E/BGR Engine Build Thoughts

[gasblender37]

Please comment....

My thoughts and questions on the engine.
Basic Engine:
Ford 5.4 L Racing Block – 3.5512” Bore, Deck Height 10.079”
Aftermarket Billet Crank – 3.24” Stroke = 257 ci
Manley 5.4 L 6.657” Pro I Beam Rods which gives a 2.05 Rod Ratio
Aftermarket Pistons with compression height of 1.80” using Zero Deck Height
Ford DOHC “B” Heads
MMR Purpose Built EFI Intake Manifold with Dual Injectors (16, 1 For Each Port)
One large Turbocharger
My thoughts:
Using tall deck 5.4 L block and 5.4 L Rods instead of 4.6 L Block and 4.6 L Rods will give a high rod ratio (2.05) which would be beneficial on the top end and less stress on the rotating assembly.
Using Ford DOHC “B” Heads because they are readily available and would require no porting. The knock on these heads is the lack of intake manifold availability and only 8 injectors for the 16 port manifold. The MMR manifold solves these issues.
My Questions:
Does the build sound rationale?
Would the 1.80” piston compression height be a problem?
What static compression ratio would I use?
What size turbo?
What camshaft specs?
Thanks,
Skip

[Dynoroom]

Well..... if it were me......

I'd use a 4.6 iron block (8.937 deck ht)
If you are going to use a billet crank might as well have it made to use WIDELY available chevy rods.
Use a 3.250 stroke and choose a rod journal you like: 1.880, 2.000, or 2.100.
All kinds of rod lengths out there with the basics being 5.700, 5.850, 6.000, 6.125, 6.200 right off the bat.
And if your worried about the rod/stroke ratio (I wouldn't) it's around 1.8 to 1.9 which is fine.
You 1.800 compression height is a killer for piston weight. With the 3.25 stroke & a 6.00 to 6.125 rod your compression height would be 1.312 to 1.187. lighter piston but still enough room for a durable ring pack.
I run more compression than most but I would run at least 9.0:1 (my current car is 10.5:1) Yes with turbos...
As for the rest, we can't tell you everything, what fun would that be? 

Good luck & have fun.

Who holds that E/BGR record anyway........    

[gasblender37]

Dynoroom,
Thanks for the reply. The current record is held by:

E          Holmes-Kugel-McGinnis    Jo. Kugel    08/96    236.036

My thinking is that back in 96 no one was using a Ford DOHC engine. Might be an advantage today in breaking the record. I was also thinking of a 10:1 CR

Thanks again

Skip

[Dynoroom]

Right.
I'll bet WAY back in '96 the engine builder used a 305 Chevy block bored to 3.750. then off set ground a 3.00 stroke crank to 2.910 to build a 257" motor. He might of had to notch the top of the bores for the exhaust valves to clear too.
I think your 4 valve idea is good.

Remember to have fun along the way..... 

[gasblender37]

I like your idea of the 4.6 block. Might save a little money rebuilding a used cobra block. Are the 6.2 chevy rods available with 1.88 rod journals? I heard there might be some advantage in using a smaller rod journal?

[Sumner]

.....I'll bet WAY back in '96 the engine builder used a 305 Chevy block bored to 3.750. then off set ground a 3.00 stroke crank to 2.910 to build a 257" motor. He might of had to notch the top of the bores for the exhaust valves to clear too. ....

....and I wonder who that builder might of been  ,

Sum

[dw230]

I agree Sum, may have some input here.

DW

[1leg]

I wonder if the 4.6 would fit better under the hood. That 5.4 is huge engine, something else to think about.

[Crackerman]

If you are spending money on billet or aftermarket rods (like r&r or the sort) the cost will be around the same for whatever rod length, pin and crank size you want. Especially for the power you are thinking.

[redhotracing]

What about a 4.8 LS with smaller crank? No need to mess with the DOHC/chain
setup, they'll handle immense amounts of power under boost and parts are not
only readily available but getting "cheap"...

[gasblender37]

Gentlemen,
Thanks for all the great input. You guys have caused me to re-think my plan.  "Sometimes you get what you want and it is not what you expect."
Skip

[SPARKY]

3.905 x 3.18==304.6 

Camaro "slightly overbored" pistons, 2" crankpin de-stroked 4.8 crank

[fordboy628]

Well..... if it were me......

I'd use a 4.6 iron block (8.937 deck ht)
If you are going to use a billet crank might as well have it made to use WIDELY available chevy rods.
Use a 3.250 stroke and choose a rod journal you like: 1.880, 2.000, or 2.100.
All kinds of rod lengths out there with the basics being 5.700, 5.850, 6.000, 6.125, 6.200 right off the bat.
And if your worried about the rod/stroke ratio (I wouldn't) it's around 1.8 to 1.9 which is fine.
You 1.800 compression height is a killer for piston weight. With the 3.25 stroke & a 6.00 to 6.125 rod your compression height would be 1.312 to 1.187. lighter piston but still enough room for a durable ring pack.
I run more compression than most but I would run at least 9.0:1 (my current car is 10.5:1) Yes with turbos...
As for the rest, we can't tell you everything, what fun would that be? 

Good luck & have fun.

Who holds that E/BGR record anyway........    

x2

Also:

What engine rpm range do you plan to use?  At high rpm heavy pistons are a BAD idea.  Calculate the max piston acceleration and the rod pin end load to make an intelligent choice.

Smaller rod journal diameter can reduce parasite drag significantly.   You need to pick a size where a quality bearing is available.

I would be VERY CAREFUL about using a rod/stroke ratio > 1.9/1 with 4 valve heads, unless you want an F1 type power curve.  With good low and mid lift flow from 4 valve heads, you are going to want to ADVANCE the point of peak flow demand.   Longer rod/stroke ratio DELAYS this.

The 'C' type heads (tumble type) are known for higher top end bhp.

Higher static compression ratio is the way to go.   You will surely need to run a wastegate.

Give some serious thought to this, BEFORE committing to expensive custom parts.  Engineering analysis and computer simulation is WAY CHEAPER than a pile of expensive parts that do not do what you wanted them to do . . . . . .
 
Fordboy

[jdincau]

If you are spending money on billet or aftermarket rods (like r&r or the sort) the cost will be around the same for whatever rod length, pin and crank size you want. Especially for the power you are thinking.

True, you can get almost any combination you want but ordering a commonly used specification will result in shorter wait times, less frustration and lower prices.

[7800ebs]

Are the 6.2 chevy rods available with 1.88 rod journals?     yes

very common in cup and on Ebay


http://www.ebay.com/sch/i.html?_sacat=0&_nkw=6.200+rods&_frs=1


http://www.ebay.com/itm/Set-of-8-Carrillo-H-Beam-6-200-Rods-NASCAR-ARCA-NHRA-L-K-Engine-Builders-/151306895026?pt=Motors_Car_Truck_Parts_Accessories&hash=item233a97feb2&vxp=mtr