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Unread 08-14-2014, 11:24 AM   #1
ChefBone
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1982 CJ8 
 
Join Date: Aug 2014
Location: Baraboo, WI
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4.0 engine swap into scrambler

Hi,
I am new here and to jeeps in general, although I have a mechanical background so I'm not totally clueless. Rather than continue reading and searching (for hours) I thought I would ask my questions and hopefully get a direct answer or link or whatever. Here it goes...

82' scrambler, 258 94 xj intake harness and computer. Have a 97 xj complete drivetrain computer, harness was cut off on passenger side were it goes through firewall and have connectors from driver's side through fire wall. I will be making a 4.6 stroker and have most of the parts to do so, but what about the crank dampener? Can it be brought over with the 258 crank? Wiring is the other issue, detailed diagrams traced out by someone who has done it? Company that makes to mate with cj8? Flashing computer needed I assume but things need to be deleted and since higher compression things changed. I have searched and found pieces of the puzzle however, the easier I make it seem to my wife even though it might not be, less crap I will get about spending money and justifying more. Oh and the fact we just got a house with a garage for the first time in ten years and now it is full of frankenjeep. Thanks guys.

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Unread 08-14-2014, 11:31 AM   #2
CSP
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Which harness and computer are you going to use, the 94 or 97?

The 94 will be easier as it's OBD I.
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Unread 08-14-2014, 11:36 AM   #3
BajaTexasJeep
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I did same swap into CJ-7. Try Hesco.us
They have all the parts to make this an easy swap.
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Unread 08-14-2014, 12:29 PM   #4
ChefBone
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I was going to use the 97' since I have no idea what was done with the 94' and I have the 97' complete drivetrain oh and it has the ax-15 5spd. I assume the vats can be deleted, I will need an o2 I think. A/C will be removed (delete pulley) and electric fan so I can remove the offset stock one. If the 94' harness and computer will work for this setup then that is fine with me. Did not know what would be easier or more cost effective.
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Unread 08-14-2014, 12:31 PM   #5
ChefBone
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I did look at hesco and hotwire...not sure what I should be looking at or for. If it is mechanical based I can usually figure it out, but the electrical seems like a pita.
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Unread 08-14-2014, 12:55 PM   #6
gmakra
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Food for thought. The 97 I believe is a drivers side drop if you plan on using the trans and xfer case. Two the 97 has two O-2 sensors pre and post cat. Your dampener will swap though you will need a spacer from Hesco.

If your asking my opinion about making the stroker I would use the crank from the 4.2 and use the 94 block and head. I assume you will be running FI on the stroker? If so be forewarned that you may have some issues with running lean and it acting up a bit on occasion. Most of this can be worked through with some patience but its not as plug and play as you would think.

WWW.jeepstrokers.com has a lot of recipes for building a stroker from mild to wild (its just a matter of how much you want to spend?
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Unread 08-14-2014, 01:05 PM   #7
ChefBone
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I have the novak adapter for a passenger side t-case. Good to know about the dampener spacer though. I am using the 258 crank and the 97 block/head. My father-in-law had mated the 94 harness, computer and fi on the 258. It worked and ran well until it started clacking and blows blue smoke at idle and billows at speed. I imagine that the piston/skirt(s) have failed. Thanks for the strokers site. Can this work with just the upper o2 sensor? I was not going to place a cat on it since it does not have one now. Thanks for all the info guys.
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Unread 08-14-2014, 01:58 PM   #8
adman02
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I'm in the midst of swapping over a 4.0L into my 79 CJ7. Google "five wires to fire" if you don't know how to connect the new wiring harness to your old scrambler one.

You might encounter some unexpected surprises like I did - fan didn't fit between the water pump and radiator, needed to have a new power steering pump hose made (with CJ gear box end and 4.0L pump end), needed to find a VSS and adapter etc.

Here are some sites that were/are helpful:
http://web.archive.org/web/200812231...sp?FORUM_ID=24 Look in the stickies
http://www.jeepforum.com/forum/f12/4...mation-537763/
http://www.pirate4x4.com/forum/jeep-...swap-help.html
http://www.jeepsunlimited.com/forums...ZJ-into-84-CJ7
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Unread 08-14-2014, 02:24 PM   #9
ChefBone
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Thanks. I will be looking into this more and will probably be back asking more questions. Any info is great.
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Unread 08-14-2014, 10:22 PM   #10
ThisGuyUKnow
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Quote:
Originally Posted by ChefBone View Post
I was going to use the 97' since I have no idea what was done with the 94' and I have the 97' complete drivetrain oh and it has the ax-15 5spd. I assume the vats can be deleted, I will need an o2 I think. A/C will be removed (delete pulley) and electric fan so I can remove the offset stock one. If the 94' harness and computer will work for this setup then that is fine with me. Did not know what would be easier or more cost effective.
I make obd1 harnesses all the time it shouldn't be hard to figure out that harness you have. You shouldn't need anything that runs through the firewall.
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Unread 08-14-2014, 10:36 PM   #11
ThisGuyUKnow
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Quote:
Originally Posted by ChefBone View Post
Hi,
I am new here and to jeeps in general, although I have a mechanical background so I'm not totally clueless. Rather than continue reading and searching (for hours) I thought I would ask my questions and hopefully get a direct answer or link or whatever. Here it goes...

