Just wondering... If you go +/-5* with cam timing, what spark/ignition timing would you look for? It'd be off, what, 5 degrees, right?

You retard exhaust timing, so would the spark timing show 15 BTDC when in actuality you were sparkin' at 20, or 10? Or would it actually read correct?

The more I think about it, I'm leaning towards reading correct, BUT the angle of the dizzy will be unusual, no?

Help me wrap my head around this one guys!

_SHig

Your physical spark would be different if you make adjustments to the exhaust cam timing, so yes it would show up by using a timing light. Would just be a simple case of readjusting by turning the dizzy though.

When you retard the exhaust cam timing, your ignition timing will also be retarded the same amount. When the exhaust cam is advance, your ignition timing will be advance.

Cool, it all makes sense. So if you'd like to maintain spark timing after an exhaust cam gear adjustment, you'll need to bump your dizzy to compensate.

Thanks!

_SHig

Yes, whenever the exhaust cam is disturbed, you have to redo your ignition timing.