Another new V8 ?

[40 Mile]

Very interesting engine discussion. 

 

And I thought it was great that a new,  Medium/HD,  truck engine is being built!

[Stray Kat]

58 minutes ago, 40 Mile said:

Very interesting engine discussion. 

 

And I thought it was great that a new,  Medium/HD,  truck engine is being built!

Many of the eventually higher power American V8’s came from the bigger truck realm. Example being the 348 then 409 then 396 Mark IV Chevrolet engines were handed down from truck duty. 
 

Did Chevrolet really need a big block in 1958 cars? Well maybe but I doubt it would have come without the development costs for it being paid by their truck needs. 
 

The 445” Ford is perfect fodder for the hot rod enthusiasts. 

[7Mary3]

I agree with much of Stray Kat's earlier post comparing the 7.3L to the LS.  But, I do think Ford designed the 7.3L to be a low cost truck engine more than anything else.  There is a good discussion going on over at 'Ford-Trucks.com' regarding the 7.3L, and I have to admit the block does not inspire a lot of confidence from an all-out high performance standpoint:

 

 https://www.ford-trucks.com/forums/1652293-boring-the-7-3l-block.html 

 

Can't for the life of me figure out why Ford stuck to 4.6" bore centers for a 7.3L displacement, my best guess is some 6.2L tooling is being re-used?  The block on the picture has been sliced an inch or two down from the deck so you don't see the cooling slots cut in the deck between the cylinders.  On the other hand that block looks very light for its size, and that's certainly not a bad thing if you are considering stuffing a 7.3L in a '56 F-100!

 

   

[blksn8k2]

In today's world I have to believe a high mileage "work truck" engine would be more likely to be replaced with a complete crate engine assembly instead of a rebuild of the original. That would probably be less expensive considering downtime, etc. There would be a refundable core charge for the old engine which could then be rebuilt and resold. Part of the rebuilding process could also include building up the worn cylinder walls using Ford's PTWA spray bore process which would eliminate the need for machining the block to an oversize bore. Which means cylinder wall thickness is less of an issue today than it used to be. And, thinner cylinder walls would promote better heat dissipation as well. 

 

None of that would help the hot rodder's when it comes to achieving maximum displacement but I doubt that was a major concern when the Godzilla was being designed. BTW, what is the max displacement possible with an LS block? 

[7Mary3]

The LS has 4.40" bore spacing and a shorter deck height than the Ford 7.3L, so generally speaking it can't be built as large.  Largest production LS has been the 7.0L, but the aftermarket tall deck LSX block can go a bit larger than 7.4L.  One feature of iron LS blocks is that they have generous cylinder walls and can tolerate substantial boost.  In particular, the new Gen. V 6.6L has a particularly heavy (245 lbs.) iron siamese bore block casting that I am told it can be bored .060" out for boosted race applications.  The 6.6L has a forged crank like the 7.3L and also has very substantial nodular iron main caps.  The block and crank are already in the GM Performance catalog.        

 

Medium duty truck engines are typically not rebuilt or replaced, they usually last the economic life of the whole vehicle.  This is true with both gasoline and diesel engines, note the majority of mid-range diesels are 'parent bore' blocks.  They do not use replaceable cylinder sleeves like heavy duty diesels do, which are typically rebuilt during the trucks economic life.  I don't believe the PTWA process is used by any engine rebuilders at present, and is probably not cost effective.  Cheaper to buy a new block. 

 

      

[ESP08]

1 hour ago, 7Mary3 said:

The LS has 4.40" bore spacing and a shorter deck height than the Ford 7.3L, so generally speaking it can't be built as large.  Largest production LS has been the 7.0L, but the aftermarket tall deck LSX block can go a bit larger than 7.4L.  One feature of iron LS blocks is that they have generous cylinder walls and can tolerate substantial boost.  In particular, the new Gen. V 6.6L has a particularly heavy (245 lbs.) iron siamese bore block casting that I am told it can be bored .060" out for boosted race applications.  The 6.6L has a forged crank like the 7.3L and also has very substantial nodular iron main caps.  The block and crank are already in the GM Performance catalog.        

 

Medium duty truck engines are typically not rebuilt or replaced, they usually last the economic life of the whole vehicle.  This is true with both gasoline and diesel engines, note the majority of mid-range diesels are 'parent bore' blocks.  They do not use replaceable cylinder sleeves like heavy duty diesels do, which are typically rebuilt during the trucks economic life.  I don't believe the PTWA process is used by any engine rebuilders at present, and is probably not cost effective.  Cheaper to buy a new block. 

