Whats damaged?

Well, to start off...I am glad to be back. I have regretted selling my 99XJ from the day it drove away. I recently picked up a 97 cheap (skyjacker lift, new 32's, pushbumper, lights, roof rack, light bar, no rust or dents, and I got it for $700.00 ) knowing it needed some work, and that is where my question is.

I was told that the guy had a leaky waterpump, continued driving it, and overheated it. The engine still runs, but very rough. I checked the oil and found no signs of water in it. What usually is the first to go on the 4.0's when they overheat? I will do a compression test when it warms up a tad (12 degrees right now), but for now.....it sits

If it needs a head, will I need a 97 or newer?

I have searched and obtained ALOT of other info from you guys about modifications and I do appreciate it.

Thx again,
JOhn

I bought my 90 after it had been driven hot and out of water for about 20 miles. The head was warped(but not cracked), 2 pistons were melted down on the sides. I had to bore the block, deck the block, and mill the head. I went ahead and did a complete rebuild obvioseley.

when mine overheated the head worped I hear its pretty common. I had it shaved for like 60 bux and did the head set. you might as well port polish it while you have it off to i didnt do mine but i should have.

mine ran very rough also and i didnt find oil in the water. 91 and newer i think bout 95% sure

mjdavis31 said:

mine ran very rough also and i didnt find oil in the water.

Click to expand...

That sounds about right then. Even with having to put a head on it I will be money ahead

Did you machine shop tell you how much they milled off? Curious what the limits are for the 4.0.

Thx again,

JOhn

Mine was bored 40 over, decked 10, milled 20. I let the machine shop do the final assembly so I could get the 2 year warranty with the motor. I put in a complete kit and re-worked the valves. The only thing I re-used was the head, block, valves, and crank.

anything 91 1/2 to 98 will work for the head.

if it overheated, the head could very well be warped.

scorpio_vette said:

anything 91 1/2 to 98 will work for the head.

if it overheated, the head could very well be warped.

Click to expand...

Great info :worship:

Thx

JOhn