I hear ya fellas. My next truck will be powered by a 351W. But ya gotta give Ford marketing a nod. All the OHC and Triton bs sold a lot of trucks.

 

i absolutly love my inline and im prayin for drops the 4.2 in favor for a re-generation of the infamous 4.9L i wonder if we petetion will we get noticed?

 

WX,
could you possibly explain why pushrod engines were great at producing low-end torque? i was just curious, thanks.

 

Correct me guys if im wrong. But, Push Rod engine provide better low end torque, because the cam shaft/push rod allowed the valves to stay open for a longer amount of time equaling more gas exchange, because of the delay (Cam to rod to rocker). More gas exchange (breathing) more torque. Because the valves stay open longer at a lower RPM the engine is able to produce high levels of torque due to the mass amount of air entering while the engine is actually reving lower.

Overhead cam engines, because the cam shaft sits directly above the rocker arms, the response is quick and more efficiant. The Cams and lifters actually make direct contact with rocker arms (the devices used to trigger the opening and closing of the valves), so they open for a shorter period of time, yet are more efficiant. However to gain the same amoung of air flow as in the pushrod engine, the engine must rev to greater revolution to keep the valves opening in a quick enough fasion where the airflow is equal to that of the rod engine.

-Again im not sure if I made an error here, or if im a little off base, please correct, but I think this is the reason.

 

Compared to the older trucks my family has had, my 5.4L wipes the floor with them. Power output, peak rpm, torque, economy, everything...

The I6 design is inherently smoother than a v8. They are naturally balanced. Yes they are great for torque, and if sufficienty motivated a manufacturer could produce another. GM's has good HP, but lousy torque (I still haven't figured out how they screwed that up).

It sounds to me, that if many of you had your way we would eventually be back driving a horse and buggy because "that's the way it should be done". The old pushrod engines may have produced more torque, but towing ability is more a function of drivetrain efficiency and gearing. Not engine output, but it helps. Many of the heaviest pulling 18-wheelers don't have the biggest, most powerful engines, they just have what works most efficiently in the configuration they need. Torque, transmission gearing, rear alxle gearing, tire traction all play into towing ability.

 

I think Ford should bring back the flathead inline six from the 1940s. Now there was a rock solid engine. That thing was so good that it actually had more horsepower than the much-raved-about-at-the-time flathead V8. He, He, but I am serious. A flathead six with a modest supercharger to overcome the inherent flow difficulties of a flathead would be much simpler than a pushrod or OHC engine. I think it would work. Just think about that with fuel injection added to it. Hey, this is for a work truck. Let the pretty boys drive their hot rod F150s; I just want a traditional, rough and tumble, bare bones work truck.

INLINE SIX POWER! '95 F150 XL
300 Cubic Inches of Low RPM Truck Torque! And twin-I-beams too!
"Drive a stick young man! There'll be time for automatics when you're old and unable."

 

>Correct me guys if im wrong. But, Push Rod engine provide
>better low end torque, because the cam shaft/push rod
>allowed the valves to stay open for a longer amount of time
>equaling more gas exchange, because of the delay (Cam to rod
>to rocker). More gas exchange (breathing) more torque.
>Because the valves stay open longer at a lower RPM the
>engine is able to produce high levels of torque due to the
>mass amount of air entering while the engine is actually
>reving lower.
>
>Overhead cam engines, because the cam shaft sits directly
>above the rocker arms, the response is quick and more
>efficiant. The Cams and lifters actually make direct
>contact with rocker arms (the devices used to trigger the
>opening and closing of the valves), so they open for a
>shorter period of time, yet are more efficiant. However to
>gain the same amoung of air flow as in the pushrod engine,
>the engine must rev to greater revolution to keep the valves
>opening in a quick enough fasion where the airflow is equal
>to that of the rod engine.
>
>-Again im not sure if I made an error here, or if im a
>little off bassed, please correct, but I think this is the
>reason.

Wrong on all counts. THe only reason the pushrods seem to produce more torque is because 1) they were an undersquare design, so they had longer strokes, which equates to more torque; 2) the pushrod setup actually makes for less overall airflow, because the time it takes for the valve to actually start opening is longer, and the same for closing, therefore not allowing as much airflow through the engine; 3) given the previous two points, more torque is created because the mixture burns more slowly, creating alot of force over a longer period of time. Hence more torque. Horsepower is sustained power over time (delivered torque over time, actually), or the ability to maintain a sustained power output, which means towing a trailer at 65 mph on a grade. Torque gives you pulling power, horsepower allows you to maintain a speed.

