Flat or single plane cranks ....????

[afterburn 549]

Ford has made this the new big deal as of late.
I think Ferrari has used these now or in the past?
I will admit my ignorance with this program.
Its not that I have not read all I could, and tried to assimilate as much of it as posable.
It is all pretty foggy to me.
I know they were not possible at one point as I understand it?
Yet, now they are.
Its harmonics, balance, firing order etc.
It would be great to attempt to bat this back and fourth few rounds.
I would like to steal some insights.

[ted]

They sound awesome...
This one with the factory muffler bypass did 98db at Laguna.
Although my old 02 C5Z seemed to keep up in 3rd gear...
I would settle for a new 5.0.
https://youtu.be/wKqCob6VH7o

[afterburn 549]

Agree with the texture of the sound.!
Speaking of more info-
What are the other benefits of said configuration?
Will or does an outside vendor make these for an older block?
Along with a cam I would have to guess.

[asphaltgambler]

I think there is still a lot of development left in a good 'ol' 'merican basic V-8 engine. I remember some TV anchor quizing a GM exec why they were still using dated push-rod valvetrain engines when the rest of the automotive world was 4- cam, 4-5 valves per cyl, etc.

His response was the current GM engine's are proven, cost effective and have as much or more torque as their complex counterparts with same displacement. Torque is what moves the vehicle down the road. That said we are working to further refine those designs for increased power and fuel efficiency.

This was circa early 90's - to a large extent I think he was spot on. Look at the current LT / LS 6.2 engine as an example.

[Aerkuld]

The benefit of the flat plane crank compared to a cross plane crank is basically a lighter crankshaft. This allows quicker response from the engine as there is less mass to accelerate.
The cross plane crank has a benefit also. It's inherently better balanced, so there is less vibration.

Older engines used flat plane cranks because they are a very simple design. It wasn't that there was any difficulty with these, it's just that the engines gave a lot of vibration. The cross plane crank was a newer design, created to improve the engines balance.

Make sense?

[afterburn 549]

Originally Posted by Aerkuld

The benefit of the flat plane crank compared to a cross plane crank is basically a lighter crankshaft. This allows quicker response from the engine as there is less mass to accelerate.
The cross plane crank has a benefit also. It's inherently better balanced, so there is less vibration.

Older engines used flat plane cranks because they are a very simple design. It wasn't that there was any difficulty with these, it's just that the engines gave a lot of vibration. The cross plane crank was a newer design, created to improve the engines balance.

Make sense?

Yea, that is where I am kind of at knowledge wise...ahem.
Changing the crank throws, of course, changes the firing order.
Does this divide it better?
(Better impulses?)

[enzo1]

[afterburn 549]

Thanx
I have watched that B4. Its great info!

[afterburn 549]

Yes, I was looking at the arrangement.
I never thought of that till now.
Thanx all.
The balance problem is a bit of a conundrum.
At 1st glance, one would think the flat plane is less of a balance issue then the uneven. .

[Bill Verburg]

Originally Posted by afterburn 549

Ford has made this the new big deal as of late.
I think Ferrari has used these now or in the past?
I will admit my ignorance with this program.
Its not that I have not read all I could, and tried to assimilate as much of it as posable.
It is all pretty foggy to me.
I know they were not possible at one point as I understand it?
Yet, now they are.
Its harmonics, balance, firing order etc.
It would be great to attempt to bat this back and fourth few rounds.
I would like to steal some insights.

All 90° V8 Ferrari use a single plane(180°) crank. As do the Porsche V8s used in the Spider RS.
what the flat crank does in a 90° V motor is change it from odd fire to even fire.

