Help Needed/Couple Questions Regarding A New Setup
Fairly straight forward ....
Find your current cams tdc # on the ICL, multiply by the rocker ratio.
Now take the proposed new cams tdc # on the ICL, multiply by rocker ratio.
Subtract the difference between too. ......walla, new ptv number.....since you already know your current ptv.
This is just an example. .....
current 227 lobe on a 108 ICL @ tdc = 0.070" x 1.7 = 0.119".....this means your intake valve is open 0.119" at the nearest point in the revolution. ..aka; tdc.
New cam lobe 236, on a 106 ICL @ tdc = 0.089" x 1.7 = 0.151"
So.......0.119" minus 0.151" = 0.32"
So, you have 0.069" minus 0.032" = 0.037" of ptv with new 236 lobe on a 108 ICL.
Remember this ^^^^ is just an example.
You just need to find out what lobe family your current cam is and what your new one will be. Also, the same math will figure the exhaust lobe ptv too.


