Timing particle bursts to object rotation

Hi all,

I have animated a stationary steam engine. I need to time a burst of 
particles with the rotation of the main flywheel.

Is it possible to trigger particle event by some link to the rotation of 
another object using pFlow? I can't just say "a burst of particles every
100 
frames" as the rotation of the system is not constant.

I'm not sure where to start with this. I have some pFlow experience, but 
obviously not enough!

Thanks in advance for any help. 
-
Nik