Re: roller rocker article

From: Klaus Wilkens (klaus@buffnet.net)
Date: Wed May 20 1998 - 22:36:00 EDT


Scott,

The .050 lift is not a standard although it is recomended by some manufacturers
(BTW Mopar does not ) for Comparison purposes. Duration is generally measured @
.006".

Even at .050 the difference in lobe lift is less than .002 which I'll bet is
almost negligible in crank degrees.

KW

svieth@ameritech.net wrote:

> Sean P. NoDecal:
>
> > >The 1.7 rockewrs do not alter the duration, only the cam lobe can do that.
> > >KW
> >
> > Oh..yeah...I know that. Sorry...should have clarified. The Magnum
> > R/T cam has a slight increase in duration along with the increase in lift.
> > *That's* the duration increase I was speaking of. 8^)
> >
> > *** 97 RPM Dakota - 14.98 @ 91.76 *** http://surf.to/real-per4mance ***
> >
> > sean meldrum
>
> You were right the first time.
>
> What is "duration"? It is the number of degrees of camshaft rotation
> that the valves are at .050 or higher. A higher ratio rocker gets
> you up to .050 quicker and keeps you there longer.
>
> Go the other way with this experiment. Put in a 1.1to 1 ratio
> rocker. The duration would be significantly decreased.
>
> The point is that using high-ratio rockers will change the
> *effective* duration of the cam. Your valves will move differently
> than the guy/woman who cut your cam had in mind.
> Before putting in the new rockers, check to see how it will
> affect duration. If you are thinking of buying a new cam,
> ask the manufacturer which rockers they had in mind when
> they designed the cam.
>
> -Scott
>
> "No, Homer, very few cartoons are broadcast live. It's a
> terrible strain on the illustrator's wrist."



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