Ok so im shoppin for another XJ & this time id like to start the build with a nicer, newer XJ, with minimal rust, & low mileage. Problem is, reliability is key here & those 00 & 01 are everywhere, but have the 0331 heads which i'll swap out as soon as i buy it if i go this route.

So my 1st motor question is that if i buy a 2k XJ, my choices are a 0630, or a head from Alabama Cyl Heads. My confusion lies in lining up the ports on the gasket since they dont. So which head will line up with which intake/exaust?? What if i got an aftermarket header & 99 intake to boot??

Second motor question, ive seen a few good deals only for me to turn away from a rebuilt motor or swap that was done. These motors should, (in my opinion), go on forever with proper matenence, so it baffles me on how many for sale ads have rebuilt motors in them. The big question here is, should i steer clear of a rebuilt motor or is this a sound decision to buy one??

Thanks

 

Ok let me simplify this thread as i realise there are many threads on this but they do get confusing!!

So it seems finding an XJ with the HO motor is rare now-a-days & the 2k XJs are a dime a dozen. So basically my solutuion in buying a 2k XJ with the 0331 head is to swap to a 0630 head & use Wilsmick's adaptor plate, (a member on naxja), but what about the 4 O2 sensors?? Im also thinkin while i have all this apart, its the optimal time for a header, Dynomax Performance 88743 - Dynomax Blackjack Painted Headers - Overview - SummitRacing.com.

Ideas, options & opinions???

 

Late model 4.0's are called powertechs. Same engine as a HO just higher output. Read here :http://en.wikipedia.org/wiki/AMC_Straight-6_engine. 4.0's improved every year right until they stopped making them. Just because an xj has an 0331 head doesn't mean its doomed to failure. I have an 0331 head with 180k and it works great. And if the head has TUPY on it its from a different foundry and not part of the supposed bad casting. Late 99 to sometime in 01 can all have the suspect heads. I find that most get rebuilt early because peeps didn't keep their stock jeep cooling system working well. If it's a solid rebuild I wouldn't let it scare you. Just use it to drive the price down.

 

Might as well do a friggen stroker before i have one!! LoL

 

I had to rebuild my 2K engine after the cam bearings went out at 160k. I wouldn't recommend buying one with a rebuilt motor unless you have an eye for seeing potential hack jobs, or they have a receipt with a reputable shop doing the work. But a fresh motor can be a good thing.

You can also check the head casting for the "updated" casting mark TUPY on the top by the valve cover. If your willing to swap heads then do it. Or get one with a bad motor and swap a 97-99 motor/intake/exhaust ect into it.

People seam to dislike the 2000-2001's I love mine.

 

So if i see the stamping TUPY then i shouldnt worry as much??

 

from what I have read, some people say it started in 01... some say 03... but ere are some links.

http://www.jeepsunlimited.com/forums...d.php?t=391831
https://www.cherokeeforum.com/f2/bes...-0331-a-91806/
https://www.cherokeeforum.com/f2/630-331-a-79648/

 

My 2000 XJ with the 0331 head has 208,000 miles on it. Its really not a concern.

 

i have 209k on mine an never had a prob

 

LOL!! Ive read each of those threads plus 5 more & ive got a "head"ache now!!

You see my position is that i want the piece of mind that the good old 4.0 I6 is a strong & true trooper & not have this 0331 head cracking wandering in the back of my mind!!!!

I owned a 95 HO for 6yrs & it was the best motored vehicle ive ever owned!! Never burned or leaked oil, compression test each year was spot on in every cyl, pressure tested the head with 0 issues, i even pulled the plugs yearly just to see how the cyliders were doing & never once did i pull a fouled plug of any kind.

I miss that motor & its like finding a needle in a hay stack tryin to get an XJ with the HO motor!! The only thing i care about is a sound motor & as little rust as possible. Everything else will be tosses as my susp & axles will go under the new XJ.