Originally Posted by
mxfred
I'm using a protracter and pointer how much more acurate is your set up? I just reacently ruined a jp by advancing the rotory valve leading edge 3deg. wich also added 3deg. of durration. No low end power no mid power lotsa top end power your on the brakes by the time it wakes up. My point? drastic change for little mod or little mod for lots of detune.

I think a half deg. could make a noticable differance. I also use light as indicater of port open-close glad to see its an accepted method
I do have some RB WS7-II/III models and all my messured timings are the same with a list published online at first-racing so I do think it is accurate. Also I do messure the exhast height wit a caliper and the distance is indeed comparing with the angle (there is also a comparing table somewhere online).
I also have done 3 degree mods and had no issues....