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Subject:Re: Hi Lift Cams, Rockers
From:pensioner
Date:Sun, 3 Jun 2001 13:51:59 -0700

Howdodeydodat...

Ratio rockers merely amplify the distance the valves open.   For a 0.5 inch
lift cam a 1.25 ratio rocker raises the motion of the valve by 25% or makes
the valve open to 0.625 inches instead of  0.5.  This may allow more of a
fuel charge to enter the cylinder.  Note the "may".  It has the same effect
as a "hi lift cam"

The degree specifications (duration) for the cam remain the same but the
lift is magnified by 1.25, 1.3 or whatever the ratio is for the particular
rocker.  EG still opens at XX deg BTDC and closes at YY deg ATDC.  Overlap
remains the same.

The effect is to have the intake valve open faster and close faster with the
obvious increased accelerations of the valve gear.  This may put a bit more
wear on the components.  Note the "may".

Coupled with intake/exhaust system smoothing and compensation in the fuel
metering, very significant power gains can be achieved.  Efficiency may or
may not increase with the modifications.

cheers,

pensioner

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