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Discussion Starter #1
Yeh i know there is alot of 4.0 swap info but nothing like im doing(least not that i found)

MY 4.2 has 30k on it( re man engine) I got a 91 4.0 XJ with 130k on it. I want to take just the head and Injection off the xj and put it on the 4.2

other than the basic 4.0 head swap (which ive read a million times) what will i need to get the FI working. I have the entire xj, computer, fuel pump ect ect ect so i sould have it all

any one know of any write ups on this. I am done with the carb. I got my jeep running but it still runs like crap.

I need help though bc everything i have found has only been either 4.0 head or complete 4.0 swaps, not head and FI.

Dan
 

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You will need to use the old 4.0 flywheel for the speed sensor. No big deal should bolt right up. The big problem is the ECT. You will need to drill some sort of mounting hole in the side of the block to mount the ECT. And hopefully the distributor will slide in where the old one is. Has to have the 4.0 distributor to figure the fuel injector timing. Other than that I think you might be ok. Of cours you should just swap the 4.2 rods and crank into the 4.0.:flipoff2:

Kevo
 

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OK this wasn't that terribly bad, but I'm on a mission


:cow:
 

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Discussion Starter #4
Steve N said:
OK this wasn't that terribly bad, but I'm on a mission


:cow:
Only if its a mission from god will it be allowed, and if you are in a suit wearing sun glasses at night... :flipoff2:


Kevo- I think you misunderstood? I am putting 4.0 head and FI on a 4.2 block, so the 4.2 crank is already there.

what do you mean by ECT, im confused reading your post... sorry
 

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What Gheto was implying is that you should build a stroker out of the 4.0 instead of doing the head swap. It makes a 4.7 out of it.

You must not have spent too much time researching this because just about everyone who has done the head swap has either done what you are talking about at the time of the swap or shortly there after. Peterson's 4 wheel and offroad even had a write up in the mag back in '99. I found it on the web somewhere. Try searching. Maybe not here on the bbs, but in the WWW. It's fun.

Oh, and don't be a smart arse to the moderators. It just pisses them off.

:flipoff2:
 

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Discussion Starter #6
Tippy said:
What Gheto was implying is that you should build a stroker out of the 4.0 instead of doing the head swap. It makes a 4.7 out of it.

You must not have spent too much time researching this because just about everyone who has done the head swap has either done what you are talking about at the time of the swap or shortly there after. Peterson's 4 wheel and offroad even had a write up in the mag back in '99. I found it on the web somewhere. Try searching. Maybe not here on the bbs, but in the WWW. It's fun.

Oh, and don't be a smart arse to the moderators. It just pisses them off.

:flipoff2:
I have yet to read one 4.0 head only swap where they added FI w/o doing a kit.

I dont want to do a 4.7L stroker bc i have a 4.2 thats good, just needs a little updateing.

And i wasnt being a smart ass in a bad way, hence the :flipoff2: :rolleyes:
 

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ECT=Engine Coolant Temp sensor.

Tells the computer how hot the motor is so that it can adjust fuel mixture accordingly. Very important to have. This is NOT the temp sender to your temp gauge.

Kevo
 

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you would need to mount the cps, they make a kit where you can mount this on a replacement harmonic balancer. i think the knock sensor would need to be in place.


your doing it all wrong though... build the xj throw all else away.
 

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Discussion Starter #9
well the xj will most likely be combined with another to live another life....


anywho.. is the ECT the sensor in the tstat housing?

I am going to get a 91+ flywheel and then cut my bell housing to fit the cps. unless i find a bell housing too.



I pulled the head off the 4.0 and the water jackets that are supposed to et plugged, wel the already are.. .more so they dont exist, but it is definately a 4.0 head, from a 91 xj HO

hmmm

this gets more and more complicated
 

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The ECT will fit the therm housing on a serpintine belt system or will go into the side of the block just below the #2 exhaust on a V-belt.

You'll have to fill a couple of water jackets in the head with epoxy as they don't match.

use the 4.2 head gasket for lower compression, the 4.0 for higher compression. Use the 4.0 exhaust gasket.

Depending on the head, you may need an alignment spacer to line the head on the block and you may need new studs from PRP as some blocks use different studs and won't fit the 4.0 heads.

Distributor, harness, computer, coil...do you need the fule pump blockoff plate?

High pressure Fuel Pump and lines.

4.0 exhaust manifold/header.

We use the crank timing sensor that goes off the harmonic...we didn't use the flywheel type as they are a hassle.

There's more but I'm tired and am not thinking straight.

Have fun and good luck. My motors turned out great with this setup...my next one for the CJ will be a stroker 4.0.
 

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Discussion Starter #11
I just confirmed that my 90 bellhousing has a spot for the cps, and my flywheel has notches on it.

Anyone know how to determine what notch pattern is needed for the cps?

Im trying to locate pictures online but havent had much luck

Dan
 
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