compression and some engine pics

[superj]

i was bored and did a check on the ol compression on the jeep.

i ran it twice and the engine was driven within an hour of this being done.

here are the plugs. number 6 is on the top



they were gapped in a wide range of setting. i cleaned them and set them all to .038 because i didn;t have the listing of what they should be and they were so badly set previously.

roughly a 3 second crank

6: 162
5: 150
4: 160
3: 165
2: 165
1: 160

roughly a 7 second crank

6: 185
5: 185
4: 185
3: 185
2: 180
1: 180

here are some pics of the head and my 4.0 head. they don;t look alike so this has to be a 4.2 head.











the 4.0 head

[SilverXJ]

Those plugs look pretty used up. Time for a new set. That head also looks like a 0331 head.

[superj]

i know. i just didn't have another set to put in. i will put some new ones in here pretty quickly.

the 4.0 head is off a 98 or 99 grand cherokee. other then that, i have no idea about it at all. i bought everything to put it on the engine in the jeep and then i found out it could be a stroker so i didn't want to mess with anything. plus, my offenhauser fits the 4.2 head, ha ha ha

[shawnxj]

hey super see the the pad i circled in red on your head?



there's another pad more towards the middle of the head that looks just like that and will have a number stamped in it.....what is that number?

[superj]

i will have to check on another computer. i am work now and the system here blocks pics from photobucket and some other image sites.

i will get the number for you though

[jsawduste]

Jason,
here is another shot of the "pad" that has the casting number.

[superj]

i still cannot see the pics but i went out on lunch and looked along the edge of hte intake and valve cover. neither of the tabs have numbers on them. here is a pic of the other tab

[superj]

right by the hose, there is a little flat tab deal but no numbers are cast into it. this head looks like it has been painted a nice shiny black at on time in the past. i could find no numbers anywhere on the outside of it.

[superj]

ok, i went outside and walked around till i could get service on my phone so i could see the pictures. i will look tomorrow morning and let you guys know what i find

[gradon]

I'm with Silver--based on the smaller rounded-square exhaust ports and your info, you probably have a 0331 head from a '99 WJ Grand Cherokee(the kind that like to crack).

[superj]

The head in the shed is probably that particular model, you guys are probably right on that. We are trying to find out what is on the jeep though so I have to try and find those numbers really quickly......

(heads outside)

Ok, no numbers on any visible exterior area of the head. There is no flat area like in the pictures above

[92tank]

could it possibly be a renix head or a clearwater head. i cant remember if the new haed i got for the 2000 had any numbers on it or not. and i dont have it anymore so i cant look either.

[superj]

Does the renix heads have offset ports like a 4.2? I never thought about those.

[SilverXJ]

Going off the valve cover bolts (many, like the 4.0L) and the center two exhaust ports (not divided) you have a 258 casting # 3661 or 2685 head, 87-90. If you pull the valve cover you will see the casting number between the #2 and #3 cylinders.

[superj]

I think it's the original 87 head. Other then the block being changed, this jeep looks like someone really took care of it for a long time