Flat Plane Crank Engine

#1
I have been in contact with a gentleman that has been working on a flat plane crank kit for v8s. Im not sure if it is legit or not. It is way way out of my engine budget price range. I thought maybe it's not for others. It is called SCG's Flat Fast Technology. He has a few youtube videos and a website. Check it out if you haven't heard of it. :thumbsup:
 
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Jac Mac

Active Member
#2
From pics it looks like the flat plane has just as much counterweight as the cross plane version, just distributed evenly along length of crank. Looks like an SLC in promos.
 
#3
Did you catch the video of the engine running on a test stand at 8400 rpm? The 289 that I'm building would probably explode like a pineapple grenade.
 

Jac Mac

Active Member
#4
Depends on your ability as an engine builder, 8400 while getting up there is not out of reach for a well built 289 with todays tech. Notice that all of the engine options are relatively short stroke. You can buy a freshened 358 ex Nascar engine for somewhere between $15/18 k USD that will run to 9k and have ~3.25" stroke & ~4.18" bore and make around 850/ 900hp on a single 4bbl, what more do you need??
 

Julian

Lifetime Premier Supporter
#6
5.2 Voodoo engines are starting to show up on eBay as GT350's get in the hands of people with more money than talent :)
 

Andy H Smith

Gold Supporter
#9
Just a note to the wise, when ordering my 5.2 Aluminator XS I spoke with the Ford techs at the Carlisle Ford Nationals. In talking about the GT350 flat plane engine they said that there was so much vibration control added to the Mustang chassis that if the GT350 were transplanted to a different vehicle the engine would vibrate things to death, this is why it will not be offered as a crate engine.
 

Jac Mac

Active Member
#10
I've had similar thoughts ever since the first pics were shown of the crankshaft with full counterweights, If it was/is as good as the PR would have us believe there would be a lot more talk and action around the engine.
 
#14
Call any reputable crankshaft builder like bryant or windberg and ask them what benefits there is other than awesome induction noise, they will build them but I think it is one of those "all care, no responsibilities " situations. They just don't have the durability of a flat plane . Cheers,
Adam
 

Randy V

Administrator
#15
Call any reputable crankshaft builder like bryant or windberg and ask them what benefits there is other than awesome induction noise, they will build them but I think it is one of those "all care, no responsibilities " situations. They just don't have the durability of a flat plane . Cheers,
Adam
Welcome to GT40s.com Adam...
Please read and follow rule number 2 at the link below::
http://www.gt40s.com/forum/faq.php

Thanks
 

Jac Mac

Active Member
#16
Call any reputable crankshaft builder like bryant or windberg and ask them what benefits there is other than awesome induction noise, they will build them but I think it is one of those "all care, no responsibilities " situations. They just don't have the durability of a flat plane . Cheers,
Adam
Did you mean flat plane in that last sentence-or cross plane?
 

Rich McD

Bronze Supporter
#17
The engine mount on the GT350 consists of a cast aluminum bracket from the block, extending beyond the exhaust manifold, attached with a single bolt to a high density rubber disc about 4 inches in diameter, itself resting on the unibody. There is a dust boot covering the disc. Poking my finger underneath the boot, all I felt was rubber. Maybe there is a miracle vibration absorbing fluid in the center that I couldn't reach without damaging the boot and burning my finger on the manifold. It all seems pretty unsubstantial to deal with an engine that supposedly vibrates excessively.
 

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#18
I am not convinced in the benefit of a flat-plane (other than the sound). If you nix the counter weights, you will still have vibration issues. If you leave the counter weights, I fail to see the benefit.

If you want a motor to rev - or rev quickly, counter weights are not the issue. With good parts, RPM is generally limited by valve train. Revving quickly is limited by all the "crap" spinning.

We have a couple of heavily restricted 305 sprint car motors. These have a 48lb crank (per rules), so full counter weights. Same stroke as a 350 (smaller bore). So not a design that lends it self to high RPM. These motors run 7200-7400rpm lap after lap and we occasionally hit 8200 (not recommended). With no balancer, flywheel, clutch, transmission, altenator to spin, they will go from idle to 120mph wheel speed about as fast as you can move the accelerator pedal. Keep in mind these are heavily restricted motors (less than 500hp). Not the monster motors in some classes.

If you really want high RPMs, go for a DOHC, 4V/Cylinder motor with GOOD internals and well built.

If you want quick revs, go for a small diameter clutch, minimal flywheel, nix all the accessories except the alternator. Run an electric water pump. And of course live with the difficulty of getting off the line...

Then the expense of a flat plane, along with custom cam and aftermarket ECU. Big bucks that could be used to build a much better motor (and 180 degree exhaust).
 
#19
Frank is exactly right - rpm limit is more valve-train limited than crankshaft. But, once you have valve-train sorted out (quad cam, no rockers, direct lobe-to-valve actuation) so you can wind 'er up.....then you DO have to start thinking about rotating mass and your crank shaft.

Needless to say, quad cam ferrari engines have valve-train sorted out (as compared to say a push rod/rockers American V8), and that's why they went to flat plane cranks to get to higher rpm's. Those engines spin up faster and develop higher hp because of it.

I've driven and worked on flat plane ferrari V8's for many years and I can tell you there's nothing particularly fancy about the engine mounts. There's some vibration but it's not especially apparent. They do as good a job as possible with the cranks to avoid harmonics and vibration and it's really not bad.

I started a flat plane SBF project a few years back but after spending a bunch of money on parts and design work my engine machinist closed up shop and took off with the parts and prints. Kind of soured me on the whole idea.......
 
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