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The New 6.8L V8 Thread


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If the 6.8L sees the light of day, I doubt that it will be based on the 6.2L.  The 6.2L is a 'dead end', it was supposed to have been one engine in a family of large Mods, none of which ever materialized for various reasons.  A shame really because the basic 'Boss' design was a good one.  I still believe the 6.8L will be an aluminum block 7.3L.

 

Keep in mind things are changing very fast and a business case for a new large high performance ICE with limited application is not going to be easy to make.     

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42 minutes ago, 7Mary3 said:

If the 6.8L sees the light of day, I doubt that it will be based on the 6.2L.  The 6.2L is a 'dead end', it was supposed to have been one engine in a family of large Mods, none of which ever materialized for various reasons.  A shame really because the basic 'Boss' design was a good one.  I still believe the 6.8L will be an aluminum block 7.3L.

 

Keep in mind things are changing very fast and a business case for a new large high performance ICE with limited application is not going to be easy to make.     

Of course it is, the high performance F150 Raptor and Mustang are money in the bank.

 

I suggested the 6.2 because it fits Ford’s well established MO of evolving existing engines

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13 hours ago, 7Mary3 said:

Keep in mind things are changing very fast and a business case for a new large high performance ICE with limited application is not going to be easy to make. 

Correct, the WSJ reports that major car companies are quickly replacing their experienced ICE and transmission engineers and staff with electrical engineers, computer programmers and battery experts... so it appears like it's already too late to save the reciprocating engine from a relatively quick demise:

 

https://www.wsj.com/articles/gas-engines-cast-aside-electric-vehicles-job-losses-detroit-11627046285

Edited by CoolScoop
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13 hours ago, jpd80 said:

Of course it is, the high performance F150 Raptor and Mustang are money in the bank.

 

I suggested the 6.2 because it fits Ford’s well established MO of evolving existing engines

It does fit the pattern, but 0.6L seems like that a pretty significant increase on its displacement. Does the 6.2 have enough excess in its block to accept that kind of increase? It's the kind of increase you get going from the old 302 to the 347 stroker, but it seems like the 6.2 already has a pretty long stroke, so is that something you want to do for a high-revving hi-po Mustang mill? (I'm not saying it's not, I'm just asking the question.)

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2 hours ago, SoonerLS said:

It does fit the pattern, but 0.6L seems like that a pretty significant increase on its displacement. Does the 6.2 have enough excess in its block to accept that kind of increase? It's the kind of increase you get going from the old 302 to the 347 stroker, but it seems like the 6.2 already has a pretty long stroke, so is that something you want to do for a high-revving hi-po Mustang mill? (I'm not saying it's not, I'm just asking the question.)

OK, just briefly,

6.2 and 7.3 have same bore spacing, 4.53”, so I was thinking, keep the 6.2’s 3.74” stroke and just change the 6.2’s block  to Siamese  bores like 7.3,  using the same 4.22” bore pistons as the 7.3, the 6.2 becomes 6.8 litres.

 

The truth is that I have no idea if this is the actual intention or if Ford is looking to just destroke the 7.3 with a 3.74” crank like the 6.2 but either method would yield a 6.8 litre engine…….further to that, either engine  could be done with an alloy block. Another fun fact, the deck height of the 6.2 is ~9.4” and the 7.3 is 9.63” so both are similar…….opportunities to mix and match.

Edited by jpd80
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Does anyone know how crank journal sizes compare between the 6.2 and 7.3? If they are the same, then swapping the 6.2 crank into a 7.3 block would seem to be a relatively easy way to get to a 6.8. Custom pistons and/or rods to accommodate the deck height of the 7.3 block would be the biggest challenge. If they went with an aluminum block then a shorter deck height could also be incorporated.

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There is a very simple strategy to get to the 6.8 liter windsorV8.

pour the block out of CGI and machine it down the same line as the 7.3 liter by just changing the cutters.(weight pretty close to aluminum)

Reduce bore to 103.4 mm and use the same stroke as the 7.3 maintaining the current 7.3 deck height.

Engine would still have ability to rev to 6800 rpm and low end torque would be better than larger bore with shorter stroke.

Greater cylinder wall thickness so it can be used on low volume supercharged vehicles without issues, possibly with full water jackets and ability for .040 over in rebuilt.

