New Ford 7.3 V8

A Hall-Scott in-line six, overhead cam, 1000 cubic inches is a big block.

colliehauler wrote:

Grit dog wrote:
^Yeah GM is still sucking wind in the gas HD truck engines, even with the new 6.6. Maybe they'll be under rated, hopefully.
As to old engines, what about 351M Ford big blocks, 360 GM truck motors and old 360 Chrysler big blocks.
LS7 is a really big small block too.....

Ford had two 351 engines a Windsor and a Cleveland one a small block the other a big block. Wasn't the original GM big block a 348 porcupine?

Deck height is the important with large displacement engines with longer strokes. The small block 400 GM is an example of what not to do, as the rod angle on the power stroke becomes an issue pushing the piston against the side wall of the cylinder.

So for this new 7.3 it would be interesting to know the deck height compared to other engines.

Generation 1: "W" Series
The first ever production big block V8 Chevrolet engine was the "W" series, released in 1958 for passenger car and truck use. This engine was an overhead valve design, with offset valves and unique scalloped rocker covers, giving it a distinctive appearance. The "W" series was produced from 1958 to 1965, with three displacements offered: 348 cubic inches (5.7 L), available from 1958 to 1961 in cars and through 1964 in trucks; 409 cubic inches (6.7 L), available from 1961 to 1965; and 427 cubic inches (7.0 L), available only in 1963.

Chris

JRscooby wrote:

LanceRKeys wrote:
A turbo big block 7.3 would require a huge fuel tank, a big fuel line, and some big radiators. The owner would need deep pockets.

I fail to understand your logic. Back in the day some trucks where sold with the same displacement diesel with and without turbos. Over time, and really a short time, the non-turbo was pretty much gone because of more power and better fuel mileage.
And doesn't Ford advertise their smaller turbo/gas engines as "Econo"?

He is right. Due to it's lower thermal efficiency, gas engines run much hotter and have much hotter exhaust than a diesel especially under load. Gas engines are regulated by air and have to stay around a 14.7:1 air/fuel ratio so the more air you put into a gas engine the more fuel it will burn along with the higher temps.

For example, just cruising down the road my diesel's EGT's right before the turbo are between 500-700F. On my old 3.5L Ecoboost, they would be between 1,000-1,200F under the same conditions. This heat is the main reason why gas engines cannot use variable geometry turbos like diesel's can without making the vanes with some exotic metal to handle the heat which increases the cost of the turbo significantly.

Diesels are regulated by fuel and since it has a much broader air fuel ratio it has to stay within(up to 70:1), it will use whatever air available to burn the fuel being added and will do it at much lower temps. This is why the more airflow you add to a diesel the more efficient it becomes and the lower the temps will be.

rjstractor wrote:

Diesel is a bit of a different animal, although it's a misnomer that the turbo engines get better mileage. Some of the early non turbo diesel pickups could get well over 20 mpg on the highway, but they had no power.

This is due to timing. Since the old diesels only had one injection event(which is what made them louder), their injection timing could be advanced more. Due to tighter emissions and NVH requirements, new diesels have multiple injection events which does not allow you to advance timing as much. Advancing the timing also creates more NOx. The only way to remove it is via tuning which will also increase your fuel mileage like the 2 mpg I gained via tuning alone.

colliehauler wrote:
Ford had two 351 engines a Windsor and a Cleveland one a small block the other a big block. Wasn't the original GM big block a 348 porcupine?

Chevy 348 and 409 where a earlier attempt at larger displacement engines, not what most of us called Big block. Better for trucks than performance cars. And GM big block? I think each division had their own engine.

Ok everyone, the big block vs small block debate is ridiculous. Obviously most of you don't know much about engines. The term came from the physical size of the engine, not the displacement!

And if we want we can give the triton motors 3 designations, the 4.6 is a small block, the 5.4 is a big block, and the 6.8 is a bigger block. The physical size of each engine is larger than the next!

Regarding the 7.3.....I've heard rumors that it is set up for DI and forced induction. So it may have more power in the future.

Grit dog wrote:
^Yeah GM is still sucking wind in the gas HD truck engines, even with the new 6.6. Maybe they'll be under rated, hopefully.
As to old engines, what about 351M Ford big blocks, 360 GM truck motors and old 360 Chrysler big blocks.
LS7 is a really big small block too.....

Ford had two 351 engines a Windsor and a Cleveland one a small block the other a big block. Wasn't the original GM big block a 348 porcupine?

^Yeah GM is still sucking wind in the gas HD truck engines, even with the new 6.6. Maybe they'll be under rated, hopefully.
As to old engines, what about 351M Ford big blocks, 360 GM truck motors and old 360 Chrysler big blocks.
LS7 is a really big small block too.....

GM 6.6L is based on the small block. Ref link below

https://www.google.com/amp/gmauthority.com/blog/2019/02/gm-planning-new-engine-larger-than-new-6-6l-v8-l8t/amp/

A small block will most likely never have the duty cycle of a big block...maybe if they spend tons and tons of $$$

Direct injection doesn’t have gasoline washing the intake port and EGR deposits won’t be washed away

Oil sprayed at the piston bottoms a nifty thermal metric

Still love my L29...but if GM comes out with a similar big block...WOW...just might get one

Direct injection will carbon up the intake tract if idled excessively. Not an issue with port injection. One of the reasons my F150 is a 5.0 and not an EcoBoost 3.5, since it is my wife's DD and mostly does short trips under 5 miles, barely getting warmed-up.

The new 7.3's basic engine architecture, right down to the coil pack locations and shorty wires to the plugs looks like a copy of GM's LS motors. Not necessarily a bad thing.

Me Again wrote:

BenK wrote:


Guessing direct injection and direct fire. All great stuff.

Nope! No out of the box to start with.

https://www.hotrod.com/articles/inside-look-fords-new-7-3l-pushrod-v8/

Ford was smart to not go with direct injection for this engine which goes into medium duty applications.