<VV> Secondary voltage at coils.(Was Bad Corvair)

[Daniel Monasterio]

Thanks Bob,This is the answer I was looking for as, never thought on the voltage changes to fire the plugs under compression.As per the primary voltages, they were always right, according to the coil used.Know, I have a better understanding on this topic.
Daniel Monasterio
From: BobHelt at aol.com
Date: Thu, 18 Oct 2012 23:35:38 -0400
Subject: Re: <VV> Secondary voltage at coils.(Was Bad Corvair)
To: dmonasterio at hotmail.com; frankcb at aol.com; vairologist at cox.net; virtualvairs at corvair.org






Hi Daniel,
There are couple of variables that have not been discussed. 
First thing is that there are two different Pertronix I coils and only one will 
really do the job. You may have the wrong one. You must check this. Get a 
quality multimeter and read the coil's primary winding resistance. It MUST be in 
the neighborhood of 1.5 ohms (spec is 1.35 to 1.42 ohms) if you have the ballast 
wiring in the coil's circuit. Next is the fact that the Pert II coil is designed 
to run on 12 volts, so you must remove the ballast resistance for this coil's 
hookup.
 
Now how are you measuring the spark voltage? I think your 
problem is that you have the engine running when you do this measuring. That is 
a problem. What happens when the engine is running, is that the high voltage 
builds up to a peak voltage until the plug fires. The plug is designed to 
fire at a MUCH lower voltage than what the coil and electronics can produce. So 
the system is capable of producing, say 25 KV, but the plug fires at say 5KV. 
That STOPS the voltage build up. That is likely what you are 
measuring. The 25KV is a safety margin to allow good plugs to fire at 
5KV and fouled plugs to still fire at say, 20 KV so the engine will still run 
OK. So 5KV at idle would be normal but not indicative of system 
performance.
 
Let us know what you find.
 
Regards,
Bob Helt
 

In a message dated 10/18/2012 7:04:43 P.M. US Mountain Standard Time, 
dmonasterio at hotmail.com writes:
This 
  topic lead me to coils secondary voltage using Pertronix.I've found that, with 
  Pertronix II and it's matching Flame Thrower coil can't get more than 8 KV at 
  idle but, it increases at high rpm, to more than 20 KV.With Pertronix I and 
  std. coil, get about 10 KV at idle and about 15 KV at more than 2,000 rpm. 
  Didn't checked with points.On simple words, Pertronix I makes passing exhaust 
  emissions tests (less HC at idle) better than with Pertronix II but, I'm still 
  concerned, on both cases, about 
the different voltages between idle and 
  high rpm as, I supposed that on this electronic devices the coil output 
  voltage shouldn't be affected by speed (excepting 0 rpm).
Daniel 
  MonasterioJust trying to learn a bit 
more