High volume when it replaced the hybrid 3.5 ecoboost engine on F150

edselford

 

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From a business case point of view, IMHO, it makes more sense for the 6.8 to be a baby Godzilla. If you can machine it with the same tooling (or at least on the same line) as the Godzilla, it helps underwrite the Godzilla project as a whole, plus it allows you to eliminate the 6.2 entirely. It doesn't help you with the 5.2, but the 5.2 was developed knowing that it would be a low-volume mill, so it probably makes more sense to keep the dedicated low-volume mill than adapt a high-volume mill to the low-volume niche.

 

The scenario that makes the most sense to me is using the 6.8 as the PowerBoost mill for the SuperDuty line, but that's just wild speculation on my part.

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2 hours ago, SoonerLS said:

From a business case point of view, IMHO, it makes more sense for the 6.8 to be a baby Godzilla. If you can machine it with the same tooling (or at least on the same line) as the Godzilla, it helps underwrite the Godzilla project as a whole, plus it allows you to eliminate the 6.2 entirely. It doesn't help you with the 5.2, but the 5.2 was developed knowing that it would be a low-volume mill, so it probably makes more sense to keep the dedicated low-volume mill than adapt a high-volume mill to the low-volume niche.

 

The scenario that makes the most sense to me is using the 6.8 as the PowerBoost mill for the SuperDuty line, but that's just wild speculation on my part.

Romeo engine that makes the 6.2 is scheduled to close late next year, as is the Romeo Niche line making the 5.2 V8.

A general production 6.8 on Raptor makes no sense, the change in capacity is too small to have any significant effect

on fuel economy and vans as the 7.3 in different power levels appears to have already effectively replaced the 6.2.

 

If we assume that the 6.8 as the new, low volume performance variant replacing the 5.2 Predator, then that gives Ford 

a couple of of choices with NA and supercharged versions. The possibilities are exciting to say the least….

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On 6/30/2021 at 8:51 AM, blksn8k2 said:

I think an aluminum block pushrod 6.8 would make great competition for the LS in the aftermarket as well. There's a decent market there and Ford is not that competitive with the overly complex and wide Coyote.

The LS aftermarket includes hundreds of thousands of them sitting in wrecker yards. The 6.8L and 7.3L Godzilla will be hard pressed to compete with that.

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34 minutes ago, 30 OTT 6 said:

The LS aftermarket includes hundreds of thousands of them sitting in wrecker yards. The 6.8L and 7.3L Godzilla will be hard pressed to compete with that.

 

Very true for someone building a street rod or anything where brand loyalty doesn't play that much of part in deciding on a powerplant. However, what really jerks my chain is seeing LS motors in Fox body Mustangs. Having the option to put a Ford in a Ford and getting the same or better performance is a good thing and that seems to be the focus of guys like Brian Wolfe.

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Tragic the 6.2 Raptor engine is probably going away. As far as SOHC Mod power plants the cylinder head design is a no compromise design in my opinion. 
 

The 4.6/5.4/6.8 SOHC 2 valve engines all have the same set of limitations. First and foremost the bore space issue and second the intake valve is on the wrong side of the camshaft centerline. 
 

With the 6.2 you have a more compact and inherently better breathing cylinder head design. The camshaft is UNDER the cam followers and the vale’s are rotated to a much more advantageous position similar to the old 427 SOHC but not exactly. 
 

Had any one or all of a few things happened differently the Mod would have been a much more powerful and thus viable engine family. 
 

First if the earliest 4.6, 5.4 and 6.8’s would have been equipped with a proper layout similar to the 6.2 the whole result would have been different. 
 

An aftermarket performance company called Trick Flow Specialties “fixed” the problem with the Mods by locating the intake valves on the intake side of the head NOT ON THE EXHAUST SIDE!!!!! Ugh!

 

Second the bore spacing was ridiculous! It is probably the tightest in the industry for that type of V8 engine. This was a huge handicap imposed primarily to allow east/west FWD vehicles to utilize this engine. That model? The very short lived FWD V8 Continental. 
 

They compromised their entire V8 future for one model that was a flop. Even the Coyote is hitched to this legacy.
 

Third the 6.2 was at least 10 years late. Had Ford built a 4.6 & 5.4 along with a wider bore space 6.2 all with the same cylinder head layout Ford would have been in a much better position. They wouldn’t be throwing away the 6.2 which is a terrible shame. 
 

A simpler than Coyote entry level V8 would have been a huge bump for both the Mustang and the F150. 
 

They never would have had to develop the stop gap 3 valver. (Even though I like the 3 valver). 
 

So much money and effort could have been saved.  

