what are better? 4.0 or 2.9

[mornin151]

ok how long does a 4.0 run for? do the 4.0s heads crack or the 2.9's. thanks

 

[Ozwynn]

a few of the early 4.0L had head cracking problems. my 91 had a lot of miles on it with no problems.

4.0L is infinitely more reliable than a 2.9

 

[CJREX]

Not only more reliable, more power with same or better gas mileage if you're running big tires.

My 2.9 struggled with my 33s. The 4.0 turns them with no probs and gets the same mileage (if I don't hotdog it constantly).

 

[rusty ol ranger]

Some 2.9's run a ridculous amount of time.

Some dont make it to 100,000.

Overall though the 2.9 is a strong running little engine you can beat the living shit out day in and day out and as long as you keep it cool it'll run forever.

Im not a big 4.0 fan.

later,
Dustin

 

[Beanmachine7000]

Some 2.9's run a ridculous amount of time.

Some dont make it to 100,000.

Overall though the 2.9 is a strong running little engine you can beat the living shit out day in and day out and as long as you keep it cool it'll run forever.

Im not a big 4.0 fan.

later,
Dustin

The 2.9 does great for what it is... It makes more horsepower per C.I. than a H.O. 5.0... They will run forever as long as you keep them cool...

BUT, the 4.0l is a much more reliable engine overall, and makes more power... The 4.0 strong point is that it makes it's most torque (~220lb/ft) at 2400rpm...

 

[2manyfords]

No brainer.... 4.0L all the way.

I own both and the 4.0L kicks the you know what out of the 2.9L any day of the week.

 

[AllanD]

The 2.9 makes it's 170ft/lb of torque by 2600rpm.

The 4.0 OTOH is making 170ftlb of torque by 1350rpm, 200ft/lb before it hits 2000rpm
and is still making 200ft/lb when it hits it's rev limiter at 4650rpm.

The 4.0 does more before it hits 1700rpm than the 2.9 CAN do.

it's just "effortless" compared to a 2.9 doing the same job.

Ovewr the years I've owned three different 2.9 powered vehicles,
two Bronco2's and my Ranger, ALL of those engines wound up in
my Ranger's engine bay at one time or another and another three
or four engines besides.

I've already owned (past tense) my last 2.9.

I was planning to switch to a 4.0 nearly ten years ago, but various factors
kept me from actually doing it until the spring of '07.

I regret waiting so long.

AD

 

[kunar]

the 4.0 is a beefed up, revised and improved version of the 2.9, does that say anything?

 

[snake]

The 2.9 makes it's 170ft/lb of torque by 2600rpm.

The 4.0 OTOH is making 170ftlb of torque by 1350rpm, 200ft/lb before it hits 2000rpm
and is still making 200ft/lb when it hits it's rev limiter at 4650rpm.

The 4.0 does more before it hits 1700rpm than the 2.9 CAN do.

it's just "effortless" compared to a 2.9 doing the same job.

Ovewr the years I've owned three different 2.9 powered vehicles,
two Bronco2's and my Ranger, ALL of those engines wound up in
my Ranger's engine bay at one time or another and another three
or four engines besides.

I've already owned (past tense) my last 2.9.

I was planning to switch to a 4.0 nearly ten years ago, but various factors
kept me from actually doing it until the spring of '07.

I regret waiting so long.

AD

Those rev limter specs were for the OHV? My auto tranny shifts at 5800 on the SOHC version 4.0. Still pulling strong up there too.

 

[4x4junkie]

Not only more reliable, more power with same or better gas mileage if you're running big tires.

My 2.9 struggled with my 33s. The 4.0 turns them with no probs and gets the same mileage (if I don't hotdog it constantly).

Not sure I can fully agree...
My 2.9L turning 35x12.50s gets 22, sometimes 23 MPG (BII).
My 4.0L turning 33x12.50s gets 21-22 MPG (Ranger) (HWY mileage).
I s'pose gearing & aerodynamics could be influencing things though.


The 2.9's major fault is the heads (easily cracks if overheated). Keep the cooling system in good order and both engines should be extremely reliable.

I do agree that the 4.0L has much more effortless power however. Given a choice, there's very little reason to pick a 2.9L over a 4.0L.

 

[Sunk]

Just one more vote for the 4.0 over the 2.9. A friend of mine had a 4.0 with 33s and 3.73s and it turned those easier than my old truck with a 2.9, 4.56s and 33s. Now my Explorer with 4.56s, a 4.0 and 33s is great.

 

[CJREX]

Not sure I can fully agree...
My 2.9L turning 35x12.50s gets 22, sometimes 23 MPG (BII).
My 4.0L turning 33x12.50s gets 21-22 MPG (Ranger) (HWY mileage).
I s'pose gearing & aerodynamics could be influencing things though.

My truck still has the 3.73s. I know I need to go 4.56 or 4.88 and maybe someday I'll get around to it. I'm sure it would help my gas mileage because I get nowhere near your numbers.

But for now, the 4.0 moves the truck so well that it's not that big of a concern. And for gas mileage, I have the CMX (Chick Magnet Xtreme, a Saturn SW2 )

The 2.9 had to stay on the boil to move it with 3.73s and 33x12.50s.

The 4.0 seems to be able to do it barely above idle.

 

[93GEN.III]

my 93 4.0 is awesome as of the drive home from work 347,438 miles and still going strong. with the install of a clutch at 236,400 miles

 

[mornin151]

thanks for all the help... so what about the newer 4.0 with the SOHC? its a 97 or a 98... with 110K ish... i have all the wireing but the ECU... its goin in a 84 ranger and its replacing a 2.8 carb... i have the A4LD? trans (motor and all that are from a 85) i also am lookin in to puttin some bigger tires on some time soon with a little lift.. nottin too huge...

thanks for all the help... im lost in what motors are good and bad right now... i picked up this 4.0 i got because i was reading they were alot better motors and i never hear about a head cracking... where i did on a 2.9... then i got it and i hear they have the same problems kinda and that the didnt last much over 140K... so i was honestly kinda worried that i got Fed over in the deal...
any advice on what i should all do when i do the swap to put it in the 84 chassis? thanks i plan on running the trans and Tcase for a little bit... till summer when im not soo busy....
how much should a ECU cost me? thanks its got this on the ECU plug in

F5SB-14A464-A
289 8A15BO b

just like that... any one able to tell anything off that?

thanks

 

[mornin151]

what year motor do you think this is?

this is the only thing that got cut anyone know what it is for?