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Unread 02-19-2012, 05:03 PM   #1
CadCaman
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4.0 Head Swap

Guys, I am going to buy a 4.0 head to swap out on my 4.2 (83 cj 7). What do I need to look for? Is there a specific head or what?

And....Is it true that I need to purchase an exhaust manifold for the 4.0 but the intake manifold will work?

Do all the holes really line up for this swap?

Is the epoxy method of plugging the water jacket holes sufficient?

Can I do fuel injection in the future?


Thanks,

Jeff from Michigan's West Coast.

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Unread 02-19-2012, 05:12 PM   #2
Pathkiller
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Did you search? This is literally one of the most well document Jeep modifications on the web. It has been covered in detail on this forum numerous times.
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Unread 02-19-2012, 06:12 PM   #3
CadCaman
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Killer

I did search and found some ambigous information. I truly did not find any specific information as to whether or not there is a classification of head I am looking for. I was also looking for some opinions on the epoxy vs. welding the unused water jacket holes. I found differing opinions on that also.

As your job of monitoring whether or not questions submitted in this forum are worthy of response or have any merit do you have any specific information on what questions are worthy of your forum. I will reference your document in the future so as not to bother you.

I might suggest however that in the future you simply ignore my ridiculous queries so as to not waste any of your valuable time that could be better used monitoring your forum.
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Unread 02-19-2012, 06:23 PM   #4
Pathkiller
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Well I somehow managed to research and finish my 4.0L head swap all by myself without asking a bunch of redundant questions. So obviously there's an abundance of information available on the web about this swap, dating back well over 10 years. Searching the web answered all of my questions, so I fail to see why yours would be any different. But if you'd rather be spoon fed the information rather than spend the time to look it up yourself, by all means, ask away.
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Unread 02-19-2012, 06:30 PM   #5
my-jeep-earl
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Quote:
Originally Posted by CadCaman View Post
Killer

I did search and found some ambigous information. I truly did not find any specific information as to whether or not there is a classification of head I am looking for. I was also looking for some opinions on the epoxy vs. welding the unused water jacket holes. I found differing opinions on that also.

As your job of monitoring whether or not questions submitted in this forum are worthy of response or have any merit do you have any specific information on what questions are worthy of your forum. I will reference your document in the future so as not to bother you.

I might suggest however that in the future you simply ignore my ridiculous queries so as to not waste any of your valuable time that could be better used monitoring your forum.
I agree, this forum is here to help, not ridicule!
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Unread 02-19-2012, 06:31 PM   #6
CadCaman
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Killer, I was under the impression that the Forum was for people to interact and to learn from each other. I am obviously way off base and I apologize for that. If you have the true meaning of the Forum's purpose by all means please pass it on so I can put an end to my ridiculous postings.

And again thank you for your help, I don't know where I would be without it.
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Unread 02-19-2012, 07:07 PM   #7
gosupes
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Quote:
Originally Posted by CadCaman View Post
Killer

I did search and found some ambigous information. I truly did not find any specific information as to whether or not there is a classification of head I am looking for. I was also looking for some opinions on the epoxy vs. welding the unused water jacket holes. I found differing opinions on that also.

As your job of monitoring whether or not questions submitted in this forum are worthy of response or have any merit do you have any specific information on what questions are worthy of your forum. I will reference your document in the future so as not to bother you.

I might suggest however that in the future you simply ignore my ridiculous queries so as to not waste any of your valuable time that could be better used monitoring your forum.
Keep asking, some of us don't spend enough time here to notice or be bothered by "redundant" questions.
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1986 CJ7, 4.2 w/4.0 head, TFI-HEI hybrid ignition, Clifford manifold w/Holley 390 w/cold air intake, OBA, 4.5" lift, Woody CV shaft and Tattons in front, 4.10 gears - lunchbox in front, Truetrac in the back, twin-sticked, blower upgrade for running topless, trying to keep it simple.