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Stray Kay,

you are right on in what you have said!

Good engineers can come up with very compromised designs when the basic assumptions are wrong or miscalculated.

the Conentental fwd 4.6 V8 was not that good and volumes did not justify 100 mm bore centers for truck, mustang and crown Victoria.

we started down the wrong road with GM switching basically everything to front wheel drive! Roger Smith thought everything should be fwd!

Then we got fwd torque steer, throttle body injection and more!.

Now everything is going electric but it may make more sense to use cars and trucks with IC engines to clean the air as they pass thru it!, something like a catalytic radiator?

over the years, I have had vehicles with the following engines:

352fe 390fe 255, 351W, 231V6, 305, 2.6MMC, 318, 360chrysler, 2.4, 3.0V6, 360amc, 454, 350 Chevy,   364 Chevy, 4.6 doc Cadillac, 4.6doc Buick, 5.4 ford, 3.5 ford, 3.0 ford, 1.6ecboost, 1.5 ecoboost, 2.0 ecoboost and current 2.3 ecoboost.

out of all these vehicles, the Galaxie 352fe , the suburban 454, the Seville 4.6 and the Explorer 2.3 ecoboost ran the best!

I have learned over the last 45 years, have a backup! Maybe the 6.8 is part of the backup plan?

edselford

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5 hours ago, Stray Kat said:

Tragic the 6.2 Raptor engine is probably going away. As far as SOHC Mod power plants the cylinder head design is a no compromise design in my opinion. 
 

The 4.6/5.4/6.8 SOHC 2 valve engines all have the same set of limitations. First and foremost the bore space issue and second the intake valve is on the wrong side of the camshaft centerline. 
 

With the 6.2 you have a more compact and inherently better breathing cylinder head design. The camshaft is UNDER the cam followers and the vale’s are rotated to a much more advantageous position similar to the old 427 SOHC but not exactly. 
 

Had any one or all of a few things happened differently the Mod would have been a much more powerful and thus viable engine family. 
 

First if the earliest 4.6, 5.4 and 6.8’s would have been equipped with a proper layout similar to the 6.2 the whole result would have been different. 
 

An aftermarket performance company called Trick Flow Specialties “fixed” the problem with the Mods by locating the intake valves on the intake side of the head NOT ON THE EXHAUST SIDE!!!!! Ugh!

 

Second the bore spacing was ridiculous! It is probably the tightest in the industry for that type of V8 engine. This was a huge handicap imposed primarily to allow east/west FWD vehicles to utilize this engine. That model? The very short lived FWD V8 Continental. 
 

They compromised their entire V8 future for one model that was a flop. Even the Coyote is hitched to this legacy.
 

Third the 6.2 was at least 10 years late. Had Ford built a 4.6 & 5.4 along with a wider bore space 6.2 all with the same cylinder head layout Ford would have been in a much better position. They wouldn’t be throwing away the 6.2 which is a terrible shame. 
 

A simpler than Coyote entry level V8 would have been a huge bump for both the Mustang and the F150. 
 

They never would have had to develop the stop gap 3 valver. (Even though I like the 3 valver). 
 

So much money and effort could have been saved.  

First, 4.6, 5.4 and the 6.8 consigned the 302, 351 and 460 to history, the efficiency of common parts design across three engines, especially with the 5.4 and 6.8 built together was a compelling argument.

 

Second, the MOD’s smaller bore and longer stroke enabled Ford to meet emission regs more easily by eliminating an air pump, the  MOD replacements matched the power and torque of the outgoing engines and they got better fuel economy.

 

Third, the 6.2 wasn’t needed for many years because the 6.8 did such a good job and being an add on to 5.4 manufacturing made almost impossible to justify the expenditure to replace it with a whole new architecture 

 

While it would have been easier to continue developing the earlier small blocks and big block Limas, Ford’s distorted view of the need for FWD V8 powered cars clearly influenced its thinking but you know what, for all of the mistakes real or perceived, Ford’s trucks and SUVs did OK sales wise.though ironically, V8 cars never did catch on………

 

 

Edited by jpd80
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6 hours ago, jpd80 said:

First, 4.6, 5.4 and the 6.8 consigned the 302, 351 and 460 to history, the efficiency of common parts design across three engines, especially with the 5.4 and 6.8 built together was a compelling argument.

 

Second, the MOD’s smaller bore and longer stroke enabled Ford to meet emission regs more easily by eliminating an air pump, the  MOD replacements matched the power and torque of the outgoing engines and they got better fuel economy.

