New Ford flat plane crank engine

[olddog]

So, if the flat plane crank shaft is easier/cheaper to manufacture, allows more RPM, better breathing, thus more power, then why hasn't racing teams been dropping flat plane cranks in every block ever raced? Why don't I see advertisements for a flat plane crank and matching cam for every push-rod V-8 ever made?

Until now I never heard of the term flat plane crank. I thought I was well read, but obviously not nearly as much as I arrogantly thought. Anyone else caught off guard on this?

[Ron61]

From what I have read and seen on videos the Flat Plane Crank engines are more race oriented and have some balance issues which will cause them to not last as long in regular use. You Tube has a few good videos on them with people explaining the differences and what to expect. They rev faster because of less weight.

Ron

[twobjshelbys]

Originally Posted by olddog

So, if the flat plane crank shaft is easier/cheaper to manufacture, allows more RPM, better breathing, thus more power, then why hasn't racing teams been dropping flat plane cranks in every block ever raced? Why don't I see advertisements for a flat plane crank and matching cam for every push-rod V-8 ever made?

Until now I never heard of the term flat plane crank. I thought I was well read, but obviously not nearly as much as I arrogantly thought. Anyone else caught off guard on this?

Most FPC engines (and they've been around for a long time even in consumer applications) are small displacement. FPC has dynamic balancing issue that increase with displacement. Voodoo is the largest FPC engine so far. There are many "warts" to keep it from vibrating. Some are on the engine, some are external to the engine. Look at photos of the underside of the GT350 and you will see weights on the exhaust aft of the catalytic converters.

The FPC also sacrifices low end torque for higher RPM operation. That's good for a track car.

Early articles in trade magazines (ASE) indicated it was unlikely that a FPC crate engine would be available.

However, Ford announced a few weeks ago the Voodoo parts (block, heads, etc) to build an engine using the standard 5.0 Coyote crankshaft, and that engine showed up as a crate engine in the past week or so. More info:

http://www.stangtv.com/features/pri-...e-engine-a52xs

[Phill Pollard]

Originally Posted by olddog

Until now I never heard of the term flat plane crank. I thought I was well read, but obviously not nearly as much as I arrogantly thought. Anyone else caught off guard on this?

But I'll bet you've heard the term "odd-fire", right?

It's the same thing. Flat plane just sounds so much better than odd-fire. That and those that know odd-fires hate 'em because they are so unbalanced they'll shake your teeth out.

Odd-fire V-6's were real popular in GM cars. The 3.8L Buick engines were odd-fire engines. Although IIRC, they also made a even fire 3.8L.


Phill

[joyridin']

Originally Posted by Phill Pollard

But I'll bet you've heard the term "odd-fire", right?

It's the same thing. Flat plane just sounds so much better than odd-fire. That and those that know odd-fires hate 'em because they are so unbalanced they'll shake your teeth out.

Odd-fire V-6's were real popular in GM cars. The 3.8L Buick engines were odd-fire engines. Although IIRC, they also made a even fire 3.8L.


Phill

An odd fire V6 is not the same as a flat plane crank if that is what you are stating. An odd fire resulted from basically removing 2 of the cylinders off a V8 giving the engine an unbalanced firing order in regards to crank timing. In the Buick V6, they used a split crank to break up the crank timing by 15 degrees.

[olddog]

The FPC in and of itself does not give up low end torque, but in a conventional pushrod engine the duration required to take advantage of the higher rpm would give up low end torque. However this is a 32 valve, variable cam timing engine.

The modular engine was able to turn a lot of rpm with moderate duration, without variable valve timing. The 4 valve per cylinder head design flows very well. They also put a butterfly on one intake port of each cylinder that was closed at lower rpm. This gives higher velocity at low rpm, which keeps the torque up at lower rpm.

This engine has all the knowledge of the modular development plus the new variable cam technology and some more tricks, I'm sure I have no idea of. From what I have read the torque curve is fairly flat, but I have not seen any dyno data.

I suppose the lighter crankshaft gives up inertia, so you may notice it is easier to stall if you let the clutch out too quick without stepping on the loud peddle.

[Jac Mac]

The 'new' Ford flat plane crank uses a lot of counterweight and places the rod journals in a one up/one down fashion along the length of the crank compared to Ferrari and others that have used- one up, two down, one up,- like a large inline four.

EDIT: with some help from people with more info than me I think I worked out the firing order for this engine, see attached dwg.

[Dumpling]

Originally Posted by olddog

The FPC in and of itself does not give up low end torque, but in a conventional pushrod engine the duration required to take advantage of the higher rpm would give up low end torque. However this is a 32 valve, variable cam timing engine.

The modular engine was able to turn a lot of rpm with moderate duration, without variable valve timing. The 4 valve per cylinder head design flows very well. They also put a butterfly on one intake port of each cylinder that was closed at lower rpm. This gives higher velocity at low rpm, which keeps the torque up at lower rpm.

This engine has all the knowledge of the modular development plus the new variable cam technology and some more tricks, I'm sure I have no idea of. From what I have read the torque curve is fairly flat, but I have not seen any dyno data.

I suppose the lighter crankshaft gives up inertia, so you may notice it is easier to stall if you let the clutch out too quick without stepping on the loud peddle.

I have seen dyno graphs, and low end torque is a major disappointment. I have also seen dyno results of Coyote engines with old old school manifold/head changes that resulted in both better HP (at lower rpm's) and torque ( throughout the range).

And, the large-displacement FPC, DOHC, Ford engine is not new...they made an 1,100 cu inch tank engine back in the day.

It's all a marketing ploy, literally sound effects.