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Unread 07-27-2011, 11:17 AM   #46
Hippie05
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Quote:
Originally Posted by foggybottombob View Post
There is a number cast into the surface of the head. The 91-95 heads were 7120. That is what I used.
Thanks. I'll check it out this evening. I didn't notice anything, but I wasn't looking for it either.

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Unread 07-27-2011, 11:47 AM   #47
John Strenk
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Just joining here, just picked up a '98 4.0 0630 head for $20.00 (Yep, Twenty Dollars) Gonna try and fix it up, Slap it on, and pray... Fortunately I have an extra engine here to fit it out on. And a MPFI and Megasquirt I to play with.
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Unread 08-02-2011, 08:12 PM   #48
Hippie05
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Well I figured out that I have the 7120 head. Got it installed and started with the borla header. That's when I figured out that the intake manifold will not work with the borla header.

Any suggestions on which intake manifold to go with? The Jeep currently has aftermarket TBI installed. I can't figure out what it is though other than it looks like a GM product.
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Unread 08-02-2011, 09:31 PM   #49
james04si
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Quote:
Originally Posted by Hippie05 View Post
Well I figured out that I have the 7120 head. Got it installed and started with the borla header. That's when I figured out that the intake manifold will not work with the borla header.

Any suggestions on which intake manifold to go with? The Jeep currently has aftermarket TBI installed. I can't figure out what it is though other than it looks like a GM product.
I used a 90 cherokee 4.0 exhaust manifold. I believe that all of them will have fitment issues with the intake. You have to grind a little off the intake where the center exhaust manifold rubs and will also probably have to dimple in the exhaust on the middle 2 pipes.
Also dont forget that the 258 intake manifold will need to sit on top of the locating pins not in the holes because the intake runners on the 4.0 head sit higher than they did on the 258 otherwise you will have a major vacuum leak where it doesnt match up.
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Unread 08-03-2011, 04:21 AM   #50
Hippie05
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Quote:
Originally Posted by james04si View Post
I used a 90 cherokee 4.0 exhaust manifold. I believe that all of them will have fitment issues with the intake. You have to grind a little off the intake where the center exhaust manifold rubs and will also probably have to dimple in the exhaust on the middle 2 pipes.
Also dont forget that the 258 intake manifold will need to sit on top of the locating pins not in the holes because the intake runners on the 4.0 head sit higher than they did on the 258 otherwise you will have a major vacuum leak where it doesnt match up.
OK, now I'm completely lost here. If I have a 4.0L head and a 4.0L Header, why will there be an issue with a 4.0L Intake? Seems to me it ought to go together seamlessly. At this point the entire upper has been rebuilt or replaced not retro-fitting anything.
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Unread 08-03-2011, 08:21 AM   #51
foggybottombob
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I used the 258 intake manifold with the 4.0 stock exhaust manifold. I think I needed wider washers to clamp the two manifolds down but I did not have to grind anything.
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Unread 08-03-2011, 08:22 AM   #52
Hippie05
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Quote:
Originally Posted by Hippie05 View Post
OK, now I'm completely lost here. If I have a 4.0L head and a 4.0L Header, why will there be an issue with a 4.0L Intake? Seems to me it ought to go together seamlessly. At this point the entire upper has been rebuilt or replaced not retro-fitting anything.
Just figured out the reason it won't work. I didn't realize the 4.0L engine was MPI. Now I understand why fitment is an issue. I've found another thread on here saying that a newer aluminum intake of a .258 will work.

Foggybottom - did you have the alum. intake or the old cast iron one? There is a huge problem with the borla header the cast iron intake I have.
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Unread 08-03-2011, 08:37 AM   #53
Mike Romain
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I put my 86 intake on my 93 4.0 HO engine. Had to grind a bit and get different length fan belts, but other than that it went sweet. I had a shop make an adapter from the 4.0 header to my new CJ pipes.
93 4.0 swap using 258 parts build - JeepForum.com
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Unread 08-19-2011, 05:41 PM   #54
Hippie05
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I've completed my head swap, with much effort and many tweaks, it's finally running. The only thing still puzzling me is why it seems to want to run hot. I put a new thermostat in it with the swap, and it was for the 4.0.

