4.0 head swap ? from 95 Grand cherokee? - JeepForum.com
Search  
Sign Up   Today's Posts
User: Pass: Remember?
Advertise Here
Jeep Home Jeep Forum Jeep Classifieds Jeep Registry JeepSpace Jeep Reviews Jeep Gallery Jeep Clubs Jeep Groups Jeep Videos Jeep Events Jeep Articles
Go Back JeepForum.com > Models > Jeep Wrangler Forums > YJ Wrangler Technical Forum > 4.0 head swap ? from 95 Grand cherokee?

Introducing MONSTALINER™ UV Permanent DIY Roll On Bed LineSavvy Billet LED Tail LightsWant to be able to SEE? DOT Approved Headlights for under

Reply
Unread 09-10-2011, 10:59 PM   #1
rksnow1
Registered User
2008 JK Wrangler 
 
Join Date: Jul 2010
Location: Morrisville, PA
Posts: 171
4.0 head swap ? from 95 Grand cherokee?

I have been reading up on the forums here and decided I want to do the 4.0HO head swap on to my 88 4.2 258. I have a donor 96 Grand Cherokee that I can get all the parts from I believe.

I have a 7120 head from a 95 Grand Cherokee and was told that will work.. I was thinking about switching over to fuel injection as well while I'm at it.

My question is... Will the harness, intake, ECU, etc work from a 95 Grand Cherokee? Everything I read on here says to get the 7120 head, intake/exhaust manifold, ECU, and harness from an XJ. Can anyone tell me if It will work, or why not if the head is the same, which parts will or will not work if so..

Thanks

rksnow1 is offline   Reply With Quote Quick reply to this message
Unread 09-11-2011, 09:22 AM   #2
4.7stroker
Registered User
1988 YJ Wrangler 
 
Join Date: Apr 2007
Location: Rio Rancho NM
Posts: 4,299
I am positive it will work but you will have to figure out the wiring.
I would get a good write up for a XJ and reverse engineer the wiring.

Dwayne
4.7stroker is offline   Reply With Quote Quick reply to this message
Unread 09-11-2011, 02:59 PM   #3
wendell
Registered User
1987 YJ Wrangler 
 
Join Date: Aug 2006
Location: grafton ohio
Posts: 3,292
I've found that putting a 4.0 head on a 258 is alot of hype, might be different with the FI. I have a built 258 and installed a clearwater 4.0 head with offy intake and holley 470 4 barrel, I was disapointed at the gain. For kicks and giggles, I had my 258 head P&P'ed, I installed it back on my 258 with the other performance parts and it was a screamer. It had a much better lowend torque cuvre and responed better throughout the rpm range with the comp cam. I lost a little on the topend, but the engine responded better up to 4,800 rpm's where I mostly operate. The FI may make a difference, but with a carb and an old school build, a ported 258 head works better, or at least it did for me.
__________________
1987 wrangler, 258 I-6, 5-speed.
2007 liberty sport 4X4, automatic
2009 ford ranger 4x4 FX4 OFF/ROAD, 5-speed
wendell is offline   Reply With Quote Quick reply to this message
Unread 09-11-2011, 08:26 PM   #4
Noltz
Registered User
YJ Wrangler 
 
Join Date: Oct 2010
Location: Hamilton, Ontario
Posts: 746
That's interesting Wendell. I found significant gains when I put a '94 4.0 Cherokee head, junk-yard stock except for welding the cooling ports closed, and using the old Carter carb and intake. I did have to make some oddball washers (teardrop shaped, sort of) to hold the intake, and I used the 4.0 exhaust manifold & modified 4.2 downpipe to save money. Other than buffing the surface clean there was no machining at all. It ran great, could even bump a short wheelie on stock 235 tires & 3.07's. I did notice my block still had crosshatching with 150k on it, so it's likely that it was freshened.

To OP; the biggest problem I see is the crank sensor. You'll need some sort of pickup - either changing the flywheel out to the 4.0 flywheel (IF that will work, I don't know), then you'll need to find a way to mount a crank sensor in the right position, and notch the transmission bellhousing if needed. I think you'd be farther along to put the whole 4.0 block in from the '96, as it will have all the correct sensor mounting bosses and the engine mounts I believe bolt up to each other. As for wiring, I'd find a '95 harness and computer. Might cost a couple hundred (if that) but then you'd have a 'correct' 4.0 YJ with all the wiring colors being correct for any future diagnostics. The bends in the wiring would be correct too, plus it'd all be plug-n-play so save you a lot of time splicing it.

You didn't mention which transmission you're going with. As I recall the transmission is ECU controlled for the GC, so you might get a check engine light if you're running a manual. I do a lot of automotive electrical work but I'm not Max when it comes to what-fits-where... wait for him to chime in
__________________
-Noltz
'91 Frankenheep YJ. 4.0, 4" BDS, Richmond 8.8, Titan 12k, 35" KM2's, rust.
'88 YJ, 4.2/4.0 head, +4½" & shackles, BFG 33's (sold)
Noltz is offline   Reply With Quote Quick reply to this message
Unread 09-12-2011, 03:15 PM   #5
rksnow1
Registered User
2008 JK Wrangler 
 
Join Date: Jul 2010
Location: Morrisville, PA
Posts: 171
Thanks for the info guys. I'm going to stick with the 4.2 motor, I was in the middle of rebuilding it when I saw the thread about the head swap and got curious.

The 4.0 motor in the donor Grand Cherokee has a bad bottom end and block thats not rebuildable, but the intake, ECU, wiring etc are all still good. I just wasn't sure if there was a reason all the info on the swap referred to using parts from an XJ (other them more room to work) simpler harness or location of connectors etc.

Im going to put the 4.0 head on with my Weber for the time being until I can find a little more info if this will definately work.. It will be nice to see how much of an improvement the head makes carbed and then with the fuel injection after...

Ill put everything off on the side in my garage for now till I get all the parts and the verdict is decided.. I think I have everything needed but the fuel pump and VSS sensors, if the Grands harness works. Worse case maybe Ill have to pull a new harness out of an XJ?
rksnow1 is offline   Reply With Quote Quick reply to this message
Unread 09-17-2011, 10:21 PM   #6
sec2776
Registered User
1988 YJ Wrangler 
 
Join Date: Aug 2009
Location: Covington, GA
Posts: 18
I'm about to do the same thing to my jeep too. I have a complete 4.0 out of a 91 Wrangler with the wiring, computer everything. Let me know what you think about the swap when it's done.
sec2776 is offline   Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.
Note: All free e-mails have been banned due to mis-use. (Yahoo, Gmail, Hotmail, etc.)
Don't have a non-free e-mail address? Click here for a solution: Manual Account Creation
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.


Thread Tools


Suggested Threads





Jeep, Wrangler, Cherokee, Grand Cherokee, and other models are copyrighted and trademarked to Jeep/Chrysler Corporation. JeepForum.com is not in any way associated with Jeep or the Chrysler Corp.