Cam timing on asymetrical cam lobes - one for the real experts

[Guest]

I don't think it affects the lobe center per se just how you calculate it. Unlike a symmetrical lobe cam where the lobe center is just that, in the center and we can use a very simple formula for figuring it out, the asymmetrical cam's lobe center is not really in the "center" and it requires a different set of calculations to figure it. My biggest problem was that the cam timings were not matching what was in the factory service manual and that was creating a ton of confusion for me. Now that I got that squared away (thanks kawasucki), I understand it all better.

[GregT]

Ok after searching for weeks I lucked out and came across a blog by a guy that rebuilt his early model ZX-11 (same cams and timing as the ZX-10) and he also came up with the same cam timings as I have. Not sure why the service manual doesn't jibe with reality but at least I feel certain now that I did everything right.

So now I want to advance the int came 6.5 degrees and the ex 6 degrees. To advance the cam timing, I need to move the cam forward in the direction of engine travel in relation to the sprocket correct?

Correct

I'm having trouble figuring why the shape of the lobe, or how steep the ramps were on either side, would have any affect on the lobe center.

The problem here is that what one refers to as the cam lobe center varies according to the level of knowledge of that person....Actually the shape of the ramps or lobe has no affect on the lobe center so long as you measure the opening/closing points well past the initial ramping.

Forget it being the peak of the cam. To compare the installation specs cam to cam, the best method is to use the geometrical center of the cam lift period.
Various people have tried grinding lobes where the max lift point does not equal the lobe centerline - and the characteristics associated with that geometrical lobe center have stayed the same. So using the geometrical lobe centers as a reference point works across all cam types.

One for you to think about - I developed a profile with my local cam grinder where due to space considerations lift was limited. So it had a dwell period at full lift of about 4 crank degrees...Set up by the geometrical lobe center method, easy as. But if you'd tried to find the point of max lift...well out.

[Guest]

Good stuff. I learned a lot through this process and still much to learn! I starting working on the sprockets tomorrow