Wouldn't there be coolant in the oil then?

 

NOE... but your plugs will look like the ones in your pic.

 

Wow... that engine needs tearing into, that's for sure!

You can drop any XJ, MJ, ZJ, or YJ 4.0L into an XJ if you want.

 

Been around these things since they were new, and never seen a cracked Renix head. And, if you warped one it was from overheating. Send it out for machining and put it back on.

Also, you wouldn't see the compression numbers change wet to dry.

No need to go down this rabbit trail....

 

I can't spend the down time taking the head off to replace rings and crap though guys, I think I'm better off grabbing a new 4.0.
How long do y'all think I can drive this thing? I think I'm just going to plug up the CCV lines so oil is not getting into the intake manifold and run it...
Cylinder two is pretty bad...I think this is why Iv been getting 7-8 mpg

 

The whole time Iv been on CF Iv never heard of it lol

 

Used motor. 87 to 99.

 

Not many motors around here with under 100k.
How do y'all feel about like titan remmans?

 

Saw this one personally when my T-stat went into thermal shock and wouldn't open first winter in MO. Cracked between the valves on the #1. Heard about this from three other people there before I pulled the head, confirmed by a machine shop. Fellow at the shop said the older ones had a habit, a small one but still there, of cracking there when hot. Said he got three or four a year at his place with this problem all "AMC era jeeps", so I am assuming he also included the 4.2.
Shop also said it was one of the few heads he would pin w/o question or worry.

 

Don't worry about finding one with less than 100K on it. I got one from the JY with 175K on it and my wife's still driving it 50K later with no issues.

 

Extremely rare then. Consider yourself one of a lucky few.

 

No comment.

 

Huh?..... that's odd?

 

It works.

 

"Preemptive", actually. (without a trailer on a hill). Well clearing 1,000K/Qt. @ 278K! (Castrol 30W is "instant death" )

That rear mount is stainless, the OD of a 1/2" copper fitting is about the 5/8". That fits well.