Offshoreonly.com - desk top dyno

If you want to compute the timing events based on duration and lobe center, it is quite simple.

Let's try a single pattern cam first. For a number lets try 250 degrees duration on 112 degree lobe separation installed with 112 intake centerline(meaning straight up,no advance or retard).

Divide 250 by 2 and subtract the lobe center(125-112) which equals 13. 13 is the intake opening event. Add 180 to that number and subtract the duration number again.(180+13-250) which equals 57. So intake opens at 13 btdc and closes at 57 abdc. Since it is a single pattern cam with no advance the cam specs will be as below.

Code:

IO  13           EC 13



IC  57           EO 57



IO=Intake opens

IC=Intake closes

EO=Exhaust opens

EC=Exhaust closes

Lets try a dual pattern camshaft of 250 intake and 260 exhaust on 112 LC "straight up"

Code:

IO 13          EC 18



IC 57          EO 62

To check your math, add the opening event and closing event then add 180 and it will equal the duration number.

Hope this helps :)