4.0 retrofitted with a distributor?

[Rowdy Fitzgerald]

I've never had the 2 side by side so I havent and can't compare them. But if they're the same block, just put larger injectors and and plug everything incorrectly then it should run...

 

[RonD]

Worth a try

Yes, 2.9l TFI setup would work on the 4.0l, same distributor setup and oil pump drive, from what I am seeing
As said 2.8l distributor wouldn't work, that comes up on duraspark conversions for 2.9l

2.9l and 4.0l used same firing order

Yes, use larger injectors to "trick" the 2.9l computer into thinking its still running the smaller engine and feeding it the same amount of fuel as before
i.e. at say 2,500rpm the computer was opening 2.9l injectors for 100milliseconds to get 1gram of fuel, to get good O2 sensor feed back
Larger injector would flow 1.2gram instead, as an example, computers none the wiser
This prevents computer setting constant Lean code

Not sure what the stock size was for the 2.9l and 4.0l, if 4.0l was larger then might work as is

2.9l used a MAP sensor system, and intake vacuum is universal on gasoline engine, so no issue with size there


Not sure on exhaust size?
You would have to check diameters

Same for radiators?

 

[fastpakr]

Ron - why isn't the deck height an issue with the 2.9 distributor? Not following that.

 

[85_Ranger4x4]

Radiators should be non-issue, I think both 2.9 and 4.0 Rangers used the same ones.

If desired a two row from a 4dr/automatic/A/C exploder drops in.

And that is all I know on this subject...

 

[Rowdy Fitzgerald]

Well the radiator is bigger for the 4.0 than the 2.9, but they bolt right in place of the 2.9 radiator.

 

[Rowdy Fitzgerald]

Ron - why isn't the deck height an issue with the 2.9 distributor? Not following that.

This would be the biggest factor I believe. If it fits, then there shouldn't be any issue with everything else.

 

[RonD]

Ron - why isn't the deck height an issue with the 2.9 distributor? Not following that.

Picture of 2.9l distributor base and 4.0l oil pump drive side by side: https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSs313VlLW1kgQVTds4OmaP_bWAjVxUYF0s_O2juwJFSADcP_Qx

Never tried myself but looks real close

 

[fastpakr]

Interesting. So the cam's position relative to the deck stays the same. Sounds good to me.

 

[Rowdy Fitzgerald]

Does anyone have a 2.9 dizzy and a 4.0 block with both upper and lower intakes that's willing to see if it fits all bolted up?
I don't have either anymore...

 

[Dirtman]

I think I've mentioned this but even if it does fit and hook right up... the 2.9's ecu will still not run a 4.0. The computer can't just randomly compensate for an extra 1.1 liters of displacement. And if you try to run a carb my god... it'll cost more than just getting a 4.0 wiring harness and ignition.

 

[85_Ranger4x4]

I think I've mentioned this but even if it does fit and hook right up... the 2.9's ecu will still not run a 4.0. The computer can't just randomly compensate for an extra 1.1 liters of displacement. And if you try to run a carb my god... it'll cost more than just getting a 4.0 wiring harness and ignition.

People have run 5.0's on 2.9 computers.

 

[Dirtman]

I'm sure that was cheap?

 

[rusty ol ranger]

I'm sure that was cheap?

I would think that the MAP sensor would basically just call for more fuel....As would the O2s....

So as long as that 2.9 computer has the means (as in, proper sized injectors) the ECM can keep them open long enough to feed the extra cubes....

Are you sure though guys have ran a 5.0 on a 2.9 ECM? How does the ECM deal with 2 more cylinders?

 

[adsm08]

I'm sure that was cheap?

A batch fire, speed/dentisy EEC-IV computer can be very forgiving.

A 2.9's cylinder is .48333L

A 5.0's cylinder is .625L

That really isn't too much of a difference, and a batch fire computer doesn't really need to know the number of cylinders, just the amount of air coming in. Engine rotation is calculated in degrees, not distance, so it still takes the same 360 degrees of crank rotation for cylinder one to come around from TDC to TDC whether you have 1 cylinder or 12. All the rest is just putting in the right amount of fuel for the air.

 

[85_Ranger4x4]

I'm sure that was cheap?

That was why they did it...