From reading many posts it sounds like the 0331 head is a bad one.

What is greyer is when was this head first used? Many say '99, others say 2000....perhaps a mid-year change?

Owning a 1999 w/distributor how do I ID my head, do I need to take the valve cover off? Where is the casting # found?

Thx

 

You can see where it is marked on this picture, (top of pic is intake/exh side)
Looks to be in the middle


No removal of valve cover needed

 

Thanks Defiance-& good news I have the 0630!

 

The 0331 head is distinctive - it's the only 242ci head that has provisions for COP/DIS. (You can't really see it in the pic - but if it were taken from the spark plug side, you'd see, I believe, four bosses that are drilled and tapped for screws. These retain the coil rail.)

The 0331 head was used 1999-2006. The WJ and TJ got it for 1999, and the XJ for 2000 (in both instances, it replaced the 0630 head.)

The heads that seem to cause all of the problems ran 1999 thru mid-2001 - afterwards, they're fine. Also, most head recon shops know what to look for, and they filter out bad cores.

Easiest way to secure a replacement? Look for a 2002-up WK, pull the head off of that, and 'tank it. Reassemble, and drop it on the short block. Problem solved.

The cracked head can be tossed in the scrap bin. If you're anywhere close to San Jose, I'm looking for a couple for research purposes...