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0331 head change results

indy_xj

NAXJA Forum User
Location
indy
hello all. I got my 0331 membership card validated about 2 months ago. Its a 2000 XJ Classic with 53,xxx on the clock. The usual symptoms, Started with a temperature jump one afternon. It didnt overheat, but the needle was leaning further right than i would have liked. This was followed by unexplained coolant loss. Oil never got 'milkshake' and my oil volume was always full, never over-full on the dipstick. I think my leak was mostly being consumed in exhaust. Confirmed the leak by pulling the valve cover. I could definitely see coolant residue on the top of the head.

I relpaced the 0331 head with a 630 head with a 1998 production date. I ordered a new exhaust header. The 'accordian' one that i have seen a couple of other guys here use.

Change was very easy, sorry no pics :( . I am an average DIY guy. It took about 10 hours. I went slow, and took my time to make sure everything was good. Worst part is scraping/cleaning the top of the block and torquing the head bolts.

I was looking for the following info while researching what head to replace with. I post my results here for others benefit.

1. the '00-'01 intake fits the 630 head fine
2. the '00-'01 exhaust will not fit
3. you need an intake/exhaust manifold gasket for a '96-'99
4. you need an exhaust header for a '96-'99
5. valve cover and gasket are same
6. head gasket is the same
7. there are no bosses for the coil rail bolts. make a bracket like others have done.
8. need a new down pipe from the header to the rest of the exhaust.
9. i used new head bolts for piece of mind (FSM says re-using once is ok)


I have one question. I got all of the head bolts torqued to spec, per the FSM. It has quite a torque, check sequence. Do i need to re-check torque in 50, 100, 200 miles? The FSM doesnt say to so i think i am ok.

hope this info is helpful to any others that join the club.

late,

ixj
 
No need to re-check torque on the head bolts, you'll be fine.
 
Hey,

Great job!

The torque doesn't need to be rechecked as the 4.0 is a low compression engine, provided you are sure you set them right the first time.

Joe
 
If you torqued your head to FSM specs, you shouldn't need to recheck.

I know it's after the fact, but a Banks header for a '00 and up covers the exhaust ports just fine on a 0630 head. I'd already changed the header prior the head crapping out on mine.

If the exhaust header you used was SS, you'll want to go back and check the torque on them around 500 miles.
 
No need to recheck - new head gaskets are made better than they were before...

I do have a question tho - since you were using (I presume) OEM parts, do you have a description - or better, a picture - of the interference between the manifolds as you tried to use them? Was it a clearance issue, or a port size issue? Where the screw holes in the wrong place?

Just wondering - I'm always trying to update my notebook on things like this...
 
5-90,

Correct, all OEM parts.

A couple of the ports would have been ok and a couple of the ports would have had some gaps

The exhaust ports on the '00+ are a fair bit smaller than the < '99.
The '00 header has square ports and the < '99 gasket has round.
The '00 gasket wouldnt line up with the 0630 exhaust ports either.
A < '99 gasket with '00 headers might have held for a while, but probably would have developed a leak. And that certianly wasnt worth it.

sorry i dont have any pictures. If you go to your favorite online parts database and look for an intake/exh gasket you can see the diff on a 2000 vs. 1998.

or google for

felpro ms94790 (1998)
felpro MS93094 (2000)
These look just like the OEM stuff.

I have federal emissions, so only 2 O2 sensor (1 pre, 1 post). The guys with cali have more O2 sensors and that would cause more problems with the exhaust.

regards,

ixj
 
Makes some sense - I know the exhaust ports were reduced in size for the 0331 casting, to "improve catalyst light-off" (keep gasses hotter until they get to the cat, and get the cat up to op-temp faster.) Still, it would seem that making the ports smaller into the larger tubes should not cause any significant trouble - I didn't think they'd moved them as well. I'll have to dig into that a little more.

For the downstream HEGO simulator, check pretty much any speed shop, like Jeg's or Summit Racing.
 
i dont have them totaly finished. Hopefully in the next day or two i will. When they're done i'll post some pics.

ixj
 
kahaikapu said:
If the o331 head is a known problem..why isnt Dam/Crysler helping out in warranting those bad heads?..Aloha Stan
These cars only carried a 3 yr/36,000 mi warranty, not the newer 7/70 or newest lifetime powertrain. By the time the first bunches started cracking they were out of warranty.

Also:
- D/C might have 'fixed' the problem by late 2002, early 2003. There are very few, if any, reports of 2003-2005 TJs having the problem. There is some disagreement on this
- Its not saftey related, so they arent forced into a recall situation
- The affected models ('00 & '01) are now 7 and 8 years old. D/C is letting this one fade off into a memory.

ixj
 
5-90

i just did this swap with a complete engine, but am still dealing with the exhausxt, i might be able to get you some pictures side by side of the difference in the exhaust manifolds (its suprising!!!)
heck give me a couple of weeks i might ship you both of them on your dime so you can compare yourself ha!
 
I picked up both the '00 and 91-98 Felpro gaskets ... the '00 matches fine in the intake side but not the exhaust, and trying to use the stock manifold with the earlier gasket won't work as the 91-98 gaskets exhaust port seals are wider that the entire cast manifold (as in there are spots where the manifold outside edge would be inside the earlier port seals).
 
kahaikapu said:
If the o331 head is a known problem..why isnt Dam/Crysler helping out in warranting those bad heads?..Aloha Stan
Chrysler has a habit of not acknowledging major problems like that. As was stated later, the warranty was already expired by the time many of the heads began to crack though.

The infamous cracked exhaust manifold is one good example. While many of us have experienced it at least once, it was never officially acknowledged by Daimler-Chrysler. Even after the TJ 4.0L owners began to have problems in large numbers, they still didn't look at it as a problem. Certainly many TJ owners had their exhaust manifolds replaced once or more under warranty, but they kept getting the same craptastic, crackable ones again. Suddenly, surprisingly, the TJ had a new "improved" exhaust manifold introduced that drastically reduced the cracking. Jeep (aka Daimler-Chrysler) still never recalled the old-style manifolds that are amazingly like ours...they simply replaced them until the warranty expired.

Jim www.yuccaman.com
 
5-90 said:
One other question (for anyone who may be reading this) - how can one tell the "original" 0331 cylinder head from the "revised" casting, that corrects the cracking issue? I've yet to sort that out, and I've been asked a couple of times...

I have read a lot of opinions on the matter and it seems to me that the heads cracked because of some faulty cast molds. If that is true there is no way to tell the good from the bad and there are no "upgraded" heads. they simply stopped using the defective molds.
If such is the case we are screwed, because we could buy a brand new from the dealer without knowing whether it is a good part.
I have a 0331 in my 01 WJ and I keep checking for signs of cracking.
 
falcon556 said:
I have read a lot of opinions on the matter and it seems to me that the heads cracked because of some faulty cast molds. If that is true there is no way to tell the good from the bad and there are no "upgraded" heads. they simply stopped using the defective molds.
If such is the case we are screwed, because we could buy a brand new from the dealer without knowing whether it is a good part.
I have a 0331 in my 01 WJ and I keep checking for signs of cracking.

So it's not so much a "revised" casting, as just the earlier castings were faulty?

Place your bets!
 
5-90, wish i knew a way to tell the diff but i don't...would love to know if ya find out in the near future as i have a 00 with a cradked head, assuming it is not a revised one... im having a huge delima, should i buy a new head from alabama cylinder head, a used head off an older model, or take a chance with a used 0331?
 
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