The Truth about the 4.0

[krugford]

Hmmm, I just glanced at this nice image posted by Will about a year ago.

When the OHV is making more torque than the SOHC, it doesn't appear to be any more than 10 ft-lbf at any given point. It appears that anywhere from about 1700 rpm on up the SOHC is making more torque than the OHV. Regardless of where it's making peak torque, it's still making more.

SOHC FTW!

Of course, I gradumatated from a 2.9L to a 4.0L SOHC, so I have no way to draw a good comparison between the OHC and SOHC versions of the 4.0L. I do know that my SOHC pulls everything that I want it too just fine and I get about 20-21mpg consistently on my daily commute (95% highway).

 

[Ranger44]

The gearing doesn't matter too much with a Manual tranny.

A OHV 4.0 is better off geared 3.73's stock. It'd make a dramatic difference....

I should know. I've driven a 3.55 geared 2.3 2wd and went back to my 4.10 geared 2.3 4wd.......night and day......as we all know the 2.3 isn't the most powerful engine.

 

[Evan]

The most important place you need torque when offroading is below 2000 RPM.

So I really see no big advantage to the SOHC when it comes to offroading.

With crappy gears in the axles (like 3.27s), a truck is slower. You can hold each gear longer, but you're still stuck with horrible gearing off the line in 1st gear, which makes the vehicle feel like a pig.

 

[427ford]

Our '94 had several problems when new. The biggie was when I pulled the dipstick and saw 'milkshake'. The service mgr at the dealership explained that they (Ford) had a bad run of head castings and some were cracking. It was common enough that the dealer had a set of heads on the shelf and had the truck done the day after we dropped it off.

Fast forward 280,000 miles. The 4.0 has never given us a problem since. I'd not hesitate to get a 4.0 again. IMHO, one of Fords better late model motors.

 

[rickcdewitt]

You have a problem with your OHV.

yeah and he's comparing apples to oranges..... or even to watermelons.
a ranger with a SOHC and i'm guessing gears that are lower than 3.27 is no comparison to a big heavy turd with the worst gearing possible.
that said,i think it would be nice to have a 4.0 that acted like my old 2.9l and reved to 6 in a hurry instead of going flat.

but i really have no complaints with my OHV and like driving the torquey low rev engines-the best truck engines have always been the stump pullers,not the ones that come in cars with aluminum wings

 

[85_Ranger4x4]

My parents have a 1994 Ex with a 4.0 OHV and a 2002 Ex with a 4.0 SOHC. The only thing the '94 does more of is drink gas.

The last highway trip the 2002 got 22mpg, after 12 years of ownership the '94 has NEVER hit 20mpg.

The 2002 Ex has 3.73's, and the 1994 has 3.27's, but the 2002 has ALOT more beef to move around as well.

More power and better milage is a hard combination to beat, aside from coming in vehicles that are better suited to offroad from the factory (TTB trucks) the 4.0 OHV quickly runs out of advandages IMO.

For crying out loud my F-150 with 3.31 gears gets better milage (18mpg) and actually has power to pass as well, with at least 1k more pounds of iron to lug around as well.

 

[rickcdewitt]

The 2002 Ex has 3.73's, and the 1994 has 3.27's, .

bingo ,apples for oranges again.3.27's are wrong,just wrong in an ex.

the three valve 4.6 is a very good motor i've seen a few that played with 20 mpg's on flat ground

 

[85_Ranger4x4]

bingo ,apples for oranges again.3.27's are wrong,just wrong in an ex.

the three valve 4.6 is a very good motor i've seen a few that played with 20 mpg's on flat ground

2002 is also the much larger and heavier bodystyle, which should take away from its milage.

Reguardless, they both seem to downshift about the same on hills with the cruise on, but the '94 still gets its butt kicked.

 

[exbass94]

I forgot to mention that I've also driven my uncle's 1999 Ranger with the OHV, and it has all the same specs my truck has (auto, 4.10s, ext cab, 4x4) and my truck has WAY more power than his. And there's nothing wrong with his OHV. (or mine for that matter) I don't hate the OHV, in fact it's the most reliable engine I've ever had, it's just that the SOHC is faster, has more power, and IMO, just an overall better engine. And that's all it is. An opinion.

 

[Hahnsb2]

Something else to compare. I haven't driven a 4.0L OHV off road yet but I can compare the SOHC to a 2.9L . Quite honestly, I prefer my 2.9 offroad to my SOHC. The one time I took my 08 down a old forestry road, a steep one, it was in 4LO. The SOHC didn't feel like it could hold the truck back, as in it felt like it had almost nothing for compression braking.

Now my wore out 2.9 is a different beast in 4LO. I can take it down a steep grade and just tap the brakes to keep the speed under control.

Both trucks have same gearing and similar sized tires.

The SOHC kills the 2.9 on the road, of course.

Just food for thought.

May be something to do with the tranny if your 08 is an auto my buddys 98 sploder auto has no compression braking even in 4 lo 1st gear.. I've noticed this 4.0 in my rig shuts the injectors off instantly when I let off the throttle, better compression braking than the 2.9, 2.9 would take 10-15 second before it would kill the injectors.

 

[86_cookiemonster]

For driving I like both the engines, the OHV and the SOHC. I will admit that the SOHC has more power.
But, the SOHC does have a major problem that brings it way down in my book. SOHC motors have "normaly" bigger heads, than just the ohv motor. Which translates into less space for you to work in the engine bay. Now most people won't have a problem, but if you are a "Johny Thumbs" like I am, then you will miss that extra space. But other than that you can't go wrong with either motor.

 

[turbo cat]

as far as talking about the ohv theres few motors that wernt built for boost that can take 20+psi of boost and hold together thats my 02

 

[atlgadawg]

Good info

Sounds like everyone likes a 4.0 of one type or another. The trucks I am looking at are newer than 2000 so I guess it will be a SOHC. It's between a 2002 4X4 and a 2004 2WD.
Thanks for all the good info.

 

[Evan]

Sounds like everyone likes a 4.0 of one type or another. The trucks I am looking at are newer than 2000 so I guess it will be a SOHC. It's between a 2002 4X4 and a 2004 2WD.
Thanks for all the good info.

If maintained properly, they're both great engines. For offroading, I'd want an OHV. For DD an SOHC.

 

[Yellowsplash]

That dyno graph is comparing a 98 motor which has smaller head ports than the earlier heads. Im not sure how much this would affect the numbers.

I personally own 2 OHVs and an SOHC. The OHVs feel like they have a better torque curve down low. The SOHC loves to rev way more than the OHV and produces a nice power curve all the way up long after the OHV cant breathe. I agree with evan as the OHV is great for offroading and the SOHC is great for DD, especially interstate travel. The newer trucks seem to come with lower gears, 4.10s in the sporttrac, compared to 3.73s in the ranger and explorer. This does have an affect on the butt dyno. Now if we want to talk about the 4.6 in the explorer....well there is where the power is at. It also likes to rev too