4.0 retrofitted with a distributor?

[Rowdy Fitzgerald]

So I picked up an 89 today. They guy had started a 4.0 swap. He took an engine out of a automatic 92 explorer and swapped the engine, harnes and computer over. I don't know if I should pull the 4.0 harness and put the 2.9 harness back in to try getting it to run with the distributor or just go through everything and double check his work to finish it up.

 

[RonD]

So I picked up an 89 today. They guy had started a 4.0 swap. He took an engine out of a automatic 92 explorer and swapped the engine, harnes and computer over. I don't know if I should pull the 4.0 harness and put the 2.9 harness back in to try getting it to run with the distributor or just go through everything and double check his work to finish it up.

???

2.9l use MAP and distributor
4.0l used MAF and EDIS-6(spark module)

Not really interchangeable unless you are swapping the 2.9l back in

 

[PetroleumJunkie412]

And if you dont want that 2.9 harness, I have a home for it.

 

[Snoranger]

And if you dont want that 2.9 harness, I have a home for it.

You still have the number off the dumpster?

 

[Rowdy Fitzgerald]

Ron- I know, I was going to try to install a distributor and see if it was possible to run a 4.0 with the 2.9 ignition system. That's why I initially started this thread. I still have a spare 93 4.0, so I may buy another Ranger later on just to try it.

 

[Rowdy Fitzgerald]

And if you dont want that 2.9 harness, I have a home for it.

We'll see what happens. I haven't looked that over yet, idk what kinda condition it's in.

 

[RonD]

Problem will be in the computer, both spark systems need "vacuum advance" which they get from the computer
Vacuum advance is Engine Load advance, the TFI and EDIS-6 both have RPM advance, but they have no way to tell what the engine Load is, thats what "vacuum advance" was for on the older systems, the computer does have engine Load i.e. throttle position and engine RPMs, and/or MAP and MAF data
So computer sends "vacuum advance"/engine load info to the spark system, and its different for 2.9l and 4.0l spark systems

And not sure if 2.9l distributor even works in the 4.0l

If it does then you could run the 2.9l computer and systems, I think 4.0l had larger injectors than 2.9l, but worse case is you would get a full time lean code until you got larger injectors


But not sure why you would even want to do that, the pre-1995 4.0l spark system was way more reliable than the TFI setup

 

[PetroleumJunkie412]

We'll see what happens. I haven't looked that over yet, idk what kinda condition it's in.

Good chunks are fine tbh. I rewire crap all the time to retrofit, pigtails and pins are useful, also ecm plugs and the stupid silicone gasket.

 

[PetroleumJunkie412]

Problem will be in the computer, both spark systems need "vacuum advance" which they get from the computer
Vacuum advance is Engine Load advance, the TFI and EDIS-6 both have RPM advance, but they have no way to tell what the engine Load is, thats what "vacuum advance" was for on the older systems, the computer does have engine Load i.e. throttle position and engine RPMs, and/or MAP and MAF data
So computer sends "vacuum advance"/engine load info to the spark system, and its different for 2.9l and 4.0l spark systems

And this is why speed density is better than maf.

Fight me.


An experiment i meant to try was converting a 2.9 to a 4.0 spark and maf setup for the adaptability. I was planning on making my modifications to try and hit the sweet spot on the 4.0 ecm. Never got around to it.

And not sure if 2.9l distributor even works in the 4.0l

So, euro boys say no, but I've never tried it. There's a deck height discrepancy in the ford performance information pdf. The 2.9s block height is incorrect, 4.0 block is taller, 2.9 shares deck height with 2.8. Been meaning to try it, but time sucks.

But not sure why you would even want to do that, the pre-1995 4.0l spark system was way more reliable than the TFI setup

If you want your TFI system to last, remote mount it. They never perform well after getting too warm. There's a noticeable performance change and they never quite come back.

EDIS wasted spark is one of the best ignition systems out there, beats the pants out of tfi.

 

[Rowdy Fitzgerald]

I wanted to try it just for the hell of it, really. Seeing as how the 4.0 is what, 50hp more? I figured it would be a easy way to boost power and not spend much money or need much experience with wiring.

 

[TigerDan]

Yes.

I'm surprised by ADSM's comment that a 2.9 distributor physically fits correctly on a 4.0. Isn't the deck height different?

The difference in height is in the lower end.... longer stroke ? About 3/4" ?

 

[TigerDan]

The 2.9 gear is backwards from the 2.8 gear.

So in that case perhaps a 2.8 distributor would work?

Either way....

Does the 4.0 even have a hole for a distributor?

I believe the 2.8's are different from the 2.9 & 4.0's I have some of the 2.8 distributors and a 2.9 as well as what is in the 4.0 will compare them....

 

[fastpakr]

The difference in height is in the lower end.... longer stroke ? About 3/4" ?

Yes, the stroke is longer, but the deck height is greater as well.
However, the difference appears to be taken up by keeping the cam at the same height relative to the deck and separating it further from the crank.

 

[PetroleumJunkie412]

Yes, the stroke is longer, but the deck height is greater as well.
However, the difference appears to be taken up by keeping the cam at the same height relative to the deck and separating it further from the crank.

Deck height on 4.0 is 0.800" greater than 2.8/2.9.

Pruett book, forget page number. Available in the tech section.

 

[DPDISXR4Ti]

Originally we were taking about getting the 2.9l computer, distributor and wiring to work on a 4.0l engine, which seems doable

Yikes, 10 pages and this ^^^ question still isn't answered. Sorry, I also don't have the definitive answer, just the question. In the Merkur world we have a more valid reason for doing this as our 2.9 has different stuff (intake, accessories, etc) from the Ranger, so just dropping in a Ranger 4.0 isn't as easy. A couple of us are contemplating a 4L swap though, but really just want to swap the long-block and leave most everything else alone. The one thing that's probably required is a "hybrid" intake manifold made using the lower portion of the 4L manifold welded to a Scorpio upper that's had it's runners cut off.

So yes, it would be nice to know if there is a way to run the 2.9 distributor in the 4.0. It sounds like perhaps it's just a matter of getting the height right?

On a side note, I've run 16.7 pph EV6 fuel injectors as found on the 2002-2004 4.6 Explorer with no other changes. The engine ran great, but was a bit rich and wouldn't go into closed-loop so I went back to 14's, just newer EV6 ones from a circa 2004 3L Ranger. So perhaps with a 4L and the 2.9 engine management, things might work well.