1996 explorer 4.0 ohv

[TexomaExplorer]

I have a 1996 ford explorer 4.0 ohv that has low compression and 270k miles.
I just bought a complete 1994 explorer 4.0 ohv with 110k that has been rebuilt.
Will the 94 drop in and plug and play or can someone lead me in the direction of what I need to do.
Thank you

 

[rasouth]

I believe the engine itself should fit with few, if any, problems. I think they are the same engine block. I think the differences in wiring, maybe exhaust, some sensors may not match up.

 

[974X4BLACKSPORT]

In the evolution of the 4.0L, FORD made production changes from year to year to improve NVH, and efficiency.
What I recommend to you so that you get the best performance and reliability from your car is that when changing
the engine with a different one, is to make sure the replacement engine is of the same, or close as possible to the
year and date production of the engine that you are replacing, this is because of production changes in combustion
chamber, piston dish, compression ratio, among others, require a specific computer calibration. When you install an
engine produced in 94', into a chassis with a PCM production year of 96', chances are the computer calibration is going
to be different, mostly being fuel trims, spark timing, and emission controls. Now, your 94' engine when all hooked up
in your 96'and running, may seem fine and normal, but it wont be, this is because the 96' chassis and PCM still think is it running
with the 96' engine with "fast burn" combustion chamber, now only has the older style chamber and piston dish design that will not only effect emission controls, but fuel mileage, power, and detonation resistance.
Here is some good reading on the 4.0 L:

Ford 4.0L V6 Engine

Exploring the Ford 4.0L Engine: Evolution, Components, and Rebuilding Tips for Rangers, Explorers, and Aerostars. Learn more here!

www.enginebuildermag.com

 

[TexomaExplorer]

Will the heads and intake fit on the 94 block? Because with my 96, I had just bought brand new heads. They are 98tms

 

[974X4BLACKSPORT]

Will the heads and intake fit on the 94 block? Because with my 96, I had just bought brand new heads. They are 98tms

The new heads will physically bolt on and work on the 94' block, however, the "dish" in the pistons in the 94' block is a different size than in the 96' block, this will change the compression ration out of the range of what the factory intended, and consequently what the PCM is programmed for, "CALIBRATION".
I think the 94' piston dish is smaller, combined with the "FASTBURN" combustion chamber design in the 96' and up year heads, you could end up with "spark knock" that the 96' PCM may not be able to compensate for. It is very important for the "dish" in the piston to match the combustion chamber design the factory had intended.
My response here is in "theory", I have no experience mixing and matching 4.0L FORD blocks and heads, however I do have decades experience building engines, be it stock, and performance modified, for carbed and fuel injected, various makes and models, mosly v8's, but the theory is the same.
For stock engines you must match production year and date OEM, or aftermarket style parts If your mixing and matching, that is called "modifying", and then that is a whole nuther book!