the 0331 head thread (help out if you have one!)

[Cheromaniac]

TUPY is a Brazilian metalcasting company, so it's possible that DC outsourced the casting of the 0331 heads in late 2001 to improve the casting quality.

[1bolt]

Awesome,who would have guessed it would be so obvious... Great detective work there Wild One. Now I guess the next question is do all 0331's after 2002 have Tupy there or did they revise the casting further in later years... I would love to see a 2005 or 2006 4.0 head... If they have Tupy cast on them as well then it will be elementary to discern a flawed 0331 from a good one, and those of us after best torque (or max effort porting of a factory head) can be confident we're not wasting time and money on something that will crack.

[03GC]

Just bought a used 2005 Wrngler head with TUPY on it . Had it checked ....no cracks. When I swap engines in Jan or Feb I will see if a 2003 Grand Cherokee head has TUPY on it.
Paul

[IH 392]

I finally popped the valve cover off of my '00 4.0 Cherokee (what I was told when I bought it) core tonight, it has the "0331" cast over the # 4 exhaust port, behind that over the #5 exhaust port is "076", under the cover "NH1" is cast between the #'s 1 & 2 cylinders, "00" appears between the # 3 & 4 cylinders, and "WJ" is cast between the valves on the #6 cylinder.
I have NO idea of the mileage on this engine but it was VERY!!! clean under the cover, WELL taken care of!, I don't believe it's cracked? the oil that PUKED out of the front crank seal when I loaded it in the pickup was BLACK!, not may'o!
Sorry, no pics, my camera took a crap on me!

[Jak Flash]

TUPY is a Brazilian metalcasting company, so it's possible that DC outsourced the casting of the 0331 heads in late 2001 to improve the casting quality.

I highly doubt that the change was to improve quality. More than likely to save $$$.


As for the information on the castings... I work for a casting company and they use these to track the castings incase of process issues etc. The item that looks like a clock is exactly that, it signifies the hour that the casting mould was made. the other is a shift indicator D/N or could possibly be a AM/PM as there are only two choices.

Hope this info helps.

[1bolt]

The first couple years were cracking and coming in as warranty calls... So yeah they changed the casting to save money. In this case it required improving the quality. The early heads all crack in the same place and nowhere else (so far anyway). No other Jeep I6 head is known for cracking. We know for a fact that they revised the 0331 and the revised casting has never showed up cracked. So it's safe to say they revised the casting to improve the quality.

[gradon]

Here's some pics of the 0331 that came out of a 172K 5/00(which is an 01 model) XJ. The head had a few intake valves that didn't seal and might be a little warped. PO of the XJ had a pretty good front end hit that took out the radiator and ac condensor, coolant was low, and engine probably overheated. I didn't see any cracks in the valve area, but do see some hairline cracks in the coolant ports that look like they would give the head gasket problems:

[unlimitedrubicon]

I have a 2005 TJ with TUPY on the head as well. I forgot to get some photos while I had the valve cover off through...

Also, here is a free 0331 head that the owner believes is cracked. For the cost of shipping it would be a great head to take a bandsaw to and autopsy it...
http://www.naxja.org/forum/showthread.php?t=918228

[gradon]

It seems that it'll have to come from Cali(or somewhere in the west coast), for it to be put to the bandsaw. . .

[BADASYJ]

I'm willing to bet that the head was outsourced to a foundry in Brazil to make up for the money lost do to redesigning the 0331 head. They don't have Unions in Brazil.
Has anyone tried contacting someone in the know at the foundry where the heads have been made? I'm sure they would be able to explain the date codes on the head and answer many questions.

[1bolt]

Labor is indeed cheap in brazil but to stay on point, so far I don't even think we need to decipher casting dates or foundry codes, the big obvious "TUPY" would seem to be unmistakable.. Unless we see A) a later head that doesn't have TUPY cast on it or B) a cracked head in the usual spot, that has TUPY cast on it: I think this is pretty much case closed... I never suspected this thread would be concluded so easily. Then again maybe it's not; As some of those later 2004 to 2006 0331 heads starts coming off we may find out something new, like a third casting revision that muddies the waters. Also possibly the Alabama Cylinder heads head might not have TUPY on it. but until something like that filters in:

If it doesn't say TUPY then it's poopy (LOL sorry)

I'm going to sticky this thread, I'd like to see further posts in this thread restricted to more example heads or any other new info. Especially later mid 2000 model year and I'd still like to see some pics of the Alabama cylinder heads 0331 bet it says TUPY on it, and they are importing it.

[ReverendOD]

I purchased a 2001 Cherokee with 126K a few months ago that turned out to have a cracked 0331. I will update with all the photos when i get the head fully removed but you can see here the crack is visible right between the #3 and #4 cylinders. I will be replacing it with a head from Clearwater Cylinder Heads in the near future. It was a slow leak but over time took it tole on the bearings as the engine has about 7-8psi at hot idle.

[ScienceguyXJ]

I've got a cracked one. Took of the valve cover and couldn't really see a crack but once I started the motor I could see some ooze with green antifreeze flowing btw # 3&4... there was all kinds of milky gunk on the valve cover too. When I drained the oil there was no water in it after wards but there was a lot of steam coming from the hot oil. I'm going to swap the motor for a stroker that does NOT have an 0331!

[ReverendOD]

[ReverendOD]

I did order a replacement from Clearwater Cylinder Head and with a quick measurement their casting has a good 1/8" more material on the head in between the #3 and #4 cylinders.