It's just a Jeep, and if you don't wheel it once in a while, it's not even that.
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Unread 02-19-2012, 07:17 PM   #8
titomars
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Your 83 block, if its original has 7/16ths head bolts. the 4.0 uses 1/2 bolts so the holes in the 4.0 head will be bigger. you can use centering washers to locate the head or you can drill and tap the block for 1/2 bolts. the head of choice is the 91 to 95 HO head, casting #7120. The stock 4.2 intake manifold will work but you have to notch the bottom for the pins to align it. I used epoxy putty to close up the coolant passages. so far no problems. I reversed beveled the passages with a dremel to give the epoxy more bite. You will need a 4.0 exhaust manifold or header. There is no getting around that. Converting to fuel injection later is easy since you can go to a wrecking yard and pull a complete system out of any HO and it will work. Or just purchase one of the aftermarket systems. either can be made to work fairly easily. Word of caution: I don't know your states smog laws but there might be issues hooking up certain smog components since the 4.0 basically has no smog equipment from the factory. EGR and AIR systems will be the big problem. Good Luck!
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Unread 02-19-2012, 11:07 PM   #9
james04si
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Agree with titomar. Only thing I would add is that the early Cherokee exhaust manifold 89-91? For a 4.0 has both a o2 and EGR bung in it. The o2 bung would come in handy for a Howell TBI fuel injection if you go that way. The EGR is not in the same spot as the 4.2 so it won't match up unless you modify the tube some if you plan to keep it at all. It does have the exact same 7/8-18 thread size as the 4.2 EGR intake bung. Also if you have power steering you will need to modify the bracket for it to fit with any intake you use since the intake sits about half an inch higher than original. I don't have exact details on that one since I don't have power steering on mine.
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Unread 02-20-2012, 07:42 AM   #10
CadCaman
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Going to the junkyards

Quote:
Originally Posted by titomars View Post
Your 83 block, if its original has 7/16ths head bolts. the 4.0 uses 1/2 bolts so the holes in the 4.0 head will be bigger. you can use centering washers to locate the head or you can drill and tap the block for 1/2 bolts. the head of choice is the 91 to 95 HO head, casting #7120. The stock 4.2 intake manifold will work but you have to notch the bottom for the pins to align it. I used epoxy putty to close up the coolant passages. so far no problems. I reversed beveled the passages with a dremel to give the epoxy more bite. You will need a 4.0 exhaust manifold or header. There is no getting around that. Converting to fuel injection later is easy since you can go to a wrecking yard and pull a complete system out of any HO and it will work. Or just purchase one of the aftermarket systems. either can be made to work fairly easily. Word of caution: I don't know your states smog laws but there might be issues hooking up certain smog components since the 4.0 basically has no smog equipment from the factory. EGR and AIR systems will be the big problem. Good Luck!
OK Tito since you were so nice I am going to pick on you a little. You know what they say about any good deed.

This is my plan, please tell me what you think.

1. Scour the junkyards for a 7120 casting head off a jeep.
2. Scour the junkyards for a fuel injection system off from the same jeep.
3. Get the head professionally re-built.
4. Get an aftermarket header and intake manifold (I have a brake booster so is that an issue when getting an intake for a 4.0 head?)

I live in Michigan and we have no smog laws. My jeep currently has the EGR blocked off and all the electric is gone. I simply have one wire going to the HEI.

Am I on the right path?

Anyone else out there please feel free to chime in.