Now, overhead valve engines are more efficient overall because as you mention they can open the valves faster and hold them open longer. All things being equal, that equates to more airflow thru the cylinder versus the pushrod setup. And, yes, more airflow affects torque because the engine can already spin up faster becasue of the lower resistance from the intake/exhaust limitations, so it seems low end torque suffers.

Seems.

Truth is, you can tune any engine to produce power at any point on a powerband, overhead cam or overhead valve or flathead. Each has limitations, but I can bet you that I can design a OHC engine to respond exactly the same way as a dinosaur flathead. It's all in the piston design (oversquare vs. undersquare), induction design, and cam profiles and timing.

As for all of you who want the return of the I6, I agree, they're great engines for smoothness and power. However, it would still benefit from modern design, and can still put out the power and torque we all expect. The best I6 I ever owned was in my '79 Toyota Supra, 2.6L, single overhead cam, fuel-injected. This thing put out 140hp and 195 ft-lbs of torque, and would pull all day long from idle in damn near any gear. Hm, gee, OVERHEAD CAM producing lots of torque?? Not bad for #1 a ricer amd #2 a '79.


For the rest of you who want the pushrods to take over the world, I think you may be suffering from "good ol' days" syndrome, and I invite y'all to join the rest of us here in the new millenium.:-X23

 

While we're at it why don't we go back to wooden dentures?? Never mind the splinters...

Flatheads had their own problems, and this is why you never see them anymore, not even in lawnmowers.

Progress is: you can't stop it, may as well embrace it and help it out by giving positive feedback on issues.

Hell, I can't wait 'til they start building continuously-variable transmissions and putting them in trucks--this place will have a hissy-fit over them.


>I think Ford should bring back the flathead inline six from
>the 1940s. Now there was a rock solid engine. That thing
>was so good that it actually had more horsepower than the
>much-raved-about-at-the-time flathead V8. He, He, but I am
>serious. A flathead six with a modest supercharger to
>overcome the inherent flow difficulties of a flathead would
>be much simpler than a pushrod or OHC engine. I think it
>would work. Just think about that with fuel injection added
>to it. Hey, this is for a work truck. Let the pretty boys
>drive their hot rod F150s; I just want a traditional, rough
>and tumble, bare bones work truck.
>
>INLINE SIX POWER! '95 F150 XL
>300 Cubic Inches of Low RPM Truck Torque! And
>twin-I-beams too!
>"Drive a stick young man! There'll be time for
>automatics when you're old and unable."

 

Wasn't the 5.4L a "stroked" 4.6L in the first place? Hence the greater torque output.

 

Bored and stroked, but still and undersquare design, if I remember correctly

>Wasn't the 5.4L a "stroked" 4.6L in the first place? Hence
>the greater torque output.

 

Good response Tex Arcana. You are right any camshaft/head configuration can be designed/tuned to do the same thing. My understanding is that the main advantage of overhead cam is in greater efficiency in high rpm operation since you don't have to run pushrods and rockers at high speed. OHC is not bad and Ford did it right on the new V8s with a chain drive. Wish they would chain drive the four bangers too. The old 70s Ford Courier pickup had a chain drive 4 banger (1800 and 2000 cc, but the 2300 was rubber band). In the 20s there was an overhead cam automobile with a shaft drive, which I think would be way better than the chain. But when they put OHC in an engine, they tend to use its advantage and go to a higher rpm band as evidenced by the new Ford V8s. Thats why I like my 300 I6--it is sort of like a tractor engine.

 

>Hell, I can't wait 'til they start building
>continuously-variable transmissions and putting them in
>trucks--this place will have a hissy-fit over them.

I am trying to figure out why they would bother with a continuously variable transmission in the first place. Why not an electric transmission? Engine powers a generator. Wheel motors power the wheels. No gears needed, just hike the voltage. I think it would be very efficient--no drive shaft, no gears. Works in locomotives.

 

This has already been done on an electric vehicle I saw one in a mag. The writer asked said they had 4 100hp motors, one at each wheel, effectively giving the vehicle 400hp. The problem with this that they are delicate critters, and a truck is exposed to too much moisture and grit for lone term use.

 

[updated:LAST EDITED ON 08-Jan-03 AT 01:23 PM (EST)]Also, would increase unsprung weight (which likely doesn't matter in a diesel locomotive as it runs on rails). Perhaps the motor could bolt to the rear frame with a link to the differential. The motor in back would add some weight. I think it needs to be explored further.

 

I had heard a romor about the 6.0 Liter Power Stroke
in the 2004 F-150 ( I HOPE IT'S TRUE )