v6 vs inline 6
 

Can someone give me a comparison of the old 6 vs the new 6? Like dependability / MPGs / performance / towing - etc?

hmmmm.....

at 300cid/4.9 liters i really don't think there is a comparison. But ford changed it for a reason....probably efficiency.

Welcome to the 4.2 forum!

I have driven several 300 I6 trucks but never owned one.
From all I have read, heard, etc. the main problem with the I6 was fuel efficiency and emissions.
That may or may not be true, but that's what I've heard.

Given the choice, I'd take the 4.2.
But, others would prefer the 300.

On average, the F150 with 3.55 rear end and 4.2 is rated to tow:
about 3,300 lbs with manual transmission.
about 5,000 lbs with auto transmission.

There are a few threads here about mpg. You can read them and get a feel for that subject. I don't know what mpg a 300 I6 got.

Thanks.

I have seen and driven a couple of 4.9 liter F150/E150 and E/F-250 with over 200k on them. Many 4.9s are working pulling/ hauling much more than their rated GCWR or GVWR daily.

Tons of low end torque with the 4.9 no reason push much past 4500 RPM I think HP is arouns 150hp with these engines stock. Lots of reliablity in the 1987-1996 fuel injected engines. I think Ford dropped this engine for emmisions and economics.

The 4.2 v-6 makes more HP but way up in the rev band. The V-6 is torquey but it is much higher in the rev band as well. The 4.2 seems to breath much better at higher RPM (anything above 3000 RPM). Seems to be a reliable engine except for the intake gasket issue (97 and early 98's and trucks with over 150k?) Some of the 4.2's have well over 200k with no problems. This engine works well in cars and light duty F-150's not used for heavy (over class III) towing.

The 4.9 is harder on fuel than a 4.2 My family owned a 4.9L in an F-150 for 12 years. It was a very reliable motor, in fact the guy I sold it to says it is still running strong today. the 4.9 is capable of 300,000 to 400,000 miles. I now have a 4.2 and the fuel economy is much better. It doesnt have the low end stump pulling torque of a 4.9 but it is still a good motor and I havent had any complaints about it.

Overall it depends what you are trying to do with your truck. For some heavy towing I would want a 4.9 but for a commuter vehicle I would want a 4.2

I did some hunting for hp and torque numbers to compare. I never could find original factory torque ratings but did find some hp numbers.

The 1978 F100 with carbuerated 300 ci inline 6 was rated at (a whopping) 114 hp.

1987 saw the introduction of fuel injection to the 300 and a jump to 150 hp.

I am quite sure these engines were designed and built with cam grinds, valves, etc. to make their power low in the rpm range. I would guess that is why they are so popular with truck owners. They (presumably) do not make tons of torque, but what they make is really low in the rpm range.

Not knowing the torque numbers, I can only guess that they would not be as high as the 4.2 is rated.

for comparison, here are the numbers for the 2000 F150 4.2 V6
Horsepower/rpm 205 @ 4950
Torque/rpm 255 @ 3700

Given all the info I could find, I'd still choose the 4.2.

the 300 was also installed in 15 ton dump trucks something a 4.2 could never come close too.

I've wondered about that, and actually, I'd think the 4.2 could be installed in a dump truck.
IF the engine was retuned to work in that environment. There have been various V6 engines used in heavy applications, and I'd guess the 4.2 could function there, but ONLY if it were properly prepared.
I'd guess those dump trucks, while they could haul a lot of dirt, couldn't cruise down the interstate at 75-80 mph and get 18 mpg while doing it.

But, there are certain traits of the 300 that make it well suited for application in a true truck environment.
In the long run, it is probably the better truck motor if you are interested in a 6 cylinder engine providing good pulling power at lower rpms.

But, my truck might be pulling a boat, or hauling my motorcycles, or running 300-400 miles, empty, at 75 mph.
I don't really need low rpm pulling power so maybe that is why I am happy with the 4.2.

As a side note, I think many folks just simply discount the 4.2 as being a viable truck engine. Makes no real difference to me.
Without a doubt, the 300 earned its reputation as a great truck motor.
The 4.2 is cut from a different piece of cloth, but it sure has served me well.

I guess it's all about what you need and want from your truck.

(If I needed more power, I'd buy a 5.4) :-X22

the 4.2 doesn't have the Bottom End built heavy enough for heavy truck use.

On the 300 I6 take away the smog and put a better exhaust on it is good for 170-180hp. They were rated for 170 before 74' when the smog crap came around.

my dad has a 4.2 and it is a good engine for what he does. Mostly commuting and a little hauling. For me when i work on the farm in the fall for my buddy after school i need the torque of the 4.9 or a diesel to haul tobacco slabs on a g/n.

DT

the 4.2 has a bottom end about as durable as a potato chip. i'd really like to see one installed in a 15 ton dump truck.

I don't think it would last 10K in one. Not that it is a bad motor just wasn't designed with Industrial Use in mind.

