A friend has an 01 xj with a cracked head.
I recommended clearwater and he asked why?
I know they're highly recommended here and elsewhere but i couldn't answer his question other than to say they're tested for cracks.

I looked at their website and it seems all they do is test 331 heads for cracks among other un-related refurbishing.

What makes their 331 replacement heads reliable?
Do they re-enforce the crack prone area(s)?

 

It's a beefier head than stock, not made from the original 0331 casting and really the best deal out there. It is brand new, not remanufactured--$450 shipped to your door with pre-paid shipping for you to send the old one back. You won't find a better deal for a new head.

 

Yes, it is a brand new casting that they specifically designed with more material and strength over the area prone to cracking (by the head bolt between cylinders 3 and 4 IIRC).

They basically designed the head that Jeep should have - IMHO it is the best head you can buy (not including the Edlebrock but that is like 3x the price and designed for power).
Also, I grew up just north of there and they have always had a reputable name

 

I have about 43,000 miles on my Clearwater head with no problems.

2001 XJ 4.0 auto

 

2 bad years,00 ,01,331 bad.
wonder what happened, how they did that. and i got one!! a 2000, still good at 170000.
another supplier doesnt want your old head,cant use it. why would cw want it?

 

No. Try again.

"Description: NEW JEEP CHEROKEE LAREDO 4.0 OHV CYLINDER HEAD"

https://www.cylinder-heads.com/cylin...ms-fits-87-06/

They do sell a lot of rebuilt cylinder heads for other engines. Not the 0331, though. Testing used 0331s for cracks wouldn't make any sense, since just because you have one that hasn't cracked doesn't mean it won't. They just avoid that problem altogether with the brand new casting.

 

I have a clearwater cylinder head and it works fine. Not many miles put on it, maybe 1000. It's a brand new casting, it doesn't say 0331 on it anywhere.

Ordered it Friday, received it Monday. Though living in Florida probably explained the fast shipping.

 

Hey thanks for the info! New custom castings, now i and my buddy will know.
This forum is a wealth of information.

By the way i had ~300K miles on my 2000 with no head cracks. Swapped the engine for other reasons at that mileage.

Yeah, i took that 'NEW' to mean a brand new 331 head from Chysler parts complete with its built in time bomb. lol

 

I think people are just saying that it replaces the 331 head. I think the Clearwater website could be more clear, but I don't see where it says they are 331 heads.

 

0331 refers to the casting number, which were used in the 2000 and 2001 XJ---0630 was the prior years' casting number, 1999 and prior for XJ's--0331 is for the coil rail --0630 is for the years they used the distributor cap. Also the exhaust manifold differed

so when you order a new one, you still need the 0331. It's not made in the same factory as the OEM head. It's an 0331 cast, but from a different mold. It has to be 0331 to fit the exhaust manifold and the coil rail. I believe an 0630 will work with an adapter for the exhaust manifold and rigging up a bracket for the coil rail. But either way the new Clearwater 0331 is very solid, and much thicker then the original. So if you are replacing an OEM 0331, you will order a new Clearwater 0331. If you have any questions you can call them. That's what I did when I ordered mine.

I also believe Clearwater is on Ebay selling cylinder heads under the name "Odessa". You will see used, re manufactured 0331's and new ones. I think it's $100 difference for a new one. Personally I would spend the extra $100 on a new one. They do not state if the re manufactured head is from the "tupy" head, or original 0331. Tupy heads were produced after they realized the original 0331's were cracking.

 

thanks much for the clearup!! if not used ,why do they want the old core.

 

they will pressure test it. If they find a crack they will scrap it. My guess is if they don't find a crack they will recondition it and sell it, but that would be a question to ask them.

 

The casting number refers to the configuration of the ports. The 0331 head had smaller exhaust ports than the 0630 that preceded it because the flow was different for the waste spark ignition system in the 2000 and 2001 XJs. The original casting that had the flaw was a 0331 head. The TUPY head that replaced it in 2002 was also a 0331. The aftermarket casting that Clearwater sells to replace it is also a 0331. Any head that meets the same specs for the ports and valves is going to be a 0331 head.

 

i wouldnt be buying a new one if mine was not cracked!, good so far.