[Diy_efi] OT - cap/rotor clearance

[Robert W Hughes]

Actually, rise time is secondary. A conductively fouled plug, common 
with leaded fuel, will load the coil output and prevent the voltage from 
rising high enough to spark. An air gap, whether between the rotor and 
cap or in the plug (auxiliary gap plug like for instance UN12Y) will 
force the voltage to rise high enough to jump the first gap before the 
plug can leak off the current. I suppose you could call this a rise time 
amplifier.
> Okay, I'm baited.
> 
> 
> The rise time is dependent on the electronics and nothing else.  The timing
> is dependent on the rise time and nothing else.   One degree of roation at
> 10,000 RPM is
> 
> 1/10000 * 60sec per min  / 360 degrees per rev  =  0.016 milliseconds
> 
> 16 microseconds and the rise time of the pulse is on the order of
> KV/microseconds so the timing delay would certainly be less than one degree
> of revolution at any reasonable engine speed.


-- 
Robert W. Hughes (Bob)
BackYard Engineering
29:40.237N, 95:28.726W or perhaps 30:55.265N, 95:20.590W
Houston, Texas "The city with too much Oxygen"
rwhughe at oplink.net