Odd fire V8 has a very distinctive exhaust because they always have 2 cylinders firing consecutively on each bank and they have irregular firing intervals

for an older(Pre LSx) series setup like this

L 1-3-5-7
R 8-4-6-2

w/ this firing order 1,8,4,3,6,5,7,2

Left__collector: B1-S0-S0-B3-S0-B5-B7-S0-B1-S0

Right_collector: S0-B8-B4-S0-B6-S0-S0-B2-S0-B8
or
L-R-R-L-R-L-L-R
on the left side 5 & 7 fire consecutively and on the right side 8 & 4 do the same. Ford uses a similar setup on both old and new small blocks, the firing intervals on the left side are 180°-90°-180°-180° and 180°-270°-180° on the right

the LS series has the same setup as far as cyl #s but the firing order is 1-8-7-2-6-5-4-3
S0-B8-SO-B2-B6-S0-B4-S0
R 2-4-6-8
L 1-3-5-7
B1-SO-B7-S0-S0-B5-S0-B3
This firing order reduces crank torsion
or L-R-L-R-R-L-R-L w/ firing intervals of 180°-90°-180° on the left and 180°-270°-180° on the right w/ only one set of consecutively firing cylinders on the right side

The Shelby 5.2 Voodoo V8 w/ flat crank
L-R-L-R-L-R-L-R
In a 90° V a 180° crank leads to vibration issues and displacement restrictions as a result

Porsche H6 is also an even fire design but w/o the 90° V restrictions because the intervals are also evenly spaced
B1-S0-B2-S0-B3-S0
L 1-2-3
R 4-5-6
S0-B6-S0-B4-S0-B5
or
L-R-L-R-L-R w/ 240° intervals between pulses on each side

flat plane crank is also also used in most I4s

Interestingly enough the firing order issue of a 90 V8 w/ 90 crank can be overcome simple by redesigning the exhaust, one cyl. from each bank has to cross over to the opposite side collector, if the right cylinders are chosen the exhaust at least is now even fire. however this does nothing for the irregular firing intervals inherent in these engines

[afterburn 549]

Thanx
i think that is what i was looking for.

[cockerpunk]

every inline 4 ever made has a flat plane crank. there isn't any particular magic to them.

the sad things is the engineering that makes the GT350s motor rev so high isn't the fact that its a flat plan crank, but very good valve train engineering. if i was on the valve train team, id be pissed the marketing guys keep trying to say the engine is magic because its flat plain

[afterburn 549]

Yea
I am hoping to get and stay beyond the elementary here.
I have read all the shallow stuff on the net.
I am visualizing the torq, odd Vs even .
I am seeing the flat plane has some advantages besides a beautiful note in the exhaust .

[beepbeep]

Passat W8 also has a flat-plane crank.

[jcommin]

Think of a flat plane v8 as (2) inline 4s. I think the biggest advantage is a lighter crankshaft.

[jcommin]

Originally Posted by Aerkuld

The benefit of the flat plane crank compared to a cross plane crank is basically a lighter crankshaft. This allows quicker response from the engine as there is less mass to accelerate.
The cross plane crank has a benefit also. It's inherently better balanced, so there is less vibration.

Older engines used flat plane cranks because they are a very simple design. It wasn't that there was any difficulty with these, it's just that the engines gave a lot of vibration. The cross plane crank was a newer design, created to improve the engines balance.

Make sense?

It does to me

[afterburn 549]

Ok
Now if i had an old V8, right about now I would be wishin a vendor would start selling a Flat plane crank and cam kit for it.
Will this ever happen?

[beepbeep]

Originally Posted by afterburn 549

Ok
Now if i had an old V8, right about now I would be wishin a vendor would start selling a Flat plane crank and cam kit for it.
Will this ever happen?

Theoretically, It would make it slightly more eager to accelerate if revved in neutral, but other than that it would not really make great difference. It would not rev higher and/or produce more power, ceterus paribus. It would weight slightly less and shake slightly more...

[afterburn 549]

You harmonics guys -
I read somewhere that engine balance is somewhat opposite of the actual cylinder deg to each other,
It was a long 10 page theisis
The essence was a 45deg engine is fabricated that way because it balances like a 90 deg engine .
So on AND so on
I have not ever had the opportunity to play with all the dynamics.
The experts say the flat 6 is purrfect balance esp if time is taken to make it all to zero grams of each other (which have always done)
I do appreciate the time taken here by people that actually have a working knowledge to help decipher all the kenitics.
Reading the internet articles -helpfull,
But there is somethings missing.
I can feel it.
Like the experience from the dirty hands that work with stuffffff.

[tcar]

Cross plane cranks need counterweights.

Flat plane cranks don't have counterweights.

Ford uses a harmonic balancer to smooth out the vibes.