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1999 Ford Explorer 4.0 SOHC swap to 4.0 OHV

Discussion in 'Stock 1995 - 2001 Explorers' started by Pckid212, December 25, 2009.

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    1. Pckid212

      Pckid212 Member

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      City, State:
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      Year and Model:
      1999 X Sport
      Unlike some people wanting to swap from the 4.0 ohv to the 4.0 sohc, I want to swap from the 4.0 sohc to the 4.0 ohv.

      Why? Simple. The 4.0 sohc has known timing chain problems. And my timing chain is failing, thats why I'm here.

      I can get a used 4.0 ohv and swap it cheaper than I can get the timing chain kit for the 4.0 sohc that I currently have.

      Now, I've done some research and if the internet is correct my 1999 Explorer should have the 5r55e transmission but just to make sure of that, how can I ID the transmission?

      What will be needed besides the 4.0 ohv engine?

      Thanks,
      Chris
       
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    3. renegadepig

      renegadepig New Member

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      been there tried that. found that the computer for the ohv will not work with the body wiring of the sohc. The only way I could find to make it work would have involved using the body wiring harness from the ohv in the sohc and then lots of things would not work. Gave up and fixed the sohc engine
       
    4. Pckid212

      Pckid212 Member

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      I can mod the wiring harness, thats not a problem for me.
       
    5. calmac06

      calmac06 Active Member

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      Really consider what you are planning on and make sure that you really wanna do it, the cost is always way more, it always takes more time, and is usually much more stressful than you plan. Just remember that if you run into problems midway through the wiring harness doctoring that you cannot stop, if you do you have an essentially worthless truck. The wiring harness re-wiring will be more of a problem than you think, especially if you are asking questions about ID-ing your transmission. I'm not trying to crush your project, but there have been a few times where instead of someone telling me to cool my jets and reconsider a project, they just said, "go for it!" on something that I didn't have the means to complete, be it money, competence or a combination of the two. Just my .02

      Keep us posted, :popcorn:
       
    6. kindred4x

      kindred4x Active Member

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      I may be wrong, but the mid 90's ohv has a 4r55e trans like mine does, it has a six bolt crank, and the 5r55e trans and sohc motors have a 8 bolt crank?
       
    7. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      I wouldn't try it

      I'm an electrical engineer and wouldn't try it. You'll lose capabilities, reliability and performance (-50 hp). Even if you're successful, you'll have a vehicle with almost no resale value because nobody else could maintain it. The OHV may have just as many problems (cracked heads are not uncommon) as your SOHC and will probably have more miles on it. Consider the possibility of buying a late model Mustang SOHC from a low mileage wrecked donor vehicle. In the end you'll probably save money and have a reliable, maintainable, better performance vehicle with all the original capabilities.
       
    8. Pckid212

      Pckid212 Member

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      I don't plan on reselling the explorer tbh. It has 205,000 miles and I plan to replace the engine and just run it till its time for the junkyard. When that happens the replacement engine (if still running) will find a new home in another project. ;)

      I'm fine with higher miles on the 4.0 ohv.. I don't plan on putting it in there bone stock anyways... When its done it will put out just as much if not more power than the sohc.

      Anyways, will the ECM for the SOHC work for the OHV?
       
    9. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      PCM pinouts

      I found the following differences in the PCM pinouts from my 2000 wiring diagrams. Probably the same for a 1999

      SOHC
      #32, knock sensor rtn
      #43, message center (fuel flow)
      #46, fuel cap indicator
      #57, knock sensor input
      #61, heated oxygen sensor #22
      #96, heated oxygen sensor #22

      OHV
      #32, not used
      #43, not used
      #46, not used
      #57, not used
      #61, not used
      #96, not used

      Electrically the SOHC PCM should support the OHV engine. The PCM will need to be reprogrammed. Do you have a flash reprogrammer? My SCT X3 Power Flash cost about $400.
       
    10. ranger7ltr

      ranger7ltr Elite Explorer

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      Or he could simply buy a PCM and wiring harness from a 99 OHV Explorer and not need to do any of that... This is the benefit of having both drivetrains in the same vehicle as options...And is there different body wiring based on the engine choice? Did the OHV engined Explorer not have the message center where the SOHC engine Explorer did? Since both engines used the same transmission and fuel systems, the only true difference I can see is the engine bay harnesses and the PCM[and possibility only the programming in the PCM]...

