TTB WJ 5.2 Motor Swap Part 1

Welcome to Part 1 of our 5.2 magnum swap, our goal is September 26th but we are hoping to be done done one week earlier for some pre testing.

Read The Rest
Part 1: It’s Finally Happening
Part 2: Out With the Old
Part 3: The Last of the Stock Components
Part 4: All About Brakes
Part 5: Pulling the 5.2 (time lapse)
Part 6: The Test Fit
Part 7: Cutting and (not) Fitting
Part 8: Broken and Upgraded Parts
Part 9: Leaky Plenum Gasket
Part 10: Side Projects and Summer Fun
Part 11: Setting the Motor
Part 12: Custom Exhaust & Driveline
Part 13: Cutting and Rebuilding
Part 14: Giant Radiator in a Little Jeep
Part 15: Custom Tube Bumper
Part 16: Driveshafts
Part 17: A Real Firewall
Part 18: Starting Final Assembly
Part 19: Extending The Engine Cage
Part 20: Still Assembling
Part 21: It Lives!
Part 22: Brakes and Wiring

It’s finally happening

It has been a long time coming and we are finally ditching the trusty i6. We have been wanting to do a v8 swap for years but it’s hard to throw away a perfectly good 4.0 i6 with less than 70K. These motors are reliable and with proper maintenance can last 300,000. Our i6 has never let us down, but it is time for more power under the hood. Currently, we are able to get up to a good cruising speed but it takes pretty much everything we have. What we are looking for is a motor that will keep us at around the same top speed, but has enough extra power to lift the front end when we come into a rough patch. We have wanted a new motor for years so we jumped on the chance as soon as a viable donor vehicle came along.

The Donor

We have had our eye on a 1993 ZJ 5.2 for a little over a year. The current owner had been playing with the idea of either fixing it up or giving it away, you probably know which way we wanted it to go. After it sat in his driveway with a broken transmission for nearly 18 months he finally gave in and signed it over to us. We couldn’t be happier, but knew we had a long way to go.

With a new battery and a little convincing it started right up and sounded good. Topped off the fluids, added some fresh gas, and we drove it around the street a few times to see what issues we could find. The only issue on the motor we could see was a leaky plenum gasket, which is expected on pretty much any 5.2 with this many miles. The transmission was a different story, it lagged a little in first and had no reverse. While we knew it was broken going into it, now that it was running we could do a proper diagnosis. Before we parked it and started our research we cut the pipe just before the cat to see what we were really dealing with.

Sound Check

The research

Now that we had a running donor vehicle the next few months would be spent scouring the internet for any and all information on the 5.2 and 46RH. We don’t like our Jeep out of commission for too long we so wanted to have every major issue figured out before we tore into the TTB WJ. Below are our initial issues and solutions we found.

Engine Wiring
We found a standalone wiring harness the makes the new motor into a 4 wire system with a 30A wire that feeds power to the ignition switch, an ignition “run” wire, an ignition “start” wire, and a fuel pump wire.

Leaking Plenum Gasket
Upgrade to 1/4” aluminum plate and fel pro gasket.

Blown Trans
We were able to narrow it down to a bad Direct Clutch in the O/D unit. We will be finding a new O/D until in the junk yard or will replace the blown clutches with OEM parts. Both are only a temporary fix until we do a full rebuild in December. (Watch out for some posts on 46RH transmission diagnosis and rebuilding)

Torque Converter Upgrade
Pushing off until December with the transmission rebuild

Transfer Case
The 242 will bolt to the 46RH after an input shaft swap from the current transfer case. We are also looking into clocking the transfer case to gain some ground clearance.

Power Steering Pump
Have new hydraulic lines made to adapt the new pump to the current gear box

Mechanical Engine Fan Delete
If there is time

Radiator and Trans Cooler
We are planning on making mounts for the ZJ radiator with plans to upgrade to an all aluminum one in the future. We will be reusing the current trans cooler set up we have.

Other outstanding issues we will deal with later are the fuel pump and regulator, trans linkage, air filter, what’s left of the stock wiring, spark plugs and wires, new transmission crossmember, skid plate, cleaning up and adding more frame plating, and I am sure some other things we have missed in this write up.

While we are mostly concerned about compatibility issues we also wanted to look at what upgrade we could do while the motor was out. We decided to keep it simple on the motor side and only do a standard 5.2 kegger mod and a larger throttle body. For the rest of the Jeep we have big plan for when we have the motor pulled.

With the engine bay empty we will have ample room to do some work we have been pushing off for a few years. This includes: relocating the coilovers to make room for future bypasses, removing the brake booster and converting to a manual dual master cylinder set up (with disk brake conversion on the 8.8), removing what is left of the factory wiring, finally tying the engine cage into the front bumper, new RRP510 Pro-Series 2-Place Intercom from Rugged Radios, and possibly moving the intake into the cabin for clean, cold air.

What’s Next

With most of the research done we will be pulling the transfer case, transmission and 4.0. Then start cleaning up the engine bay to make room for new brakes.

Don’t forget to check back next Tuesday for updates.