'01 Motor blown. Which year to replace it with?

I have a 2001 XJ with 120k miles. It is in great shape and is my daily driver.

Sadly, apparently a head gasket leaked and now my motor is seized. The local mechanic said it will probably be cheaper just to replace the whole motor. I'm not real crazy about the spark plug coil packs that my stock motor came with, plus, it would often have issues running rough and throwing a check engine light when first started, if it was really hot outside.

I'm wondering if it would be wise to replace it with a '99 motor?... or just stick with a straight 2001 replacement?

4.0L block from any late model XJ, TJ, ZJ, WJ should work. Best to have an 0331 TUPY head. In 00-up they have coil packs vs dizzy, and precats. So you would most likely be using your existing manifolds, unless you get more complete engine with the 00-up manifolds.

The head ports changed over the years so you would have some issues if you went a head earlier than 0331.

Then you'd have some electrical issues if you tried to change back to the distributor and coil setup.

And you need to keep the pre-cats w/ 4 O2 sensors to please the computer and federal emissions laws.

So I would get a 01+ engine or maybe a 00 CA engine. I think in 2000 they had both Federal and California emissions, but in 2001 they were all the same.

The coil pack setup isn't really bad. No wires, no distributor, no pick up, and no coil to go bad. And the coil packs are pretty darned reliable.

You may find with the new engine you do not have hot start issues. If you do, wrap the fuel injectors of cylinders #3 and #4 with insulating material. Cured mine. The TSB calls for only one cylinder but I found doing both cured the issue.

Look for an engine with a 0331 TUPY head or a totally new head without the defect of the original 0331 heads.

There are tons of threads about 0331 head replacements that will discuss the issues of using earlier heads. The head and electrical in your case trumps the block.

And I wonder if it was really a head gasket that blew or if the head cracked. Engines with 0331 heads usually have a cracked head rather than a blown head gasket.

Stay with the 2001 engine controls, and solve the heat soak issues that cause the rough running.

Any 1990-2001 XJ Cherokee or 1993-98 ZJ Grand Cherokee 4.0 L engine block will interchange.

Remove and re-use ( or replace with new ) as needed or required from your original engine: Intake/Exhaust manifolds, flex plate/flywheel, cylinder head, distributor-less ignition or distributor assembly, engine sensors, fan belt driven accessories, and/or mounting brackets.

If your 2000-2001 XJ Cherokee has a cracked 0331 head, buy a good used redesigned and more durable TUPY 0331 head from a 2002+ 4.0L TJ Wrangler or WJ Grand Cherokee 1999-04.

Rebuild the one u have, & have a brand new engine when u are done.

While everything will bolt onto an earlier engine the main problem you will run into is the exhaust manifold vs. the later ports. There is very little area for the head to seal on a stock cast manifold plus the manifold makes a wall for the exhaust gases to run in to. Neither is desirable. As said you probably have a cracked head. Even if not I wouldn't keep the current head. If you want to go with an earlier head the easiest solution would be to go with an aftermarket header that will cover the earlier head ports.

A later 03+ "TUPY" head (TUPY is cast in to the head under the valve cover between #3 adn #4 cylinders) fixed the cracking issue and will bolt up to the stock manifolds without issue. The problem there is that the engine block that that head is attached to won't work in your XJ.

So you have 3 options:
1) Earlier engine w/ earlier head + after market header
2) Earlier block with later TUPY head.
3) Rebuilt current block with new aftermarket strengthened head.

As far as the ignition system is concerned it would be a lot of work and parts to convert to the earlier style distributor. Harness, distributor, PCM, and probably some emissions related stuff.

While the coil rail isn't the source of the rough running (its the injectors with heat soak, insulate them) I have replaced the coil rail with a Viper coil. See link in my sig.

Talyn said:

1) Earlier engine w/ earlier head + after market header

Click to expand...

lazyxj said:

There is a 4th option. Install an earlier engine and exchange the stock exhaust manifold for a Banks Torque Tube header.

Click to expand...

Your kidding right? That is the first option I have listed. And there is nothing special about the Banks Torque Tube over all the rest of the 00+ headers.

you can get rid of the coil pack and run a coil from a mini van there is a write up on here somewhere. or use the viper coil.. there is a good write you with what all you need

Talyn said:

Your kidding right? That is the first option I have listed. And there is nothing special about the Banks Torque Tube over all the rest of the 00+ headers.

Click to expand...

Sorry, didn't read it right or mean to jump on your response, just wanted to confirm the Banks headers would fit in this application.

I have no idea about other brands of headers built for the 0331/ dual mini-cat combination fitting earlier heads.
Since none of this is in the advertising literature, one would need to inspect each brand's header to say if they would fit an earlier head or are cut just to fit the 0331's unique exhaust ports.
Years ago, before anyone made an exhaust header that would fit the older heads, it was a problem for those with cracked 0331 heads who wanted to switch to an earlier head.
The dual mini-cat headers do not adequately cover the earlier exhaust ports.
There used to be a guy here, on , that sold an adapter plate that fit between the head and header that allowed keeping the stock exhaust.
I do not remember reading about headers that would fit, I'm old and probably forgot it.

1999

I put a 98 motor in my 01. I used the cam sensor, intake and coil pack from my 01. I also used a 99 down header. I also swapped the 01 pcm for a 00 federal pcm to eliminate the rear bank O2 sensors, leaving me with two O2 sensors, and then had the pcm programmed to eliminate the down stream, now leaving me with one O2, in the down pipe.

Build a simple bracket to hold your stock coil rail and go wheeling.