 

      

 

Typically the smaller bore LSs are a lot better at handling/sealing high cylinder pressures than the larger displacement LSs.  

 

LS7 vs 5.3, note the difference in the amount of material between the cylinders.  

[coupe3w]

 

[7Mary3]

5 hours ago, ESP08 said:

 

Typically the smaller bore LSs are a lot better at handling/sealing high cylinder pressures than the larger displacement LSs.  

 

LS7 vs 5.3, note the difference in the amount of material between the cylinders.  

 

 

Yes, and the iron blocks are more stable as well.  The LS7 has cast in iron liners with a 4.125" bore, and that's about the reliable limit for a naturally aspirated aluminum LS block.  6.2L's and the new iron 6.6L are 4.060" bore.  

[Stray Kat]

So are we all keeping in mind that the photos of the GM engines are of deck detail whilst the Ford picture is a cutaway showing actual cylinder wall?

 

Notice the oval shaped major diameter I believe first pioneered on the mid-80’s 5 liter blocks. These of course put emphasis on the thrust sides of the cylinders. 
 

I must admit General Motors has always been generous with wall thickness in many areas of their various but not all V8 cylinder blocks. 
 

The Ford approach appears to me to have always been accurate castings with “engineered” wall thicknesses to save weight and probably costs. 
 

When I worked for an engine rebuilder I used to cringe when the big block Chevy stuff came across the bench. You’d truly have to wrestle that stuff around. 
 

I always thought if they felt that much like an anchor on the workbench, think about what a counterweight they must be in any vehicle that is intended to have some decent driving dynamics. 
 

It’s no wonder the little 289 GT350 Mustangs used to give the Corvettes fits in road racing. The bitty block Ford was a flyweight powerhouse. 

[jpd80]

15 hours ago, 7Mary3 said:

The LS has 4.40" bore spacing and a shorter deck height than the Ford 7.3L, so generally speaking it can't be built as large.  Largest production LS has been the 7.0L, but the aftermarket tall deck LSX block can go a bit larger than 7.4L.  One feature of iron LS blocks is that they have generous cylinder walls and can tolerate substantial boost.  In particular, the new Gen. V 6.6L has a particularly heavy (245 lbs.) iron siamese bore block casting that I am told it can be bored .060" out for boosted race applications.  The 6.6L has a forged crank like the 7.3L and also has very substantial nodular iron main caps.  The block and crank are already in the GM Performance catalog.        

 

Medium duty truck engines are typically not rebuilt or replaced, they usually last the economic life of the whole vehicle.  This is true with both gasoline and diesel engines, note the majority of mid-range diesels are 'parent bore' blocks.  They do not use replaceable cylinder sleeves like heavy duty diesels do, which are typically rebuilt during the trucks economic life.  I don't believe the PTWA process is used by any engine rebuilders at present, and is probably not cost effective.  Cheaper to buy a new block. 

 

      

The 7.3 block is 9.63” deck vs 9.74” for the LSX, the production LS 9.375”, the Boss 6.2 at 9.4”.

Edited March 9, 2021 by jpd80

[ESP08]

On 3/5/2021 at 3:56 PM, jpd80 said:

Those coyote cylinder heads are magnificent.

Comparing the atmo 327 coyote with Brian's atmo 7.3, I noticed that the 7.3 had around 500 lb ft down at 4500 

where the coyote seems to be around 400 lb ft just below 5,000 but yeah from about 6,000 the two engines were 

making 550 lb ft and 575 lb ft respectively, the coyote is very impressive.

 

Not sure about VP C16 vs say E85, I thought E85 might be better for dyno runs than high octane gasoline,

I'd love to hear your experiences with fuels an power...

 

 

The Coyote in the vid ran C25.  

 

In my experience even though E85 is typically less timing tolerant than C16 it still produces substantially more power. 

 

[jpd80]

6 hours ago, ESP08 said:

 

The Coyote in the vid ran C25.  

 

In my experience even though E85 is typically less timing tolerant than C16 it still produces substantially more power. 

 

Thanks, that answers what I suspected, that E85 is affordable performance fuel that has its place 

but obviously C16 and higher are the kings of gasoline performance and are more expensive.

 

The the truck heads are holding back the 7.3, it kind of reminds me of porting 5.0 factory heads

back in the day and seeing the power potential. Throw on a good set of aftermarket heads and

 it's night and day.  I'm just interested to see the Segway to the 6.8 as the successor to the DOHC

Voodoo 5.2 which had its roots in the cammer 5.0. How is Ford going to frame this I wonder....

