Lets talk WJ

[87Warrior]

Ha! The JoCo drivers scare me to death. I was born and raised in a place much, much more rural than this. Its nice having my TJ to push around the 'benze people.

 

I know the 4.0 would be plenty for highway, city, and trail. The 8 would be nice for pulling trailers or hauling anything too heavy for the MJ. The WJ 4.0 also has a hotter cam than the TJ. I ran a 01 WJ 4.0 uh my TJ for a few months, had way more pep.

 

Hope to get behind the wheel of a few WJs next week.

[Eagle]

The dealer I bought it from had put these tires on it. They are about 4 sizes up from normal (according to door sticker), but they don't rub the fenders and they do clean out the mud that gets caked up in the wheel well.

They sure don't look like four sizes too big. In fact, they don't even look one size too big. What size does your sticker call for? IIRC my '99 came with 245/70R16s

[mythreesons]

It's raining cats, dogs and small furry animals right now. I can't go out in that, I'll melt. :D

 

I'll check tomorrow and let you know.

 

Edit: I forgot that I parked the GC under the porch. Don't worry I didn't get wet.

 

Tag on the door calls for 225/75/16.

Tires on it are 245/75/16.

[terrawombat]

Keep in mind that the the 4.0L that came in the WJ from '99 to '01 were equipped with the oh-so-famous 0331 head casting that is known for cracking between the #3 and #4 exhaust ports and allows coolant to mix in with the crankcase oil. I have had three 0331 head'ed engines in my lifetime - one is at 83k miles (no problems), another went to 154k miles (before spinning a rod bearing, but the head appeared to be fine), and another went to 150k miles before the head cracked and the crankcase slowly filled with coolant. Jeep/Chrysler never owned up to their mistake, but I believe they changed cylinder head manufacturers in '02 as the later 0331 heads are stamped with TUPY, which I believe is the revised version of the head that does not crack.

 

I dunno - it's a toss-up. Just go over to the NAXJA forums and search for "0331 head" and you'll get allll kinds of fun info!

[Sir Sam]

Keep in mind that the the 4.0L that came in the WJ from '99 to '01 were equipped with the oh-so-famous 0331 head casting that is known for cracking between the #3 and #4 exhaust ports and allows coolant to mix in with the crankcase oil. I have had three 0331 head'ed engines in my lifetime - one is at 83k miles (no problems), another went to 154k miles (before spinning a rod bearing, but the head appeared to be fine), and another went to 150k miles before the head cracked and the crankcase slowly filled with coolant. Jeep/Chrysler never owned up to their mistake, but I believe they changed cylinder head manufacturers in '02 as the later 0331 heads are stamped with TUPY, which I believe is the revised version of the head that does not crack.

 

I dunno - it's a toss-up. Just go over to the NAXJA forums and search for "0331 head" and you'll get allll kinds of fun info!

 

I've had 8 0331 heads, none of them have ever been a problem. I think naxja overstates the 0331 head problem, lots of people pick up on that and then repeat it like every 0331 head is seconds away from total failure.

[terrawombat]

Keep in mind that the the 4.0L that came in the WJ from '99 to '01 were equipped with the oh-so-famous 0331 head casting that is known for cracking between the #3 and #4 exhaust ports and allows coolant to mix in with the crankcase oil. I have had three 0331 head'ed engines in my lifetime - one is at 83k miles (no problems), another went to 154k miles (before spinning a rod bearing, but the head appeared to be fine), and another went to 150k miles before the head cracked and the crankcase slowly filled with coolant. Jeep/Chrysler never owned up to their mistake, but I believe they changed cylinder head manufacturers in '02 as the later 0331 heads are stamped with TUPY, which I believe is the revised version of the head that does not crack.

 

I dunno - it's a toss-up. Just go over to the NAXJA forums and search for "0331 head" and you'll get allll kinds of fun info!

 

I've had 8 0331 heads, none of them have ever been a problem. I think naxja overstates the 0331 head problem, lots of people pick up on that and then repeat it like every 0331 head is seconds away from total failure.

 

I agree that NAXJA overplays the 0331 head problem, but having had one fail and crack in the exact spot that it was "supposed" to, I've got to somewhat jump on the "0331 heads suck" bandwagon. There are a number of people that have also reported the same. I'm sure it's not as widespread as NAXJA makes it out to be, BUT, it is still an issue with some heads. But even with one of my own 0331 heads cracking and all of the threads on NAXJA that talk about it, I STILL bought an '00 4.0L engine for a spare. I'll take my chances...head swaps are easy.

[FXWorks]

I've got 200,000 kms on my 0331.

[HOrnbrod]

0331 Heads (From the Stroker Forum)

 

Just to clear up some confusion there are some widely held beliefs about the HO heads that aren't true, but are considered "common knowledge" just because they've been repeated so often. Try as I might, I can't get people to stop furthering the myths.

 

The 7120 (91 to 95) head and the 0630 (96 to 99/2000) are basically

identical Same flow, ports are identical in size and shape, a temp gauge sensor bung that is deleted in some years of 0630 (or plugged with a hex head bolt in some cases) The biggest difference is that the 0630 has a redesigned valve cover mating surface, and a steel stamped OEM valve cover that is far and away the best sealing (least leaky) cover in the engines entire history. The mating surface shape is slightly changed so this and the excellent rubber o-ring style gasket is incompatible with the aluminum covers (unless you grind off the inside lip of the aluminum cover).