82' scrambler, 258 94 xj intake harness and computer. Have a 97 xj complete drivetrain computer, harness was cut off on passenger side were it goes through firewall and have connectors from driver's side through fire wall. I will be making a 4.6 stroker and have most of the parts to do so, but what about the crank dampener? Can it be brought over with the 258 crank? Wiring is the other issue, detailed diagrams traced out by someone who has done it? Company that makes to mate with cj8? Flashing computer needed I assume but things need to be deleted and since higher compression things changed. I have searched and found pieces of the puzzle however, the easier I make it seem to my wife even though it might not be, less crap I will get about spending money and justifying more. Oh and the fact we just got a house with a garage for the first time in ten years and now it is full of frankenjeep. Thanks guys.
To answer your question about the dampner, the 258 crank is longer than the 4.0 one. In order to mount the 4.0 crank dampner you will need a spacer to seat the crank pulley fully. You can make this it hesco makes one.

Since you are using the ax15 you will not need the hesco cps relocation kit as long as you use the 4.0 fly wheel.

The stroker from what little I have read, I thought that reprogramming of the ecm is necessary, I seem to recall that you needed like an adjustable map sensor and fuel pressure regulator or something. I am pretty sure that the 4.0 ecu isn't programmable.
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Unread 08-14-2014, 10:39 PM   #12
SLO_Ken
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The '97 will run just fine without the second O2 sensor. It is only there to monitor the performance of the cat. It is not part of the air/fuel ratio feedback loop.

One thing to remember is that your 258 crank pulley is likely set up for V-belts, whereas the 4.0 is a serpentine. Also, the water pump on the 4.0 spins backwards compared to the 258.
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Unread 08-14-2014, 10:41 PM   #13
ThisGuyUKnow
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Everything you need to thin out and set up a OBD1 4.0 cherokee harness is in these three diagrams.
http://ww2.justanswer.com/uploads/on...44406_wire.gif
http://ww2.justanswer.com/uploads/Db...kee_wiring.gif
http://www.jeepforum.com/forum/attac...-ecupinout.jpg
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Unread 08-14-2014, 10:48 PM   #14
CSP
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Quote:
Originally Posted by ChefBone View Post
I assume the vats can be deleted
Pretty sure it can't be. The '94 ECM would be much easier to use.
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Unread 08-14-2014, 10:51 PM   #15
RenoF250
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Quote:
Originally Posted by gmakra View Post
Food for thought. The 97 I believe is a drivers side drop if you plan on using the trans and xfer case. Two the 97 has two O-2 sensors pre and post cat. Your dampener will swap though you will need a spacer from Hesco.

If your asking my opinion about making the stroker I would use the crank from the 4.2 and use the 94 block and head. I assume you will be running FI on the stroker? If so be forewarned that you may have some issues with running lean and it acting up a bit on occasion. Most of this can be worked through with some patience but its not as plug and play as you would think.

WWW.jeepstrokers.com has a lot of recipes for building a stroker from mild to wild (its just a matter of how much you want to spend?
Does that work? I wanted to do that but my 258 accessories would not bolt on and they sit at a bit different distance so I ended up using all the 4.0 stuff. I took my engine from a Cherokee and I just put the fan on the WP but I had to get a YJ WP and the right pulley and make an AC delete bracket. Worked out well because the 4.0 alt is 90A and the CJ was 40A. Also the 94 PCM cnotrols the alt and may whine if it is not there.

Hesco has everything but it is expensive. I made my own spacer and got my speed sensor from RockAuto. I intend to have a speedometer shop make me a new cable that will fit rather than buy the Hesco adapter.

The harness is fairly straightforward but tedious. Download the full FSM and you can get all of the color codes in there.

One thing to be aware of that no one told me is the PCM tach signal it only 2 pulses per rev so set you tach for 4 cylinder.

Also, pay attention to where the bolts go when you take it apart. There is a ridiculous mix of metric and SAE and to make it worse the SAE will thread into the metric holes. Someone needs to be kicked in the head for that.

If you use the 94 you do not need to and probably can't flash the PCM. For OBDII "flyinryan" can help you with reprogramming.

I did not follow the herd on the "deck the block and get the quench down" I used IC944 pistons and no machining on block or head surfaces. I have not gotten down to 87 octane yet but I have over 1k miles and no ping with 91 down to 1,500' altitude.

What is the casting number on your 97 head? I believe the 0331 head has cracking issues. You may want to stick with the 94 head, the 7120 is supposed to be best.

What injectors are you going to run? They need to be larger or it will run lean when open loop and at high rpm.

What kind of engine do you want to make? As much power as you can get or a reliable low-end torque pig? I went for the latter.
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