 

Third, the 6.2 wasn’t needed for many years because the 6.8 did such a good job and being an add on to 5.4 manufacturing made almost impossible to justify the expenditure to replace it with a whole new architecture 

 

While it would have been easier to continue developing the earlier small blocks and big block Limas, Ford’s distorted view of the need for FWD V8 powered cars clearly influenced its thinking but you know what, for all of the mistakes real or perceived, Ford’s trucks and SUVs did OK sales wise.though ironically, V8 cars never did catch on………

 

 

I don’t disagree with you but certainly a smaller bore can just as easily be put in a little bit wider bore spacing. This would leave some room to grow for trucks which are not subject to the same emissions standards. 
 

Second the 6.2 head type could just as well shared parts with different displacements. 
 

The Mods with the cam over follower over valve are unnecessarily tall and wide.  
 

I’m just saying if Ford laid out the Mod head and bore spacing a little differently it would or at least could have saved a ton of money by not having to develop the 7.3 and discontinuing the excellent 6.2. 
 

 

That being said I’m already a big fan of the 7.3. I hope Ford makes a billion of them and they know the LS off its high horse. 
 

I would like nothing beter than to see thousands of 7.3 Ford powered brand X, Y, and Z cars to counter all the Ford’s that have been ruined with shit motors from the enemy. 

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5 hours ago, Stray Kat said:

I don’t disagree with you but certainly a smaller bore can just as easily be put in a little bit wider bore spacing. This would leave some room to grow for trucks which are not subject to the same emissions standards. 
 

Second the 6.2 head type could just as well shared parts with different displacements. 
 

The Mods with the cam over follower over valve are unnecessarily tall and wide.  
 

I’m just saying if Ford laid out the Mod head and bore spacing a little differently it would or at least could have saved a ton of money by not having to develop the 7.3 and discontinuing the excellent 6.2. 
 

 

That being said I’m already a big fan of the 7.3. I hope Ford makes a billion of them and they know the LS off its high horse. 
 

I would like nothing beter than to see thousands of 7.3 Ford powered brand X, Y, and Z cars to counter all the Ford’s that have been ruined with shit motors from the enemy. 

Hey I get it but just sayin’ that once Ford baked in the short engine length required for FWD, that was that

and the trucks, SUVs and RWD cars just fell into line.

 

While we’re playing woulda, coulda, shoulda, imagine its 1958 and Ford decides that it’s not going to chase 
Oldsmobile alloy V8 but instead delivers a small block with 9.53” bore span in 8.2”, 9.2” & 10.2” deck heights.

Most  of its needs could have been covered by those three configurations…..

 

And yeah, Ford probably throws away lots of repower engine sales by not seeing the potential…

For a company that’s supposed to be all seeing all knowing, their vision of the future is often wrong.

Edited by jpd80
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23 hours ago, Stray Kat said:

Tragic the 6.2 Raptor engine is probably going away. As far as SOHC Mod power plants the cylinder head design is a no compromise design in my opinion. 
 

The 4.6/5.4/6.8 SOHC 2 valve engines all have the same set of limitations. First and foremost the bore space issue and second the intake valve is on the wrong side of the camshaft centerline. 
 

 

Right, and the reason having the intake valve on the "wrong side" on the intake cam is it results in one of the worst intake valve angles seen in recent memory. 

It's an absolute flow killer on an engine that was already valve area limited due to bore diameter.    

It just shows that Ford was never overly concerned with the 2V as a performance application.  

Thankfully there were the 4V engines.  

 

OEM 2V on the left, TFS on the right.  

2V intake valve angle.JPG

Edited by ESP08
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12 hours ago, Stray Kat said:

I don’t disagree with you but certainly a smaller bore can just as easily be put in a little bit wider bore spacing. This would leave some room to grow for trucks which are not subject to the same emissions standards. 
 

Second the 6.2 head type could just as well shared parts with different displacements. 
 

The Mods with the cam over follower over valve are unnecessarily tall and wide.  

 

The Coyote was able to reduce engine width while retaining the Mods cam over follower arrangement.  

The Mods cam over follower arrangement is probably the most ideal RFF setup as it retains the roller follower (lower friction and longer life than the more compact DAMB) while minimizing reciprocating mass and failure points.

 

The 6.2's rocker arm arrangement, while allowing for ideal valve angles with a single cam per bank, is clearly not as reliable nor any more compact that the Mod's RFF arrangement.  

