Our beloved Teal-J Jeep has seen her share of modifications over the years, and one area where we never seemed to get enough performance was the stock 4.0L six. Its factory-rated 181 hp at 4,600 rpm and 222 lb-ft of torque at 2,800 rpm were adequate for the vehicle in base trim, but with the hundreds of pounds of extra weight that we've bolted onto our Jeep in the form of aftermarkets axles, wheels, tires, and body armor, our 4.0L was beginning to act a bit sluggish, leaving us looking for power upgrades. This is why, when we saw a 345 hp 5.7L Hemi-equipped TJ Unlimited at Tera Manufacturing's booth at last year's SEMA show, we were hard-pressed to take it for a spin. So we asked, and much to our surprise, they said sure. One blip of the skinny pedal and we were sold.
Thanks to Tera, this swap is easier than you might think. Not only are these engines popping up everywhere as late-model Dodge Rams are wrecked, the swap itself has been totally mapped out, so very little homework is necessary to execute the conversion. Our donor Hemi came out of a 3/4-ton '04 Ram--which can save thousands of dollars over the cost of a complete new Hemi turnkey assembly - and it exceeded our expectations in both fuel economy and acceleration.
We decided to break up this install into two parts because it's composed of so many steps. So follow along as we show off the stuff you'll need to get a Hemi under your TJ's hood. Next month, we'll tackle the cooling system, exhaust, and transmission shifter as well as showing off the Teal's Hemi-enhanced performance both on- and off-pavement.
Step By Step
1. As with any motor swap, the first step is to remove the original engine. The professionals at Mepco made quick work of this time-intensive process. Once out, the stock five-speed and Atlas 2 transfer case were removed as well.
2. The whole engine bay was then given a thorough bath. This assists in a clean installation, and as long as the engine's out of the vehicle, it's a good time to do it anyway.
3. Next, the factory engine wiring harness was removed. TeraFlex then modified the stock harness to work with the new Hemi PCM. For customers who send TeraFlex their factory harnesses, this process should take about two to three weeks to complete.
4. While the wiring gurus went to work on Teal-J's factory harness, the guys at Mepco disassembled the Atlas 2 transfer case so that a new input shaft could be installed. This ensured that the transfer case would bolt up to the Grand Cherokee 545RFE five-speed automatic transmission we decided to use.
5. The Hemi engine requires completely different motor mounts from those of the straight-six. Here, you can see the stock mounts getting torched from the frame.
6. The new TeraFlex Hemi motor mounts are laser-cut from 1/4-inch-thick plate steel and machined from DOM tubing. These mounts are designed to locate the engine at precisly the right spot under the hood. A 1-inch body lift is necessary for proper clearance. Luckily, Teal-J already had such a body lift. Mepco installed the mounts by welding the above frame tabs to Teal's framerails.
7. Once the motor mounts were in place, the new Hemi was lowered into its new home. Weighing only 57 pounds more than the stock 4.0L, the Teal's front coil springs hardly noticed the new, bigger powerplant.
8. These new motor mounts use high-quality rubber bushings to isolate engine vibration. We like this setup because it offers no-nonsense beef in an easy-to-reach location.
9. Our new Hemi came with a sizable chunk of wiring. This is normally the most difficult part of an engine swap. In our case, getting the vehicle sensors and actuators wired correctly to the PCM was no harder than plugging in the connector with the corresponding label. Yes, you read right--the process of hooking up this mess was made simple by TeraFlex's wiring modifactions. The factory TJ harness, once returned from surgery, simply plugged right into the Hemi harness. No tedious wire splicing or late-night schematic sessions were required to make everything work properly.
10. Next, the stock instrument cluster and wiring loom were replaced with a unit out of a wrecked '01 TJ. This was necessary because all pre-'01 TJ instrument clusters use a different communication protocol than what the newer Hemi PCM uses. Our new instrument cluster bolted right in, though some wire splicing was necessary to install the new cluster plug-in connectors onto the OEM chassis harness. TeraFlex handled this modification with ease.
11. Because the Hemi engine is driven by wire instead of using a throttle cable, a brand-new gas-pedal assembly from an '05 Grand Cherokee was used (PN 52109683AB). TeraFlex supplied us with one of these from a local Jeep dealership. The mounting bracket used to locate the new pedal was built by TeraFlex.
12. Next, the automatic transmission and freshly assembled Atlas 2 transfer case were installed under Teal-J. A new rear driveshaft was built by Tattons of Salt Lake City. The front shaft didn't require any modifactions to work with the new setup.
13. TeraFlex provided a belly-up skidplate to replace Teal's beat-up old factory unit. This is nice because it increases ground clearance by up to 2 3/8 inches over stock and features laser-cut holes for easy mounting.
14. With the powertrain installed, the guys at Mepco moved on to smaller details such as making up new battery cables, which ensure adequate voltage to our new engine.
15. One of the coolest parts of the TeraFlex Hemi conversion is the OEM-style plugs used in the modified wiring harness. Each harness is built specifically for each conversion application. All functions related to onboard diagnostics (OBD II) remain intact, and the new engine is readable by any Chrysler dealership as a Hemi-powered Ram pickup.
Project Teal-J II, Intro
Project Teal-J II, Part 1
Project Teal-J II, Part 2
Project Teal-J II, Part 3
Project Teal-J II, Part 4
Project Teal-J II, Part 5
Project Teal-J II, Part 6
Project Teal-J II, Part 7
Project Teal-J II, Part 8
Project Teal-J II, Part 9
Project Teal-J II, Part 10
Project Teal-J II, Part 11
Project Teal-J II, Part 12
Project Teal-J II, Part 13
Project Teal-J II, Part 14
Tera Manufacturing Inc.
Sandy, UT 84070