Edited March 11, 2021 by jpd80

[edselford]

Well maybe Ford needs the 6.8 V8 to compete with the new grand Wagoneer which has a 6.4 liter Hemi. It would not take much for GM to up the anti on a future gmc Delani to offer a light duty version of the 6.6 V8.  The Jeep 6.4 is at 471 hp with a cast iron block!

[.I.]

19 minutes ago, edselford said:

Well maybe Ford needs the 6.8 V8 to compete with the new grand Wagoneer which has a 6.4 liter Hemi. It would not take much for GM to up the anti on a future gmc Delani to offer a light duty version of the 6.6 V8.  The Jeep 6.4 is at 471 hp with a cast iron block!

ICE vehicles will be dead by 2030. The V8s are dead right now (only used in Mustang and some trucks). A new V8 for the big SUVs is a waste of money. The current V6 Ecoboost is the right choice, and the hybrid can fight every other engine from Stellantis .  

Edited March 11, 2021 by falconlover 1

[edselford]

6.8 based off of the 7.3 we think. 7.3 same bore centers as current 6.2SOC V8. 

Ford needs a bridge to 2030 EV or whatever year it happens. As the gvw goes up, the EV powertrain becomes more complicated and costly. Grad ability concerns increase and force multi speed transmission solutions to maintain an acceptable range in cold and very hot weather, Nuclear power plants are too dangerous. Coal plants produce CO2 with natural gas, Less so.

hybrids are the best way to go for the next ten years unless someone has invented a

new way of charging lithium batteries..????

edselfor

[7Mary3]

I think a lot of manufacturers have already given up on hybrids.  BEV tech is advancing exponentially.  Larger trucks will likely eventually be hydrogen fuel cells, but natural gas may replace diesel in the interim.  Don't worry about the grid, steps are being taken as we speak.     

[slemke]

Whatever the new Fiat is called puts the 392 hemi in anything it will fit.  At 471hp, it slides right in between the 460hp coyote in the Mustang gt and the 480hp version in the mach1.   Torque is ~10% less on the coyote, but gearing can fix that.  No real need for Ford to come out with a 6.8L v8 to compete with the 392.  Hopefully the 6.8l is aimed for something higher than that.

 

For higher torque applications, the HO 3.5L ecoboost is available.  7.3L if you want Naturally aspirated.  It will be interesting to find out where the 6.8 fits in the lineup.

[jpd80]

Being around 10% more capacity than the GM 6.2, it's a safe bet that the 6.8 will probably  have around 500 HP/500 lb ft 

and as a torque provider, it won't be found wanting against the 3.5 EB. Let's face it, the whole reason Ford is doing a 6.8 

is exactly because a big enough group of eager HP buyers exist and Ford intends on filling the need for a big cube V8.

Edited March 12, 2021 by jpd80

[ESP08]

14 hours ago, edselford said:

Well maybe Ford needs the 6.8 V8 to compete with the new grand Wagoneer which has a 6.4 liter Hemi. It would not take much for GM to up the anti on a future gmc Delani to offer a light duty version of the 6.6 V8.  The Jeep 6.4 is at 471 hp with a cast iron block!

 

The Gen 3 Mustang 5.0 has the 6.4 Hemi more than covered.  

 

10 hours ago, slemke said:

Whatever the new Fiat is called puts the 392 hemi in anything it will fit.  At 471hp, it slides right in between the 460hp coyote in the Mustang gt and the 480hp version in the mach1.   Torque is ~10% less on the coyote, but gearing can fix that.  No real need for Ford to come out with a 6.8L v8 to compete with the 392.  Hopefully the 6.8l is aimed for something higher than that.

 

For higher torque applications, the HO 3.5L ecoboost is available.  7.3L if you want Naturally aspirated.  It will be interesting to find out where the 6.8 fits in the lineup.

 

That's how I see it at well.  What torque the Coyote gives up due to displacement is more than made up for by slightly shorter gearing a much broader rev range (more average HP).    

[slemke]

17 hours ago, jpd80 said:

Being around 10% more capacity than the GM 6.2, it's a safe bet that the 6.8 will probably  have around 500 HP/500 lb ft 

and as a torque provider, it won't be found wanting against the 3.5 EB. Let's face it, the whole reason Ford is doing a 6.8 

is exactly because a big enough group of eager HP buyers exist and Ford intends on filling the need for a big cube V8.

