OHV to SOHC swap

[92lxsleeper]

Has anyone attempted this? if its possible and feasible, i would like to do it to my 95 Sport. 4.0L OHV 5 speed manual 4X4

 

[briwayjones]

I'm not an expert but I think it might be a lot easier and probably cheaper to get a donor vehicle with a SOHC and just swap the whole thing over computer and all.

 

[92lxsleeper]

well the thing is that i want to keep my 5 speed and 4X4, and im not sure if the had that option on the SOHC. i know they had AWD, and i do not want that.

 

[CDW6212R]

The SOHC had 4WD, never AWD, but I don't know about the manual trans. I bet that it did, but dealing with the PCM will be a harder issue. If you do not have OBDII(under dash diagnostic port), then I'd leave the PCM in there and change external engine parts. Meaning keep the parts from your engine and place on the SOHC engine. They use the same block so almost everything should bolt on. Good luck,

 

[joecrna]

AWD was on V8s. The SOHC used a transfer case for 4x4. Don't forget, everything is computer controlled; TC, trans, engine, brakes. They all talk to eachother, a byproduct of OBDII. Doable but never easy. Swapping the whole drivetrain complete with wiring harnesses and computers is always far easier.

 

[Stic-o]

You just need the engine, and all wiring plus computer. However, it must be from another manual, as the newer Auto are computer controlled and are part of that system. If you installed a computer from a auto, it would keep throwing codes looking for the trans.

 

[410Fortune]

Actually you dont need the computer
Brett has a 94 Explorer sport, 5 speed.

He installed a SOHC 4.0L from a 03 Ranger along with the Ranger 5 speed and his 93 transfer case

he is using the 94 OHV computer to run the SOHC engine
His SOHC is a very tight fit in his gen I, but since your truck is a 95 this is not an issue.

It IS POSSIBLE to put a SOHC in place of the OHV and use the OHV computer to run the SOHC engine. You just have to ignore one of the cam position sensors

The other alternative is to convert your 95 truck to OBD-II and run all the electronics from a donor SOHC truck. If you are going to go through all that trouble you may consider the V8 conversion also..

My vote is get SOHC engine, one before the retunless style fuel system, bolt it in and wire it to your existing computer.

 

[briwayjones]

well the thing is that i want to keep my 5 speed and 4X4, and im not sure if the had that option on the SOHC. i know they had AWD, and i do not want that.

The 2001-2003 Sports had manual transmissions with the SOHC, as well as Rangers. Yours will bolt right up. The manuals behind the SOHC are just a little beefier version internally than the ones behind the OHVs. But if you don't drive it real hard you would probably be ok. Or you might be able to find one with a manual.

I'm surprised you can use a OHV computer with a SOHC. The timing isn't different or anything or the SOHC tuned to give optimized power with the SOHC engines?

 

[410Fortune]

Briway nope, they are VERY similar engines as far as the computer is concerned.

The cam position sensor is only used during start up

Brett was not the first person to do this, people have been running the SOHC block with the OHV computer for some time, especially the So Cal desert crowd.

I believe Doug on this forum years ago was running a turbo SOHC with an OHV computer? Somebody was.
The problem is the SOHC is a HUGE SOB, so fitting it into a Gen I truck is really really tight... I mean TIGHT. Tighter then my 5.0L BIG TIME. Brett's hits the heater box (with AC) and the power steering gear box, also close to the frame and firewall in a few spots.
I looked at the work he did and the fitment and said WOW Ill keep my V8.

However he spent little $$$$ to get a really powerful SOHC in there with a 03 Ranger 5 speed (identical dimensions to the older Mazda 5 speed, just like you said strionger inside) his biggest challenge was to convert the 03 SOHC back to the return style fuel system, I believe he used 97 SOHC intakes/fuel rail.

You ignore the overhead cam postion sensor, hook up the "dummy" cam position sensor on the back of the SOHC and it purrs like a kitten

of course there is more wiring then that, swapping out some sensors for the gages and computer where you can... but I can tell you his lifted 94 sport on 33's with the 5 speed will give my 5.0L BII auto a run for its $$$$ big time... the truck straight scoots and oh so fun to drive with the 5 speed...

