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4.0 Cylinder Head

Roger D said:
Is the 4.0 head from a 1999 Grand Cherokee the same as the head on a 1999 4.0 XJ?
Click to expand...


Yes, if not... close enough... rip it up!
 
Just got my 16 year old a 2000 xj that has the 0331 head, when I saw this ad on Craglist thought it might be worth the drive to pick it up.

Cylinder head From 1999 Gr. Cherokee Engine had 130K and threw a rod. Never lost oil to the head.Still ran.Complete w/manifolds,Throttle Body and sensors,have cam sensor and Coilpack.Need it Out of the shop;Going to the scrap guy on Saturday

Thanks XJRubicon

IM003705Small.jpg
 
the 0331 head casting problems seem to be a bad batch in 2000...MAYBE in 01, but I think most of the problems were with 2000. I've never had a problem with mine (160k+).

i would suggest getting a 4.0 head from an 01+ XJ, TJ or WJ - IF you want the pre-drilled coilpack hold-downs. Get a 0630 head if you dont care about that and can jerry-rig a hold down.

Best thing to do is to just not let you rig overheat. take care of the cooling system.
 
Last edited:
Not necessarily. I think the XJ was fitted with COP/DIS in 2000, while the TJ and WJ got it in 1999. Does your 99XJ have distributorless ignition?

The 0331 head can be used on any XJ with a distributor tho (you just won't use the coil rail,) but the exhaust ports on the 0331 head are a bit more restrictive than those on the 0630 head - this was done to improve catalyst "light-off" time. So, the exhaust ports may not line up. However, I think someone here has done an adapter plate for 0630-0331 installations, and it may work in reverse as well.

Thought I had that thread somewhere - http://www.naxja.org/forum/showthread.php?t=919384. I don't know if it will work in both directions, but it probably will. Might want to ask the guy that developed the plate himself.
 
Mine has the coil packs and the 0331 head. I thought if the G.Cherokee head was the earlier style that it might be nice to have. I know the coil holder and the ex manifold would be an issue with the earlier style head.If the G.Cherokee head is a 0331, that is good to. Have it checked at the machine swap and it is a direct swap if the original bites the dust.

I would not think about swapping unless the original setup developed a crack. I love this board and the way you guys exchange info without copping attitudes:eeks1:
 
Strange... our 99' XJ has a distributer... I didn't think the coil rail was till 00' on either the XJ or WJ.


XJR
 
x2, 99 for WJ and TJ, 00 for XJ....

i suppose there could be some really really late model 99s with a coil pack...? who knows...
 
My sons XJ is a 2000 model. I was just curios if the 99 XJ and WJ heads were the same. I pickep up the complete motor today for $30 complete with a big hole in the block where it threw a rod. It does have the coilpack head 0331 I assume. I will try to look and see the differance in it and the 2000 XJ motor tommorow.
 
Roger D said:
My sons XJ is a 2000 model. I was just curios if the 99 XJ and WJ heads were the same. I pickep up the complete motor today for $30 complete with a big hole in the block where it threw a rod. It does have the coilpack head 0331 I assume. I will try to look and see the differance in it and the 2000 XJ motor tommorow.
Click to expand...

As I said, you can mount it. If you have a distributor, you won't need the COP/DIS rail, and can run without it. However, the ports will be different - and I posted the link for how to see to that little nuisance...
 
I appreciate the info 5-90. I was probably not clear on the earlier post. My 2000 XJ has the coil packs /DIS with no distributor and so does the Grand Cherokee motor. The head is supposedly good on the G Cherokee motor. Even if the head turned out to be bad the intake,coil packs, throttle body/fuel rail and exhaust manifolds should make it worth what was paid for it.
 
Roger D said:
I appreciate the info 5-90. I was probably not clear on the earlier post. My 2000 XJ has the coil packs /DIS with no distributor and so does the Grand Cherokee motor. The head is supposedly good on the G Cherokee motor. Even if the head turned out to be bad the intake,coil packs, throttle body/fuel rail and exhaust manifolds should make it worth what was paid for it.
Click to expand...

Yah. As mentioned (by me and others,) the XJ got COP/DIS one year after the WJ and TJ. So, you're fine.

Early 0331 heads seem to be 50/50 for cracking - probably until 2001 castings. After that (2002-2007,) it seems to have sorted itself out. I don't know how to identify a "revised" early casting (no-one has told me yet,) but you'll find out. You might think about having the head X-rayed or Magnafluxed - I would think the flaw could be identified upon internal inspection.
 
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