What is it bringing to the table at 500/500 that isn’t already there, or obtained with slight changes to existing engines?  A 5.2L coyote is easily over 500hp.  Torque would be around 450lbft, so it would sacrifice some there, but not the end of the world.  3.5L standard output ecoboost is already 500lb ft.  So no gain there using your numbers.  7.3L wouldn’t take much effort to get to 500/500.  What is to be gained from a 6.8L pushrod engine making 500/500?  Use the 7.3l where big block torque is desired.  The coyote for high rev horsepower applications and the 3.5L HO ecoboost where cafe and/or compact dimensions are needed.  The 6.8L needs to bring substantially more to the table than a 10% improvement due to displacement over the LT2 and hemi.

 

I would have rather seen the investment go to a short deck coyote to make a more compact engine.  Something in the 4-4.5L range with twin turbos.  No accessories...all electric like the Mercedes 3.0l I6.  Ford made the call to invest in a 6.8L engine.  We will find out soon if it was money well spent.

[jpd80]

1 hour ago, slemke said:

What is it bringing to the table at 500/500 that isn’t already there, or obtained with slight changes to existing engines?  A 5.2L coyote is easily over 500hp. 

A big capacity V8.

The reason why Ford is building it is because they have data that says enough will buy it.

Think about it, all those questions you posed have been asked, researched and answered 

They will charge a premium for it and buyers will line up for it, this is a no brainer.

Edited March 13, 2021 by jpd80

[slemke]

8 hours ago, jpd80 said:

A big capacity V8.

The reason why Ford is building it is because they have data that says enough will buy it.

Think about it, all those questions you posed have been asked, researched and answered 

They will charge a premium for it and buyers will line up for it, this is a no brainer.

I did think about it.  They have an even bigger V8.  If big is good, bigger is better...so use a HO 7.3L.  The 7.3L is narrower than a coyote, so width isn’t an issue.  Length of the 6.8L isn’t any shorter than than the 7.3L, so not that either.  That leaves height.  Shouldn’t be an issue in Fseries, but maybe Mustang.  Seems like a small market to me, especially considering buyers are already paying a premium for a supercharged predator.  I also question the wisdom of thinking Ford will get a premium for this engine if it is a 6.8L pushrod making 500/500.  It doesn’t scream premium, rather cost reduced/penny pinched.  Ford has made enough  questionable engine choices over my lifetime for me to be skeptical.  Whatever they build I hope it works out for them as I am a stock holder.  I could be completely wrong on the output of this engine and actual premium demand for it. I have no data and am just using my preferences. Time will tell.  At this point, I’m not seeing the wisdom in the decision.  I will reassess as more information is known about it and the applications for it.  Getting ~700hp out of it would do it for me.  The shorter stroke and deck height may be needed to achieve the high rpms needed to reach 700.  A naturally aspirated high revving 700hp v8 would be unique enough to warrant the added development cost.

[edselford]

I was also surprised by the 6.8 V8 announcement given how close it is to the 7.3.

Although everyone is talking short stroke version of the 7.3, I think you will see a smaller bore version of the 7.3 say 103.4 X 101 for about 414 cubic inches. It’s just much easier to get to 6.8 than reinventing the wheel.

ya except for ford 427, 428 cobra jet, 351 Cleveland and the current 5.0/5.2 DOC V8’s over the last 66 years, ford V8 on the street were not that competitive.

I had a 1966 Ford Galaxie with a 352 that was faster than a 1966 XL 390 four barrel. I never had a production 390 that could beat a Chevy 327.  
the 4.6/5.4 were durable but slow.

the 351 W used too much gas and never could compete with the Chevy 350.

Ford made the 427, 428 and 429 engines at the same time for a while, also 351W and 351C at the same time. It was confusing!

Lets not forget two different 4.6 SOC in Romeo Mi  and Windsor engine plants.

edselford

[LSchicago]

On 3/6/2021 at 6:19 PM, theoldwizard1 said:

Going E85 on a boosted engine requires a whole different tune a possibly different injectors.

Yes, My 5.0 in my 18 GT required a whole new return fuel system with 2 525 Hellcat pumps, 95# injectors vs the factory 19# injectors to run E85 at 13-14# of boost. The stock DI injectors remain. The tune will be an E85 specific tune, not flex tune because of the boost. To run 93 Octane will require a 10 PSI pulley, and switching tunes.

[LSchicago]

I may be in the minority, but I'd  buy a 6.8 V8 over a 3.5EB ten out of ten times.