0331 Head question.

I've been doing some searching on here and I've gotten some mixed answers.
One thread stated that the later production 99's with the coil pack were the start of the 0331 head. Another poster disputed that saying his had a distributor AND an 0331 head....I was always under the assumption that it was the 00/01 years that had the 0331 head. Educate me please...

I have a 2000, and assumed the bosses for coil packs on 0331 head new casting may have led to issue with cracking

Not sure how reliable this is but from a chrysler supplier that will be anonymous...
"They changed suppliers for the head around 2000-01. To see if you have the new head, take off the oil fill cap and look for the word 'TUPY' cast in. Tupy was the new supplier. Get a Tupy-head engine if you can."


Also I checked this and no mention of XJ with 0331 head other than 00-01:
http://remanufactured.com/AMC_Jeep_Engines.htm

I own a 95 and a 92 XJ....Looking at buying a 99 XJ. Just don't want the bunk head.

jeepman121 said:

Looking at buying a 99 XJ. Just don't want the bunk head.

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I saw one unconfirmed post from somebody with a late 99 that had the 0331 head. Again, unconfirmed but possible.

It's easy to know which head is on the 99 you're looking at. The number is stamped into the very edge of the head. You definitely can read it; I've done it on a couple of them. On the drivers side, clean off grease with a rag and degreaser if necessary and look closely with a flashlight to help see the number about midway down.

My 99 has the 0630 head and that is probably what you'll find with the one you're looking at.

Where's 5-90 when ya need him? lol...

My 99 has a 0630 head but I was looking at another 99 prior to this one and it had the 0331 and a distributor setup. Best way to confirm is in fact the casting number on the head.

RiXJeeper said:

Not sure how reliable this is but from a chrysler supplier that will be anonymous...
"They changed suppliers for the head around 2000-01. To see if you have the new head, take off the oil fill cap and look for the word 'TUPY' cast in. Tupy was the new supplier. Get a Tupy-head engine if you can."

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Interesting. I swapped out an 0331 head from my '01 XJ for a 0630 head off of a '98 XJ. Going to check out the old head to see if it is a TUPY-head. That'd be quite an unnecessary expense I went through if it is!

The best way to determine if you have an 0331 head is to look for the coil pack mounting embosses on the right side of the engine - there should be four of them. If there is a coil pack in the way, then it's definitely an 0331 head. If there is a distributor setup AND the coil pack embosses are on the head, it's STILL an 0331 head.

jeepman121 said:

I was always under the assumption that it was the 00/01 years that had the 0331 head. Educate me please...

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The 0331 head was put into the XJ in 2000, the WJ in 1999 and the TJ in 2000. Not 100% sure on the TJ part there. I have never heard of a 99 XJ having the 0331 head. The vehicle may have been built in 99, but it would be considered a 2000 model year vehicle. Also, someone could have swapped that head on.

RiXJeeper said:

I have a 2000, and assumed the bosses for coil packs on 0331 head new casting may have led to issue with cracking

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Nope, the bosses aren't the reason for the cracking. The 0331 casting was a major change which resulted in the crack between the 3 and 4 cylinders.

Not sure how reliable this is but from a chrysler supplier that will be anonymous...
"They changed suppliers for the head around 2000-01. To see if you have the new head, take off the oil fill cap and look for the word 'TUPY' cast in. Tupy was the new supplier. Get a Tupy-head engine if you can."

Click to expand...

They changed their supplier in 2002, not earlier. The "TUPY" will be between the valve springs for #3 and #4 cylinders.You have to remove the valve cover to find this.

jeepman121 said:

I own a 95 and a 92 XJ....Looking at buying a 99 XJ. Just don't want the bunk head.

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You should be fine. However if you want to be certain look on the head between the manifold and valve cover. Near the center you will see a cast in number. For a 99 it will say 0630.

TerraWombat said:

Interesting. I swapped out an 0331 head from my '01 XJ for a 0630 head off of a '98 XJ. Going to check out the old head to see if it is a TUPY-head. That'd be quite an unnecessary expense I went through if it is!

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If it is the original head it isn't a TUPY head.

Talyn said:

The 0331 head was put into the XJ in 2000, the WJ in 1999 and the TJ in 2000. Not 100% sure on the TJ part there. I have never heard of a 99 XJ having the 0331 head. The vehicle may have been built in 99, but it would be considered a 2000 model year vehicle. Also, someone could have swapped that head on.

Nope, the bosses aren't the reason for the cracking. The 0331 casting was a major change which resulted in the crack between the 3 and 4 cylinders.

They changed their supplier in 2002, not earlier. The "TUPY" will be between the valve springs for #3 and #4 cylinders.You have to remove the valve cover to find this.

You should be fine. However if you want to be certain look on the head between the manifold and valve cover. Near the center you will see a cast in number. For a 99 it will say 0630.

If it is the original head it isn't a TUPY head.

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Yay :clap: