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Stray Kat

The New 6.8L V8 Thread

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Engine stand on one of the videos indicates 6.8L V8 has forged crankshaft, contradicting other source.  It will be interesting to see which is correct.

 

7D191543-0329-4423-BB3B-1F0623CA2ED4.thumb.jpeg.c4a7000a88d9643b5e2c5477da9a17c8.jpeg

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35 minutes ago, Rick73 said:

Engine stand on one of the videos indicates 6.8L V8 has forged crankshaft, contradicting other source.  It will be interesting to see which is correct.

 

7D191543-0329-4423-BB3B-1F0623CA2ED4.thumb.jpeg.c4a7000a88d9643b5e2c5477da9a17c8.jpeg

FYI, the 7.3 crankshaft is a factory forging, so the 6.8 being a forging is unsurprising 

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Whole thing is crazy.  The 6.2L cost more to manufacture than the 7.3L, but the 7.3L was an extra cost option.  This new 6.8L probably costs the same to manufacture as the 7.3L (maybe slightly less if it does indeed have a cast crank), so Ford will bump the power of the 7.3L in order to differentiate it from the 6.8L and continue to be able to charge a premium for it.  I believe someone suggested that if they kept the same bore as the 7.3L and used the 6.2L crank the result would be a 6.8L.  Looks like that's exactly what Ford did!  Probably even used existing 6.2L crank tooling to make the 6.8L crank.  So basically Ford replaced the 6.2L with a smaller 7.3L and eliminated an ICE engine family without spending very much money.

 

I hope Ford doesn't charge a ridiculous premium for the 'new' 7.3L, if they do it's a total rip.   

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6 hours ago, 7Mary3 said:

Whole thing is crazy.  The 6.2L cost more to manufacture than the 7.3L, but the 7.3L was an extra cost option.  This new 6.8L probably costs the same to manufacture as the 7.3L (maybe slightly less if it does indeed have a cast crank), so Ford will bump the power of the 7.3L in order to differentiate it from the 6.8L and continue to be able to charge a premium for it.  I believe someone suggested that if they kept the same bore as the 7.3L and used the 6.2L crank the result would be a 6.8L.  Looks like that's exactly what Ford did!  Probably even used existing 6.2L crank tooling to make the 6.8L crank.  So basically Ford replaced the 6.2L with a smaller 7.3L and eliminated an ICE engine family without spending very much money.

 

I hope Ford doesn't charge a ridiculous premium for the 'new' 7.3L, if they do it's a total rip.   

 

 

Ford preliminary specs indicate stroke was reduced to 3.68 inches (93.5 mm), which is slightly shorter than 95 mm from discontinued 6.2L V8.  If displacement is calculated using 95 mm stroke, it would round up to 6.9L, not 6.8L.

 

I find it interesting that 3.68 inches (93.5 mm) stroke with 107.2 bore results in 6.751 liters, the shortest crank they could use and still call it a 6.8L V8.  It seems to me 6.8 displacement of older V10 must have significant marketing value. 

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7 hours ago, 7Mary3 said:

Whole thing is crazy.  The 6.2L cost more to manufacture than the 7.3L, but the 7.3L was an extra cost option.  This new 6.8L probably costs the same to manufacture as the 7.3L (maybe slightly less if it does indeed have a cast crank), so Ford will bump the power of the 7.3L in order to differentiate it from the 6.8L and continue to be able to charge a premium for it.  I believe someone suggested that if they kept the same bore as the 7.3L and used the 6.2L crank the result would be a 6.8L.  Looks like that's exactly what Ford did!  Probably even used existing 6.2L crank tooling to make the 6.8L crank.  So basically Ford replaced the 6.2L with a smaller 7.3L and eliminated an ICE engine family without spending very much money.

 

I hope Ford doesn't charge a ridiculous premium for the 'new' 7.3L, if they do it's a total rip.   

 

Simple. Ford will set the price as high as customers are willing to pay. Ford and other manufacturers do very extensive marketing research and tiered sales projections, along with supply availability and production capacity, that help them determine pricing. The research and sales projections show them expected sales at various price points but never doubt that Ford will charge as much as the market will bear!

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9 hours ago, akirby said:


Guys that bolt on blowers on the 6.8 instead of the 7.3 are idiots,

You utterly and completely missed my point. 

