<VV> Spark Plug gap for Pertronix II and Flamethrower II coil

[BobHelt at aol.com]

In a message dated 7/31/2006 9:28:15 AM US Mountain Standard Time,  
tom.a.cepak at lmco.com writes:

I'm  going to install the Bosch 7502's this
evening.  Do you guys who use  Pertronix or other electronic ignitions
set the spark plug gap larger than  what is stated in the shop manual?
If so, what do you guys set it  to?



Tom,
Yes, you can open up the plug gaps with this setup. 40 thou would be about  
right in my opinion. 
 
BUT, let me give you a caution.
 
Plugs are designed to have the ground electrode exactly perpendicular  to the 
center electrode. The purpose of this is to allow the spark to jump at  many 
points within this gap.This evens out the electrode wear and tends to  
maintain a relatively constant gap since the wear is spread over the entire area  
within the gap. If you should use 7502s and open the gap to 40 thou, this config  
will not be maintained and the spark will jump between the shortest distance  
between electrodes. This will concentrate all the wear at one point and will  
cause the gap to open up sooner when the gap is set as described first. So my 
 suggestion is to use some other plugs that are designed to have 
perpendicular  electrodes at a larger gap. I don't remember which plugs are suggested, but 
 if you will contact Dave Herrin at the Source, he can advise you and supply 
them  too.
 
Regards,
Bob Helt