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FE Power Forums => FE Technical Forum => Topic started by: gregaba on May 04, 2019, 11:24:50 AM

Title: Wondering
Post by: gregaba on May 04, 2019, 11:24:50 AM

Hi
Anybody ever thought about a flat plane for the FE engines?
I am not an engineer, just a mechanic  so don't know all that is involved, but a 5 inch stroke and 9000 rpm redline interest me a lot.
Greg

Title: Re: Wondering
Post by: turbohunter on May 04, 2019, 11:38:22 AM

I’m not an engineer either but I believe you’d sacrifice a bit of torque to get those rpms.

Title: Re: Wondering
Post by: machoneman on May 04, 2019, 12:29:08 PM

I did read long ago harmonics at certain rpm ranges were a pretty big issue in long-running engines (think Indy 500, F-1, NASCAR).

If any Ford designed or Ford paid-for engines could have used a flat plane crank, it was a.) the 255 CID 4-cam Indy car engine (in many later permutations, up to 900 hp in turbo form, b.) the all-conquering 3.0 liter Cosworth Ford 4-cam F-1 (and FIA distance race)  and much later c.) various turbo in-line 4 cylinder, Cosworth-headed FIA sports car and late Trans-Am Mustangs (Tom Gloy's cars).

Yet, IIRC none not only never had a flat crank but none were even talked about. Maybe Ford's engineers passed for a variety of reasons.   

Title: Re: Wondering
Post by: gregaba on May 04, 2019, 01:16:57 PM

The reason I brought this up is my friend recently bought a new Shelby GT 350 with the 5.2 flat plane crank.
I used to let him drive my 2014 Boss 302 at the track and now that his car is broken in he let me make a few banzi passes with it yesterday.
I didn't notice a lose of torque at lower RPM's in normal driving or any vibration.
I understand Ford used a different rod journal layout then the euro cars so may be that is the reason.
Red lineing at 8500 is a real thrill and very hard to get used to even my boss red lined at 7500.
Greg

Title: Re: Wondering
Post by: machoneman on May 04, 2019, 01:24:19 PM

Read this: https://www.onallcylinders.com/2015/01/15/cross-plane-vs-flat-plane-crankshafts/

Title: Re: Wondering
Post by: gregaba on May 04, 2019, 01:34:23 PM

Thanks that was an interesting link.
Greg

Title: Re: Wondering
Post by: Heo on May 04, 2019, 02:04:15 PM

5 inch stroke and 9000 rpm, pretty high piston speed ???

Title: Re: Wondering
Post by: gregaba on May 04, 2019, 02:10:28 PM

Piston speed should be less then a 350 stroke or do I have it backwards.
Greg

Title: Re: Wondering
Post by: Heo on May 04, 2019, 02:33:05 PM

You have it backwards piston have to travel 5 inch under the
same time regardless of cross or flatplane crank

Title: Re: Wondering
Post by: gregaba on May 04, 2019, 02:40:05 PM

Thanks
Greg

Title: Re: Wondering
Post by: turbohunter on May 04, 2019, 04:00:14 PM

I was thinking that because you have two up and two down on each side with nothing in between you’d have to lose a little torque.
Obviously not a problem in a road race application but for a drag car maybe.
Just thinking out loud at work while having a wonderful work day. ::)
Thanks for the link btw, that’s cool.

Title: Re: Wondering
Post by: gregaba on May 04, 2019, 04:29:16 PM

Yes would love to see a SOHC with a flat plane. I imagine with the stroke increase you could get using the FP crank over the CP  would make up any difference.
Just thinking-Couldn't afford one if someone made it anyway.
Greg