      It is a doable project and I believe you have a handle on the wiring differences so I can't see any other black holes you will run into...

      Good luck if you proceed!!!
       
    11. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      Message center & PATS

      I don't know but suspect the message center was part of a trim package that included the SOHC.

      You're right that buying the OHV PCM and engine wiring harness with the engine would simplify the wiring. The main engine harness to chassis connector (C115) appear to be the same. I wonder about PATS however. It may be necessary to reprogram the ignition keys to match the OHV PCM.
       
    12. Pckid212

      Pckid212 Member

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      I don't have a programmer but would be willing to buy one seeing the demand for flashes around my area since it would over time pay for itself.

      Maybe someone could work a $ deal to flash my PCM? That'd be cheaper.. hopefully.

      I will have to look at the differences between the harnesses. I'm fine with cutting connectors from an OHV ranger or explorer at a junkyard, soldering, and heat shrinking the connectors onto my harness if needed. But if i can find the correct harness that would be awesome.

      BTW, this project will start in the spring.
       
    13. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      X3 & wiring harness

      The X3 Power Flash is limited to five vehicles to prevent buyers from reducing the market. Each time a different vehicle is programmed the X3 reads the VIN and stores it. Also, I believe a vehicle's PCM has to be returned to the stock program before the X3 will allow programming a different PCM. When 5 VINs are stored the X3 can no longer be used on any other vehicles for programming. To unlock one or more VINs the X3 has to be returned to an SCT dealer who charges around $150 I believe.

      Finding an engine wiring harness should not be a problem and could come with the engine if you limit the year to 2000. I've heard that the 2001 wiring is different from the 2000 and earlier.
       
    14. storlied

      storlied Well-Known Member

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      If you're going to do an Engine swap, why not do the 5.0L v8 swap? SOHC to OHV is gonna give you a performance hit. At least in the v6 market. the SOHC has 210, and the V8 has 215. I believe the OHV V6 had like 150hp? Doing the V8 swap will give your vehicle a much longer life than doing anything with the v6.. the tranny is near bullet proof and the engine has proved itself in more vehicles than you might think over many many years.
       
    15. renegadepig

      renegadepig New Member

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      I don't know but suspect the message center was part of a trim package that included the SOHC.

      You're right that buying the OHV PCM and engine wiring harness with the engine would simplify the wiring. The main engine harness to chassis connector (C115) appear to be the same. I wonder about PATS however. It may be necessary to reprogram the ignition keys to match the OHV PCM.

      You are correct that the message center is part of the trim package. Also the connector for the engine looks the same however it will not connect together because of the tab in the connector. I got the mitchells wiring diagrams for both of the 98's that I had and when you start comparing the wiring and the pinouts for the various circuits the differencs are more than meets the eye. If you really want to do it I would only suggest research before you delve into it so that you are not disappointed. Dave
       
    16. Pckid212

      Pckid212 Member

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      I don't want to have mod anything past the transmission... Meaning if I do a V8 it must use a transmission that is an almost direct bolt in, in place of the 5r55e. I don't want to have to replace my t-case, front drive shaft, or rear drive shaft..

      With a V8 I might as well go with a 5 speed.. cuz a v8 with an auto isn't much fun.. Now thats going to force me to change the gauge cluster, the steering column, the brake pedal, install the clutch pedal, the list goes on and on... too much work in my mind for an explorer that has 205,000 miles and it also being my first car.

      The V6 ohv is a direct bolt in, which will just will require some electrical modifications (including flashing my pcm). I'm also going to change the pistons to v6 sohc pistons (raise compression) and cam it. Nothing that can't be done in a week or less.
       
    17. Pckid212

      Pckid212 Member

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      Has anyone figured out a way to bypass the PATS system yet?

      My 99 Sport:
      [​IMG]
       
    18. storlied

      storlied Well-Known Member

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      If you think about it, with a complete swap to V8.. all those miles don't mean anything anymore other than suspension and a few other electrical issues... anything mechanical will have a very nice low mileage. That truck can last another truck lifetime. [for the most part, since your current is pretty old] And it's more of a dependable drivetrain than any of the V6 w/their trannys IMO. Auto can be improved with a shift kit if anything.

