Asymmetrical cam followers?

In THIS thread, Yves mentioned asymmetrical cam followers, but not to turn his rebuild thread into a cam thread. Thus, here is a new cam thread.

So, are they fast ramp opening, slow ramp closing, or vice-versa?

What is the science/mechanics of them, and what benefit?

Yes grandpaul they are "fast ramp opening, slow ramp closing".

The PW3 cam has valve bounce problems at high RPM because the ramps are too abrupt and when the valve slams down it bounces back up - 2 or three times if its revved too high. The Asymmetrical cam followers change the geometry so the lift is even more abrupt in exchange for a more gradual closing and reduction of valve bounce. But you still have the problem of a severe opening ramp.

Asymmetrical cams on the other hand have the more gradual exhaust ramp designed into the lobe without having to add strain to the intake opening or having to put an offset radius grind on the lifters. Todays cam software makes this easier than it used to be. Below is the opening/closing graph of a JS2 cam (improved version of the PW3). Both the intake ramp and especially the exhaust ramp are more gradual (than the PW3) to alleviate valve bounce. Look closely at the image below and you will see that the tail of the closing ramp is longer than the tail of the opening ramp - its asymmetrical.



Many hidden hours have been invested into the designing and testing of these asymmetrical cams.

grandpaul said:

In THIS thread, Yves mentioned asymmetrical cam followers, but not to turn his rebuild thread into a cam thread. Thus, here is a new cam thread.

So, are they fast ramp opening, slow ramp closing, or vice-versa?

What is the science/mechanics of them, and what benefit?

Click to expand...

Hi Grandpaul,
The only thing I know: it works, I use the JS 2 smootramp with the JS followers on the 920 Big Spender and I never sale this parts, they are still like brand new.
This parts will go in the 750 Sunburst soon.
Yves