I have a 00XJ, and the opportunity to buy a 99 engine with 25K on it. Will this combo work, or do I have to use a 00 engine. both engines, the one in mine and the one I am gonna get are both 4.0 I6's. Anything I need to be aware of when making the swap if it will work.

Thanks in advance.

 

Engine blocks are the same,but the controls are different. The 2000 has coil on plug vs a distributor. I think you will be ok if you use just the longblock from the 99 and none of the controls.

 

Correct.

 

Any particular reason you want to swap the engines? Did the one in your XJ go?

If it's still running fine without any issues, I wouldn't touch it. These engines go forever with proper maintenance (easily 250,000 miles).

 

Partially...

The heads on the '00 are set up for the coils packs, the '99 are not.

 

My 00XJ has either a warped or cracked head and 209K. With that, i have a hard misfire in cylinders 3 and 4 along with cylinder pressure of 20PSI in each. the head needs to be replaced no matter what.

Now, to replace just the head myself, i am looking at about 800-1K in parts and such, and this engine has 25K miles and is 500 bucks.

I was planning on swaping over my intake, the coil rail, and the sensor that replaced the distributor. maybe the injectors if the connectors were different.

 

ok, what is the exact differance between them? According to the Jeep dealership i talked to i could use a head between 99-01

 

The exact difference? Well now we're get all techy-like.

The cylinder head casting number for 96-99 is 0630, whereas the 00-01 is a 0331.
The 0331 heads were redesigned to allow for faster engine warm up which means the engine goes into closed loop faster. This was accomplished by reducing the size of the exhaust ports. The 0331 heads simply don't flow as well as the 0630 or earlier 7120 heads. Another down side to the 0331 head it's prone to cracking between the #3 and #4 combustion chamber.

The 0331 is also machined to accept the coilpacks in a bolt on rail configuration, the 0630 head is not.

 

I dont mind Techy... the more i know the better

So is the Casting number on the head? if so where do i look for/find it on the head?

Then why would the dealership tell me that i could use the 99 head if there is such a differance with them?

 

The casting number is on the top of the head, outboard of the valve cover gasket surface, drivers side.

As far as the dealers comments, they are partially correct. All H.O 4.0L heads are interchangeable as fars as bolting them on is concerned, but obviously the 00-01 heads are set up differently than than the previous heads. Could be an honest mistake on their part. Could be ignorance. Did you talk to a Service Writer or one of the more experienced techs?

 

the guy i talked to was supposed to be the parts manager... I was even diliberate to ask about the distributorless ignition system that i have and if it would bolt to the head... again i was told that i could use it... i dont know, i know some people are stupid, but they should be working in a field like that if they dont know or dont know were to get the correct info

 

ok, got that. Now one other question... if i were to get the 99, can i drill and tap the holes needed to accept the coil rail that i have on mine? is there enough metal on the 99 head to allow this?

 

Honestly I don't know the answer to that.

 

never hurts to ask, th ansk for the honisty

 

alot is possible with the engines.. there are not tooo many big differences with any of them. there are a few tweaks that they do year to year but nothing major. for ex. i put a 99 engine in my 91. i pretty much used the block and head. i switched everything over on it. the brackets are a little different but it will work. and if i were you check your oil pressure regulator because it was different on mine so i dont know if it will be from 99 to 2000