      [Edit: Ooo.. You have a nice light 2 door, with a v8 that would be pretty quick.]
       
    19. Pckid212

      Pckid212 Member

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      ..alright V8 swap it is. What will I need for the swap besides the 5.0? What tranny? What all will need to be modded?
       
    20. Pckid212

      Pckid212 Member

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      I have only found one thread about the v8 swap into a 99 Sport, which wasn't all that detailed but it helped a bit. I guess it's rarely done.

      Is my gauge cluster going to need to be replaced or will the tachometer have the option for the V8? Will it still pass PA emissions? Can I use an older 5.0 or does it have to be the same year or newer? Will the motor mounts have to be replaced for the 5.0? What about the wiring harness for the 5.0?
       
    21. hworksinc

      hworksinc Elite Explorer

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      The tachometer should work fine - it reads a processed signal from the PCM. Nothing else in the cluster should be different. If you do a stock installation, it should pass emissions just like any other V8 Explorer. I'd recommend to swap from a 98-2000 vehicle, since any relevant wiring will be a closer match. (Some things changed between 97 and 98).

      As indicated before, you'll definitely need to swap the engine harness (not plug and play) and modify some of your body wiring related to emissions, O2 sensors, and transmission control.

      The V8 PCM is designed to work with the 4R70W transmission (not the 5R55E that you have). I don't know if it can be modified to work with the 5 speed. I'd recommend swapping to the 4 speed anyway - prevailing opinion here is that the 4 speed is a much stronger transmission.

      There are several threads here about doing a V8 swap into a 4-door. It shouldn't really be any different than yours, with the possible exception of the driveshaft (if you swap the trans to the 4 speed).

      The sport with the V8 would be awesome.
       
    22. 2000StreetRod

      2000StreetRod Staff Member Moderator Elite Explorer

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      Driveshaft & thread

      Since your Sport is shorter than the 4 door models that came with the V8/4R70W you will need a shorter driveshaft. I don't know if the front U joint is any different on the V8 driveshafts vs the V6 driveshafts. Also, there may be differences in the rear axle (traction rod) and the transfer case to consider.

      I suggest that you start a new thread with a title containing SOHC to V8 swap to draw the attention of those with related experience.
       
    23. 410Fortune

      410Fortune ELITE BRONCO2ERER Moderator Emeritus

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      simple pimple

      find a 99-01 Explorer 5.0L with lowish miles

      either 2wd or AWD depending on your truck, buy the whole vehicle

      park them next to each other and BOLT the entire V8 drivetrain, wiring, transmission, everything into your 99 sport

      You will have to modify the exhaust and rear driveshaft a little bit, thats it!

      BLAMO V8 sport
       
    24. Pckid212

      Pckid212 Member

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      Could this possibly be done in a driveway? I keep hearing from people it's too much work. I know enough that I can pull it off (my pap is a mechanic, so this stuff is pretty easy for me to understand and do) and I like challenges.

      Just wanted to see what you guys had to say...
       
    25. 410Fortune

      410Fortune ELITE BRONCO2ERER Moderator Emeritus

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      it could be done in a 3 day weekend if you are good at this sort of thing and know what you are getting into... but I would plan a bit more time then that and plan to run into some problems and spend some $$$

      make a timeline and a budget, then DOUBLE IT


      because your truck is a 1999 and they made a 1999 with a 5.0L V8 its a bolt in conversion 100%, as long as you have all the parts, can modify the exhaust when its all bolted in and can get a rear driveshaft modified, you should be golden!

      it can be done in a driveway, for sure? I did mine in a barn with 3' of snow on the ground
       
    26. Pckid212

      Pckid212 Member

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      Alright thats what I wanted to hear. I have the tools but I need to buy a 2 Ton Harbor Freight Engine Crane. My dad had a good one but it got stolen, grr.

      I won't need an engine stand because ill just set the old engine in a tire, and then transfer the V8 to mine :D.

      I'll work on planning everything out. Because of the rear driveshaft having to be shortened does that mean my t-case is going to be pushed back? What about my front driveshaft? Will it have to be lengthened?
       

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