Which is the better engine, 6.4lit or the 6.7lit?

Thanks!
Lee

 

6.7L hands down.

 

6.4l gets near as poor old school 460 big block gas, fuel economy........and diesel fuel costs more.i wouldn't want to feed one daily.
ever seen your oil level rise? it does so with this engine as diesel fuel dilutes the oil over time.

6.7l? no thanks.a multi thousand dollar engine with no warranty against water in the fuel system and no history at all to speak of to know how well they'll hold up over time.you better have some very deep pockets if you want to run one of these trucks.the risk to reward just isn't there and many who buy them know it.

 

6.4
Most power on just tuner and exhaust/ intake.
Sucks with emissions system on it
5 speed trans

6.7
Runs great stock.
6 speed trans
Emissions system works great.


No question, if the emissions are staying on, go 6.7.
If it can be tuned, the 6.4 is a great truck, almost the same truck as the 6.7, but IMHO the engine is stronger, and you only have a 5 speed trans.

When a 6.4 HPFP goes, it seems to always only be the pump. When a 6.7 pump goes, it seems to be the entire fuel system is finished.

 

Also a deleted 6.4 can get great fuel economy, and put down power a 460 never could.

 

define: "great"?
source of info with proper hand calculated records like mine please?
(no interest in someones questimates running a srw 2wd pickup empty on the interstate one time,going by the lie-o-meter.)

Details: chip truck - 1993 ford F250HD DUALLY CONVERSION XLT Fuel Economy - EcoModder.com

Details: log truck - 1993 Ford F-450/F-Superduty XLT Fuel Economy - EcoModder.com

 

Mine {2WD) gets 16-17 all day long hand calculated CITY DRIVING. Freeway is 19 +, lie o meter is just what its called, 26-30 on the freeway, maybe it should be called the wish o meter.
Hmm
Same post as on the 6.4 forum.

 

interesting report.that there is running empty city driving? where are your economy records?

 

It's empty, and if you really want records I can get them. I use gas buddy on my phone, all recorded, i just have to figure out how to download them, shouldn't be a big issue.

 

yes id appreciate that.thank you.

here is my personal experience with the 6.4l:

i went with my old man to pickup an '08 a few yrs ago when he bought a used one.
the radiator had failed in the lot when picking it up.i pointed out the coolant leak and he couldn't take it home.they had to replace the radiator.
after a few days we went back to get it and it was a monster.great power and comfortable truck.
'08 psd f350 4wd srw.

i was between trucks and borrowed his '08 for a couple months.the lie-ometer showed fair readings of 12-13 mpg working the truck as i do mine.i say fair,but imho that's kinda poor for a srw pickup bed truck in this day and age.
however realistically she only got around 10-11 mpg.pretty old school bb ford poor economy plus fuel costs more.my overhead was much higher than i liked during the borrow time especially considering it didn't even have a large dump bed or anything.
i went to fill it up one day (luckily it was just here in town) and she just quit right in the road.they fixed it under warranty but that was a heavy truck to push off the road.i towed her home with the old idi truck i had just bought.
i can't recall exactly what it was now,but a plugged egr emissions bs of some sort i think.
i didn't care for how it had a message display "regen" and blew white smoke occasionally either.scared the crap out of me the first time.i thought she was burning up.
shortly after the old man went to change the oil and it had way too much in there and that's when he learned about the issue.he now changes it much sooner.
great fun power.great big comfortable truck.very expensive to operate.the super duty style since '99 doesn't exactly appeal to me but that's not much ya can do about.
looking under the hood it looks just like a van with the engine tucked way up under the cowl......that's what parts you can look at and "think" might be engine.id never want to work on one.

 

I had to pay for the app to be able to download the info, 2.99 down the drain LOL
If you want a trouble free 6.4 that gets good mileage you have to get rid of the DPF, that's all there is to that. The 6.7 has the same radiator issues I hear.

9,May 2014
Odometer: 90354.1
Qty: 15.29
Consumption: 16.7496

16,May 2014
Odometer: 90662.3
Qty: 17.15
Consumption: 17.9706

24,May 2014
Odometer: 90985.8
Qty: 22.08
Consumption: 14.6513

5,Jun 2014
Odometer: 91381.1
Qty: 24.02
Consumption: 16.4573

11,Jun 2014
Odometer: 91674.5
Qty: 17.68
Consumption: 16.5949

13,Jun 2014
Odometer: 91925.5
Qty: 13.72
Consumption: 18.2945

14,Jun 2014
Odometer: 92235.1
Qty: 18.21
Consumption: 17.0017

15,Jun 2014
Odometer: 92742
Qty: 25.14
Consumption: 20.163

6,Jul 2014
Odometer: 93333.4
Qty: 19.9
Consumption: 20.8095

11,Jul 2014
Odometer: 93526.1
Qty: 17.78
Consumption: 20.8095

17,Jul 2014
Odometer: 93674.1
Qty: 10.6
Consumption: 13.9623

8,Aug 2014
Odometer: 94135.9
Qty: 27.68
Consumption: 16.6834

22,Aug 2014
Odometer: 94417.3
Qty: 17.26
Consumption: 16.3035

2,Sep 2014
Odometer: 94727.4
Qty: 19.182
Consumption: 16.1663

15,Sep 2014
Odometer: 95043.7
Qty: 21.751
Consumption: 14.5421

*Sent via Fuel Buddy

 

thanks Bubba.that's amazingly higher than i ever saw with dads.it looks like you never work the truck at all? (nor does my dad with his.nor could i when i borrowed it.have no large trailers to make use of that kind of power.iv never used it for anything.far as i know,he still hasn't either.) looks like you might have went camping or something and hauled a camper around mid July or something but you always just run the thing around empty otherwise?

whats the total cost to delete all emissions?

 

I had to go to Traverse City to rescue the wife, alternator on our E 250 died. She could have done it but I Didn't know how big a job it was going to be so, I just opted to take a drive, only about 4 hours each way so no big deal.
The hardest part is filling it up the same every time, the pump kicks of 4 to 5 gallons light of a full tank so getting the same every fill up is near impossible.

 

If i had to make this choice i would unfortunately go with the 6.7 . The ONLY reason is for the 6 speed trans that can lock the converter in any gear. This always seems to be over looked when considering fuel milage between the two. With the newer designed trans you get the benefits of a manual and an automatic. This alone is a significant advantage in the milage the engine gets. The 6.7 is a light duty motor compared to the 6.4. The 6.4 is a true medium duty engine that does have some inherent flaws but the 6.7 is a light weight light duty engine. Before you bash this opinion you should look at the connecting rods side by side or the size of the main bearings for starters. You will be amazed how the 6.7 produces what it does with such smaller parts. I can only assume its advances in quality of metals they use.

In addition the emission's are not apples to apples. SCR decreases the amount of active regens, newer technology not used by international or ford back in 08. I look at the 6.4 as the ginny pig for emissions where the 6.7 engine emissions are much more refined.

But like i said if i had a choice between the two the 6.7 would win the debate as it has more pros then cons when looking at the whole package and not just the engines.

 

Yes, It would be interesting to see a 6.7 run without SCR, and use the amount of EGR the 6.4 uses, I bet it would be crappier than the 6.4.

About the transmission, you could run a lower stall torque converter, if you feel like taking stuff apart, and the RPM's will stay lower in town. I want one. I see no reason for RPM's to be so high with such low throttle input.