Thanks,

Jeff
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Unread 02-20-2012, 11:27 AM   #11
titomars
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Yes. You are planning a fairly very easy swap. The booster is not an issue since there is no carb to get in the way. if you are planning on the 4.0 MPI injection system, you will need the distributor and intake off the donor too. Remember to pull the entire ECM harness from the donor. It is easier to thin it out after you get it home. I would suggest going to the pick n pull yard and looking at the Cherokee line any 91 to 95. It will have what you want. if your Jeep is a stick look for a Cherokee with a stick for the ECM. Not Essential for you but us Californians have to have the right ECM to pass smog (check engine light). Why not just use the factory exhaust manifold off the donor? They work just fine. Just try and find the updated one with the bellows joints between the end cylinders. the ones without tend to crack. If you are planning a TBI system, there are other guys out there that are more knowledgeable on that than me.
Last word of advise while collecting parts for this, when is doubt grab it. It's better to have more than you need than extra trips to the wreckers. Also don't be surprised if you end up collecting parts off a few of them. It might help to take a few photos before you rip and tear off the donor for reference later.

i went with a carb on mine here is a photo for you.
81-cj7-101711-3-.jpg  
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Unread 02-20-2012, 01:13 PM   #12
82CJ_Chemist
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Thanks for the thread cadCaman. Makes me a little less nervous about a 4.0 head conversion. Need move it up in the timeline a bit. Be interested to know how you like the conversion.
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Unread 02-20-2012, 03:12 PM   #13
CadCaman
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Quote:
Originally Posted by titomars View Post
Yes. You are planning a fairly very easy swap. The booster is not an issue since there is no carb to get in the way. if you are planning on the 4.0 MPI injection system, you will need the distributor and intake off the donor too. Remember to pull the entire ECM harness from the donor. It is easier to thin it out after you get it home. I would suggest going to the pick n pull yard and looking at the Cherokee line any 91 to 95. It will have what you want. if your Jeep is a stick look for a Cherokee with a stick for the ECM. Not Essential for you but us Californians have to have the right ECM to pass smog (check engine light). Why not just use the factory exhaust manifold off the donor? They work just fine. Just try and find the updated one with the bellows joints between the end cylinders. the ones without tend to crack. If you are planning a TBI system, there are other guys out there that are more knowledgeable on that than me.
Last word of advise while collecting parts for this, when is doubt grab it. It's better to have more than you need than extra trips to the wreckers. Also don't be surprised if you end up collecting parts off a few of them. It might help to take a few photos before you rip and tear off the donor for reference later.

i went with a carb on mine here is a photo for you.
Thanks Tito, I am going to go in stages. I need more power so I am going with the head swap first. I am going to see how it works with my Weber 32/36 and stock intake. I will go with the exhaust manifold from the head donor and then see how it goes. The only reason I am considering Fuel injection is because of the dunes here on Lake Michigan. They are pretty steep.

Is that a stock intake manifold on your pic? If so is the EGR welded off?

BTW I love the look of your Holley. What version is that?

Thanks for everything, Jeff
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Unread 02-20-2012, 03:14 PM   #14
CadCaman
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Quote:
Originally Posted by 82CJ_Chemist View Post
Thanks for the thread cadCaman. Makes me a little less nervous about a 4.0 head conversion. Need move it up in the timeline a bit. Be interested to know how you like the conversion.
Tito is the one you should thank. He is really very kind.

I am also looking forward to this. I will let you know how it goes.

Jeff
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Unread 02-20-2012, 03:24 PM   #15
titomars
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Quote:
Originally Posted by CadCaman View Post
Thanks Tito, I am going to go in stages. I need more power so I am going with the head swap first. I am going to see how it works with my Weber 32/36 and stock intake. I will go with the exhaust manifold from the head donor and then see how it goes. The only reason I am considering Fuel injection is because of the dunes here on Lake Michigan. They are pretty steep.

Is that a stock intake manifold on your pic? If so is the EGR welded off?

BTW I love the look of your Holley. What version is that?

Thanks for everything, Jeff
That sounds like a good plan. Just so you know any intake set up will leave the power steering brace too low to mount correctly on the intake. But it's an easy work around.
My intake is a Clifford Research the Holley is an #8007-4 which is a 390CFM.
i am old school and carbs used to be my specialty. So I a a bit stuck in the past.
Besides if i ever do decide to go with FI, I have a 94 Cherokee 5 spd. as my beater. I already have everything i need to do a conversion.
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