Gregory,
My understanding on this is limited to what I have learned recently on a
new cam I had made for my car. All this means is the lobe is different
on the opening & closing side of the ramp. For instance, a more
aggressive rise on the opening side of an intake valve allows for an
early & longer duration for fuel/air to be drawn in. These designs are
not available for all motors because of lifter & valve train designs.
There are limitations on the tappet /lifter to glide on the lobe without
scuffing. Roller set ups and overhead cam engines can benefit from this
design.
There are many web sites & books that go in to cam design & theory. What
started out as a chore became interesting. The cam is hub of the motor
that determines the timing & sequence of everything else to happen.
--
Mitch Seff
Oceanside, N.Y.
75 TR6
http://www.angelfire.com/ny4/triumph5/
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