 

The 0331 head despite what many people think, is actually higher

performance than any other head in the AMC I6 line. It was dedesigned by a guy named Rick Mudge who is notable for being the head porter who ported the worlds fastest NHRA AMC I6 powered dragster (Gary Hill 8 second quarters with a 4.0 based 500-ish horse power build). Rick redesigned the exhaust ports, the header (dual output iron) and the intake (99 equal runner) for improved torque and hp in the engines operating range. This necessitated smaller more efficient exhaust ports to improve scavenging... The bigger exhaust ports actually HURT power, unless you can get your engine to rev to 6500-7000 RPM's the old ports are WAY too big.

 

The 0331's intake ports are higher and slightly bigger cross section and flow significantly better than all other past heads, the exhausts

coupled with the iron "header" which has much longer primaries than past OEM headers (average 6.5" on old HO headers to the iron manifolds 10" average length) coupled with the equal runner intake manifold with much longer runners (11.5 inch vs 8.5-9") is all far more efficient for power in the off idle to 4800 RPM range. Especially for low and mid torque.

 

The first run (99 to early 2001) of the last head casting (0331) cracked around 100k miles between the intake and exhaust rocker mounting boss' on the 3rd cylinder. That head was revised in 2001 and the revised heads can be identified by the letters "TUPY" cast in the same area where the cracks used to happen. From then up to 2006 the 0331 head is good stuff (so far anyway).

 

This can all be confirmed (don't take my word for it) by reading the

sticky thread on head porting, and the 0331 head thread (also sticky) on Jeepstrokers.com in the Stroker performance area... Two people (Myself and and a guy named Adam on the forum side who works in a Race shop with a flow bench) have flow tested the 0331 head verses the earlier ones and found the intakes to flow significantly better, while the exhausts "flow" only a little lower CFM even though they were reduced in size by almost HALF. The reduction in size was done by raising the port floor, eliminating the "lazy" spot found in past flow bench supported porting work (done by John Young AKA NOSIGMA and contained in that sticky thread) The exhausts flow at higher velocity due to eliminating this lazy area. So contrary to popular believe, the bigger ones are the ones that are worse performing.

 

Anyway old rumors die hard but hopfully we can squash these.

[Sir Sam]

I agree that NAXJA overplays the 0331 head problem, but having had one fail and crack in the exact spot that it was "supposed" to, I've got to somewhat jump on the "0331 heads suck" bandwagon. There are a number of people that have also reported the same. I'm sure it's not as widespread as NAXJA makes it out to be, BUT, it is still an issue with some heads. But even with one of my own 0331 heads cracking and all of the threads on NAXJA that talk about it, I STILL bought an '00 4.0L engine for a spare. I'll take my chances...head swaps are easy.

 

I don't disagree with that either, its just in every E-warrior naxja post, which there are many of, everyone immediately jumps on the 0331 head like its just a ticking time bomb that is going to fail at any instant - much like driving around sitting on a land mine waiting for one good bump to set it off.

[Eagle]

I don't disagree with that either, its just in every E-warrior naxja post, which there are many of, everyone immediately jumps on the 0331 head like its just a ticking time bomb that is going to fail at any instant - much like driving around sitting on a land mine waiting for one good bump to set it off.

This is understandable. Jeep may have soldiered on with the 4.0L engine for a few more years, but for the XJ fans the universe ended in May of 2001. If the revised/improved heads came on-line later than that, they aren't found in ANY Cherokees, so for all practical purposes they don't exist. It is nice to know that there's a viable replacement to be found in junkyards, but as an owner of TWO 2000 Cherokees, it is not a nice feeling to know that I'm driving ticking time bombs and that the only question is "when" (not "if") my heads are going to crack.

[Sir Sam]

I don't disagree with that either, its just in every E-warrior naxja post, which there are many of, everyone immediately jumps on the 0331 head like its just a ticking time bomb that is going to fail at any instant - much like driving around sitting on a land mine waiting for one good bump to set it off.

This is understandable. Jeep may have soldiered on with the 4.0L engine for a few more years, but for the XJ fans the universe ended in May of 2001. If the revised/improved heads came on-line later than that, they aren't found in ANY Cherokees, so for all practical purposes they don't exist. It is nice to know that there's a viable replacement to be found in junkyards, but as an owner of TWO 2000 Cherokees, it is not a nice feeling to know that I'm driving ticking time bombs and that the only question is "when" (not "if") my heads are going to crack.

 

I have every confidence in my 0331 head. I don't think its a "when" I think its a "maybe someday possibly if my karma isn't up to par"

 

There are plenty of 300k mile 0331 heads out there that are just fine. I sure as hell don't think its a question of "when" but rather, "at all".

[Pete M]

so then the debate is whether it's more like a Dana 35 or a Peugeot? aka; is it simply a common failure, or an inevitable failure? :D

[Sir Sam]

so then the debate is whether it's more like a Dana 35 or a Peugeot? aka; is it simply a common failure, or an inevitable failure? :D

 

I'd rather have 1000 0331 heads than a single peugeot.

[Geonovast]

so then the debate is whether it's more like a Dana 35 or a Peugeot? aka; is it simply a common failure, or an inevitable failure? :D

 

I'd rather have 1000 0331 heads than a single peugeot.

 

Well duh, that gives you plenty of replacements. :dunce: