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compression and some engine pics
Posted: June 17th, 2012, 7:25 pm
by 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

Re: compression and some engine pics
Posted: June 17th, 2012, 8:42 pm
by SilverXJ
Those plugs look pretty used up. Time for a new set. That head also looks like a 0331 head.
Re: compression and some engine pics
Posted: June 17th, 2012, 8:48 pm
by 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
Re: compression and some engine pics
Posted: June 18th, 2012, 2:39 pm
by 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?
Re: compression and some engine pics
Posted: June 18th, 2012, 2:50 pm
by 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
Re: compression and some engine pics
Posted: June 18th, 2012, 5:42 pm
by jsawduste
Jason,
here is another shot of the "pad" that has the casting number.

Re: compression and some engine pics
Posted: June 18th, 2012, 7:21 pm
by 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
Re: compression and some engine pics
Posted: June 18th, 2012, 7:22 pm
by 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.
Re: compression and some engine pics
Posted: June 18th, 2012, 7:27 pm
by 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
Re: compression and some engine pics
Posted: June 18th, 2012, 9:38 pm
by 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).
Re: compression and some engine pics
Posted: June 19th, 2012, 7:19 am
by 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
Re: compression and some engine pics
Posted: June 20th, 2012, 5:01 am
by 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.

Re: compression and some engine pics
Posted: June 20th, 2012, 6:04 am
by superj
Does the renix heads have offset ports like a 4.2? I never thought about those.
Re: compression and some engine pics
Posted: June 20th, 2012, 7:37 am
by 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.
Re: compression and some engine pics
Posted: June 20th, 2012, 7:59 am
by 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