I do think i would want to ride in a 4.2 dump truck it would be more like a Holy Crap thing wanting to see how it actually performed.

Have to have alot of gears. The rod's bottom end and main bearings would get cooked from the heat from working it so hard and they are just small bearings. And only 4 main's

Any way's they need to make a new big 6. After all trucks mostly had I6's till the 60's.

A v8 is cool for racing i have a 351W going in my ranger. But for a truck for work i'd take a 6 over an 8. Most people don't know that 8's came around mainly for cars and then adopted to trucks while all the big trucks had I6 gassers to start with.

DT

I can say the 4.2 is a tough motor. I use one in my NRCS work truck, a 99 F150, 205 horse. The radiator has been plugged with corn stalks, crop residue, etc. and overheated the motor to the point where it boiled over. Not realizing it was that bad, I drove it back to the office, where I refilled the radiator, and all was fine. I did this not once, but several times. There was very little coolant left in the motor.

I couldn't find any obvious clogs despite looking, which is the reason I did it three or four times. Finally sent it back to the dealer, where they took off the skirt, finding all kinds of crud up there.

It's an adequate motor for the F150, and it will scoot if you bury your gas pedal all the way to the floor, but as a truck engine, it's not as good as the 300 c.i. inline six it replaced. My reasoning:

1) Mileage has consistently averaged between 12.8 and 14, and that's nearly all (90-95%) open road driving. My 300's beat that. Best the 4.2 ever did was 15 mpg, at 55 mph. 75 mph really sucks fuel.
2) It doesn't have very good low speed torque, and must downshift to do EVERYTHING. This despite fairly low gearing in my diff. Low speed torque is sacrificed so the V6 engine can generate impressive horsepower numbers, which actually make it less suitable for a truck. It must rev twice as high to put out comparable torque to the inline six. (EFI 300-265 lb/ft @ 2000 rpm, 4.2 V6 250-255 lb/ft at 3800 rpm). Despite a considerable breathng handicap, the inline made more torque, especially in the practical sense. A 3800 rpm torque peak is unavailable, or undesirable, in a towing motor, especially one of modest displacement. At clutch engagement engine speeds of around 1000 rpm, it's no contest. The 300 puts out way more than the 4.2, which is why it's considered a stump puller.
3) The inline's flat torque curve vs. the V6's much more peaked curve. At towing speeds, you're right in the 300's powerband, with full peak torque available. With the V6 you're 1500-1800 rpm below peak torque, on a sharply sloped curve. Result? When you hit hills pulling a load, the V6 downshifts sooner, and revs like mad. Doing this occasionally is not a big deal, but gets really annoying after your fifth hill. Revving engines build up a lot of heat, too, not good. High revs, frequently=bad things when towing.

For a full time puller, gimme the 300 every time. Both motors are better with stick shifts, but both models were stuck with light trannies, the 300 at the end of its production, and the 4.2 as currently produced. That's why my harder working 300 (of the two I own) has a T18. Both the 300 inline and 4.2 V6 COULD be rated to tow approximately the same load, but the bigger displacement, lower revviing inline is a lot more satisfactory, and will last longer while doing so.

Its weakness was that it was so gagged for breathing during its production that it was around 25-50 hp and 50-90 lb ft below its potential. This could be obtained with a better exhaust and intake, which could have easily been done. No fancy mods or high revs needed, and it would still retain the low speed torque (this would increase too). Still, it's hard to sell a lower hp engine these days, which is why a 205 hp V6 seems to be more attractive as a motor (230+hp soon!), and seems to represent progress, as hp is all most people know about.

Where the engine makes its power is more important.

If'n you wanna race though, the I6 will not keep up with the V6. Revving motors win races. The suitability of the motor for a given application depends upon how you want to use it, and the jobs you are asking it to do.

Which is why some prefer one type over another.

OK, you guys win.
The 300 is a better truck engine.
When all things are consdered, it comes out on top.

But.....
a POTATO CHIP!?
it ain't that bad!

A 300 stomps the 4.2 as a truck motor, and I've had both engines. I had a 4.2 in a 99 f150, and have a 300 in a 88. the 4.2 has more hp, but will have to rev to get any torque. the 300 makes it at 2000 rpms. it was in f250's and 350's. Dt and 390gashog know what im talkin about! Hell, My buddy has a '99 f150 with a 4.6 and my 300 has more torque! they are both rated at 265 ft.lbs, but i got it at 2000, not at 4000 or what not. as for reliability, the 300 is a 300k+ motor when maintained. I have no idea about the V6. but the V6 might get more mpg's. It depends, i dont think there are 2 300 I6's ive ever seen with the same mpg's.

performence wise the 4.2 is quicker, but i doubt you can move around easily with a nice heavy load makeing the bed sit low like you can with the I6.

I does dawn on me now that we really are comparing apples and oranges.
The 300 was designed and mfgrd in a different era with a different intended purpose.

FWIW, I couldn't give to hoots (personally) about which is the "better" truck motor.

To each his own.