GlassGoblin

Hey everyone, New Guy here. I found some great info already through various searches. I recently bought a stock 1987 AMC era XJ with (all indication) a blown 4.0l engine. (Overheated and was parked 17 years ago). The seller also included a 4.0 from a 1996 jeep (don't know what model). My plan is to swap the engines (the donor only has 20k miles supposedly), and then try to rebuild/sell the original engine. What do I need to know about this swap? Specific differences in the years of engines. Things I should do while I have the whole thing torn asunder? Advice, tips, tricks, jokes are all welcome. I am not a certified mechanic. I have rebuilt engines, and done a lot of mechanic work. This is my first engine swap, as well as my first 4.0. Thanks in advance.

cruiser54

You're good to go!!CRUISER'S MOSTLY RENIX TIPS

HO INTO RENIX SWAP

OCTOBER 31, 2015 SALAD 70 COMMENTS EDIT

This swap is easier than some will lead you to believe. And generally Pooh-poohed by those who have never done it. Those of us who have done it, like myself, will share with you the things that need to be done for a successful swap. Just think of it as swapping in a long block.

• XJ Cherokee and ZJ Grand Cherokee 4.0L engine blocks interchange.
• 2000+ TJ Wrangler and WJ Grand Cherokee 4.0L engine blocks interchange.
• YJ and 1997-1999 4.0L TJ blocks will interchange in XJ/ZJ
• XJ/ZJ blocks, and the 2000+ TJ/WJ blocks do not interchange without significant modifications.

TJ/WJ 4.0L Engine blocks underwent clean sheet design changes effective in the 1999 WJ Grand and 2000 TJ Wrangler. These blocks are not interchangeable with XJ/ZJ engine blocks. The reason is motor mount bolt holes and belt driven accessory mounting bolt holes are in different locations, or not present at all, TJ/WJ vs. XJ/ZJ.

Now that we know which engines we can use, let’s get down to business.

The HO and Renix have some differences but none that can’t be overcome very easily.

One running change was that the rear of the head was no longer drilled and tapped for the temperature gauge sender beginning in the 96 model year. The sender can be relocated to the threaded hole in the thermostat housing taken from an HO engine. You’ll have to extend the wire to that location. Some brave souls even drill and tap the HO head at the rear for the sender.

You will be using the intake and exhaust manifolds from your Renix, along with all your sensors and wiring. Since the intake ports of the HO are slightly different, you use a new Renix gasket. Exhaust ports are identical.

An alternative on exhaust manifolds:

As far as exhaust, you can use the Renix exhaust manifold and be fine.
If you want to use the HO exhaust manifold, you must go with an HO headpipe and screw your O2 sensor into that headpipe. Standard Renix harness is plenty long to do so.
A bung can be welded into the HO manifold to accept the EGR tube.

You will need to use your Renix distributor as it is different than the HO design. See Tips #12 – Setting Your 4.0 to #1 TDC and #13 – Distributor Indexing to be sure you get the distributor installed correctly.

The flywheel or flexplate from the Renix must be used so your CPS gets the correct signals. The valve cover from the Renix allows you to keep your CCV system intact and requires no modifications.

The HO block will have a plug in the coolant galley on the driver’s side of the block, closest to the front, which needs to be removed so your Coolant Temp Sensor can be installed in it’s place just as it is on the Renix. It requires a 5/16” square drive or a modified 3/8” drive that has been ground down to fit. Do this before installing the engine.

As for the knock sensor, which is located just above the oil pan on the driver’s side of the engine about mid way, all the blocks I’ve seen are threaded for it. If not, I’ve heard they may be drilled but not tapped. Tap the hole if that’s the case.



XJ: “Regular” (not Grand) Cherokees ’84-’01
ZJ: Grand Cherokee ’93-’98 (Gen1)
WJ: Grand Cherokee ’99-’04 (Gen2)
YJ: Wrangler ’87-’95 (Gen1)
TJ: Wrangler ’97-’06 (Gen2)

GlassGoblin

THANK YOU! this is absolutely priceless!
You are the first person on all the forums I'm on to take the time to write all of that out. This gives me an incredible starting point.

BlueRidgeMark

Ah, don't give him too much credit. It'll go to his head. Anyway, he just copied and pasted from some website. www.cruiser54.com

You need to bookmark that site.

frank.longo86

thats the go to guy for sure helped me with an issue i had a while back on my overheating problem

BillyB

I paid 2K for a 93 and it had problems. Floor pans had to be replaced due to rust. One thing I noticed when I bought mine was continuous water dripping from the bottom of the engine. The previous owner told me he just washed it. I got it home and there was a small amount still leaking. I soon learned one of my freeze plugs was leaking. To properly replace the freeze plugs, you have to removed all the engine components on the driver side of the block. So if you haven't bought it yet, be sure and look for water or antifreeze leaking from the bottom of the engine. Some other mechanical things you might expect the with a Jeep that old are bad shocks, worn out rear leaf springs, rear drum brakes, front brakes, rotors, and bearings, fuel pump, corroded battery wires, bad ground connections, blown fuses, bad alternator, starter, and thermostat, probably worn out u joints (7 of them all together), also a leaky radiator. Those are some things to think about when negotiating your price. I paid too much for mine with all I had to replace. Oh one last thing, if the driver side door sags when you open it, it's because the top door hinge is broken. It can be fixed, but you'll need to know a good welder.