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I just watched a video that says the 6.8 has a forged crankshaft and the same 4.22” bore as the 7.3 with a shorter 3.68” stroke. 

Edited by Stray Kat

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1 hour ago, Stray Kat said:

You utterly and completely missed my point. 


Your point was IF the 6.8 had a cast crank it wouldn’t be good to add a SC.  But the 7.3 is forged so why would anyone try to SC a cast crank 6.8 when the forged crank 7.3 is available and would make more power?  Makes no sense.

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46 minutes ago, Stray Kat said:

I just watched a video that says the 6.8 has a forged crankshaft and the same 4.22” bore as the 7.3 with a shorter 3.68” stroke. 

 

I assume that was the TFL Truck video in which the Ford engineer also mentioned that customers will really like the quick revving characteristics of the new 6.8. That is at least partially due to the big bore/short stroke design.

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Well, it looks like ford is placing itself into a good market position with the lower cost 6.8 V8 when compared to the 6.2 it replaced.

6.8 competes with the GM 6.6 LT8 as base engine in super-duty trucks with 7.3 as a profit generating option!

It will be interesting to see the rod/stroke spec, probably around 1.75 if 6.8 deck height is the same as the 7.3. A little like the old Chevy 327 V8.

Horsepower and torque numbers need to exceed that of the GM LT8 so figure around 415 hp and 475 lbs-ft. I am surprised DI was not included at this point.

edselford

 

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Here's a little known fact from NASCAR history. Back in the late 60's NASCAR wanted to reduce the displacement of the engines so they came up with a power to weight formula which allowed teams to run a lighter car based on the reduced output of its engine. Ford's response to this new rule was to destroke their 427 FE racing engines by using the forged crankshaft from the 361 cu in truck engine. The resulting 396 was a result of using the 427's 4.23" bore and the 361's 3.5" stroke. That engine would scream to over  8000 rpm and won a lot of races in the lighter Fairlane chassis.

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What’s the deal with port injection and “bowl” pistons. Seems like those would be more in line with a DI system. 
 

 

It will be interesting to see the breakdown here. 

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So the answer to why both the 6.8 and 7.3 is apparently just marketing.  I wonder what the premium will be for the HO diesel?  $10k?

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1 hour ago, blksn8k2 said:

Here's a little known fact from NASCAR history. Back in the late 60's NASCAR wanted to reduce the displacement of the engines so they came up with a power to weight formula which allowed teams to run a lighter car based on the reduced output of its engine. Ford's response to this new rule was to destroke their 427 FE racing engines by using the forged crankshaft from the 361 cu in truck engine. The resulting 396 was a result of using the 427's 4.23" bore and the 361's 3.5" stroke. That engine would scream to over  8000 rpm and won a lot of races in the lighter Fairlane chassis.

 

And now the Ilmor NT1/396 is the spec for ARCA and the Truck Series.  Not Ford/FE based, but a 396 nonetheless.

 

HRG

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36 minutes ago, Stray Kat said:

What’s the deal with port injection and “bowl” pistons. Seems like those would be more in line with a DI system. 
 

 

It will be interesting to see the breakdown here. 

 

I suppose it's possible that the 6.8 is set up for a future switch to DI or, more likely, a dual injection design similar to what is currently used on all F-150 engines. For 2023 that is apparently not necessary yet. However, the "bowl" pistons would seem more conducive to a forced induction setup rather than DI. One of the benefits of DI is that it allows for a higher compression ratio due to the cooling effect of spraying fuel directly into the combustion chamber. As witness, the gen III Coyote has a 12:1 CR.

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23 minutes ago, akirby said:

So the answer to why both the 6.8 and 7.3 is apparently just marketing.  I wonder what the premium will be for the HO diesel?  $10k?

 

The 6.7L Power Stroke Diesel V8 is $10,250 already. Yeah, it'll be interesting to see what Ford prices the HO version at. Probably not $10K but $4-5K wouldn't surprise me. 

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28 minutes ago, HotRunrGuy said:

 

And now the Ilmor NT1/396 is the spec for ARCA and the Truck Series.  Not Ford/FE based, but a 396 nonetheless.

 

HRG

 

True, but it's not far from being Ford SB Windsor based....

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29 minutes ago, blksn8k2 said:

 

True, but it's not far from being Ford SB Windsor based....

