Hi! I bought a truck with a blown 4.0 OHV, head gasket leak from hell. My buddy has a wrecked 2001 Explorer with the 4.0 SOHC and automatic tranny. My truck is a 5 speed 4x4. What do I need to do to make the motor from the Explorer work in my truck?

 

Welcome to the forum

I assume you would like to keep manual trans and 4x4?

You will need 4.0l SOHC engine, its full engine wiring harness all the way back to computer, and part of exhaust system, back to just passed the rear O2 sensor(1994 doesn't have that one)
You will need a 2001-2003 4.0l SOHC computer from a manual trans Ranger or B4000, with at least 1 matching KEY, they have anti-theft transponder keys
The Computers come in two types, automatics and manuals, Explorers will all be automatics, Rangers or B4000 can have either

There are people that can program these computers, and they can delete the automatic transmission software, and the anti-theft as well, so you could use the Explorer computer, if you can find someone that can do that, local Speed Shops often know people that can do that, I don't anyone
It usually runs $200-$300, so check prices on manual trans computer as well to see a comparison
2WD or 4x4 doesn't matter to computer, just transmission type

Also need a flywheel for a 4.0l SOHC engine, your 1994 from the 4.0l OHV won't fit, 6 hole, SOHC needs 8 hole

The 4.0l SOHC and 4.0l OHV used the same basic Engine Block so motor mounts and transmissions are interchangeable

 

I gotcha. I can't use the computer thats already in my truck? Also, if I go to a junkyard and found one on a SOHC manual tranny truck would it just plug right in? As for wiring harness, are you talking the whole thing back to the firewall or farther back? Would I need the ignition lock cylinder too to fit the key or is it a fob that sits on a keychain? Doesn't the automatic 4 liter have a flywheel or is it different between the manual and auto? Can I have my existing ECU flashed to 2001-2003 spec or does it have to be a newer ECU?

Also, my fuel tank seems to have a very slight leak. Will an Explorers tank fit in my Ranger or do I need to get a OEM replacement?

Sorry for the flood of questions, trying to get this done right the first time

 

Automatics use Flex plates with torque converters
Manuals use flywheels and clutches

The 1994 4.0l OHV computer OBD1 couldn't run the 4.0l SOHC engine
You could get a 1990 to 2000 4.0l OHV engine and swap over your 1994 intakes to match 1994 wiring, that would be fairly plug and play

4.0l SOHC is a BIG swap into a 1994, a little less complicated than V8 swap but still a BIG swap
4.0l OHV was 160HP
4.0l SOHC was 207HP
BIG difference in how computer needs to control fuel injectors and spark, it would be an interesting project to try, you for sure would need to run 91 or 93 octane fuel using 4.0l OHV computer with a 4.0l SOHC engine

 

Gotcha gotcha. So I'd need 90% of the donor cars wiring harness then down to the OBDII port?
Will the SOHC motor need 91-93 if I use the proper ECU for it or will 87-89 octane be just fine?

 

Yes, getting the OBD2 connection with wiring would be good, that can be installed in engine bay, was put in the cab for convenience

4.0l SOHC engine and computer used Knock Sensor so it could run 87 octane, has more power with 91 octane but runs just fine on Regular gas using the correct computer