Hey my Chevy has Ford Rods !!!!!!

[Daniel and Laura Burk]

The piston is not necessarily moving "slower" per se. After all, it still has to
move 3.48 inches up and 3.48 inches down in the same amount of time. The piston
speed is a function of RPM and stroke.

The benefit of the longer rod is that the acceleration "rate of change" is lower
at TDC and BDC.  The piston's lower rate of acceleration change yields more
acceleration 'area under the curve'. Thus peak acceleration can be lower and
still yield the proper change in velocity that results in 3.48 inches of
displacement.

You'd probably find that piston velocity is HIGHER at the mid stroke point with
the longer rods, but at this point it doesnt really matter that much.

However, from what I read, I think you meant to say this. right?

--Daniel Burk

The Dupuis wrote:

>
> Anyway, I think the point of the long rod comparison is that the piston is
> closer to TDC for longer, and it's moving slower at every point between +/-
> 90* from TDC.  This causes less heat build-up in the charge, and because the
> piston is moving slower at the top of the stroke it gives the expanding
> gases more time to fill the slower-expanding combustion chamber.  Obviously,
> the slower piston speed means less vacuum therefore less intake charge, but
> by adjusting the valve events to suit (wider lobe separation, for one) this
> can be compensated for.  Also, because the piston is moving slower at the
> top half of the stroke, there is less chance of rod failure due to "toss".
> As you mentioned, the side loading is lower too, so less power is lost due
> to friction and theoretically better piston wear AND better ring wear.
>
> This is all theory, as interpreted by me.  I'm not offering the end-all,
> be-all of answers here, but rather throwing out the article to see what you
> thought of it.  Thanks for the response!
>
> Matt
>
> > -----Original Message-----
> > From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
> > Behalf Of David Hunt
> > Sent: January 5, 2002 9:41 PM
> > To: diy_efi at diy-efi.org
> > Subject: Hey my Chevy has Ford Rods !!!!!!
> >
> >
> > Glen,
> >
> > Thanks especially for the link to the monte-list.  I looked at the rest of
> > the site and was especially impressed by the articles on F and G body
> > springs and body stiffening below the package tray.  I now have
> > two projects
> > for the spring, neither of which are budget killers and both of which will
> > (I hope) give tangible results.
> >
> > Regarding the Hot Rod article.  The article didn't seem to mention it but
> > the parts list pointed out that the cam was a roller cam, the heads were
> > aluminum,  the gas was an unknown quantity (no-name I think they
> > called it)
> > and so forth.  I have an iron headed 69 Camaro that runs just as
> > well on 87
> > as 93 with a 10.5:1 compression ratio. (And the stock 307 heads with 1.5"
> > intake valves, or at least that's what they look like)  That's with a 5.7"
> > rod on a 3.48" crank (I bored and stroked it on the last
> > rebuild.)  I have a
> > Crane 'fireball' cam 215 degree intake on 112 center.
> >
> > If I had AFR aluminum heads and a roller cam I bet I'd be near the same
> > horsepower numbers with the 5.7" rods.  I certainly wouldn't publish an
> > article claming the rods were the difference without being able to put in
> > short and long rods and compare the differences.
> >
> > Ford rods in a Chevy, cute, but I don't see the numbers.  For example, was
> > the hp corrected?  If so was the correction for high humidity?
> > If so, then
> > that alone could account for the ability to use 87 gas.
> >
> > I just subscribed to Hot Rod for the first time in over a decade.
> >  The last
> > three issues were warmed over Car Craft and I've read at least three
> > articles on 'look how much better we are now.'  This is the type article
> > that caused me to stop reading Hot Rod.  I'll renew my subscription to
> > Circle Track (although it's not as good without Smokey) but not
> > Hot Rod.  I
> > believe that the name refers to the editors not the writing.  In
> > my opinion,
> > this list is more informative ( and sometimes disinformative)
> > than Hot Rod.
> >
> > I'm still looking for quantitative information on the advantages
> > of a longer
> > rod. For example, how would one calculate the reduced side
> > loading of a long
> > rod vs. a shorter rod with appropriate offset.  There is a lot more to a
> > good engine design than peak horsepower.  I'm not sold yet that a long rod
> > engine is significantly better than a well designed short rod engine.
> >
> > Bruce recently pointed out that cars that run 89 octane tend to
> > last longer
> > than cars that run on 87 octane.  I know that in tear downs the
> > better fuel
> > cars have less deposits, less core crud (in the water jackets) and .010"
> > pistons instead of .030" pistons.  I don't have a lot of money and what I
> > have has to last.  I typically keep my cars for 100,000 miles
> > plus and do my
> > own engine work.
> >
> > That's real world and Hot Rod doesn't know real world as it pertains to
> > working on a car that takes you work as opposed writing about folks that
> > work on their cars for years. Then there is the concept of writing about
> > pieces that suppliers give you (and often install and tune and....), maybe
> > that's the reason everything they install works so well, it keeps the
> > pipeline open.  Maybe not, but hey, gratuitous writing should be
> > taken into
> > account.
> >
> > After all, what is so special about Vic's '57?  Looks pretty normal to me.
> >
> > All I'm saying is, look at these magazine articles with a grain of salt.
> > Hot Rod et. al. doesn't sell articles about cars, they sell ad space to
> > aftermarket manufacturers (and prospective aftermarket manufacturers).
> > Where are the numbers?  How were the comparisons done?
> >
> > dh
> >
> > > Date: Thu, 3 Jan 2002 18:27:40 -0700
> > > From: "The Dupuis" <dupuis10 at telusplanet.net>
> > > Subject: RE: Maximum Piston Speed
> > >
> > > Thanks, Glen - I was actually going to type it out for the guy!
> > >
> > > > -----Original Message-----
> > > > From: owner-diy_efi at diy-efi.org [mailto:owner-diy_efi at diy-efi.org]On
> > > > Behalf Of Glen and Sarah Hankins.
> > > > Sent: January 2, 2002 5:57 PM
> > > > To: diy_efi at diy-efi.org
> > > > Subject: Re: Maximum Piston Speed
> > > >
> > > >
> > > >
> > > > > I'm interested in reading more but don't have access to
> > > > backissues of Hotrod.
> > > > > Would anyone be kind enough to scan and e-mail it to me?
> > > > > The Dupuis wrote:
> > > > >
> > > > > > Have a look at Hot Rod June '97:  400 block bored .030,
> > > > 307/327 crank, Ford
> > > > > > 300 I-6 rods (6.209"), JE pistons, Air Flow Research 305- style
> > heads,
> > > > > > 215/215 @.050" Comp camshaft, 11:1 C/R, 87 octane fuel, 412.3
> > > > hp @5700 and
> > > > > > 435.0 ft-lbs @3800, with 390 ft-lbs from 2400 to 5400 rpm.
> > > >
> > > > http://www.monte-list.nu/articles.shtml
> > > >
> > > > It's on this page.  You'll need an unzip utility.
> > > >
> > > > -Glen
> >
> >
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