 

[briwayjones]

the truck straight scoots and oh so fun to drive with the 5 speed...

Yup, oh I do like my '03 Sport SOHC with 5 speed.

 

[jah81592]

The obd2 computer can be swapped in, the camshaft position sensor is used all the time. You can make it work and I feel it would be worth your time. You will definately need a donar vehicle to ease the financial strain. If i am not mistaken, the physical dimensions are the same.

 

[410Fortune]

So donor vehicle vs just buy a SOHC engine? hmmm.... on a budget one is far cheaper then the other.

Of course the full OBD-ii conversion is better, but its also alot more work and alot more $$$$ IMO to get similar results.

 

[Stic-o]

Jamie, does the just swaping motors thing work on OBD2 as well? Another words could I just swap my '99 ohv out for a SOHC and it would be plug any play for the most part? I know the trans is the same so the computer would not care.

 

[CDW6212R]

That is also a good bet, the OHV 4.0 engine didn't change hardly at all through the years. The advantage of the OBDII is that if needed you can pay for a flasher and program any modifications.

 

[410Fortune]

Stic-o look around you mang LOL the guys at Camburg are racing Sohc's in their trucks for years this way. All these guys with A4LD's got fed up with them for the desert, they go C5 right? well they soon realized that the Sohc would also bolt up to the C5 and run with the OHV computer that is the HOT SETUP aside from the SBF of course

imagine SOHC, simplified to EEC-iv electronics (MAS, DIS) with a reverse manual valve bodied C4(c5 bellhousing) with the ability to go 2wd or 4wd.

The answer is yes, you can remove your OHV, drop in a SOHC and keep the OHV computer

There is SOME wiring, I am not 100% clear on what it is because Brett did this conversion on his own (I only helped a couple of times and drooled over it when it was done)
There is one cam sensor for the overhead cam, this sensor is ignored on his truck.
The wiring to some of the remaining sensors may have to be customized a bit, like running a ground wire to the rear cam sensor, figuring out which wire is which on the crank sensor, etc things like this.
Because the SOHC is basically the same block as the OHV many of the OHV parts will even fit it (so say you had a 93 and your 93 crank sensor has 3 wires, etc new sohc only has two...what do you do? reasearch time if you can bolt on teh OHV sensor, easy choice)

There is one additional sensor on the SOHC over the OHV and the engine will run without it, the computer will still adjust timing, fuel, spark, etc just like if it was an OHV
No more pushrods and additional chains does not = more difficult to control for a computer.

Plug and play, pretty damn close if you get a SOHC from a 99 -2001 I believe (returnless style)

And dont quote me on this stuff, this is from memory its been months (almost a year, getting married! Yeah!) since I dove into this stuff so I am not fresh

 

[Stic-o]

It's just a nice thought that I could just swap a SOHC motor in and gain 50 ponies at anytime My biggest consern was smog and OBD2 throwing codes. Smog wise a 4.0, is a 4.0

With 145k on my OHV though, I think it still has alot of life in it. It runs like it has less then half that. I could always swap it out and and sell it too Colin though:

By the way my crank sensor is a 2 wire already

 

[410Fortune]

I was just pulling numbers out of my A*& I think all crank sensors are two wires...

Colin has a perfectly good 4.0L OHV LOL it only had 200K on it when I pulled it and shipped it to him

that 50 ponies feels like more after 3250 RPM the SOHC is a rev happy SOB, great for a 5 speed

 

[Stic-o]

Yeah I know I use to have a '99 Sport SOHC, remember (wife's old car)

I'm guess sense your just swaping motors and not computers then this would have no effect on PATS.

 

[410Fortune]

pats wont care
the exhaust pipes are a bit different I think, but remember my knowledge is based on a 03 into a 94

 

[spitfiresk822]

I have the ohv in my 98, and I love it.
Just out of curiosity, what's so much better about the sohc?