today) - I’m going to start looking at which engine accessory set to use (CJ vs XJ). Each has challenges, so I’m going to go out shortly to look each over then dive in. Wiring up the EFI will likely wait for another day, but the Saturday helper emailed the full 98 XJ wiring harness .pdf to me. I’ll just need time to work through that with a clear head.
 
I high school friend had a CJ7 with an LS1 engine. He had to be careful though because it still had the D20 rear axle. He goosed it just a hair too much and had to have the axle housing repaired.
That thing moved.

Sent from my SM-G970U using Tapatalk
 
Plugging an update into this thread…. Engine and all accessories are in, but at a steep cost to my sanity!

I’m using a 98 XJ engine in the CJ7. I opted to reuse my CJ accessory brackets which helps with simplicity, but complicated the aftermarket dampener and accessory mounting.

I had to fabricate a bracket for my PS pump which allowed me to eliminate one of the idler pulleys, but I can’t seem to track down the correct length serpentine belt. That’s all resolved now with the exception of a cut-to-fit spacer in place of the washers and nuts to align the pulley deprh…

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My buddy went through the factory 4.0 harness to weed out all the garbage to leave behind only the critical few circuits. The harness started out as 15+ wires and is down to ~5.

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The next obstacle is that the XJ computer is geared towards an automatic or manual trans…which don’t interchange. I’m waiting for a custom flashed computer from an outfit in FL for my manual trans. That’s the final big item before I can do final checks and test drive!

So far the Jeep has been down 3 weeks. I’m not sure how anybody could do this in a 3 day weekend…. Maybe I just had some bad luck, but this doesn’t seem possible to do faster!

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Man I'd love to be there to help/watch/drink beer and cheer you on!

I did a 77 CJ7 Golden Eagle frame-off restoration back in the late 90's. Bought it off of the back row of
a car lot with a blown engine for $800, sold the hard top for $700! The only rust anywhere was the size of a nickel where the "Hinkles Jeep" logo was screwed on.
Spent twice as much money rebuilding the 304 as a SBC would have cost, rebuilt the AT, rebuilt front/rear ends. Painted the body myself.
Drove the dang thing about 3k miles and traded it for all of the excavation work when we built our house in 99.
 
Lookin nice my friend…

I have decided on keeping my 4.2, and have a .30bore, earson cam clevite bearings…a 4.0 head with a Clifford intake and a Holley sniper or something similar
 
SDIVER2006 said:
Lookin nice my friend…

I have decided on keeping my 4.2, and have a .30bore, earson cam clevite bearings…a 4.0 head with a Clifford intake and a Holley sniper or something similar
Click to expand...
This is pretty much the same setup I want to do in my CJ with the rebuilt Jasper 4.2 in it. I am fascinated with how much power can be gained from the 4.0 liter headswao.
 
lowcountry said:
This is pretty much the same setup I want to do in my CJ with the rebuilt Jasper 4.2 in it. I am fascinated with how much power can be gained from the 4.0 liter headswao.
Click to expand...
I am looking for a 7120 head, and have it re worked…but not sure if it would be better to do that or just ect one from Clearwater cylinder head..
 
I would love to get this, but pretty sure my budget will say nope.
www.quadratec.com

Edelbrock Performer Aluminum Cylinder Head for 76-06 Jeep Vehicles with 4.0/4.2L

This new Performer cylinder head is designed as a bolt-on performance upgrade for 1987-2006 Jeeps with a 4.0L inline six cylinder engine. It features all-new better flowing intake and exhaust ports, a modern combustion chamber design with back cut and swirl polished valves.
www.quadratec.com www.quadratec.com
 
As an update…. Here are some adjectives to capture my attitude towards this project.

Frustrated
Disappointed
Exhausted

The engine and all mechanicals are finished. My buddy did a great job with the wiring and things look great!! However, I’m hitting a wall. I’ve spent countless hours looking at wiring and testing things… despite my efforts, I’m in the same spot. The relays aren’t kicking the fuel pump on and I can’t seem to get it to fire, even after bypassing the relays with a direct battery hookup to the pump. It’s likely something dumb like a ground or a flip-flopped relay connection, but I’m tired of chasing my tail.

I’m about ready to roll it out, throw on a car cover and ignore it for a while.
 
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