[DeTomaso] Ford 392 rev limit?

[Doug Scott]

This is probably more off topic than the F1 reference, but..

You can see real world numbers along the lines of F1 if you look at the
600cc sport bikes.  Yamaha R6 bike in 2010 had a 1.67" stroke, and peak
hp(133hp) taken at 14500rpm.  Piston speed is 4043fpm at 14500rpm.  You can
bet that Yamaha is using the lightest, but strong, reciprocating parts they
can get in the price line of the bike.

The R1 model(998cc) has a 2.06" stroke in 2010, with a max rpm of 13750rpm.
Piston speed on that bike is 4720fpm.  HP is 179.

Bike engines are an excellent example of how to deal with high piston
speeds.  Won't work in car engines very well though, you need weight in the
reciprocating mass to keep engine running during low speed driving(flywheel
effect).

 

doug

 

From: michael at michaelshortt.com [mailto:michaelsavga at gmail.com] 
Sent: Friday, September 6, 2013 11:37 AM
To: boyd casey
Cc: detomaso at poca.com; mike Drew; Doug Scott; Jeff Cobb; Pantdino
Subject: Re: [DeTomaso] Ford 392 rev limit?

 

Slightly off topic, several years ago, F1 engines eere hitting 22k and some
hit 23k, FIA set an 18k limit which will be dropping to 15k next season. I
read that the stroke on the 22-23K engines was about 1.75" 

Michael Shortt

On Sep 6, 2013 11:32 AM, "Boyd Casey" <boyd411 at gmail.com
<mailto:boyd411 at gmail.com> > wrote:

Saying piston speed is not the issue is like saying jumping out of an
airplane is not what kills you , it's the sudden stop when you hit the
ground! The faster the piston is moving the more stress is induced when it
has to stop and change direction 

It's simple physics A body in motion tends to stay in motion  When a piston
hits the bottom of its power stroke and is traveling at 5000 fps it wants to
keep going, so if you have a weak crank, weak wrist pin  or weak mains (to
name just a few potential areas of stress it will keep going! You can break
criminal laws, you can break civil laws, but you can't break the laws of
Physics.

Boyd

 

On Fri, Sep 6, 2013 at 11:07 AM, michael at michaelshortt.com
<mailto:michael at michaelshortt.com>  <michaelsavga at gmail.com
<mailto:michaelsavga at gmail.com> > wrote:

I think because Buick had a 425 back then, Dodge had already made 426
famous, they (Ford) had 428 ...so 427 was left available. Marketing
probably made that decision is my guess.

Michael Shortt

On Sep 6, 2013 11:02 AM, "Doug Scott" <doug at pickbbs.com
<mailto:doug at pickbbs.com> > wrote:

> Ford has known since the early 60s that short stroke, big bore is the
> recipe
> for race engines.  Take a look at the bore and stroke of the 427 compared
> to
> the 428.  Don't know why they call the 427 a 427 though, the displacement
> is
> closer to a 425.
>
> doug
>
> -----Original Message-----
> From: detomaso-bounces at poca.com <mailto:detomaso-bounces at poca.com>
[mailto:detomaso-bounces at poca.com <mailto:detomaso-bounces at poca.com> ] On
> Behalf
> Of MikeLDrew at aol.com <mailto:MikeLDrew at aol.com> 
> Sent: Friday, September 6, 2013 10:50 AM
> To: cengles at cox.net <mailto:cengles at cox.net> 
> Cc: detomaso at poca.com <mailto:detomaso at poca.com> ; pantdino at aol.com
<mailto:pantdino at aol.com> ; zumzum at cox.net <mailto:zumzum at cox.net> 
> Subject: Re: [DeTomaso] Ford 392 rev limit?
>
>
> In a message dated 9/6/13 6 44 23, cengles at cox.net
<mailto:cengles at cox.net>  writes:
>
>
> > FWIW: on the Speed Talk website Engine Forum, the professional
> > machinists and engine builders have commented that the factory crate
> > engines have been found to have, ahem, factory seconds used as parts.
> > It is perhaps not in all the engines, but it has happened often enough
> > that the pros have commented on it.
> >
>
> >>>They do make one hell of a spec sheet though:
>
> http://www.fordracingparts.com/parts/part_details.asp?PartKeyField=10757
>
> I don't know if the engine in Jeff's car is *this* 392 or if they sold a
> lower-spec version.   It appears Ford has gotten out of the 392 business
> and
>
> gone completely over to 427 Windsors now:
>
> http://www.fordracingparts.com/crateengine/main.asp#tfo
>
> I've heard enough bad things about Ford crate motors from people who have
> had them, that I would never get one.   They are absolutely fine for
street
> rods and things like that, or even for a Pantera that will only be driven
> on
> the street, but for a Pantera that would see track duty (abuse) as mine
> does, there's just too much likelihood that something would let go....
>
> Mike
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