Jeep Wrangler YJ Engine Swap

Jeep Wrangler YJ Engine Swap? Is it because the engine went bad or worn out? Or, is it for the quest of more power or something different? 

More time than not, engine swaps are because something went wrong with the original. I have many many times pulled the original engine just to do an upgrade to more cubic inches. Or, same cubic inches with LOTS more power because the replacement engine was seriously modified and built.

Jeep Wrangler YJ Engine Swap time - Transmission DONE for

It's time to replace the engine and transmission in the Jeep. It mostly came about because the transmission is making some seriously nasty noises. Yes the Wrangler engine is a tad wore out with its less than 5lbs oil pressure when the engine is warm. But the mighty 4.0 was still reliably chugging right along as my daily driver. One day I heard a weird pop in the transmission and it was all grinding for the 1st and 2nd gear. From 3rd up to 5th was fine. After lots of scouting around, with the help of a friend of mine, another transmission was found. But the bonus was that it was attached to a freshly built 4.0 engine. Got the whole package for seriously cheap! Sooo .. time for the Jeep Wrangler YJ Engine Swap! Check out the YouTube vids of the swap.

Jeep Wrangler Engine extraction!

Doing a Wrangler engine swap really isn't too difficult. Basically disconnect anything that attached to it. But disconnect in a way that will allow reassembly to go easy. Disconnect the wiring harness and either lay them over the fenders or tie them up out of the way so the wires don't get snagged or broken as you pull the engine out of the bay. Things such as fuel lines need to be protected especially. Wires can be soldered and patched. Fuel lines are under high pressure when the engine is running. So if you damage the fuel line during an engine swap, that could mean replacing the lines therefore spending money that would have otherwise been saved. Save those old shoe laces, they are a perfect addition to your tool box for these situations. With a Jeep Wrangler, pull the front grill/radiator support so you can bring the whole assembly straight out the front.

Putting the engine back in

The re-install can be a bit more hectic than the removal. The YouTube video below proves that. About 95% of the swaps I've ever done went pretty straight forward. But, every now and then comes a stubborn one. For the most part re-installing the Jeep engine was painless. The only complications was that I put the chain in the wrong spot for a proper balance point, but it wasn't so far off that I couldn't improvise. The drivers side engine mount bolt was being totally a pain! But it finally went!

Best to use an engine leveler if you have one. I loaned it out once and it never came back. If you hang the engine by a chain like I did in the video, make sure the tail of the transmission hangs down at about a 15 degree angle. It makes placing the engine in the bay much easier.

When reinstalling an engine in a Jeep or any other vehicle for that matter, you really should replace any parts that are hard to get at. Parts such as the clutch kit and throw-out bearing if it does't come with the kit. For the Wranglers and some Cherkokee XJs there are 2 different clutch kits.

One has an internal slave cylinder (like my 1991) such as this kit on Amazon - Click here to see the internal slave cylinder kit.

The later model Wranglers and Cherokees have an external slave cylinder like this kit on Amazon - Click here to see the external slave cylinder kit.

These kits are for the 4.0 liter engine with the AX15 transmission. Please check to make sure the kit you are going to purchase is correct for your application. Especially if your Jeep Wrangler YJ or Cherokee XJ have the 2.5 liter 4 cylinder engine.

When you are doing your Jeep Wrangler YJ engine swap, are you planning any performance upgrades? If so there are some other parts that would be a good idea to upgrade. I'll list them below:

1. Engine mount should be high on the list! At least install new factory replacements. Check the current pricing on Amazon.

Click here for the 6 cylinder mounts.

Click here for the 4 cylinder mounts.

If you wanna upgrade you mounts to something stronger, here are you some choices. Keep in mind that upgraded engine mounts have polyurethane inserts instead of rubber. You will feel a lot more of the engines vibrations transmitted through the Jeep.

Jeep Polyurethane Engine Mounts

2. If you are swapping on a stock engine into your Jeep you may not require an upgraded radiator. A new stock replacement may work just fine. Click here for current Amazon pricing for a stock replacement.

If your new power plant has more compression, longer stroke or even a high performance cam. You really should look into a radiator upgrade. There are so many different configurations of engine upgrades, I simply created a search link into Amazon to allow you to more quickly find what you need for your Jeep engine swap upgrade. Click here for lots of choices.

Good luck on you Jeep Wrangler YJ Engine Swap! Have a great day!