Re: roller rocker article

From: svieth@ameritech.net
Date: Wed May 20 1998 - 03:26:31 EDT


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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