Did any one notice an increase in the operating temperature when they did the swap? I'm talking about 205 or so. The thermostat is a 195. Before the swap it ran just below 200.

I've ran the motor with the radiator cap off to let the trapped air escape, I've replaced the clutch fan and when I'm running low speeds it seems to run lower temperature.

By the way, the swap did seem to add some ponies. We barked the 33 BFG MT's in second and it idled up a nice hill in 2wd. I hope to put a write-up on the site soon about my experience to add to the community knowledge.
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Unread 08-20-2011, 09:11 PM   #55
james04si
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I put a 180 degree thermostat in mine and it barely goes over 185. I did replace my original radiator which was a 2 core with fixed fan with a 3 core with fixed fan. I ran a little hot with the old 232 at about 210 degrees or so but so much cooler now.
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Unread 08-20-2011, 10:12 PM   #56
Hippie05
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Where did you find the thermostat? I could only find 195
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Unread 08-20-2011, 10:51 PM   #57
james04si
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I got it from rockauto.com it was a closeout stant 45358. They don't have it anymore but do show several available ranging from 160-195 degree for a 1992 jeep wrangle with 242 engine.
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Unread 11-04-2013, 11:38 AM   #58
NH2112
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Well, I know I'm reviving an old thread, but all the rest I've found were either for a complete 4.0l swap or had very few posts. I'm having a hell of a time getting my 4.0l head to seal on my 4.2l block after a rebuild. I bought the Jeep (in my sig) with the work already done so I can't tell you any more than what's in there. In Aug 2012 I blew the engine, and it sat through the winter. I had the block bored 0.030" over, crank ground, and a complete head job including new valve seats. I'm on the 3rd head gasket (1 that came with the 4.2l engine kit, and 2 Fel-Pro 4.0l) and can't get it to seal without leaking. The 4.2l gasket was obvious, but both 4.0l gaskets let small trickles run down the driver side of the block. I checked the block & head with a straightedge and can't fit the smallest blade (0.05mm) in at any point with any orientation of the straightedge. I found out about the Hesco kit here and have a few questions for anyone who can answer them.

1) On the Hesco website it looks like only the very outermost coolant jacket ports are filled in. Is this because they're outboard of the head bolts and more susceptible to leak? We have several really good welding shops here that I could have do the welding for me, then bring it to my machine shop to be planed.

2) After reading about the intake ports I dry-fit the intake to the head and noticed the poor clamping with the stock cupped washers. It seems like guaranteed vacuum leaks to me, which would definitely explain why my engine ran so erratically. What does Hesco do to modify the head for use with 4.2l intakes? Will a Clifford intake fit and seal tightly without the modifications? How about other brands, like Offy? Will any year of 4.2l intake fit correctly? I'm running a Weber 32/36, I wasn't impressed with it and was considering going with a Motorcraft but after reading this thread and discovering things about my engine I'm sure the carb was never the issue.

3) How about a cam swap to take advantage of the 4.0l head's better flow characteristics? I'm running stock cast pistons and can't tell you how much was removed from the head & deck, but the machinist said it'll still run on 87 octane. I've been told swapping to a. 4.0l head is a bolt-on 40hp and that with the right cam & jetting I'll see a nice increase in torque off idle as well, I might as well take advantage of it! If I can't get this thing right on the next try it's coming out and I'm swapping a diesel in like I should have done in the first place!
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Unread 11-04-2013, 07:13 PM   #59
captkhaos
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NH2112,
Tried to send a PM to you but your message limit has been exceeded. I'm in the middle of a swap now on my 1980 Cj7. Clear some of your messages so I can send you my email etc. Let's talk. Cheers, Khaos
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Unread 11-04-2013, 07:20 PM   #60
NH2112
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Quote:
Originally Posted by captkhaos
NH2112, Tried to send a PM to you but your message limit has been exceeded. I'm in the middle of a swap now on my 1980 Cj7. Clear some of your messages so I can send you my email etc. Let's talk. Cheers, Khaos
Messages are cleaned out, where the heck did all those thumbs ups come from LOL. I'm looking forward to picking your brain on this! Thanks.
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