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7 hours ago, jpd80 said:

Hey I get it but just sayin’ that once Ford baked in the short engine length required for FWD, that was that

and the trucks, SUVs and RWD cars just fell into line.

 

While we’re playing woulda, coulda, shoulda, imagine its 1958 and Ford decides that it’s not going to chase 
Oldsmobile alloy V8 but instead delivers a small block with 9.53” bore span in 8.2”, 9.2” & 10.2” deck heights.

Most  of its needs could have been covered by those three configurations…..

 

And yeah, Ford probably throws away lots of repower engine sales by not seeing the potential…

For a company that’s supposed to be all seeing all knowing, their vision of the future is often wrong.

Gosh that’s funny you mention that. I’ve often thought “why did Ford ever leave the FE 4.63” bore spacing?” 
 

This whole small block/big block thing is a chevy construct. When chevrolet was offering 265’s and 283’s Ford was selling 332’s and 352’s in the same price category. 
 

Now certainly the FE was a more expensive engine to build but it could have evolved into a very (actually it did) flexible and long lasting engine line. 
 

Just keeping the bore spacing and cam and crank location and dimensions and the bell housing flange and Ford really could have capitalized on that architecture to a huge degree. 
 

A lot of criticism against Ford V8’s is that critical things changed a lot. Oil pans intake manifolds and bell housing flanges have change or are incompatible. 

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Forgive me fellas, what is the “DAMB” setup?

 

Is that camshaft over a bucket/shim setup?

 

Anyways the end result is you have engines that are outrageously wide. Combination of the necessary tall deck to maintain rod/stroke ratio with small bore long stroke and the tallest and bulkiest possible single cam two valve head known to man. 
 

Don’t get me wrong the Mods have been great for their exact purpose but not much more. They haven’t been embraced by enthusiasts as a whole while GM and Chrysler just rack up new and younger car enthusiasts. 
 

The Coyote not withstanding of course but one can hardly call that an inexpensive entry level V8. 
 

Ford handed GM sole ownership of that market. 

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37 minutes ago, Stray Kat said:

Don’t get me wrong the Mods have been great for their exact purpose but not much more. They haven’t been embraced by enthusiasts as a whole while GM and Chrysler just rack up new and younger car enthusiasts. 

 

Mods haven't been attractive for swaps because the 2V is the LS junkyard competitor and the OE ECU wasn't capable of supporting the RPM needed to make really powerful 4V combos -- being capped to 7000 rpm before experiencing coil driver induced misfires.  

 

Regardless, *NO* engine family has been as quick or as fast as the Mod with OE cylinder head and block castings in either the 1/4 mile or standing mile.  

Not bad for an engine family that hasn't been embraced by enthusiasts.  

 

The Gen 3 Hemi also hasn't been embraced by enthusiasts in the way the LS has in spite of also having some inherent architectural performance advantages, FYI.   

The late model Ford aftermarket is *much* stronger than Mopar's.   

 

DAMB is the Ford verbiage for direct acting mechanical bucket.  

 

 

Edited by ESP08
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26 minutes ago, ESP08 said:

 

Mods haven't been attractive for swaps because the 2V is the LS junkyard competitor and the OE ECU wasn't capable of supporting the RPM needed to make really powerful 4V combos -- being capped to 7000 rpm before experiencing coil driver induced misfires.  

 

Regardless, *NO* engine family has been as quick or as fast as the Mod with OE cylinder head and block castings in either the 1/4 mile or standing mile.  

Not bad for an engine family that hasn't been embraced by enthusiasts.  

 

The Gen 3 Hemi also hasn't been embraced by enthusiasts in the way the LS has in spite of also having some inherent architectural performance advantages, FYI.   

The late model Ford aftermarket is *much* stronger than Mopar's.   

 

DAMB is the Ford verbiage for direct acting mechanical bucket.  

 

 

Yes please don’t get me wrong. I’m mostly talking about the 2V version of the Mod family. 
 

I wonder if you’re familiar with the new short track phenomenon based around Crown Vic/Grand Marquis chassis?

 

Its a very limited spec class that looks to be a whole lot of fun. 
 

The original 4.6 in an unmodified state is required so while the Panther chassis will get lots of love the 4.6 is slated to be just the workhorse that it was intended to be. 
 

I’d like to try this new class out though. From what I understand they’re at every short track now. 
 

Apparently the Panther cars make great short track stock cars. 

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