I don’t know how true it is but I heard Robert Yates had some input on the LS cylinder heads. 

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10 hours ago, 7Mary3 said:

Whole thing is crazy.  The 6.2L cost more to manufacture than the 7.3L, but the 7.3L was an extra cost option.  This new 6.8L probably costs the same to manufacture as the 7.3L (maybe slightly less if it does indeed have a cast crank), so Ford will bump the power of the 7.3L in order to differentiate it from the 6.8L and continue to be able to charge a premium for it.  I believe someone suggested that if they kept the same bore as the 7.3L and used the 6.2L crank the result would be a 6.8L.  Looks like that's exactly what Ford did!  Probably even used existing 6.2L crank tooling to make the 6.8L crank.  So basically Ford replaced the 6.2L with a smaller 7.3L and eliminated an ICE engine family without spending very much money.

 

I hope Ford doesn't charge a ridiculous premium for the 'new' 7.3L, if they do it's a total rip.   

 

That was me. But as others have pointed out, the 6.8 actually uses a slightly shorter stroke than even the 6.2 Boss did (3.68" vs 3.74"). One of the things that I wondered about with the 6.2 crank was that with it being a SOHC designed if there was some special machining on the snout of the crank to accommodate the mounting of sprockets to run the camshaft for each cylinder head. That would obviously be unnecessary for a pushrod design like the Godzilla. So, if the crank couldn't be used as is without extra machining, then why not optimize the stroke for the 6.8L application? I suppose it's even possible that they are still using the same raw forging as the 6.2 but altering the machining to suit the 6.8.

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31 minutes ago, blksn8k2 said:

 

True, but it's not far from being Ford SB Windsor based....

 

It's LS based.

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This answers the question of the 6.8L seeing action in the Mustang. With an iron block it will weight the virtually the same as the 7.3L, to which the 307 Coyote is a lightweight in comparison (by 135 lbs).

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42 minutes ago, 7Mary3 said:

 

It's LS based.

 

No offense but... no kidding. The point I was trying to make is that if you look at the overall design of not only the LS but also the GM SB2 NASCAR cup engine they look more like evolutions of Ford engines than they do the small block Chevy. Especially the cylinder head design. If anything, the SB2 is probably more similar to the Ford Cleveland head design but that has more to do with current NASCAR engine rules for cylinder head valve angles, etc.

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1 hour ago, blksn8k2 said:

 

That was me. But as others have pointed out, the 6.8 actually uses a slightly shorter stroke than even the 6.2 Boss did (3.68" vs 3.74"). One of the things that I wondered about with the 6.2 crank was that with it being a SOHC designed if there was some special machining on the snout of the crank to accommodate the mounting of sprockets to run the camshaft for each cylinder head. That would obviously be unnecessary for a pushrod design like the Godzilla. So, if the crank couldn't be used as is without extra machining, then why not optimize the stroke for the 6.8L application? I suppose it's even possible that they are still using the same raw forging as the 6.2 but altering the machining to suit the 6.8.

Interestingly, the 7.3L crank still has two sprockets, the second one is for the oil pump.

Video: Ford 7.3L Godzilla Engine Overview (Part 2) – Camshaft, Valve Train  & Oil Pump

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5 hours ago, akirby said:

So the answer to why both the 6.8 and 7.3 is apparently just marketing.  I wonder what the premium will be for the HO diesel?  $10k?

The 6.8 is offered so that Ford can continue charging more for the 7.3. The 6.8 being less costly to manufacture than the 6.2 is an improvement in savings while also allowing Ford to close Romeo engine. Ford is making the 6.8 available in XL and XLT so obvious that it’s main market is fleet sales - keep in mind that this will compete against GM’s 6.6, so still slightly more capacity but cheaper to produce…

 

and yes, it’s also marketing spin that Ford has something new while increasing the power and torque of 7.3 to justify continuing the premium price, same for high output 6.7 Diesel. It all about saving money while charging more and making the customer think it’s a good deal.

Edited by jpd80

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4 hours ago, 30 OTT 6 said:

Interestingly, the 7.3L crank still has two sprockets, the second one is for the oil pump.

Video: Ford 7.3L Godzilla Engine Overview (Part 2) – Camshaft, Valve Train  & Oil Pump

They found less power used with chain drive oil pump, did Coyote go this way too?

I think ther was talk of that.

Edited by jpd80

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