will a 4.0 crank fit the 2.9 block

HYPED_87 · Dec 11, 2008

im not sure but i was doing some research on the site and the stroke is not that different would that mean i have to get shorter connecting rods or wut??? If it was to fit would that be stroking it??? Can anybody give me some info on some of this stuff that would be appreciated.Ive already done a lot to my 2.9l [ported and polished heads,upper,lower intake,4.6 interceptor throttle body,headers,hotter plugs,msd coil,accel control moudule,electric fan,removed egr system,no cats,custom collector into dual 2.5 pipes with quite mufflers until romped on] i could go on but i would like to build a dumb v6 or am i just wasting time should i stuff the 351cleveland in that bitch...???
Thanks guys i appreciate it glad to help anyway i can...

Psychopete · Dec 11, 2008

The simple thing would be just to swap in a 4.0L if you want a stroked 2.9L.

A windsor small block would probably be the most practical cost wise, but a 351 cleveland swap is certainly possible. Aftermarket is a little more expensive for 351C.

Custom forged pistons were going to cost $700 alone for my S/Ced 2.9L, so I scrapped the project, did some trading around, and obtained a '87 5.0L engine. The only thing that's stock in it at this point is the crank, rods, and the block. All the rest is aftermarket and later model parts.

I do have a few suggestions, but take them with a grain of salt -

Removing the EGR can ultimately cause rich conditions, you might consider swapping to a later model computer from a non-EGR truck (88+). With aftermarket stuff, you might as well go with a 1990 MAF computer from a California Emissions Ranger (see MAF conversion in tech library). That is non-EGR as well, but adapts much better to changes.

Removing the cats only changed the sound, not much of a gain (if any), and it's not legal.

You've done all of that porting, but nothing is done internally to increase the demand for air.

A cam made a big improvement in the upper RPM bands in my experience.

I believe that you will need to modify the 2.9L block for the 4.0L counter weights on the crank shaft. This has been done apparently by Sven Pruett, which he indicated that the engine wasn't happy. I'd guess that you'd need custom made rods (probably another 600), but who knows if you couldn't find something that would work.

The only practical way (cost/feasibility/everything considered) of getting good power out of this motor is with forced induction or nitrous oxide.

I am a big fan of building engines like this, but N/A - $ vs hp = not good. You end up building something to make stock V8 power, when you could have just swapped in a V8, and have an engine in stock form to build up on. Depends on how you look at it...

Pete

HYPED_87 · Dec 11, 2008

so is there anything i can do internally to increase the airflow and i have been wanting to get a cam but its 350 and im stuck between saving my money and doing the 5.0 swap or wut about a supercharged 3.8 out of a supercoupe...thanks

MAKG · Dec 11, 2008

If $350 is out of your budget, no, there is nothing you can do. That will barely buy a major valve job.

Though a running junkyard 4.0L is a possibility.

Psychopete · Dec 11, 2008

HYPED_87 said:
so is there anything i can do internally to increase the airflow and i have been wanting to get a cam but its 350 and im stuck between saving my money and doing the 5.0 swap or wut about a supercharged 3.8 out of a supercoupe...thanks

3.8L wouldn't be much different than a 5.0L swap.. Only difference is that 5.0L swap has been done several times, where as the 3.8L has not. Again, V6 with a S/C making 5.0L HO V8 numbers. A V8 with a S/C would be so much more. I really haven't heard many good things about the 3.8L blowers either. That is going to be a "uniqueness" thing.

Increasing the duration will keep the valves open longer, but at the cost of losing low end. Depending on the timing of everything, the result could allow the piston to pull in more air. This engine is going to like higher RPMs, your heads are going to be the weak link here - particularly the valve springs.

There is a lot to a performance camshaft, I would HIGHLY recommend you speak with a professional cam grinder for some ideas on what cam would work best with your setup and what you want to use it for. Than he can tell you what's required spring wise. If you're in there, I would recommend doing the free floating rocker conversion. Roller tip rocker arms are REALLY expensive for the 2.9L. This is why I gave up on it, the aftermarket is slim and expensive.

Most cams you will find in a "catalog" are not very radical due to the computer that's typically found in Rangers. Basically "RV" style cams, which may not even be what you want. Typical Rangers use a MAP sensor, which is based off of vacuum. The MAS on a mass air setup "detects" the amount of air flowing actually coming in. Swapping in that MAF computer is really the only way to get over the camshaft limitation.

Pete

Edit:
+1, to the $350 budget. I wish it were all that cheap.

AllanD · Dec 12, 2008

The first thing to mention is that a 4.0 block is WIDER because the crank counterweights would hit the 2.9's pan rail... that's an Oops you can't get around.

The wiring to retrofit a 4.0 isn't really all that bad.

Good 4.0's are nearly as common as dirt... with as many explorers
sitting in junkyards with dead A4LD's....

when you add in that a 4.0 WILL bolt up to your exsisting trans, bolt to your
exsisting motor mounts and to your Exsisting Y-pipe....

Basically the 4.0 was very specifically designed to fit where the 2.9 had been...
In a Ranger engine bay.

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will a 4.0 crank fit the 2.9 block

HYPED_87

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Psychopete

Well-Known Member

HYPED_87

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MAKG

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Psychopete

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AllanD

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