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Unread 09-09-2009, 05:37 AM   #1
wilson101
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1988 YJ Wrangler 
 
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4.0 Fuel injection swap on a 4.2.

I looked into the FAQ and saw alot of engine swaps and alot of heads swaps.
But i was wondering if it possible to just swap the 4.0 head, fuel injected intake manifold along with all the ecu and wiring harness onto a 4.2 engine.

My only concern is will the distributor from a 4.0 will fit the 4.2 block, since im guessing its what houses the crank angle sensor.

I could compensate for the extra .2 liters by crushing the FPR alittle bit to increase the fuel pressure until i get to the right AFR.


If you havent figured it out i drive a 1988 4.2 L Wrangler

Thanks

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Unread 09-09-2009, 08:22 AM   #2
93jeepyj
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What you want to do is very common and absolutly possible. the distributor will drop right in and you may not even have to mess with the fuel pressure.
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Unread 09-09-2009, 09:23 AM   #3
cbrseadude
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You shouldnt have to mess with the fuel pressure like that, it will be close enough. Im looking to do this also, looks like the only special things you need are the front damper and crank sensor mount which is available from several places.
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Unread 09-09-2009, 10:02 AM   #4
wilson101
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Quote:
Originally Posted by cbrseadude View Post
You shouldnt have to mess with the fuel pressure like that, it will be close enough. Im looking to do this also, looks like the only special things you need are the front damper and crank sensor mount which is available from several places.
Front damper? What is that?

Thanks for the info guys.
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Unread 09-09-2009, 10:17 AM   #5
deerslayer123
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Wilson, your still gonna need several more parts for that swap. Keep researching. your still gonna need the exhaust manifold, flywheel, 02 sensor, map sensor,etc.. Search for a head off 91-95 as they say it the best head for the swap. It has 7120 cast on the head. There's lot of good info out here and if you google it. Here's a link to a guy hwo did the exact swap you want with parts list and pictures.

Jeep Strokers • 4.0 head and EFI on a 4.2 block

Good luck!!
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Unread 09-09-2009, 10:33 AM   #6
cbrseadude
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What i mean by special is, parts you cant pirate off of a production vehicle in a junk yard or a vehicle someone is parting out. The damper or dampner, depending on who your are talking to is on the front of the crankshaft, the specialized one allows for a crank sensor to read off of it instead of messing with flywheels and stuff like that. If you google and look, you will find that you really dont need alot of specialized parts, just a few, the rest is production parts that there are tons off out there.
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Unread 09-09-2009, 11:06 AM   #7
wilson101
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Quote:
Originally Posted by deerslayer123 View Post
Wilson, your still gonna need several more parts for that swap. Keep researching. your still gonna need the exhaust manifold, flywheel, 02 sensor, map sensor,etc.. Search for a head off 91-95 as they say it the best head for the swap. It has 7120 cast on the head. There's lot of good info out here and if you google it. Here's a link to a guy hwo did the exact swap you want with parts list and pictures.

Jeep Strokers • 4.0 head and EFI on a 4.2 block

Good luck!!
Thanks Deerslayer thats exactly what I was looking for. I guess i'll be hitting the junkyard in the next few days.
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Unread 10-12-2009, 04:37 PM   #8
poppatello
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What is the point of swapping the head on a 4.2 to a 4.0? I would think the 4.2 head is better...
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Unread 10-12-2009, 07:06 PM   #9
ElvisV04290
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Originally Posted by poppatello View Post
What is the point of swapping the head on a 4.2 to a 4.0? I would think the 4.2 head is better...
The 4.2's head has intake ports at a 90 degree angle, while the H.O. 4.0s head has intake ports at ~45 degree angle. What this adds up to is the 4.0 head breaths better and increases engine efficiency, so you get a boost in HP and TQ.
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Unread 10-12-2009, 08:04 PM   #10
poppatello
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what is the difference in the HP and torque?
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Originally Posted by berserker View Post

Sometimes it a good idea to pull a vacuum hose before the wife rides in it--you can tell her you need a new ____ and once you get your new ____ you can reconnect the hose. :)


84 Cj 7 w/ 4-Banger, 4.5" BDS lift, 1/2 Trans Drop, Twin Stick, 32" Tire, Front Aussie Locker, No Sound System Yet, No Armor, Warn 8274 Not Installed, Webber Carb Upgrade, Luckycheese Ing. Upgrade...
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Unread 10-12-2009, 09:56 PM   #11
Douglas S.
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Originally Posted by poppatello View Post
what is the difference in the HP and torque?
Signifigant, I've heard as much as 50hp, not sure about torque
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